Supplementary krill meal and uses thereof

Abstract

The present invention relates to an improved method for preparing an aquaculture feed, a method for preparing a supplemented krill meal, and a krill meal supplemented with sticky juice. By utilizing not only the krill meal, but also resources available in the sticky juice, the invention provides a more sustainable ingredient for fish feed for the fish farming industry. Further, in addition to being more sustainable, the inclusion of viscous juice-derived ingredients has been demonstrated to increase feed intake and improve growth in fish feeding tests.

Description

Technical Field

[0001] The present invention relates to methods for preparing aquaculture feeds, which methods involve supplementing krill meal with stick water; to methods for preparing supplemented krill meal, and krill meal compositions that have been supplemented with stick water. By utilizing not only conventional krill meal, but also the resources available in stick water, the present invention provides a more sustainable ingredient for feeds for the fish farming industry. Further, in addition to being more sustainable, the supplemented krill meal produced by the methods of the present invention has also been shown to increase feed intake and improve growth in fish feeding trials. Background Art

[0002] Global human consumption of salmon has increased substantially over the past few decades, enabled by extensive fish farming, with Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) being the main species.

[0003] Initially, salmon feed was mainly based on marine resources, and therefore naturally rich in omega-3 fatty acids and other marine nutrients. However, due to the increase in global fish farming (including non-salmon species) and the increase in direct human consumption of marine oil, the marine resources of capture fisheries can no longer meet the needs of fish farming. In order to understand the contribution of aquaculture to global seafood, efficiency assessments of marine ingredients are usually applied. The main principle of these assessments is to ensure that aquaculture does not have an adverse impact on wild fish populations. Feed conversion ratio (FCR), fish input-output ratio (FIFO), and feed-fish dependency ratio (FFDR) are methods for analyzing feed effectiveness. Previous assessments have shown that most aquaculture species groups are net producers of fish, but salmon and trout aquaculture are net neutral, producing as much fish biomass as consumed. Overall, global aquaculture currently produces three to four times more fish than consumed (Aquaculture [Aquaculture] Vol. 528, November 15, 2020, 735474). To ensure a positive contribution and net production of fish, both FIFO and FFDR are parameters that limit the use of marine ingredients from caught fish in feed. In addition, Life Cycle Analysis (LCA) is used to assess the environmental impact of feed and feed ingredients.

[0004] As the importance of salmon in aquaculture increases, salmon farmers are forced to provide more sustainable, healthy and high-quality products for human consumption. This means replacing current marine raw material ingredients with new, sustainable products rich in alternative protein sources to ensure the zootechnical performance of the fish. A lot of resources have been invested in finding alternatives to marine resources, and over the past decade, the composition of salmon feed has shifted from being mainly marine to being mainly agricultural. Concurrently with the shift in the composition of salmon feed, a decrease in the omega-3 content of farmed salmon has been observed. Without being bound by theory, it is believed that the observed decrease in omega-3 is due to an increase in the amount of vegetable oils with a lower omega-3 content in the feed.

[0005] In addition to the omega-3 issue, the fish farming industry faces several other challenges caused by the increasing amount of plant products in fish feeds. Plant products such as soy meal have different organoleptic characteristics than fish meal. Reduced palatability as well as anti-nutritional factors that cause low digestibility may lead to impaired growth performance of fish. Although plant-based ingredients are available, they do not meet the nutritional requirements of fish and contain anti-nutritional factors that affect the palatability of aquafeeds and trigger unwanted immune responses.

[0006] Therefore, there is a need for alternative as well as effective and viable ingredients to replace marine resources in capture fisheries.

[0007] In recent years, the use of marine algae and krill has attracted considerable interest in the search for such alternatives. Krill is a schooling, pelagic crustacean like shrimp, known to represent a viable alternative to fishmeal due to its high levels of marine protein, phospholipid-bound omega-3 fatty acids and feeding stimulants. Krill is a proven solution to the challenges faced by the aquaculture industry. It supports sustained, healthy and rapid growth of fish, in addition to displaying nutritional characteristics and taste that promote feed intake, improve feed conversion and enhance fillet quality. In addition, krill is also known to strengthen the fish immune system, thereby playing an important role in reducing disease and mortality.

[0008] Although krill meal has been identified as a promising candidate for inclusion in fish feeds, there remains a need in the art for more sustainable fish feeds with improved properties.

[0009] Therefore, there is a need in the art to optimize harvesting and processing techniques in order to produce sustainable ingredients in fish and shrimp feeds. Summary of the invention

[0010] In a first aspect, the present invention provides a method for preparing an aquaculture feed, wherein the method comprises the following steps: (a) providing krill ( Figure 1 , A); (b) subjecting krill to heat treatment ( Figure 1 , B and Figure 1 , D), (c) separating the heat-treated krill ( Figure 1 , E) into pressed cake ( Figure 1 , O) and squeezed juice ( Figure 1 , F); (d) from the squeezed juice ( Figure 1 , F) separation ( Figure 1 , G) viscous juice; (e) mixing the viscous juice with the pressed cake ( Figure 1 , O) mixing; (f) drying ( Figure 1 , M) the mixture to obtain the supplemented krill meal ( Figure 1 , N); and (g) formulating the supplemented krill meal into an aquaculture feed.

[0011] The present invention also includes a method according to the first aspect that does not involve step (g), for example the method may omit the step of formulating the supplemented krill meal into an aquaculture feed. In this way, the present invention provides a method for preparing supplemented krill meal.

[0012] These examples demonstrate that the aquaculture feed produced by the method of the present invention significantly increased total feed intake of fish in feeding trials, increased fish biomass, and reduced mortality compared to a comparative aquaculture feed comprising krill meal not supplemented with mucus. Without wishing to be bound by any particular theory, it is hypothesized that the aquaculture feed has improved digestibility, which makes the ingredients in the aquaculture feed more readily available to aquatic organisms.

[0013] In a second aspect, the present invention provides an aquaculture feed prepared by the method of the present invention.

[0014] In a third aspect, the present invention provides krill meal supplemented with mucilage, wherein the krill meal has a free amino acid concentration of at least 1 g / 100 g krill meal, optionally between 1 g-3 g / 100 g krill meal.

[0015] In a fourth aspect, the present invention provides a method for preparing supplemented krill meal, wherein the method comprises the following steps: (a) providing krill ( Figure 1 , A); (b) subjecting krill to heat treatment ( Figure 1 , B and Figure 1 , D), (c) separating the heat-treated krill ( Figure 1 , E) into pressed cake ( Figure 1 , O) and squeezed juice ( Figure 1 , F); (d) from the squeezed juice ( Figure 1 , F) separation ( Figure 1 , G) viscous juice; (e) mixing the viscous juice with the pressed cake ( Figure 1 , O) mixing; (f) and drying at a temperature below 95° C. using a vacuum dryer ( Figure 1, M) the mixture to obtain krill meal ( Figure 1 , N).

[0016] In a fifth aspect, the present invention provides a method for preparing krill meal, wherein the method comprises the following steps: (a) providing krill ( Figure 1 , A); (b) subjecting krill to heat treatment ( Figure 1 , B and Figure 1 , D); (c) separating the heat-treated krill ( Figure 1 , E) into pressed cake ( Figure 1 , O) and squeezed juice ( Figure 1 , F); and (d) drying ( Figure 1 , P) to obtain krill meal ( Figure 1 , Q); wherein the heat treatment of step (b) comprises using excess heat from the drying of step (d) to heat the krill; and / or wherein water evaporated from the press cake during the drying of step (d) is recovered, converted into steam, and the steam is used during the heat treatment of step (b). It has been found that this method provides improved efficiency, for example produces lower CO2 emissions.

[0017] The present invention also includes methods according to the fifth aspect, which methods further include step (e), wherein step (e) is formulating the krill meal into an aquaculture feed. In this way, the present invention provides a further method for preparing an aquaculture feed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Demonstrated production line for processing krill (A) into krill meal (Q), oil (I), sludge (H), slime (J) and supplemented krill meal (N).

[0019] Figure 2 The seasonal variation in total protein content of krill meal supplemented with mucus juice at different relative ratios of krill meal and mucus juice is shown. From bottom to top, the data points and connecting lines represent krill meal, krill meal + 6% mucus juice by dry weight, krill meal + 12% mucus juice by dry weight, and krill meal + 18% mucus juice by dry weight.

[0020] A timeline is presented along the X-axis. Each month is represented by two measurement points, one measurement point representing the first half of the month and the second measurement point representing the second half of the month. The first two measurement points along the X-axis represent the first half and second half of January, while the last two measurement points represent the first half and second half of August. The total protein percentage at a moisture level of about 6% by weight is represented on the Y-axis.

[0021] Figure 3 The set-up in the feeding trial as demonstrated in Example 2 is shown.

[0022] Figure 4 This demonstrated a mortality reduction corresponding to 5%-7% in feeding trials containing SW.

[0023] Figure 5 It was demonstrated that feed intake and growth (biomass) were higher with QSW compared to QA and control.

[0024] Figure 6 It was demonstrated that the percentage of water-soluble protein was higher in both batches of QSW powder compared to QA powder.

[0025] Figure 7 : The percentage of free amino acids that stimulate appetite is higher in QSW powder compared to QA powder.

[0026] Figure 8 : The percentage of free amino acids that stimulate appetite was higher in the feed with QSW compared to the QA and control feeds.

[0027] Fig. 9 : A method for preparing supplemented krill meal involving recycling excess heat from drying to heat the viscous juice.

[0028] definition

[0029] The term "indirect heating" refers to a process in which the material is not allowed to come into direct contact with a heating agent, such as steam, to change the final temperature of the material.

[0030] The term "direct heating" refers to a process in which a material is directly contacted with a heating agent, such as steam, to change the final temperature of the material.

[0031] The term "feed intake" as used herein is measured as a percentage of body weight per day.

[0032] The term "feed conversion ratio (FCR)" as used herein refers to the mass input (mass of fish feed) divided by the mass output (weight of fish).

[0033] The term "specific growth rate (SGR)" is calculated according to the following formula: (ln(final weight in grams)-ln(initial weight in grams) x 100) / t(days).

[0034] Unless specifically defined herein, all technical and scientific terms used have the same meanings as commonly understood by those skilled in the fields of medicine, pharmacology, medicinal chemistry, biology, biochemistry and physiology.

[0035] Where numerical limitations or ranges are stated herein, the endpoints are included. Furthermore, all values ​​and subranges within the numerical limitations or ranges are specifically included as if expressly written.

[0036] All methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, wherein suitable methods and materials are described herein. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. In the event of a conflict, the present specification including definitions shall prevail.

[0037] Headings are for organizational purposes and should not be construed as limiting the subject matter herein. DETAILED DESCRIPTION

[0038] Provide Krill

[0039] Krill lives in all major oceans around the world. For example, it can be found in the Pacific Ocean (Euphausia pacifica), the North Atlantic Ocean (Meganyctiphanes norvegica), and the Southern Ocean off the coast of Antarctica (Euphausia superba). As a keystone species in the ocean, it is a food source for many animals such as fish, birds, sharks, and whales. The total biomass of Antarctic krill (E.superba) is estimated to be in the range of 300-500 million metric tons. Preferably, the krill used in the present invention is Antarctic krill.

[0040] Antarctic krill feed on phytoplankton during the short Antarctic summer. However, in winter, its food supply is limited to ice algae, bacteria, marine debris, and consumption of internal protein for energy (Virtue et al., Mar. Biol. [Marine Biology] 126, 521-527). For this reason, the nutritional value of krill varies in different seasons and to some extent every year (Phleger et al., Comp. Biochem. Physiol. [Comparative Biochemistry and Physiology] 131B (2002) 733). In order to adapt to changes in food supply, krill have developed efficient enzyme digestion equipment that rapidly breaks down proteins into amino acids (Ellingsen et al., Biochem. J. [Journal of Biological Chemistry] (1987) 246, 295-305). This autoprotein hydrolysis is also very efficient after death, which makes it a challenge to capture and store krill in a way that maintains the nutritional quality of krill.

[0041] The krill in step (a) may be provided by catching wild krill from the sea or ocean. The vessel may tow a trawl configured to catch the krill. The krill is then transferred from the trawl to the vessel and processed.

[0042] Overall, harvesting krill in a commercially viable and environmentally friendly manner is challenging. Traditional trawling methods, where the catch is hauled onto a deck and discharged into tanks before processing, are not suitable.

[0043] Krill have a fragile shell that is easily crushed when caught in a net. Once the shell is crushed, the enzymes trapped in its digestive system cause the flesh to rot rapidly. Therefore, it is preferred that the krill be pumped out of the bottom of the net and directly into the vessel while in the water to ensure that the krill remain intact. The pump system may be included in a tube extending to the trawl underwater, and the pumping action is provided by injecting air into the tube below the waterline so that the krill are continuously drawn or pumped out of the trawl, through the tube and onto the vessel. Preferred trawl systems with pumps are described in PCT applications WO 07 / 108702 and WO 05 / 004593, which are incorporated herein by reference.

[0044] The krill that can be used in step (a) include Antarctic krill, Pacific krill and northern krill. Preferably, the krill that can be used in step (a) is Antarctic krill. The krill in step (a) can be fresh or frozen, but is preferably fresh.

[0045] To prevent krill degradation and to maintain nutritional quality, krill can be processed into krill meal as an alternative to reducing enzyme activity. This process is preferably carried out on board the fishing vessel immediately after capture and is generally a high energy demand process. To meet the needs of the aquaculture industry and as a competitive alternative to agricultural ingredients, there are significant advantages in reducing the energy consumption in the offshore processing of krill into krill meal. This will also reduce the CO2 footprint of the final product and make krill a more attractive and sustainable ingredient.

[0046] Thus, steps (a) to (f) may be carried out immediately after the krill are caught. Steps (a) to (f) may be carried out on board a vessel, while step (g) is carried out on shore. The time between steps (f) and (g) may be at least 1 week or at least 1 month. Advantageously, the supplemented krill meal may be stored on board a vessel for a period of time before being formulated into an aquaculture feed, for example the time between steps (f) and (g) may be up to 36 months.

[0047] The reduction in energy consumption and increase in final product yield has been shown to result in reduced CO2 emissions per unit of powder produced.

[0048] Subjecting krill to heat treatment

[0049] The krill may be heat treated in step (b) in a variety of ways. For example, the heat treatment in step (b) may include raising the temperature to about 80°C to 100°C. Alternatively, the heat treatment in step (b) may include a first heat treatment ( Figure 1 , B); and then subjecting the krill to a second heat treatment by raising the temperature to about 80°C to 99°C ( Figure 1 , D). Raising the temperature to a specific temperature involves raising the temperature so that the krill reaches a desired temperature before further processing the krill. Optionally, the krill may be kept at the desired temperature for at least 1 minute, such as 1-10 minutes. For example, the heat treatment in step (b) may include a first heat treatment by raising the temperature to about 40°C to 60°C and keeping the krill at that temperature for at least 1 minute, or 1-10 minutes, or 3-5 minutes; and then subjecting the krill to a second heat treatment by raising the temperature to about 80°C to 99°C and keeping the krill at that temperature for at least 1 minute, or 1-10 minutes, or 1-2 minutes. Including a first heat treatment ( Figure 1 , B, about 40°C to 60°C), followed by a second heat treatment ( Figure 1 , D, about 80°C to 99°C) has the effect that the process becomes more efficient and the overall output is increased, thus providing an overall reduced energy consumption on board.

[0050] The first heat treatment may include heating the krill using an indirect heater, and preferably further includes continuously removing material from the surface of the indirect heater. Continuously removing material from the surface prevents scorching or material accumulation, and ensures that the heating surface is always clean for optimal heat transfer, thereby further improving efficiency and yield.

[0051] The second thermal treatment may include direct heating, such as direct steam injection.

[0052] It is known in the art that krill meal production can involve a two-step separation process. In WO 2009 / 027692, the first step involves removing proteins and phospholipids from the krill, which are precipitated as a coagulant during the addition of large amounts of liquid water. In the second stage, the krill freed of proteins and phospholipids are cooked. After this, residual fat and astaxanthin are removed from the krill using a mechanical separation method.

[0053] In contrast, the examples demonstrate that supplementing krill meal with mucus produced by a process that does not remove fat and protein from heat-treated krill has a higher amount of free amino acids, which are known to stimulate appetite. Without wishing to be bound by any particular theory, by ensuring that no fat and protein are removed from the heat-treated krill, this allows the mucus to have a particularly advantageous composition for supplementing krill meal for use in aquaculture.

[0054] Therefore, preferably no filtering step is performed between steps (b) and (c). Preferably, no step that would remove fat and protein from the heat-treated krill is performed between steps (b) and (c). The heat-treated krill from step (b) may be introduced directly into the separation device used in step (c).

[0055] Furthermore, methods known in the art (such as those described in WO 2009 / 027692) require large amounts of water, such as fresh water. As discussed above, it is preferred that the krill are processed directly on board a vessel after they are caught. Therefore, it is difficult to store the fresh water required for these methods on board a vessel, and the production of fresh water from seawater is energy intensive.

[0056] The claimed method preferably does not require the addition of large amounts of fresh water. For example, preferably during steps (a)-(c), if liquid fresh water is added to the krill, the amount added is no more than 2 parts water to 1 part krill by mass, or no more than 1 part water to 1 part krill by mass, or no more than 0.5 parts water to 1 part krill by mass. Steps (a)-(c) may be carried out without adding liquid fresh water to the krill. The term "liquid water" is understood to exclude seawater, such as water containing low concentrations of dissolved salts, and may include water recovered from an evaporation process.

[0057] The heat treatment of step (b) may comprise using excess heat from the drying of step (f) to heat the krill; and / or recovering water evaporated from the press cake during the drying of step (f), converting the recovered water into steam, and using the steam during the heat treatment of step (b).

[0058] The inventors have realized that the efficiency of the process can be further improved by recycling the heat and / or water generated by the drying step (step (f)) in the thermal treatment step (step (b)). In this way, the CO2 emissions of the process can be further reduced.

[0059] When the heat treatment in step (b) comprises a first heat treatment ( Figure 1 , B); and then subjecting the krill to a second heat treatment by raising the temperature to about 80°C to 99°C ( Figure 1 , D), the first heat treatment and / or the second heat treatment may comprise heating the krill using excess heat from the drying in step (f). Preferably, the first heat treatment comprises heating the krill using excess heat from the drying in step (f). It has been found that excess heat is particularly suitable for the first heat treatment using indirect heating.

[0060] When the heat treatment in step (b) comprises a first heat treatment ( Figure 1 , B); and then subjecting the krill to a second heat treatment by raising the temperature to about 80°C to 99°C ( Figure 1, D), water evaporated from the press cake during the drying of step (f) can be recovered, converted into steam, and used during the first thermal treatment and / or the second thermal treatment. Preferably, water evaporated from the press cake during the drying of step (f) is recovered, converted into steam, and used during the second thermal treatment. It has been found that steam is particularly suitable for the second thermal treatment using direct heating.

[0061] Separation of heat-treated krill into press cake and press juice

[0062] Separation of the heat-treated krill into presscake and press juice can be performed using a centrifuge such as a 2- or 3-phase decanter centrifuge (e.g., a tricanter) or using a press such as a screw press. Centrifuging or pressing the krill produces a liquid portion called press juice and a solid portion called presscake.

[0063] Separation of viscous juice from pressed juice

[0064] The step of separating the viscous juice from the pressed juice (step (d)) may comprise separating the pressed juice ( Figure 1 , F) separated into viscous juice ( Figure 1 , J), oil part ( Figure 1 , I) and sludge part ( Figure 1 , H). The separation can be achieved, for example, by centrifuging the press juice into a viscous juice, an oil fraction and a sludge fraction using a 2- or 3-phase decanter centrifuge.

[0065] Mucus is the water-soluble part of krill produced as an intermediate product during the production of krill meal ( Figure 1 , J). It constitutes about 20% to 50% of the wet weight of the krill feedstock and is typically discharged into the sea. The resulting mucus may contain 57g to 87g of water-soluble protein per 100g of protein-containing material on a dry weight basis. Thus, the use of mucus in the present invention provides a more sustainable supplemented krill meal as it utilizes parts of the krill that might otherwise be discarded.

[0066] The examples demonstrate that the mucus produced during the claimed process has high levels of water-soluble protein levels and amounts of trimethylamine (TMA) + trimethylamine N-oxide (TMAO). Further, referring to Table 3 provided herein, the molecular weight distribution of water-soluble peptides is also different in the mucus and krill meal. Based on the composition of the mucus, adding the mucus concentrate back to the krill meal increases the content of the following ingredients: such as free amino acids, peptides, small proteins, minerals, water-soluble vitamins and low molecular weight (less than 4000 Da) components such as taurine, proline, carnosine (see Tables 2-5).

[0067] Thus, the amount of trimethylamine and the amount of trimethylamine oxide in the mucus juice may be in the range of less than 2500 mg N / 100 g, such as 1100 mg N to 2500 mg N / 100 g mucus juice on a dry weight basis. The amount of trimethylamine and the amount of trimethylamine oxide in the supplemented krill meal may be in the range of less than 250 mg N / 100 g, such as 100 mg N to 250 mg N / 100 g supplemented krill meal on a dry weight basis.

[0068] In some embodiments, 0.1% by dry weight to 0.5% by dry weight of water-soluble proteins in the mucus have a molecular mass in the range of 10 kDa to 15 kDa. In some embodiments, 0.2% by dry weight to 1% by dry weight of water-soluble proteins in the mucus have a molecular mass in the range of 8 kDa to 10 kDa. In some embodiments, 1% to 2.4% by dry weight of water-soluble proteins in the mucus have a molecular mass in the range of 6 kDa to 8 kDa. In some embodiments, 70% to 80% by dry weight of water-soluble proteins in the mucus have a molecular mass of ≤ 200 Da.

[0069] Prior to step (e), the method may include reducing the viscosity ( Figure 1 , J) in water ( Figure 1 , K) to obtain a viscous juice concentrate ( Figure 1 , L). The resulting viscous juice concentrate may have a moisture content of 40%-80%, or 50%-70% or 55%-65%. Step (e) may include mixing the viscous juice concentrate with the press cake.

[0070] Sustainable means reducing energy consumption and reducing waste. One of the most effective ways to reduce waste is to use as much wild catch as possible. In a first step towards a more sustainable harvest of krill, the inventors of the present invention have discovered an improved device for slime recovery. One proposed solution is to include a reduction in slime ( Figure 1 , J) moisture content and the final product ( Figure 1 , N) in a more energy-efficient and gentle way. The technical solution consists in using a dryer ( Figure 1 , M), such as a tray dryer, to reduce the moisture content in the new composition. In addition, the inventors have proposed to reuse the water evaporated from the viscous juice. The water evaporated from the krill is passed through a condenser ( Figure 1 , R) to recover. The water is then used as a boiler ( Figure 1 , S) and produce pressurized steam, which is injected into heat treatment #2 ( Figure 1 , D). The need for desalination of seawater to produce water for the direct steam heater is thus reduced, since water recovered in the viscous juice evaporator is used instead.

[0071] The inventors have also realised that the efficiency of the process can be further improved by using the heat generated by the drying step (step (f)) to concentrate the viscous juice in step (d). In this way, the CO2 emissions of the process can be further reduced.

[0072] For example, reducing the amount of water in the viscous juice may include using excess heat from the drying step (f) to heat the viscous juice and reduce the amount of water in the viscous juice, such as Fig. 9 As shown in .

[0073] Different solutions offer cost-effective ways to capture components that were previously discharged into the sea.

[0074] By including the mucilage in the krill meal, the inventors were also able to significantly increase the yield. Overall, the reduced energy consumption and increased yield of the final product have been shown to result in reduced CO2 emissions per unit of meal produced.

[0075] Mix the sticky juice with the pressed cake

[0076] The amount of mucus in the supplemented krill meal may vary. For example, the relative proportions of mucus and press cake mixed in step (e) may range from 1 part mucus by dry weight to 25 parts press cake by dry weight to 1 part mucus by dry weight to 3 parts press cake by dry weight. The supplemented krill meal produced in step (f) may contain mucus at a concentration of 3%-25% w / w, or 3.5%-10% w / w, or 4%-7% w / w of total dry matter.

[0077] Drying the mixture to obtain supplemented krill meal

[0078] The drying step is discussed in detail below with respect to the method for preparing the supplemented krill meal. It should be understood that the discussion of the drying step with respect to the method for preparing the supplemented krill meal is equally applicable to the method for preparing the aquaculture feed as disclosed herein. Likewise, it should be understood that the discussion of the drying step with respect to the method for preparing the supplemented krill meal is equally applicable to the method for preparing the krill meal as disclosed herein.

[0079] The examples demonstrate that the supplemented krill meal produced by the method of the present invention has a higher amount of free amino acids, which are known to stimulate appetite. Thus, the supplemented krill meal may have a free amino acid concentration of at least 1 g / 100 g of the supplemented krill meal. In a preferred embodiment, the supplemented krill meal has a free amino acid concentration of between 1 g-3 g / 100 g of the supplemented krill meal. The free amino acids may include one or more amino acids selected from the group consisting of alanine, proline, arginine, leucine, glutamine and glycine. Preferably, the free amino acids include alanine, proline, arginine, leucine, glutamine and glycine. The combined concentration of alanine, proline, arginine, leucine, glutamine and glycine in the supplemented krill meal may be at least 2.5%, or 3.0%-15% or 3.2%-10% w / w of the total protein in the supplemented krill meal.

[0080] Formulating supplemented krill meal into aquaculture feeds

[0081] Results reported to date indicate that inclusion of krill meal in fish feed improves both growth and yield. Further, krill meal has also been shown to increase i) growth performance, ii) feed utilization efficiency, iii) diet digestibility, and improve i) palatability, ii) intestinal development, iii) innate immunity and iv) disease resistance in olive sole (Aquaculture Research, February 2020, DOI: 10.1111 / are.14573). Some reports have also demonstrated that when fish are fed a diet supplemented with krill meal, fillet quality is improved and in particular the gaping score is reduced and the firmness of the meat and fillet is increased (WO 2015185993). Further, there is also publicly available data demonstrating that krill meal has a positive impact on the heart health of fish and has also been shown to have a positive impact on the prevention of viral diseases in fish (WO 2017029558). Therefore, all data published to date point to conventional krill meal as a promising alternative to fish meal in fish feeds.

[0082] By supplementing krill meal with mucus, the inventors were also able to significantly increase the yield of processed krill.

[0083] The supplemented krill meal can be formulated into an aquaculture feed by mixing it with additional ingredients such as one or more of marine protein (e.g., fish meal), vegetable protein (e.g., soy protein, sunflower extract, wheat gluten, pea protein, guar meal), fish oil, vegetable oil (e.g., rapeseed oil, soybean oil, camelina oil), starch (e.g., wheat), vitamins, minerals, antioxidants, fats, and sealants. The formulation of the aquaculture feed will depend on the species of aquatic organism for which the aquaculture feed is intended, and suitable formulations are known in the art.

[0084] The aquaculture feed may comprise different amounts of supplemented krill meal. For example, the aquaculture feed may comprise supplemented krill meal at a concentration of at least 2% w / w, at least 4% w / w, at least 5% w / w, at least 6% w / w, at least 10% w / w, at least 20% w / w, at least 30% w / w, or at least 40% w / w. In a preferred embodiment, the aquaculture feed comprises supplemented krill meal at a concentration of at least 2% w / w. The aquaculture feed may comprise supplemented krill meal at a concentration of 3%-50% w / w, or 4%-30% w / w, or 5%-15% w / w. The combined concentration of alanine, proline, arginine, leucine, glutamine, and glycine in the aquaculture feed may be at least 0.60% w / w of the total protein in the aquaculture feed.

[0085] Formulating an aquaculture feed may include replacing the supplemented krill meal with some or all of the fish meal in a typical aquaculture feed. For example, the aquaculture feed may be free of fish meal. Alternatively, the aquaculture feed may contain both fish meal and supplemented krill meal. The relative proportions of fish meal and supplemented krill meal in the aquaculture feed may range from 5 parts supplemented krill meal: 1 part fish meal to 1 part supplemented krill meal: 5 parts fish meal.

[0086] The present invention also includes a method according to the first aspect that does not involve step (g), for example the method may omit the step of formulating the supplemented krill meal into an aquaculture feed. In this way, the present invention provides a method for preparing supplemented krill meal.

[0087] Aquaculture methods

[0088] The present invention also provides aquaculture methods, which methods include preparing aquaculture feeds by the method of the present invention, and feeding aquatic organisms with the aquaculture feeds. The aquatic organism can be any marine fish, for example, organisms, such as salmon, halibut, sea bream, sea bass, flatfish, tilapia from the salmon family. Preferably, the aquatic organism is from the salmon family, such as salmon. The species of salmon include Atlantic salmon, Chinook salmon (Oncorhynchus tshawytscha) (Chinook salmon), salmon (Oncorhynchus keta) (dog salmon), silver salmon (Oncorhynchus kisutch) (silver salmon), cherry trout (Oncorhynchus masou) (Ma Su salmon), humpback salmon (Oncorhynchus gorbuscha) (pink salmon) and sockeye salmon (Oncorhynchus nerka) (red salmon). Preferably, the salmon is Atlantic salmon.

[0089] The aquatic organism may be a shrimp. The species of shrimp include Litopenaeus vannamei (white-footed shrimp), Penaeus monodon (black tiger shrimp), Acetes japonicus (autumn sauce shrimp), Trachysalambria curvirostris (southern rough shrimp), Fenneropenaeus chinensis (Chinese prawn), Fenneropenaeus merguiensis (banana shrimp) and Pandalus borealis (Arctic sweet shrimp). Preferably, the shrimp is Litopenaeus vannamei (white-footed shrimp).

[0090] The aquaculture feeds and supplemented krill meal produced by the method of the present invention are particularly useful for feeding aquatic organisms that are experiencing stressful periods. During these stressful periods, aquatic organisms lose their appetite. Examples have shown that supplemented krill meal increases feed consumption, which is believed to be due to the presence of amino acids in the mucus that stimulate appetite. An example of a stressful period for anadromous fish such as salmon is when they are transferred from fresh water to salt water, a physiological process known as silvering. Therefore, palatability plays an important role in aquaculture feeds for salmon during their transfer to seawater. Therefore, aquaculture feeds are preferably fed to aquatic organisms that are being transferred from fresh water or have been transferred from fresh water to salt water during the silvering process. For example, an aquaculture method can include the steps of transferring an aquatic organism from fresh water to salt water and feeding the aquatic organism with an aquaculture feed prepared by the method of the present invention.

[0091] When farmed salmon are transferred from early production in land tanks to seawater cages, this constitutes a challenging environment, and fish may experience significant mortality before reaching harvest size. There is a large amount of evidence showing that dietary phospholipids can improve the growth, survival and health of fish in the pre-larval and juvenile stages. It has also been shown that before being transferred to seawater, the inclusion of phospholipids found in krill meal in the diet of Atlantic salmon in the freshwater period increases weight gain, reduces the hepatosome index (HIS) and improves gill health during the stressful period of transfer (Kvingedal et al., Effects of Different Phospholipid Sources on Growth and Gill Health in Atlantic Salmon in Freshwater Pre-Transfer Phase [Different phospholipid sources on the growth and gill health of Atlantic salmon in the freshwater pre-transfer stage]. Animals [animals] 2023, 13, 835. https: / / doi.org / 10.3390 / ani13050835 ). The effects related to the increase in fish weight gain appeared to be associated with the increase in krill meal included in the freshwater stage. Thus, the demonstrated effects appear to be dependent on the amount of krill meal consumed, and aquaculture feeds including the described supplemented krill meal produced according to the invention demonstrated an even further increase in fish feed intake. Thus, aquaculture feeds produced by the method of the invention and supplemented krill meal are preferably fed to aquatic organisms during the silvering process, including before, during and after transfer from freshwater to saltwater.

[0092] Process for preparing supplemented krill meal

[0093] The present invention provides methods for preparing supplemented krill meal. These methods include the following steps: (a) providing krill ( Figure 1 , A); (b) subjecting krill to heat treatment ( Figure 1 , B and Figure 1 , D), (c) separating the heat-treated krill ( Figure 1 , E) into pressed cake ( Figure 1 , O) and squeezed juice ( Figure 1 , F); (d) from the squeezed juice ( Figure 1 , F) is separated ( Figure 1 , G) viscous juice; (e) mixing the viscous juice with the pressed cake ( Figure 1 , O) mixing; (f) and drying at a temperature below 95° C. using a vacuum dryer ( Figure 1 , M) the mixture to obtain krill meal ( Figure 1 , N).

[0094] Surprisingly, it was also demonstrated that upgrading the drying process to have a gentler drying has a positive impact on the flour composition and reduces the risk of protein aggregation and browning.

[0095] Heat processing krill meal at 100°C for 5-15 minutes is considered critical to ensure food safety. It is believed that this high temperature is required to reduce the viral load in wild krill, and therefore, achieving a temperature of 100°C during processing may be a regulatory requirement. However, the inventors have theorized that this heat processing changes the protein in the krill meal and may even cause the protein to be indigestible due to heat-induced non-enzymatic browning (the so-called Maillard reaction), oxidation, and exposure of hydrophobic surfaces. The Maillard reaction is a complex set of chemical reactions induced by heat and occurs mainly between amino acids and sugars. Here, heat triggers a large number of reactions that may lead to the formation of flavor compounds and a characteristic brown color, but also to the formation of toxic compounds such as acrylamide. The main amino acid that reacts in the Maillard reaction is the essential amino acid lysine, which means that the Maillard reaction leads to a reduction in essential amino acids. Excessive heat also drives the formation of free radicals, that is, the formation of reactive oxidative species (ROS). Free radicals can change amino acid side chain groups by generating, for example, protein carbonyls, disulfides, and dityrosine. These altered amino acids can form a stable network of covalent bonds between already heat-denatured proteins, thereby reducing the number of these amino acids and forming stable aggregates that shield other parts of the protein from access by digestive enzymes. Aggregate formation can also be driven by thermal denaturation of proteins. In a hydrophilic environment, this drives the formation of protein aggregates, where the hydrophobic parts within the protein structure strive to associate, held together by van der Waals interactions.

[0096] The inventors have surprisingly discovered that lower temperatures are sufficient to maintain the safety of krill meal. Based on this knowledge, they designed an improved method for preparing supplemented krill meal. The new method uses a vacuum dryer at a temperature below 95°C. A vacuum dryer has several advantages, for example it allows drying at lower temperatures. As described above, subjecting krill meal to high temperatures has several disadvantages. As a result of the new drying process, the digestibility of the krill meal is improved due to reduced denaturation and aggregation of the protein, and the visual properties are improved due to less browning.

[0097] Thus, the present invention provides a method for preparing a supplemented krill meal composition, wherein the drying step is performed using a vacuum dryer at a temperature below 95°C. This step is preferably also implemented as part of the method for preparing an aquaculture feed of the first aspect. For example, the drying in step (f) may comprise a vacuum dryer at a temperature below 95°C.

[0098] Preferably, the temperature is in the range of 80-90° C. or 80-85° C., such as at about 85° C. or 82° C. Vacuum drying occurs at subatmospheric pressure, for example at <0.9 bar, <0.75 bar or <0.6 bar.

[0099] The moisture content of the supplemented krill meal may be in the range of 0-25 wt%, 1-15 wt% or 3-10 wt%.

[0100] In another step towards an attractive alternative ingredient in aquaculture, the present inventors decided to test a new composition comprising krill meal with added mucilage in a feeding trial, as shown in the Examples. The hypothesis was that improved digestibility due to reduced denaturation and aggregation of the protein would make it easier for the test subjects to utilize these ingredients.

[0101] As will be shown in the subsequent examples, krill meal supplemented with mucus juice has an effect on feed intake, specific growth rate, feed conversion ratio and thermal growth coefficient. In Example 2, 9 different diets were produced and formulated according to the recipes presented in Table 4. QA refers to krill meal (analysis is provided in Table 1). QSW refers to supplemented krill meal, in which the dry matter derived from mucus juice corresponds to 6.5% or 4.9% w / w of the total dry matter.

[0102] After analyzing QA and QSW, the inventors found that the proportion of water-soluble protein was generally higher in QSW, especially the levels of free amino acids alanine, proline, arginine, leucine, glutamine and glycine were higher ( Figure 6 ). These amino acids belong to a group of amino acids known to be feed stimulating amino acids. In addition, the inventors found a dose-response effect of the inclusion of QSW on the percentage of free amino acids that stimulate appetite. The higher the QSW included, the higher the percentage of these free amino acids ( Figure 7 and 8 ). Based on this analysis, the inventors suggest that the higher feed intake of QSW is due to a higher percentage of water-soluble protein and free amino acids that stimulate appetite. Interestingly, the results obtained from the feed used during the feeding trial support this.

[0103] In view of the above, it is clear that the composition comprising krill meal supplemented with mucus according to the claimed invention provides increased feed intake. By increasing feed intake, more krill-derived products, including components derived from mucus and krill meal, will be provided to the fish. As a result, all the positive effects of krill meal on fish will be enhanced, such as:

[0104] - Improved growth performance (Aquaculture Research, February 2020, DOI: 10.1111 / are.14573);

[0105] - Improved feed utilization efficiency (Aquaculture Research, February 2020, DOI: 10.1111 / are.14573);

[0106] - Improved dietary digestibility (Aquaculture Research, February 2020, DOI: 10.1111 / are.14573);

[0107] - Improved intestinal development (Aquaculture Research, February 2020, DOI: 10.1111 / are.14573);

[0108] - Improved innate immunity (Aquaculture Research, February 2020, DOI: 10.1111 / are.14573);

[0109] - Increased disease resistance (Aquaculture Research, February 2020, DOI: 10.1111 / are.14573);

[0110] - Improved fish fillet quality (WO 2015185993);

[0111] - Positive effects on heart health (WO 2017029558); and

[0112] - Positive impact on the prevention of viral diseases (WO 2017029558).

[0113] In another aspect, the present invention therefore provides krill meal supplemented with mucilage, wherein the krill meal has a free amino acid concentration of at least 1 g / 100 g krill meal, such as a free amino acid concentration of between 1 g-3 g / 100 g krill meal. The free amino acids preferably include one or more amino acids selected from the group consisting of: alanine, proline, arginine, leucine, glutamine and glycine; optionally wherein the free amino acids include alanine, proline, arginine, leucine, glutamine and glycine. Thus, the present invention also provides krill meal supplemented with mucilage, wherein the combined concentration of alanine, proline, arginine, leucine, glutamine and glycine in the supplemented krill meal is at least 2.5%, or 3.0%-15, or 3.2%-10% w / w of the total protein in the supplemented krill meal.

[0114] The level of water soluble protein in the krill meal may be greater than 15% of the total protein, optionally wherein the level of water soluble protein in the krill meal is 17%-25%.

[0115] A comparison between the krill meal content (analytical data presented in Table 1) and the mucilage content (analytical data presented in Table 2) when taking into account the moisture content shows that the amounts of certain components are very different between the two products. In particular, the amounts of water-soluble proteins and trimethylamine (TMA) + trimethylamine N-oxide (TMAO) are much higher in the mucilage compared to krill meal, and the molecular weight distribution of water-soluble peptides is also different in the two products.

[0116] Based on the latter analysis, it seems to be concluded that increasing the amount of water-soluble protein has a positive effect on feed intake, which demonstrates the advantages of the composition according to the claimed invention. Further, it is also reasonable to believe that high levels of TMA and TMAO have a positive effect on feed intake, which further confirms the use of the composition as claimed herein. In addition, compared to krill meal, the mucus contains significantly higher levels of water-soluble short peptides with a molecular mass equal to or lower than 200 Da (Table 3), and these short peptides are also expected to have a positive effect on feed intake. It should also be mentioned that feed intake has been shown to be positively correlated with the thermal growth coefficient ( Figure 2 Previous research supports that some free amino acids are associated with a higher appetite in salmon (Kousoulaki et al., Aquaculture Nutrition, 2013 19; 47-61).

[0117] In Example 2, amino acids belonging to the group of alanine, proline, arginine, leucine, glutamine and glycine were found to be present as free amino acids at higher levels in QSW compared to QA, see Example 2. The results of Example 2 support that the addition of krill meal supplemented with a material containing water-soluble krill proteins recovered from mucus to fish feeds will increase feed intake and improve growth in aquaculture.

[0118] In a specific embodiment, the water-soluble krill protein-containing material comprises free amino acids selected from the group consisting of alanine, proline, arginine, leucine, glutamine and glycine.

[0119] The impact of water-soluble amino acids from krill has also been demonstrated by another study in which different protein fractions of conventional krill meal were prepared into shrimp feed. In this study (unpublished results), the protein of conventional krill meal (excluding mucus) was separated into a fraction of water-soluble krill protein (krill protein hydrolysate) and a fraction of water-insoluble protein and compared to the krill meal starting material. Conventional krill meal, the water-soluble protein fraction from krill (krill hydrolysate) and the remainder of the insoluble protein from krill were added to shrimp feed and tested against a negative control feed that did not contain krill-derived material. The results demonstrated that the addition of 0.25% w / w of the water-soluble protein fraction had a significantly improved effect on shrimp growth, the same as seen with 3% w / w of conventional krill meal, while the insoluble krill protein had the same growth as the negative control. Since these effects were only demonstrated for the water-soluble protein product, the effects may be associated with enhanced shrimp feed intake due to the water-soluble protein fraction acting as an attractant and palatability enhancer, rather than being associated with the nutritional enrichment of the diet. These findings support that the addition of krill meal supplemented with mucus (eg, additional water-soluble krill protein) will result in increased feed intake and improved shrimp growth.

[0120] In summary, the inventors have demonstrated that the inclusion of ingredients from mucus juice has an overall positive impact on feed conversion ratio, as it increased growth in feeding trials and reduced waste during production. A life cycle analysis (LCA) also found that krill meal containing mucus juice had a significantly lower CO2 footprint compared to conventional krill meal produced without the inclusion of mucus juice.

[0121] Method for preparing krill meal

[0122] The present invention also provides a method for preparing krill meal. The method comprises the following steps: (a) providing krill ( Figure 1 , A); (b) subjecting krill to heat treatment ( Figure 1 , B and Figure 1 , D); (c) separating the heat-treated krill ( Figure 1 , E) into pressed cake ( Figure 1 , O) and squeezed juice ( Figure 1 , F); (d) and drying ( Figure 1 , P) to obtain krill meal ( Figure 1 , Q); wherein the thermal treatment of step (b) comprises using excess heat from the drying of step (d) to heat the krill; and / or wherein water evaporated from the press cake during the drying of step (d) is recovered, converted into steam, and the steam is used during the thermal treatment of step (b).

[0123] The inventors have realised that the efficiency of the process is improved by recycling heat and / or water produced by the drying step (step (d)) in the thermal treatment step (step (b)). In this way, the CO2 emissions of the process can be reduced.

[0124] The method for preparing krill meal may further comprise step (e), wherein step (e) is formulating the krill meal into an aquaculture feed. In this way, the present invention provides a method for preparing an aquaculture feed.

[0125] When the heat treatment in step (b) comprises a first heat treatment ( Figure 1 , B); and then subjecting the krill to a second heat treatment by raising the temperature to about 80°C to 99°C ( Figure 1 , D), the first heat treatment and / or the second heat treatment may comprise heating the krill using excess heat from the drying in step (d). Preferably, the first heat treatment comprises heating the krill using excess heat from the drying in step (d). It has been found that excess heat is particularly suitable for the first heat treatment using indirect heating.

[0126] When the heat treatment in step (b) comprises a first heat treatment ( Figure 1 , B); and then subjecting the krill to a second heat treatment by raising the temperature to about 80°C to 99°C ( Figure 1 , D), water evaporated from the press cake during the drying of step (d) can be recovered, converted into steam, and used during the first heat treatment and / or the second heat treatment. Preferably, water evaporated from the press cake during the drying of step (d) is recovered, converted into steam, and used during the second heat treatment. It has been found that steam is particularly suitable for the second heat treatment using direct heating.

[0127] The first heat treatment may include heating the krill using an indirect heater, and preferably further includes continuously removing material from the surface of the indirect heater. Continuously removing material from the surface prevents scorching or material accumulation, and ensures that the heating surface is always clean for optimal heat transfer, thereby further improving efficiency and yield.

[0128] The second thermal treatment may include direct heating, such as direct steam injection.

[0129] Water evaporated from the press cake during the drying of step (d) may be recovered.Recovering water from the drying step (d) may prevent fresh water from being wasted and thus provide a less wasteful and more environmentally friendly process.

[0130] Unless otherwise indicated, any of the features or effects described in the preceding sections of the present application may be read in conjunction with this section relating to "Process for preparing krill meal", i.e., the entire application as a whole. This means that all of the various optional and preferred features of the processes, compositions and / or methods described herein may be incorporated into the process for preparing krill meal described in this section.

[0131] Having generally described the present invention, further understanding can be obtained by reference to the examples, which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.

[0132] Examples

[0133] Example 1: Production of krill meal (QA), sticky juice (SW) and combination product (QA+SW)

[0134] Use a surface scraper heater ( Figure 1 , B) the krill mixture in water ( Figure 1 , A) is subjected to indirect heating, thereby raising the temperature of the mixture to about 40°C. Material accumulated on the surface of the surface scraper heater is continuously removed from the surface to prevent burning or material accumulation ( Figure 1 , C). Use surface scraped heaters to ensure the heating surface is always clean for optimum heat transfer.

[0135] The krill and water mixture was then subjected to direct heating ( Figure 1 , D): Steam is injected directly into the mixture, thereby raising the temperature of the mixture to about 92°C.

[0136] Thereafter, the mixture was separated into pressed cakes ( Figure 1 , O) and squeezed juice ( Figure 1 , F). For pressed cake ( Figure 1 , (2) indicated a moisture content of about 58 to about 62 wt %.

[0137] Squeeze out the juice ( Figure 1 , F) is adjusted to about 95°C, and then the squeezed juice ( Figure 1 , F) subjected to high-speed centrifugation ( Figure 1 , G) to squeeze out the juice ( Figure 1 , F) is separated into sludge part ( Figure 1 , H), oil part ( Figure 1 , I) and sticky juice ( Figure 1 , J).

[0138] Then make the sticky juice ( Figure 1 , J) in the evaporator ( Figure 1 , K) to reduce the water content and thereby obtain a viscous juice concentrate ( Figure 1 , L). The evaporator utilizes the Figure 1 , M) of excess heat, improving the efficiency of the process. Figure 1 , L) indicated a moisture content of about 62% by weight. In an alternative embodiment, water evaporated from the sap can be reused to heat the krill and water mixture ( Figure 1 , D). The water evaporated from the krill passes through the condenser ( Figure 1 , R) to recover. This water is then used as a reboiler ( Figure 1 , S) and produce pressurized steam, which is injected into heat treatment #2 ( Figure 1 , D).

[0139] Make some pressed cakes ( Figure 1 , O) in a tray dryer ( Figure 1 , P) to form krill meal ( Figure 1 , Q). The pressed cake ( Figure 1 , O) and the remaining portion of the viscous juice concentrate ( Figure 1 , L) in 1 part of viscous juice concentrate ( Figure 1 , L) and 25 parts by dry weight of pressed cake ( Figure 1 , O) to 1 part by dry weight of viscous juice concentrate ( Figure 1 , L) and 3 pressed cakes by dry weight ( Figure 1 , (0) in different ratios. The combined product is then dried in a tray dryer ( Figure 1 , M) to form a combined product having a moisture content of about 6 wt % ( Figure 1 , N). A vacuum of -0.48 bar allows drying at lower temperatures of about 81°C to about 95°C, rather than drying at 100°C. This process reduces the risk of protein denaturation and browning, and ensures improved digestibility and visual properties of the final product.

[0140] Analysis of krill meal ( Figure 1 , Q) content, and the data provided are presented in Table 1 below. Analysis of viscous juice ( Figure 1 , J), and the obtained data are presented in the following Table 2. Further, the molecular weight distribution of water-soluble proteins and peptides in krill meal and mucus is presented in Table 3.

[0141] Table 1: Analysis of krill meal (QA)

[0142]

[0143]

[0144]

[0145] *A25: ISO16634-1-Dumas analysis of N / 100g by combustion

[0146] Total amino acids in the flour were measured by first performing protein hydrolysis and quantifying the entire amino acids (A42 method).

[0147] Table 2: Analysis of viscous juice (SW)

[0148]

[0149]

[0150] Table 3: Analysis of viscous juice (SW)

[0151] Krill Meal Sticky juice Mw-peptide>20000 % of water-soluble peptides 0,1 <0,1 Mw-peptide 20000-15000 % of water-soluble peptides 0,2 0,1 Mw-peptide 15000-10000 % of water-soluble peptide 1,1 0,3 Mw-peptide 10000-8000 % of water-soluble peptide 1,6 0,6 Mw-peptide 8000-6000 % of water-soluble peptide 4 1,7 Mw-peptide 6000-4000 % of water-soluble peptides 7,3 4,5 Mw-Peptide 4000-2000 % of water-soluble peptide 8,5 7,9 Mw-peptide 2000-1000 % of water-soluble peptides 4,1 4,2 Mw-peptide 1000-500 % of water-soluble peptide 2,6 2,6 Mw-peptide 500-200 % of water-soluble peptide 4,4 3,2 Mw-Peptide 200- % of water-soluble peptides 66 74,9

[0152] Table 4: Compared with conventional krill meal (krill meal without mucus component = QA), the results of five tests on krill meal containing Average values ​​of the composition of the mucus juice from the analysis of different batches of krill meal (QSW)

[0153]

[0154]

[0155] *A25: ISO 16634-1 - Dumas analysis of N / 100 g by combustion. A20: Water extraction followed by Dumas analysis.

[0156] Table 5: Comparison of the composition of krill meal supplemented with mucus juice and krill meal not supplemented with mucus juice

[0157]

[0158]

[0159] *Total amino acids in the flour are measured by first performing protein hydrolysis and quantifying the total amino acids (A42, A99 and A100 methods). For determination of free amino acids (A105 method), the protein hydrolysis step is omitted to allow measurement of only the free amino acids present in the flour.

[0160] Example 2: Feeding trial

[0161] The main objective of this feeding trial was to compare the effects of including mucus in krill meal on feed intake and growth performance of Atlantic salmon. Figure 3 shows the setup.

[0162] The growth trial was conducted on salmon for a total of 9 months between July and May. After the 9-month feeding trial, the following parameters were calculated: feed intake (in grams), FCR and growth (in grams of weight). The results showed a positive effect of QSW on feed intake and growth (in grams of biomass).

[0163] Experimental diet

[0164] Nine isoprotein and isolipid diets were formulated and produced. The formulas of the feeds are provided in Table 6.

[0165] Table 6: Diet formulation, total feed

[0166]

[0167] Diets 1, 4 and 7 were fish feeds containing 30, 15 and 7.5% fish meal by weight.

[0168] Diets 2, 5 and 8 were similar to the fishmeal diets (1, 4 and 7) except that 7.5% of the fishmeal was replaced by krill meal (QA). Diets 3 and 6 were similar to the fishmeal diets (1, 4 and 7) except that 7.5% of the fishmeal was replaced by QA + 6.5% SW; and Diet 9 was similar to the fishmeal diets (1, 4 and 7) except that 7.5% of the fishmeal was replaced by QA + 4.9% SW.

[0169] Diets 3, 6 and 9 are referred to herein as QSW diets, and these were obtained by adding the QSW composition according to the present invention ( Figure 1 , N).

[0170] The diets were analyzed for moisture (dried to constant weight at 103 °C; ISO 6496:1999), crude fat (Soxhlet with acid hydrolysis; EC 152 / 2009), crude protein (Nx6.25, Kjeltech automated system; Tecator, Höganäs, Sweden). Sweden), ash (combustion at 550 °C, ISO 5984:2002), starch, astaxanthin and gross energy (bomb 20 calorimetry; ISO 9831:1998). In addition, the amino acid composition of the feed (ISO 13903:2005, EU 152 / 2009; tryptophan EU 152 / 2009) and the fatty acid composition of the feed were analyzed.

[0171] Feeding trial

[0172] The experiments were performed according to the guidelines and protocols approved by the European Union (EU Council 86 / 609; DL 27.01.1992, No. 116) and the national animal care and welfare guidelines issued by the Norwegian Ministry of Education and Research.

[0173] During the period from July 2020 to May 2021, in Dennar The LetSea experimental station in Norway conducted a growth trial with Atlantic salmon for a total of 9 months. The fish arrived and were acclimatized in the cages for a period of 2 weeks (temperature, oxygen and salinity) before distribution.

[0174] Feeding trial, start sampling

[0175] The fish were initially weighed in bulk and the length and weight of 20 fish were measured individually. The fish were fed ad libitum.

[0176] Feed intake

[0177] Daily feeding amount and feed losses were recorded to estimate feed conversion ratio (FCR).

[0178] Feeding trial, mid-term 1, mid-term 2 and final sampling

[0179] Fish were batch weighed after two months of feeding trial (mid-term 1), four months of feeding trial (mid-term 2) and nine months of feeding trial (final sampling). In addition, 12 fish / tank were sampled and their fork length, weight, visceral weight to measure fatness (CF) and carcass % (D%) were measured individually.

[0180] After mid-term 2 and last sampling, 10 fish / water tanks are sliced ​​immediately under the pre-rigidity state after slaughter.Fish fillet is packed in sealed plastic bag separately and stored on ice for one week, and then analyzed.Fish fillet quality analysis comprises processing suitability, and this processing suitability is analyzed as the fillet crack degree (0-5 points) after simulating commercial processing conditions (FHF industrial standard), fillet firmness (in terms of instrument, using the TA-XT2 of the stable microsystem company (Stable Micro Systems Ltd.) of England Surrey (Surrey, England) and 1mm s-1 flat head 189 12.5mm 20 probes under the compression speed), fillet color (visual assessment under the standardized illumination conditions in salmon colorimetric box, SalmoFan color scoring, DSM (DSM) (Heerlen, Netherlands)) and melanization muscle segment (sarcomere) quantity. Firmness and color were analyzed above the lateral line, just below the dorsal fin at the head, and between the dorsal fin and the viscera at the tail (ie, 25 Norwegian quality cut, NQC). NQC was used to analyze protein, fat and astaxanthin content, fatty acid composition, and collagen properties.

[0181] result

[0182] After 9 months of feeding trial, the following parameters were calculated: mortality, feed intake (in grams), FCR and growth (weight in grams). Mortality was lower in the group fed QSW compared to QA and control, see Figure 4 The results showed that QSW had a positive effect on total feed intake and growth (biomass in grams) compared to QA and control, as Figure 5 As shown in .

[0183] After analyzing QA and QSW, the inventors found that the water-soluble protein ( Figure 6 ) and feed-stimulated free amino acids ( Figure 7 ) percentage is higher. Figure 6-8 The results presented in are based on the data found in Table 5. The free amino acids summarized in the figure that are associated with appetite are alanine, proline, arginine, leucine, glutamine and glycine. Figure 7 The difference between the amount of free amino acids that stimulate appetite in two batches of QSW and QA is shown in FIG. The inventors also found a dose-response effect of the inclusion of QSW on the percentage of free amino acids that stimulate appetite. The higher the QSW included, the higher the percentage of these free amino acids ( Figure 7Based on these results, the inventors suggest that the higher feed intake of QSW is due to a higher percentage of water-soluble protein and free amino acids that stimulate appetite. Interestingly, similar results were found in the feeds used during the feeding trial (see Figure 8 ).

[0184] Figure 7 It was shown that the percentage of appetite-stimulating free amino acids (alanine, proline, arginine, leucine, glutamine and glycine) was higher in QSW powder compared to QA powder.

[0185] Figure 8 It was shown that the percentage of appetitive free amino acids (alanine, proline, arginine, leucine, glutamine and glycine) was higher in the feed with QSW compared to the QA and control feeds.

[0186] in conclusion

[0187] The results clearly indicate that increased feed intake and improved growth can be achieved by increasing the level of water-soluble proteins and free amino acids that stimulate appetite in fish feed. Those water-soluble proteins can be sustainably obtained by utilizing the components present in the mucus. This can be beneficial to fish farmers, particularly during stressful periods. Stressful periods such as transfer to the sea, treatment periods for salmon lice or other diseases, treatment, etc. may have an adverse effect on the appetite of fish. Appetite reduction may have an adverse effect on the growth and welfare of fish. Therefore, by including mucus in the feed, appetite can be stimulated during these stressful periods, and this may eventually make the growth and welfare of fish better. In addition, in terms of pigmentation and firmness, the quality of fish fillets is equally good in QA and QSW (with two inclusion levels). In addition, compared with the control group, the FCR in QA and QSW is numerically better. Based on these results, the inventors have concluded that QSW is a relatively more sustainable raw material with the same benefits demonstrated with QA.

[0188] Example 3: CO2 Emissions

[0189] Fuel consumption and krill meal production data for excursions where krill were caught and processed into meal on board a vessel were used to calculate CO2 emissions per unit of meal produced. A comparison was made between excursions where meal was not supplemented with mucus juice and excursions where meal was supplemented with mucus juice using excess heat from a tray dryer to heat the mucus juice in accordance with the present invention. The method of supplementing with mucus juice was found to reduce CO2 emissions, as indicated in Table 7.

[0190] Table 7: Comparison of powder production and fuel consumption for three consecutive excursions. Inclusion of sticky juice in excursion 3

[0191] Short Trip 1 Short Trip 2 Short Trip 3 The powder MT produced 2237.85 2036.525 3148.5 Fuel consumed in MT 905.1 840.17 1006.57 Fuel / Powder 0.404 0.413 0.32 CO2e / Kg powder* 1.313 1.34225 1.04

[0192] *Calculation based on ship emissions. Several parameters affect CO2 equivalent / kg powder, but

[0193] Part of the reduction is attributed to the addition of sticky juice to the powder.

[0194] Numbered implementation plan

[0195] The present invention includes the following numbered embodiments.

[0196] 1. A method for preparing an aquaculture feed, wherein the method comprises the following steps:

[0197] (a) Provide krill ( Figure 1 , A);

[0198] (b) subjecting the krill to a heat treatment ( Figure 1 , B and Figure 1 , D),

[0199] (c) separating the heat-treated krill ( Figure 1 , E) into pressed cake ( Figure 1 , O) and squeezed juice ( Figure 1 , F);

[0200] (d) extracting the juice from the Figure 1 , F) is separated ( Figure 1 , G) sticky juice;

[0201] (e) mixing the viscous juice with the pressed cake ( Figure 1 , O) mixing;

[0202] (f) Drying Figure 1 , M) the mixture to obtain the supplemented krill meal ( Figure 1 , N); and

[0203] (g) formulating the supplemented krill meal into an aquaculture feed.

[0204] 2. The method according to embodiment 1, wherein the aquaculture feed comprises the supplemented krill meal at a concentration of at least 2% w / w, or 3%-50% w / w, or 4%-30% w / w or 5%-15% w / w.

[0205] 3. The method according to any one of the preceding embodiments, wherein the relative proportions of the viscous juice and the press cake mixed in step (e) range from 1 part viscous juice by dry weight to 25 parts press cake by dry weight to 1 part viscous juice by dry weight to 3 parts press cake by dry weight.

[0206] 4. The method according to any one of the preceding embodiments, wherein the supplemented krill meal produced in step (f) comprises viscous juice at a concentration of 3%-25% w / w, or 3.5%-10% w / w, or 4%-7% w / w of total dry matter.

[0207] 5. The method according to any one of the preceding embodiments, wherein the viscous juice contains 57 g to 87 g water-soluble protein per 100 g protein-containing material on a dry weight basis.

[0208] 6. The method according to any one of the preceding embodiments, wherein the amount of trimethylamine and the amount of trimethylamine oxide in the viscous juice is in the range of 1100 mg N to 2500 mg N / 100 g viscous juice on a dry weight basis.

[0209] 7. The method according to any one of the preceding embodiments, wherein:

[0210] a. 0.1% to 0.5% by dry weight of these water-soluble proteins in the viscous juice have a molecular mass in the range of 10 kDa to 15 kDa;

[0211] b. 0.2% to 1% of these water-soluble proteins by dry weight in the viscous juice have a molecular mass in the range of 8 kDa to 10 kDa;

[0212] c. 1% to 2.4% of these water-soluble proteins by dry weight in the viscous juice have a molecular mass in the range of 6kDa to 8kDa; and / or

[0213] d. 70% to 80% of these water-soluble proteins in the viscous juice by dry weight have a molecular mass of ≤200 Da.

[0214] 8. The method according to any one of the preceding embodiments, wherein the amount of trimethylamine and the amount of trimethylamine oxide in the supplemented krill meal is in the range of 100 mg N to 250 mg N / 100 g supplemented krill meal on a dry weight basis.

[0215] 9. The method according to any one of the preceding embodiments, wherein the supplemented krill meal has a free amino acid concentration of at least 1 g / 100 g of supplemented krill meal, optionally between 1 g-3 g / 100 g of supplemented krill meal.

[0216] 10. A method according to embodiment 9, wherein the free amino acids include amino acids selected from the group consisting of: alanine, proline, arginine, leucine, glutamine and glycine; optionally wherein the free amino acids include alanine, proline, arginine, leucine, glutamine and glycine.

[0217] 11. The method according to any one of the preceding embodiments, wherein the combined concentration of alanine, proline, arginine, leucine, glutamine and glycine in the supplemented krill meal is at least 0.60% w / w of the total protein in the supplemented krill meal.

[0218] 12. The method according to any one of the preceding embodiments, wherein the heat treatment in step (b) comprises raising the temperature to about 80°C to 100°C, and optionally maintaining the krill at this temperature for at least 1 minute or 1-10 minutes.

[0219] 13. The method according to any one of the preceding embodiments, wherein the heat treatment in step (b) comprises a first heat treatment ( Figure 1 , B); and then subjecting the krill to a second heat treatment by raising the temperature to about 80°C to 99°C ( Figure 1 , D).

[0220] 14. The method according to any one of the preceding embodiments, wherein before step (e), the method comprises reducing the viscosity ( Figure 1 , J) in water ( Figure 1 , K) to obtain a viscous juice concentrate ( Figure 1 , L) step, and step (e) comprises mixing the viscous juice concentrate with the press cake.

[0221] 15. The method according to embodiment 14, wherein the viscous juice concentrate has a moisture content of 40%-80%, or 50%-70% or 55%-65%.

[0222] 16. The method according to any one of embodiments 14 and 15, wherein reducing the amount of water in the viscous juice comprises using excess heat from the drying of step (f) to heat the viscous juice.

[0223] 17. The method according to any one of embodiments 14-16, wherein water evaporated from the viscous juice is recovered, converted into steam, and the steam is used during the thermal treatment of step (b).

[0224] 18. The method according to any one of the preceding embodiments, wherein step (d) comprises Figure 1 , F) separated into viscous juice ( Figure 1 , J), oil part ( Figure 1 , I) and sludge part ( Figure 1 , H).

[0225] 19. The method according to any one of the preceding embodiments, wherein the drying in step (f) comprises vacuum drying, optionally at a pressure of about <0.9 bar, <0.75 bar or <0.6 bar.

[0226] 20. The method according to embodiment 19, wherein the vacuum drying is at a temperature below 95°C, or 80°C-90°C or 80°C-85°C.

[0227] 21. The method according to any one of the preceding embodiments, wherein the relative proportions of fish meal and supplemented krill meal in the aquaculture feed are in the range of 5 parts supplemented krill meal: 1 part fish meal to 1 part supplemented krill meal: 5 parts fish meal.

[0228] 22. The method according to any one of embodiments 1-20, wherein the aquaculture feed does not contain fish meal.

[0229] 23. The method according to any one of the preceding embodiments, wherein steps (a) to (f) are performed immediately after the krill is captured.

[0230] 24. The method according to any one of the preceding embodiments, wherein steps (a) to (f) are performed on board a vessel and step (g) is performed on shore.

[0231] 25. The method according to any one of the preceding embodiments, wherein the time between steps (f) and (g) is at least 1 week or at least 1 month, optionally wherein the time between steps (f) and (g) is at most 36 months.

[0232] 26. An aquaculture feed prepared by the method according to any one of the preceding embodiments.

[0233] 27. A method of aquaculture, the method comprising preparing an aquaculture feed by the method according to any one of embodiments 1 to 25, and feeding an aquatic organism with the aquaculture feed.

[0234] 28. The method of embodiment 27, wherein the aquatic organism is from the family Salmonidae, such as salmon; optionally wherein the aquatic organism is Atlantic salmon.

[0235] 29. The method of embodiment 27, wherein the aquatic organism is shrimp.

[0236] 30. Krill meal supplemented with mucilage, wherein the krill meal has a free amino acid concentration of at least 1 g / 100 g krill meal, optionally between 1 g-3 g / 100 g krill meal.

[0237] 31. The krill meal of embodiment 30, wherein the free amino acids comprise amino acids selected from the group consisting of alanine, proline, arginine, leucine, glutamine and glycine; optionally wherein the free amino acids comprise alanine, proline, arginine, leucine, glutamine and glycine.

[0238] 32. The krill meal according to any one of embodiments 30 or 31, wherein the level of water-soluble protein in the krill meal is greater than 15% of the total protein, optionally wherein the level of water-soluble protein in the krill meal is 17%-25%.

[0239] 33. The krill meal according to any one of embodiments 30-32, wherein the combined concentration of alanine, proline, arginine, leucine, glutamine and glycine in the meal is at least 2.5%, or 3.0%-15, or 3.2%-10% w / w of the total protein in the meal.

[0240] 34. A method for preparing supplemented krill meal, the method comprising following the method according to any one of embodiments 1-23, but omitting step (g).

[0241] 35. A method for preparing supplemented krill meal, wherein the method comprises the steps of:

[0242] (a) Provide krill ( Figure 1 , A);

[0243] (b) subjecting the krill to a heat treatment ( Figure 1 , B and Figure 1 , D),

[0244] (c) separating the heat-treated krill ( Figure 1 , E) into pressed cake ( Figure 1 , O) and squeezed juice ( Figure 1 , F);

[0245] (d) extracting the juice from the Figure 1 , F) is separated ( Figure 1 , G) sticky juice;

[0246] (e) mixing the viscous juice with the pressed cake ( Figure 1 , O) mixing;

[0247] (f) and drying at a temperature below 95°C using a vacuum dryer ( Figure 1 , M) the mixture to obtain the supplemented krill meal ( Figure 1 , N).

[0248] 36. A method as described in embodiment 35, wherein the drying in step (f) comprises vacuum drying, optionally at a pressure of about <0.9 bar, <0.75 bar or <0.6 bar.

[0249] 37. The method according to embodiment 36, wherein the vacuum drying is at a temperature below 95°C, or 80°C-90°C or 80°C-85°C.

Claims

1. A method for preparing supplemented krill meal, wherein the method comprises the following steps: (a) Providing krill (Figure 1, A); (b) subjecting the krill to a heat treatment ( FIG. 1 , B and FIG. 1 , D), (c) separating the heat-treated krill ( FIG. 1 , E) into pressed cake ( FIG. 1 , O) and pressed juice ( FIG. 1 , F); (d) separating ( FIG. 1 , G) the viscous juice from the pressed juice ( FIG. 1 , F); (e) mixing the viscous juice with the pressed cake ( FIG. 1 , O); (f) Drying ( FIG. 1 , M) the mixture to obtain supplemented krill meal ( FIG. 1 , N).

2. A method for preparing an aquaculture feed, the method comprising preparing a supplemented krill meal according to claim 1 and further comprising step (g), wherein step (g) is formulating the supplemented krill meal into an aquaculture feed.

3. The method according to claim 2, wherein: The aquaculture feed comprises the supplemented krill meal at a concentration of at least 2% w / w, or 3%-50% w / w, or 4%-30% w / w, or 5%-15% w / w.

4. A method according to any one of the preceding claims, wherein: The relative proportions of the viscous juice and the press cake mixed in step (e) range from 1 part of the viscous juice by dry weight to 25 parts of the press cake by dry weight to 1 part of the viscous juice by dry weight to 3 parts of the press cake by dry weight.

5. A method according to any one of the preceding claims, wherein: The supplemented krill meal produced in step (f) comprises viscous juice at a concentration of 3%-25% w / w, or 3.5%-10% w / w or 4%-7% w / w of total dry matter.

6. A method according to any one of the preceding claims, wherein: The viscous juice contains 57 g to 87 g of water-soluble protein per 100 g of protein-containing material on a dry weight basis.

7. A method according to any one of the preceding claims, wherein: The amount of trimethylamine and the amount of trimethylamine oxide in the viscous juice ranges from 1100 mg N to 2500 mg N / 100 g of the viscous juice on a dry weight basis.

8. A method according to any one of the preceding claims, wherein: a. 0.1% to 0.5% by dry weight of these water-soluble proteins in the viscous juice have a molecular mass in the range of 10 kDa to 15 kDa; b. 0.2% to 1% of these water-soluble proteins by dry weight in the viscous juice have a molecular mass in the range of 8 kDa to 10 kDa; c. 1% to 2.4% of these water-soluble proteins by dry weight in the viscous juice have a molecular mass in the range of 6kDa to 8kDa; and / or d. 70% to 80% of these water-soluble proteins in the viscous juice by dry weight have a molecular mass of ≤200 Da.

9. A method according to any one of the preceding claims, wherein: The amount of trimethylamine and the amount of trimethylamine oxide in the supplemented krill meal is in the range of 100 mg N to 250 mg N / 100 g supplemented krill meal on a dry weight basis.

10. A method according to any one of the preceding claims, wherein: The supplemented krill meal has a free amino acid concentration of at least 1 g / 100 g of supplemented krill meal, optionally between 1 g-3 g / 100 g of supplemented krill meal.

11. The method according to claim 10, wherein: The free amino acids include one or more amino acids selected from the group consisting of alanine, proline, arginine, leucine, glutamine and glycine; optionally wherein the free amino acids include alanine, proline, arginine, leucine, glutamine and glycine.

12. A method according to any one of the preceding claims, wherein: The combined concentration of alanine, proline, arginine, leucine, glutamine and glycine in the supplemented krill meal is at least 0.60% w / w of the total protein in the supplemented krill meal.

13. A method according to any one of the preceding claims, wherein: The heat treatment in step (b) comprises raising the temperature to about 80°C to 100°C, and optionally maintaining the krill at this temperature for at least 1 minute or 1-10 minutes.

14. A method according to any one of the preceding claims, wherein: The heat treatment in step (b) includes a first heat treatment by raising the temperature to about 40°C to 60°C ( FIG. 1 , B ); and then the krill is subjected to a second heat treatment by raising the temperature to about 80°C to 99°C ( FIG. 1 , D ).

15. A method according to any one of the preceding claims, wherein: Prior to step (e), the method comprises a step of reducing the amount of water ( FIG. 1 , K) in the viscous juice ( FIG. 1 , J) to obtain a viscous juice concentrate ( FIG. 1 , L), and step (e) comprises mixing the viscous juice concentrate with the press cake.

16. The method according to claim 15, wherein: The viscous juice concentrate has a moisture content of 40%-80%, or 50%-70%, or 55%-65%.

17. The method according to any one of claims 15 and 16, wherein: Reducing the amount of water in the viscous juice comprises using excess heat from the drying of step (f) to heat the viscous juice.

18. The method according to any one of claims 15 to 17, wherein: The water evaporated from the viscous juice is recovered, converted into steam, and the steam is used during the heat treatment of step (b).

19. A method according to any one of the preceding claims, wherein: Step (d) comprises separating the pressed juice ( FIG. 1 , F) into a viscous juice ( FIG. 1 , J), an oil fraction ( FIG. 1 , I) and a sludge fraction ( FIG. 1 , H).

20. A method according to any one of the preceding claims, wherein: The drying in step (f) comprises vacuum drying, optionally at a pressure of about <0.9 bar, <0.75 bar or <0.6 bar.

21. The method according to claim 20, wherein: The vacuum drying is at a temperature below 95°C, or 80°C-90°C, or 80°C-85°C.

22. The method according to any one of claims 2 to 21, wherein: The relative proportions of fish meal and supplemented krill meal in the aquaculture feed range from 5 parts supplemented krill meal: 1 part fish meal to 1 part supplemented krill meal: 5 parts fish meal.

23. The method according to any one of claims 2 to 21, wherein: This aquaculture feed does not contain fishmeal.

24. A method according to any one of the preceding claims, wherein: Steps (a) to (f) are performed immediately after the krill are captured.

25. A method according to any one of the preceding claims, wherein: Steps (a) to (f) are performed on board the vessel and, if step (g) is performed, step (g) is performed on shore.

26. The method according to any one of claims 2 to 25, wherein: The time between steps (f) and (g) is at least 1 week or at least 1 month, optionally wherein the time between steps (f) and (g) is at most 36 months.

27. An aquaculture feed prepared by the method according to any one of claims 2 to 26.

28. A method of aquaculture, the method comprising preparing an aquaculture feed by the method according to any one of claims 2 to 26, and feeding an aquatic organism with the aquaculture feed.

29. The method according to claim 28, wherein: The aquatic organism is from the family Salmonidae, such as salmon; optionally wherein the aquatic organism is Atlantic salmon.

30. The method of claim 28, wherein: The aquatic organism is a shrimp.

31. Krill meal supplemented with mucilage, wherein the krill meal has a free amino acid concentration of at least 1 g / 100 g krill meal, optionally between 1 g-3 g / 100 g krill meal.

32. The krill meal according to claim 31, wherein The free amino acids include one or more amino acids selected from the group consisting of alanine, proline, arginine, leucine, glutamine and glycine; optionally wherein the free amino acids include alanine, proline, arginine, leucine, glutamine and glycine.

33. The krill meal according to any one of claims 31 or 32, wherein The level of water-soluble protein in the krill meal is greater than 15% of the total protein, optionally wherein the level of water-soluble protein in the krill meal is 17%-25%.

34. The krill meal according to any one of claims 31 to 33, wherein The combined concentration of alanine, proline, arginine, leucine, glutamine and glycine in the meal is at least 2.5%, or 3.0%-15, or 3.2%-10% w / w of the total protein in the meal.

35. A method for preparing supplemented krill meal, wherein the method comprises the steps of: (a) Providing krill (Figure 1, A); (b) subjecting the krill to a heat treatment ( FIG. 1 , B and FIG. 1 , D), (c) separating the heat-treated krill ( FIG. 1 , E) into pressed cake ( FIG. 1 , O) and pressed juice ( FIG. 1 , F); (d) separating ( FIG. 1 , G) the viscous juice from the pressed juice ( FIG. 1 , F); (e) mixing the viscous juice with the pressed cake ( FIG. 1 , O); (f) and drying the mixture using a vacuum dryer at a temperature below 95°C (Fig. 1, M) to obtain supplemented krill meal (Fig. 1, N).

36. The method of claim 35, wherein: The drying in step (f) comprises vacuum drying, optionally at a pressure of about <0.9 bar, <0.75 bar or <0.6 bar.

37. The method of claim 36, wherein: The vacuum drying is at a temperature below 95°C, or 80°C-90°C, or 80°C-85°C.

38. A method for preparing krill meal, wherein the method comprises the following steps: (a) Providing krill (Figure 1, A); (b) subjecting the krill to a heat treatment ( FIG. 1 , B and FIG. 1 , D ); (c) separating the heat-treated krill ( FIG. 1 , E) into a pressed cake ( FIG. 1 , O) and a pressed juice ( FIG. 1 , F); and (d) drying ( FIG. 1 , P) the pressed cake to obtain krill meal ( FIG. 1 , Q); wherein the heat treatment of step (b) comprises using excess heat from the drying of step (d) to heat the krill; and / or Wherein water evaporated from the press cake during the drying in step (d) is recovered, converted into steam, and the steam is used during the heat treatment in step (b).

39. A method for preparing an aquaculture feed, the method comprising preparing krill meal according to claim 38 and further comprising step (e), wherein step (e) is formulating the krill meal into an aquaculture feed.

40. The method of claim 39, wherein: The aquaculture feed comprises the krill meal at a concentration of at least 2% w / w, or 3%-50% w / w, or 4%-30% w / w, or 5%-15% w / w.

41. The method according to any one of claims 38 to 40, wherein: The heat treatment in step (b) comprises raising the temperature to about 80°C to 100°C, and optionally maintaining the krill at this temperature for at least 1 minute or 1-10 minutes.

42. The method according to any one of claims 38 to 41, wherein: The heat treatment in step (b) includes a first heat treatment by raising the temperature to about 40°C to 60°C ( FIG. 1 , B ); and then the krill is subjected to a second heat treatment by raising the temperature to about 80°C to 99°C ( FIG. 1 , D ).

43. The method of claim 42, wherein: The first heat treatment and / or the second heat treatment comprises using excess heat from the drying of step (d) to heat the krill; preferably wherein the first heat treatment comprises using excess heat from the drying of step (d) to heat the krill.

44. The method according to claim 42 or 43, wherein: Water evaporated from the press cake during the drying in step (d) is recovered, converted into steam and used during the first heat treatment and / or the second heat treatment; preferably the steam is used during the second heat treatment.

45. The method according to any one of claims 38 to 44, wherein: The drying in step (d) comprises vacuum drying, optionally at a pressure of about <0.9 bar, <0.75 bar or <0.6 bar.

46. ​​The method of claim 45, wherein: The vacuum drying is at a temperature below 95°C, or 80°C-90°C, or 80°C-85°C.

47. The method according to any one of claims 39 to 46, wherein: The relative proportions of fish meal and krill meal in the aquaculture feed range from 5 parts krill meal: 1 part fish meal to 1 part krill meal: 5 parts fish meal.

48. The method according to any one of claims 39 to 46, wherein: This aquaculture feed does not contain fishmeal.

49. The method according to any one of claims 38 to 48, wherein: Steps (a) to (d) are performed immediately after the krill are captured.

50. The method according to any one of claims 38 to 49, wherein: Steps (a) to (d) are performed on board the vessel, and if step (e) is performed, step (e) is performed on shore.

51. The method according to any one of claims 39-50, wherein: The time between steps (d) and (e) is at least 1 week or at least 1 month, optionally wherein the time between steps (d) and (e) is at most 36 months.

52. An aquaculture feed prepared by the method according to any one of claims 39-51.

53. A method of aquaculture, the method comprising preparing an aquaculture feed by the method according to any one of claims 39 to 51, and feeding an aquatic organism with the aquaculture feed.

54. The method of claim 53, wherein: The aquatic organism is from the family Salmonidae, such as salmon; optionally wherein the aquatic organism is Atlantic salmon.

55. The method of claim 53, wherein: The aquatic organism is a shrimp.

56. The method according to any one of claims 28-30 or 53-55, wherein Feeding aquatic organisms includes feeding aquatic organisms that are experiencing periods of stress.

57. The method of claim 56, wherein: The aquatic organism is an anadromous fish, such as salmon, and wherein the stressful period is galvanization.

58. The method according to any one of claims 38 to 51, wherein: The water evaporated from the press cake during the drying in step (d) is recovered.

59. The method according to any one of claims 1 to 26, wherein: The heat treatment of step (b) comprises using excess heat from the drying of step (f) to heat the krill.

60. The method of any one of claims 1-26 or 59, wherein: Water evaporated from the mixture during the drying in step (f) is recovered, converted into steam, and the steam is used during the heat treatment in step (b).

61. The method according to any one of claims 59 or 60, wherein: The heat treatment in step (b) comprises a first heat treatment by increasing the temperature to about 40°C to 60°C (FIG. 1, B); and the krill is then subjected to a second heat treatment by increasing the temperature to about 80°C to 99°C (FIG. 1, D); and wherein the first heat treatment and / or the second heat treatment comprises heating the krill using excess heat from the drying of step (f); preferably wherein the first heat treatment comprises heating the krill using excess heat from the drying of step (f).

62. The method according to any one of claims 60 or 61, wherein: The heat treatment in step (b) comprises a first heat treatment by raising the temperature to about 40°C to 60°C ( FIG. 1 , B); and then the krill is subjected to a second heat treatment by raising the temperature to about 80°C to 99°C ( FIG. 1 , D); Wherein water evaporated from the mixture during the drying in step (f) is recovered, converted into steam and used during the first heat treatment and / or the second heat treatment; preferably the steam is used during the second heat treatment.

63. The method of any one of claims 14, 42-44 or 61-62, wherein: The first heat treatment comprises heating the krill using an indirect heater, and preferably further comprises continuously removing material from a surface of the indirect heater.

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