Feed for fish

Abstract

The present invention addresses the problem of providing a feed that stimulates feeding by fish and has heightened palatability, or an additive therefor. Moreover, the present invention also addresses the problem of providing a feed that improves fattening of fish and has heightened feed efficiency, or an additive therefor. This feed for fish contains cacao husks. Moreover, said problems are solved by using cacao husks as an active ingredient in a feed additive for stimulating feeding by fish and / or for promoting fattening.

Description

fish feed

[0001] The present invention relates to a fish feed containing cocoa husk and an additive for fish feed.

[0002] Traditionally, marine resources such as krill and small fish have been used as live bait in fish farming. However, the large amount of waste generated because the live bait is not always consumed, and the excrement of farmed fish have adverse effects on the water quality and bottom sediment of fishing grounds (self-pollution), resulting in reduced productivity and environmental pollution. For this reason, in recent years, fish farming has been shifting from live bait to formulated feed in order to prevent environmental pollution of the ocean, including fishing grounds. Furthermore, various formulated feeds have been developed from the perspectives of feed nutrition and stable supply. In particular, there is a demand for feeds that improve feed efficiency and fattening ability, and various feeds that are palatable to fish have been proposed (e.g., Patent Document 1).

[0003] Incidentally, with regard to cacao fruits (cacao pods), which are the raw material for chocolate and the like, unused portions are discarded after the production of chocolate and the like. With regard to such waste material, cacao husk, secondary uses are being considered from the viewpoint of protecting the environment and food resources. For example, it has been proposed to incorporate ground cacao husk or extract into feed for terrestrial animals (Patent Documents 2 and 3). However, the usefulness of cacao husk when used as aquatic feed is not fully known.

[0004] Japanese Patent No. 5030043 Japanese Patent Application Laid-Open No. 2017-176065 Japanese Patent Application Laid-Open No. 2015-205913

[0005] In terms of fish palatability, live baits such as krill and small fish have been extremely useful. However, as mentioned above, live baits tend to be avoided due to the significant environmental impact of live baits, including fishing grounds. Formula feeds developed as alternatives to live baits have yet to be found that are satisfactory in terms of fish palatability. While krill, fish meal, and other ingredients are often used in formula feeds, reducing the amount of fish-derived feed ingredients is considered desirable from the perspective of protecting marine resources. Furthermore, there has been insufficient research into the reuse of waste materials from food production, such as cocoa husk, in feed, including the effectiveness of such reuse. In light of this situation, an objective of the present invention is to provide a feed or additive therefor that has a low environmental impact, does not consume marine resources, stimulates fish feeding, and enhances fish palatability. Another objective of the present invention is to provide a feed or additive therefor that improves fish fattening and feed efficiency.

[0006] As a result of intensive research conducted by the present inventors to solve the above-mentioned problems, they found that when cocoa husk is added to feed and given to fish orally, the feeding attraction is increased and fattening ability is improved, and based on these findings, they have completed the present invention.

[0007] That is, one aspect of the present invention is fish feed containing cocoa husk. In this aspect, the content of cocoa husk is preferably 0.2 to 5% by weight of the entire feed.

[0008] Another aspect of the present invention is a feed additive for stimulating feeding intake and / or promoting fattening ability of fish, containing cocoa husk as an active ingredient. The feed additive of this aspect can be preferably contained in fish feed with improved palatability and / or fattening ability. In such a case, the content of the feed additive, in terms of the amount of cocoa husk, is preferably 0.2 to 5% by weight of the total feed.

[0009] Another aspect of the present invention is a method for improving feeding stimulation and / or fattening performance of fish, comprising feeding said fish with feed containing cocoa husk.

[0010] In this specification, weight refers to dry weight unless otherwise specified. Furthermore, "%" refers to "% by weight" unless otherwise specified. Furthermore, the numerical ranges in this specification include the numerical values ​​before and after "to".

[0011] According to the present invention, it is possible to provide a feed or an additive therefor that stimulates feeding in fish to increase palatability, or improves fish fattening performance and feed efficiency. Since the effects of improving feeding attraction, palatability, and fattening performance are exerted regardless of the aquaculture temperature range, it is also useful in that fish can be fattened without strictly controlling the temperature conditions during aquaculture. Furthermore, according to the present invention, cocoa husk, which is a waste product of food production, can be effectively reused as a feed ingredient, which is useful both economically and environmentally. Furthermore, since the waste is regularly discharged, the feed and additives therefor of the present invention are also useful in that a stable supply can be expected. Furthermore, since these plant-based ingredients have a smaller environmental impact during biodegradation than live feed, and since they are highly palatable to fish as described above, they are less likely to produce feed residues, which reduces the risk of self-contamination in fishing grounds. The feed or additives therefor of the present invention can satisfactorily replace conventional live feed or compound feed from the viewpoints of fish farming efficiency, marine environmental protection including fishing grounds, protection of marine resources, and stable supply.

[0012] Graph showing the effect of oral administration of cacao husk on the daily feed intake of coho salmon. A feeding test was conducted for 7 days with feeding times of 5 minutes per day. The graph shows the mean ± standard deviation (n=5), with the same symbols indicating significant differences (t-test). Graph showing the effect of feed supplemented with cacao husk on the 5-minute satiation feed intake of coho salmon reared at an optimum temperature (16°C). The graph shows the mean ± standard deviation (n=5), with * indicating a significant difference from the control group (p<0.05). Graph showing the effect of feed supplemented with cacao husk on the 5-minute satiation feed intake of coho salmon reared at a high temperature (20°C). The graph shows the mean ± standard deviation (n=5), with * indicating a significant difference from the control group (p<0.05). Graph showing the effect of feed supplemented with cacao husk on the 5-minute satiation feed intake of coho salmon reared at a low temperature (7.5°C). Graphs show mean values ​​± standard deviation (n=5), with * indicating a significant difference from the control group (p<0.05). Graph showing changes in feeding time of coho salmon when they were fed 2% of their body weight per day, five times a week, for approximately one month. Graph showing the effect of administering a diet supplemented with cocoa husk on the feed intake of juvenile coho salmon when reared under normal or low-oxygen conditions. * indicates a significant difference from the control group (p<0.05), and + indicates a significant difference from the control group under low-oxygen (low Do) conditions (p<0.05). Graph showing the effect (feeding attractant effect) of administering a diet supplemented with cocoa husk on the daily feed intake of coho salmon under normal oxygen conditions and an optimum temperature (16°C). * indicates a significant difference from the control group (p<0.05). A diagram showing the effect (feeding attractant effect) of administering a diet containing cocoa husk on the daily feed intake of coho salmon under hypoxic conditions and a moderate temperature (16℃). * indicates a significant difference from the control group (p<0.05). A diagram showing the effect (feeding attractant effect) of administering a diet containing cocoa husk on the daily feed intake of coho salmon under normal oxygen conditions and a low temperature (7.5℃). * indicates a significant difference from the control group (p<0.05). A diagram showing the effect (feeding attractant effect) of administering a diet containing cocoa husk on the daily feed intake of coho salmon under normal oxygen conditions and a high temperature (20℃). * indicates a significant difference from the control group (p<0.05).A diagram showing the feed efficiency of Coho salmon when fed a feed containing cocoa husk under normoxic conditions and an optimum temperature (16°C). A diagram showing the feed efficiency of Coho salmon when fed a feed containing cocoa husk under hypoxic conditions and an optimum temperature (16°C). A diagram showing the feed efficiency of Coho salmon when fed a feed containing cocoa husk under normoxic conditions and a low temperature (7.5°C). A diagram showing the feed efficiency of Coho salmon when fed a feed containing cocoa husk under normoxic conditions and a high temperature (20°C). A diagram showing the feed efficiency of Coho salmon when fed a feed containing cocoa husk in the case of restricted feeding or satiation feeding under normoxic conditions and an optimum temperature (16°C). A diagram showing the feed efficiency of Coho salmon when fed a feed containing cocoa husk in the case of restricted feeding or satiation feeding under hypoxic conditions and an optimum temperature (16°C). Graph showing the feed efficiency of Coho salmon when fed a diet containing cocoa husk in the case of restricted feeding or satiation feeding, under normal oxygen conditions and low temperature (7.5°C). Graph showing the feed efficiency of Coho salmon when fed a diet containing cocoa husk in the case of restricted feeding or satiation feeding, under normal oxygen conditions and high temperature (20°C). Graph showing the effect of oral administration of cocoa husk on the body length and weight of goldfish. The daily feeding rate was restricted to 2% of body weight, and the rearing period was 4 weeks, with the water temperature at 20°C. The graph shows the mean ± standard deviation (n=5). Graph showing the effect of feed containing cocoa husk on the amount of satiation feed given to juvenile flounder in a 5-minute period. The graph shows the mean ± standard deviation (n=5), with an asterisk (*) indicating a significant difference from the control group (p<0.05). A: Feed with 5% cocoa husk added, B: Feed with 2% cocoa husk added. A diagram showing the effect of oral administration of cacao husk on food intake of red sea bream juveniles.

[0013] The present invention will now be described in detail. However, the present invention is not limited to the following embodiments and can be freely modified within the scope of the present invention.

[0014] The fish feed or feed additive of the present invention essentially contains cocoa husk.

[0015] Cocoa husk refers to the outer shell and germ of the seed of the cacao (Theobroma cacao L.), a tree of the Sterculiaceae family that is the main ingredient in chocolate and cocoa. Large quantities of this material are generated during the manufacturing process of chocolate and other products, but most of it is disposed of unused as food waste. Typically, after harvesting, the cacao fruit (cocoa pod) is fermented and dried together with the cocoa pulp to become cocoa beans. Generally, the cocoa beans are roasted and crushed, and the crushed cocoa beans are aired to separate them into cocoa nibs (endosperm) and cocoa husk (germ and seed coat) based on their weight. This is just one example of a method for obtaining cocoa husk, and is not particularly limited.

[0016] The cacao husk separated from the cacao nibs can be added to the fish feed or feed additive of the present invention as is or after being further pulverized or crushed. There is no particular limitation on the size of the cacao husk to be added to the feed or its additive, but it is preferable that the cacao husk be added to the fish feed or feed additive of the present invention as pulverized material with a particle size of about 0.01 to 1 mm.

[0017] The content of cocoa husk in the fish feed of the present invention may be adjusted appropriately depending on the fish species and is not particularly limited, but is preferably 0.2 to 5% by weight, more preferably 0.5 to 5% by weight, of the total feed. Furthermore, when the feed additive of the present invention is added to fish feed, the amount of cocoa husk is not particularly limited, but is preferably 0.2 to 5% by weight, more preferably 0.5 to 5% by weight, of the total feed. By adding cocoa husk to the feed within such a range, it becomes easier to stimulate the fish to feed and also to improve the fattening ability of the fish.

[0018] In the present invention, "for fish" refers to use in the farming (raising) of fish, and may be rephrased as "for fish farming." It may also be categorized as "fish feed." The type of fish in the present invention is not particularly limited, and may be a saltwater fish, a freshwater fish, or a freshwater / brackish water fish. Examples of fish species include those of the Sparidae family, genus Pagrus, such as red sea bream; those of the Pleuroceridae family, genus Pleurocerus, such as flounder; those of the Carangidae family, genus Seriola, such as amberjack and yellowtail; those of the Tetraodontiformes family, genus Pufferfish, such as pufferfish; those of the Scombridae family, genus Thunnus, such as tuna; those of the Scombridae family, genus Scombridae, such as chub mackerel and yellowtail mackerel; those of the Anguillididae family, genus Anguillididae, such as eels; those of the Scallopidae family, genus Scallops, such as sea bass; those of the Cyprinidae family, subfamily Cyprinidae, genus Carassius, such as goldfish and crucian carp; those of the Smelinidae family, subfamily Ayuidae, genus Ayu, such as sweetfish; those of the Salmonidae family, subfamily Salmoninae, genus Salmonidae, such as coho salmon, Atlantic salmon, rainbow trout, chinook salmon, cherry salmon, and king salmon; those of the Cichlidae family, genus Oreochromis, such as tilapia; and those of the Siluridae family, genus Silurus, such as catfish. Among these, those of the Sparidae family, genus Pagrus; those of the Pleuroceridae family, genus Paralichthys; those of the Cyprinidae family, subfamily Cyprinidae, genus Carassius; and those of the Salmonidae family, subfamily Salmonidae, genus Salmon are preferred. Of these, red sea bream, flounder, coho salmon, goldfish, and mackerel are more preferred. These fish are the targets for ingesting (orally administering) the feed of the present invention.

[0019] The fish feed of the present invention can provide a feeding stimulus to fish. This can also be said to produce a feeding inducer. The fish feed of the present invention can also be said to have improved palatability for fish. The feed additive of the present invention can also impart such effects to the feed to which it is added. That is, the feed additive of the present invention can be used to stimulate feeding and / or promote fattening in fish. Generally, fish feeding habits and feed intake tend to decrease under low or high temperatures outside the optimum temperature range, or under conditions with insufficient oxygen supply. The feed of the present invention can increase fish feeding habits even under such conditions that may be unfavorable for rearing (farming). Therefore, fish can be fattened without strictly controlling the temperature conditions during aquaculture. Here, terms such as "high feeding appetite," "feeding stimulus provided," and "feeding inducement" refer to an increase in the amount of feed consumed per unit time by fish compared to a control, i.e., a good "bite." The present invention can increase the feeding activity of fish, and therefore the daily feed amount can be increased, which is expected to have an effect of promoting fish growth.

[0020] Furthermore, according to the present invention, cocoa husk, which is waste material after food production, can be effectively reused as a raw material for feed, which is beneficial both economically and environmentally. Furthermore, since the waste material is normally discharged, the feed and its additives of the present invention are also useful in that a stable supply can be expected. Furthermore, since these plant-based raw materials have a smaller environmental impact when biodegraded than live feed, and as mentioned above, they are highly palatable to fish, they are less likely to leave behind feed residues, which makes them less likely to cause self-pollution in fishing grounds. Furthermore, from the perspective of protecting marine resources, they can be an alternative to conventional compound feeds that use fish-derived raw materials.

[0021] The fish feed of the present invention can enhance (promote) the fattening ability of fish. This can also be expressed as having high (superior) feed efficiency. The feed additive of the present invention can also impart such an effect to the feed to which it is added. Here, "high, promoted, or improved fattening ability" refers to an increase in the weight or body length of fish or the rate of increase in these compared to a control. Alternatively, it may refer to a large weight or body length of fish for a given amount of feed fed.

[0022] Another aspect of the present invention is the use of cocoa husk in the production of fish feed. Such fish feed may have improved palatability and / or fattening properties. Another aspect of the present invention is the use of cocoa husk in the production of a feed additive for stimulating feeding and / or promoting fattening properties of fish. Another aspect of the present invention is the use of cocoa husk in stimulating feeding and / or promoting fattening properties of fish. Another aspect of the present invention is cocoa husk used for stimulating feeding and / or promoting fattening properties of fish. Another aspect of the present invention is a method for improving feeding stimulation and / or fattening properties of fish, comprising feeding fish with feed containing cocoa husk. Note that "feeding fish to feed" may be synonymous with "administering to fish". Intake may be voluntary (ad libitum intake) or forced (forced intake). Furthermore, intake is usually oral intake (oral administration).

[0023] The timing and duration of intake (administration) of the feed of the present invention are not particularly limited and can be appropriately selected depending on various conditions, such as the type and growth stage of the target fish. The feed of the present invention may be fed continuously throughout the entire aquaculture (rearing) period, or only for a portion of the period. "A portion of the period" may refer, for example, to 10% or more, 20% or more, 30% or more, 50% or more, 70% or more, or 90% or more of the entire aquaculture (rearing) period. The period for feeding the feed of the present invention may be, for example, 1 to 4 months, or approximately 2 months. Furthermore, the feed of the present invention may be repeatedly continued and interrupted over any period. The feed of the present invention can be applied, for example, even during periods when the fish are placed in an aquaculture environment that is generally unfavorable for fish (e.g., low or high water temperature conditions, low oxygen concentration conditions, etc.).

[0024] The form of the feed of the present invention is not particularly limited as long as it is in a form that can be ingested by the target fish. That is, the feed of the present invention may be in any form, such as powder, granules, pellets, cubes, paste, gel, liquid, etc., and when solid, it may be in a dry or wet state. The same applies to the form of the feed additive of the present invention. When preparing the feed of the present invention or when preparing feed by adding a feed additive, it is preferable to carry out a treatment that can prevent the denaturation and reduction of the taste and aroma stimulants contained in the cocoa husk, so that the feeding attraction effect of the cocoa husk is maintained. Specifically, it is preferable to avoid heat and pressure treatment, or to carry out such treatment as quickly and gently as possible, and the form of moist pellets (wet state) or dry pellets (dry state) that are suitable for such treatment are preferred. It is also preferable to avoid using the feed in combination with ingredients that can mask the taste and aroma stimulants contained in the cocoa husk.

[0025] The feed or feed additive of the present invention may optionally contain ingredients similar to those contained in ordinary fish feed. Specific examples include fish meal, wheat flour, wheat gluten, alpha starch, vegetable oil cake, vitamin mixtures, binders (such as carboxymethylcellulose and alginic acid), bone meal, yeast, eicosapentaenoic acid, and docosahexaenoic acid. Among these, eicosapentaenoic acid and docosahexaenoic acid are preferred as ingredients in feed for fry or young fish.

[0026] The feed of the present invention may also contain any aquatic additives, for example. Specific examples include aquatic medicines such as erythromycin preparations, ampicillin preparations, praziquantel preparations, lysozyme chloride preparations, oxytetracycline hydrochloride preparations, spiramycin preparations, sodium nifurstyrenate preparations, lincomycin hydrochloride preparations, flumequine preparations, and glutathione preparations, vitamins such as vitamin C, vitamin B1, vitamin A, vitamin D, and vitamin E, nutritional supplements such as amino acids such as lysine, methionine, and histidine, and pigments such as β-carotene, astaxanthin, and canthaxanthin.

[0027] The feed of the present invention may be fed once a day or divided into several times a day. The feed of the present invention may also be fed once every few days. The amount of the feed of the present invention fed at each feeding may or may not be constant in terms of the amount of cocoa husk.

[0028] Fish farming (raising) can be carried out by a conventional method for farming (raising) fish, except for feeding the feed of the present invention. Farming (raising) can be carried out, for example, in offshore fish cages or land-based tanks. Farming also includes propagation farming, which only produces seedlings (fry), and farming, which produces parent fish.

[0029] The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

[0030] [Reference Example] Preparation of Feed Additives The cocoa husk added to feed in the following examples was prepared by removing the husk (germ and seed coat) from roasted cocoa beans (produced in Ghana), pulverizing them in a commercially available mill, and using the husk that passed through a 0.5 mm mesh sieve.

[0031] Example 1: Study of feeding stimulant and fattening properties for Coho salmon Juvenile Coho salmon (weighing approximately 70 g) were used as test fish. The fish were fed 2% of their body weight per day, five days a week, and reared at 14°C for four or six weeks. The control group was fed a trout feed (Masu Seseragi, Feed One Co., Ltd.) that had been crushed and remolded, while the test groups were fed the same feed with a specified amount of each test material added and remolded. Cocoa husk was added at 1% or 5% of the feed. At the end of the rearing period, the fish were removed and their body length and weight were measured. The feeding attraction effect was also examined.

[0032] The effect of administering cocoa husk alone on the daily feed intake of coho salmon (feeding attraction effect) is shown in Figure 1. The groups administered feed containing 1% or 5% cocoa husk consumed significantly more feed than the control group, demonstrating the feeding attraction effect.

[0033] Example 2: Examination of feeding stimulation and fattening ability of Coho Salmon under different temperature conditions. The optimum temperature range for culturing salmonids, including Coho Salmon, is usually 8 to 18°C. However, if the rearing environment is favorable other than temperature, such as high dissolved oxygen concentration in the water, they can survive at around 25°C and exhibit feeding behavior even at 20°C. Furthermore, Coho Salmon in freshwater aquaculture exhibit high feed efficiency at around 16°C. Therefore, the effects of temperature conditions were examined using freshwater Coho Salmon (weighing approximately 80g) that had been reared and acclimatized for two weeks under low water temperature conditions (7.5°C), optimal temperature conditions (16°C), or high temperature conditions (20°C). Other than the water temperature conditions, the experiment was conducted in the same manner as in Example 1.

[0034] Figures 2 and 3 show the feed intake (5-minute satiation feed amount) of Coho salmon at rearing water temperatures of 16°C (optimal temperature conditions) and 20°C (high temperature conditions). At a rearing water temperature of 16°C, the feed supplemented with 2% and 5% cocoa husk showed the best feeding rate, significantly higher than the control group, and feed intake was stable. At a rearing water temperature of 20°C, the feed supplemented with 2% and 5% cocoa husk showed good feeding rate and high feed intake.

[0035] Figure 4 shows the amount of food intake by Coho salmon at a rearing water temperature of 7.5°C (low temperature conditions). The groups fed with 2% and 5% cocoa husk had good feeding and high food intake.

[0036] Figure 5 shows the change in daily feeding time after approximately one month of feeding 2% of body weight per day, five times a week. When fed a diet containing added cocoa husk, feeding time tended to increase immediately after the start of the experiment, but within a few days, this time became shorter than that of the control group. In particular, feeding time for the 2% cocoa husk-added diet was the shortest of all the test groups, and a high feeding rate was observed throughout the experiment. However, in the group fed a 5% cocoa husk-added diet, an increase in feeding time was observed from around day 20 onwards. Three levels of cocoa husk were added (2%, 5%, 12.5%). While there was little difference between the 2% and 5% levels, feed intake significantly decreased at 12.5%. Furthermore, feed supplemented with 0.2% cocoa extract or cocoa mass resulted in significantly poorer feed intake throughout the experiment. This shows that cacao husk is an effective ingredient in feed.

[0037] Table 1 shows the growth (total initial body weight at the start of rearing, total body weight at the end of rearing), daily weight gain, and feed efficiency of Coho salmon over a 4-week rearing period (24 feeding days) in which the fish were fed 2% of their body weight per day, 5 times a week. The values ​​in the table are mean values ​​± standard deviation (n=5). No statistically significant differences were observed in the initial and final body weights between the rearing groups, but the group fed 2% cocoa husk was found to have a higher feed efficiency. On the other hand, a decrease in feed efficiency was observed in the group fed 5% cocoa husk.

[0038]

[0039] [Example 3] Examination of feeding stimulation and fattening ability of coho salmon under different oxygen conditions Coho salmon juveniles (weighing around 50g and 150g) were used as test fish. The dissolved oxygen concentration in the water was set to 7.0-8.5ppm (normal conditions) or 5.0-6.0ppm (low oxygen conditions), and the rearing temperature was set to 16°C. The amount of cocoa husk added was 0.5, 1, 2, 4, or 5% of the total sample. The rest of the test was carried out in the same manner as in Example 1. Four weeks after the start of rearing, the fish were taken out and their body length and weight were measured.

[0040] Figure 6 shows the effect (feeding attraction effect) of oral administration of cocoa husk on the daily feed intake of coho salmon under normal and hypoxic conditions (expressed as relative values ​​with the value for the normal control group set at 100) (average values ​​for four experiments with groups of 5 individuals each weighing around 50g). The group with 2% cocoa husk added had significantly higher feed intake than the control group, demonstrating the presence of a feeding attraction effect. On the other hand, under hypoxic conditions, the feed intake of the control group decreased. However, the values ​​for the 2% and 5% cocoa husk added groups all recovered, and the value for the 2% low DO cocoa husk group was significantly higher than the low DO control group (the low DO 5% cocoa husk group showed an increase, albeit not significant, and recovered to a level that was not different from the control group raised under normal conditions). These results suggest that even when rearing under hypoxic conditions, i.e., when rearing conditions are somewhat deteriorated, adding 2% or 5% of cocoa husk to the feed will increase feed intake and there is a high possibility of recovery of growth and health.

[0041] [Example 4] Examination of feeding stimulation and fattening ability of Coho salmon under different temperature and oxygen conditions. Coho salmon (weighing approximately 80 g) reared in freshwater and acclimatized for two weeks were used as test fish. Temperature conditions were low (7.5°C), moderate (16°C), or high (20°C). The dissolved oxygen concentration in the water was 7.0-8.5 ppm (normal conditions) or 5.0-6.0 ppm (hypoxic conditions). Cocoa husk was added at 0.1, 0.2, 0.5, 1.0, 1.0, or 5.0% of the total sample. The fish were reared for four weeks under feeding conditions of 2% of their body weight (restricted feeding) or 10 minutes (satiation feeding), six days per week. Other rearing conditions were the same as in Example 1.

[0042] 7 to 10 show the effect of oral administration of cacao husk on the daily feed intake (feeding attraction effect) of coho salmon under normoxic or hypoxic conditions, or under high, optimum or low temperature conditions. Figures 11 to 14 show the effect of oral administration of cacao husk on the feed efficiency of coho salmon under normoxic or hypoxic conditions, or under high, optimum or low temperature conditions. Figures 15 to 18 show the effect of oral administration of cacao husk on the feed efficiency of coho salmon in cases of restricted feeding or satiation feeding, under normoxic or hypoxic conditions, or under high, optimum or low temperature conditions. These results suggest that even when rearing under hypoxic or low or high temperature conditions, i.e., when rearing conditions are somewhat deteriorated, there is a high possibility that feed intake will increase and feed efficiency will improve by adding cacao husk to the feed. Furthermore, under normal oxygen and optimum temperature conditions, no such effect was observed when cocoa husk was added to the feed at 0.1%, but it was also observed that when cocoa husk was added to the feed at 0.2% or more, the feed intake increased and the feed efficiency improved.

[0043] Example 5: Study of feeding stimulation and fattening ability in goldfish Goldfish (weighing approximately 10 g: stomachless fish) were used as test fish, and the rearing temperature was 20°C. A commercially available base feed for goldfish (Angel, Nippon Pet Food) was used. The rest of the rearing test was carried out in the same manner as in Example 1. At the end of the rearing period, the fish were taken out and their body length and weight were measured.

[0044] The fish took to the bait containing added cocoa husk well, and compared to the control group, they ate it all in a shorter time than the control group. Therefore, it was determined that these test materials had a feeding attraction effect, similar to that of coho salmon.

[0045] The effect of administering cacao husk on the body length and weight of goldfish is shown in Figure 19. Under restricted feeding conditions (when the daily feeding amount was 2% of body weight), no significant changes were observed in the body length or weight of the fish in a 4-week rearing test using feed containing 1% cacao husk.

[0046] [Example 6] Study on feeding stimuli and fattening ability for flounder Flounder (weighing around 10g) were used as test fish, the rearing temperature was 16°C (the optimum water temperature for flounder), and the dissolved oxygen concentration in the water was 7.0-8.5ppm. The amount of cocoa husk added was 0.5, 1, 2, 4, or 5% of the total sample. The base feed used was a general feed used for flounder farming (Hirame EP, Nisshin Marubeni Feed Co., Ltd.). Other than that, the rearing test was carried out in the same manner as in Example 1.

[0047] Figure 20 shows the feed intake of flounder fry in rearing water at 16°C (optimal water temperature). Feeding a diet containing 5% cocoa husk did not have a feeding attractant effect on the flounder fry (Figure 20A). In an evaluation when 2% cocoa husk was added, the feed intake significantly increased in the group fed the same diet, demonstrating the feeding attractant effect of cocoa husk (Figure 20B).

[0048] Table 2 shows the effect of adding cocoa husk to feed on the growth of flounder fry (four weeks of rearing) in a restricted feeding test (feeding 2% of body weight per day). Even in the case of flounder fry, it is thought that an addition rate of cocoa husk to feed of around 2% is appropriate.

[0049]

[0050] Example 7: Study of feeding stimuli and fattening potential in red sea bream. Red sea bream fry (weighing approximately 3.5 g) were used as test fish. The rearing temperature was 18°C ​​(the optimum water temperature for red sea bream), and the dissolved oxygen concentration in the water was 7.0-8.5 ppm. Cocoa husk was added at 0.5, 1, 2, 4, or 5% of the total sample. A feeding test was conducted using a reconstituted feed (unheated, unpressurized dry feed) added to a base feed commonly used for sea bream aquaculture (Red Sea Bream EP Measure, Nisshin Marubeni Feed Co., Ltd.). After one week of preliminary rearing, feed intake (considered as satiation feed intake) was measured for 15 minutes per day over a 10-day period. At the end of the rearing period, the fish were removed and their body length and weight were measured.

[0051] Figure 21 shows the change in feed intake (amount of food consumed per day by a fish weighing 1g) when a feeding test was conducted on red sea bream fry weighing around 3.5g using the reconstituted feed (unheated, unpressurized dry feed). The feed intake of the group with 1% added cacao husk increased significantly compared to the control group. The daily feed intake (g) of the control group and the group with 1% added cacao husk was 0.034±0.010 and 0.051±0.011 respectively, and a feeding attraction effect was observed in the control group and the group with 1% added cacao husk.

[0052] Example 8: Study of feeding stimulant and fattening effects on mackerel. Juvenile mackerel (weighing approximately 950 g, 15 fish in a 1-ton tank) were used as test fish. The fish were fed satiation once daily and reared at 16.0-17.3°C for one week. The control group was fed a completely fishmeal-free extruded-pellet (EP) diet (see Aquacult. Sci. 63 (1), 29-38 (2015)). The test group was fed the same diet with 1% concentrated soy protein replaced with cocoa husk. At the end of the rearing period, the fish were removed and weighed. The feeding attraction effect was also examined. Table 3 shows the weight gain, total feed intake, and feed intake rate (total feed intake relative to body weight) of juvenile mackerel fed a diet supplemented with cocoa husk during the test period. The group fed a diet containing 1% cocoa husk had a greater weight gain and total feed intake than the control group, and the feed intake rate of the group fed a diet containing 1% cocoa husk was significantly higher than that of the control group. These results demonstrate that cocoa husk has fattening and feeding attraction effects on mackerel as well.

[0053]

Claims

1. Fish feed containing cocoa husk.

2. The feed according to claim 1, wherein the feed contains 0.2 to 5% by weight of cocoa husk.

3. A feed additive for stimulating feeding and / or promoting fattening of fish, containing cocoa husk as an active ingredient.

4. Fish feed containing the feed additive according to claim 3, which has improved palatability and / or fattening ability.

5. The feed according to claim 4, wherein the feed additive is contained in an amount of 0.2 to 5% by weight of the total feed in terms of the amount of cocoa husk.

6. A method for stimulating feeding and / or improving fattening ability of fish, comprising feeding said fish with feed containing cocoa husk.

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