Fish feed and method for producing fish

Abstract

An object of the present invention is to provide a fish feed capable of efficiently producing fish.SOLUTION: The problem can be solved by a fish feed containing the oil and fat-producing yeast of the present invention, or a method for producing fish comprising a step of feeding the fish feed to fish.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fish feed and a method for producing fish. According to the present invention, fish can be produced efficiently. [Background technology]

[0002] Fish feed is supplemented with yeast extract and feed oil to ensure good growth rates. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Morimoto Y. et al., Journal of Cell Science (2022) 135 (16), jcs259996 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a need for the development of fish feed that can efficiently produce fish. An object of the present invention is to provide fish feed that allows for efficient production of fish. [Means for solving the problem]

[0005] The present inventors have conducted extensive research into fish feed that allows for efficient production of fish, and have surprisingly found that fish can be produced efficiently by adding oil-producing yeast, such as a Lipomyces yeast (Non-Patent Document 1), to fish feed. The present invention is based on this finding. Therefore, the present invention provides [1] Fish feed containing oil-producing yeast; [2] The fish feed according to [1], wherein the oil-producing yeast contains 30% by weight or more of oils and fats. [3] The oil-producing yeast is Lipomyces starchii (accession number NITE BP-03940, accession number NITE BP-03941, accession number NITE BP-03942, or accession number NITE BP-03943). Lipomyces starkeyi ) or Ls100 strain, [4] The fish feed according to [1] or [2], which is for eels. [5] A method for producing fish, comprising a step of feeding the fish feed according to [1] or [2] to fish; and [6] The method for producing fish according to [5], wherein the fish is an eel. Regarding. [Effects of the Invention]

[0006] According to the fish feed and the method for producing fish of the present invention, a superior weight gain rate can be obtained in raising fish compared to conventional fish feed. [Brief explanation of the drawings]

[0007]

Figure 1

Figure 2

[0008] [1] Fish feed The fish feed of the present invention contains an oil-producing yeast. Conventional fish feed can be used except that it contains an oil-producing yeast. That is, the fish feed of the present invention can be obtained by adding the oil-producing yeast to each fish feed that is normally fed to fish, as described below.

[0009] As described above, the fish feed may be a fish feed commonly used in this field. The content of the oil-producing yeast added to the fish feed is not particularly limited as long as the effects of the present invention are obtained. The upper limit is, for example, 50% by weight or less, in one embodiment, 40% by weight or less, in one embodiment, 30% by weight or less, in one embodiment, 20% by weight or less, in one embodiment, 10% by weight or less, in one embodiment, 8% by weight or less, and in one embodiment, 5% by weight or less. The lower limit is also not limited as long as the effects of the present invention are obtained. For example, the upper and lower limits can be appropriately combined. It is presumed that the effects of the fish feed of the present invention are obtained by the oils and fats contained in the Lipomyces yeast. Therefore, if the Lipomyces yeast has a high oil and fat content, the effects of the present invention can be obtained even if the content of the Lipomyces yeast in the fish feed is low. On the other hand, in the case of Lipomyces yeast, which has a relatively low content of fats and oils, the effects of the present invention can be achieved by increasing the content of Lipomyces yeast in fish feed.

[0010] The fish feed of the present invention allows fish to feed oils and fats using oil-producing yeast. Therefore, the amount of feed oil contained in conventional fish feed can be reduced. The amount of feed oil contained in the fish feed is not limited, but is 10% by weight or less, in some embodiments 5% by weight or less, in some embodiments 3% by weight or less, in some embodiments 2% by weight or less, in some embodiments 1% by weight or less, in some embodiments 0.5% by weight or less, and in some embodiments 0.1% by weight or less. Preferably, feed oil is not actively added (is not included). By reducing the amount of feed oil, the water quality of the aquaculture farm can be maintained clean. Conventionally, feed oils have been supplied in the form of Alaska pollack oil, sardine oil, saury oil, squid oil, menhaden oil, anchovy oil, salmon oil, cod oil, capelin oil, herring oil, blue whiting oil, sand lance oil, or Norway pauw oil, but the fish feed of the present invention can reduce the amount of these fish oils added.

[0011] The feed oil is a source of ω-3 fatty acids (DHA, EPA, etc.). In the fish feed of the present invention, vitamins and the like are supplied by the Lipomyces yeast in addition to the fats and oils described below. Supplying vitamins and the like can promote the growth of fish.

[0012] Other ingredients The fish feed of the present invention may contain other ingredients, such as anchovy meal, defatted soybean meal, corn gluten meal, feather meal, wheat flour, pregelatinized starch, rapeseed oil, vitamins, choline chloride, minerals, monocalcium phosphate, defatted rice bran, sushi rice bran, and cellulose, as long as the effects of the present invention are achieved.

[0013] 《Oil-producing yeast》 The fat-and-oil-producing yeast can be used without any particular limitation as long as it contains fats and oils, and examples thereof include yeasts of the genus Lipomyces, Oidium, Endomyces, Candida, Rhodotorula, Cryptococcus, and Rhodosporidium. For example, yeasts of the genus Lipomyces include Lipomyces starkeyi, Lipomyces arxii, Lipomyces doorenjongii, Lipomyces japonicus, Lipomyces kockii, Lipomyces kononenkoae, Lipomyces lipofer, Lipomyces mesembrius, Lipomyces oligophaga, Lipomyces orientalis, Lipomyces smithiae, Lipomyces spencer-martinsiae, Lipomyces suomiensis, Lipomyces tetrasporus, Lipomyces yamadae, and Lipomyces yarrowii. Examples of Lipomyces starkeyi include the Ls100 strain (NBRC1289), the Ls66 strain (accession number NITE BP-03940), the Ls76 strain (accession number NITE BP-03941), the Ls63 strain (accession number NITE BP-03942), and the Ls93 strain (accession number NITE BP-03943). Lipomyces starkeyi ) are mentioned.

[0014] 《Oils and fats》 The fats and oils contained in the oil-producing yeast include, but are not limited to, triacylglycerol (neutral fat). The constituent fatty acids include oleic acid, palmitic acid, linoleic acid, linolenic acid, palmitoleic acid, and stearic acid. In particular, oleic acid and palmitic acid are contained in large amounts. The content of fats and oils contained in the fat-producing yeast is not particularly limited in the effects of the present invention, but is 20% by weight or more, preferably 30% by weight or more, preferably 40% by weight or more, preferably 50% by weight or more, preferably 60% by weight or more, preferably 70% by weight or more, and preferably 80% by weight or more. Furthermore, the content of oils and fats derived from oil-producing yeast contained in the fish feed of the present invention is not limited, but the upper limit is, for example, 30% by weight or less, in one embodiment 20% by weight or less, in one embodiment 15% by weight or less, in one embodiment 10% by weight or less, in one embodiment 8% by weight or less, in one embodiment 6% by weight or less, in one embodiment 4% by weight or less, and in one embodiment 2% by weight or less. The lower limit is not particularly limited as long as the effects of the present invention are obtained, but is 0.1% by weight or more, in one embodiment 0.2% by weight or more, in one embodiment 0.4% by weight or more, in one embodiment 0.6% by weight or more, in one embodiment 0.8% by weight or more, in one embodiment 1% by weight or more, in one embodiment 1.2% by weight or more, and in one embodiment 1.4% by weight or more. The upper and lower limits can be appropriately combined. By keeping the content within the above ranges, excellent weight gain rates and waist circumference gain rates can be obtained.

[0015] <<How grease accumulates>> Accumulation of fats and oils in the fat-producing yeast used in the present invention can be carried out according to a conventional method for accumulating fats and oils. For example, a preliminary culture may be performed in advance, and the resulting culture may be inoculated into an appropriate medium for inducing lipid accumulation to carry out the main culture. The culture temperature may be, for example, 20 to 35°C, and the culture may be performed with shaking for about 1 to 7 days.

[0016] Furthermore, by culturing the oil-producing yeast under specific culture conditions, oils and fats can be produced more efficiently. For example, fat or oil production can be achieved by culturing the bacteria in a YPD medium as a pre-culture and then inoculating the bacteria into an N medium. Additionally, in a preferred embodiment of the present invention, the amount of fat or oil produced can be further increased by culturing the bacteria in a YPD medium until the bacteria reach the stationary phase. For example, cells are pre-cultured at 26°C using YPD medium (2% D-glucose, 1% yeast extract, 2% hypopolypeptone) and harvested in the logarithmic growth phase. After washing three times with sterile water, the cells are transferred to N medium (0.3% sucrose, 0.025% KH2PO4, 0.066% MgSO4·7H2O, trace element solution (FeCl3·6H2O 1.7 mg / L, MnSO4·6H2O 0.51 mg / L, ZnSO4·7H2O 4.5 mg / L)) at a cell density of approximately 3 x 10 6 By inoculating the yeast so that the number of cells / mL is reached and initiating culture at 26°C, fats and oils can be accumulated within the cells of the fat-producing yeast.

[0017] In the present invention, the accumulation of fats and oils in the oil-producing yeast can be confirmed and quantified by conventionally known methods. Examples include a method in which the fats and oils are stained with a stain such as Oil Red, and then a photograph of the yeast is taken under a microscope to visually confirm the amount of fat and oil, and a method in which the cell wall is dissolved or physically destroyed to prepare a cell extract, and the fat and oil components present in the extract are separated and quantified (for example, a commercially available measurement kit (e.g., Triglyceride E-Test Wako (Wako))).

[0018] For example, in the case of the Ls76, Ls63, or Ls93 strains of Lipomyces yeast, it is efficient to accumulate fats and oils by the following fat accumulation method. Hereinafter, the Ls76 strain will be referred to as a first fat-accumulating yeast mutant strain, and the Ls63 and Ls93 strains will be referred to as second fat-accumulating yeast mutant strains. The first lipid-accumulating yeast mutant strain can be synchronously arrested in the G1 phase by pre-culturing at 23 to 26°C, followed by raising the temperature to 32 to 35°C and carrying out main culturing. The second lipid-accumulating yeast mutant strain can be subjected to synchronous arrest in the G2 / M phase by pre-culturing at 20 to 23°C, followed by raising the temperature to 30 to 35°C and carrying out main culturing. These mutant strains accumulate more lipids than the conventionally known Lipomyces strains and can be used as efficient lipid-producing bacteria. The mycological properties of the Ls76, Ls63, and Ls93 strains are budding yeasts, which grow well at 23°C but stop growing at temperatures above 30°C.

[0019] The fat and oil accumulation method can be carried out in accordance with a conventionally known fat and oil accumulation method, except that the first or second fat and oil-producing yeast mutant strain is used and the mutant strain is cultured under conditions that allow synchronous arrest at the desired cell cycle (particularly the G1 phase or the G2 / M phase). For example, in the method for accumulating fats and oils, a preliminary culture is carried out in advance, and the culture is then inoculated into an appropriate fat accumulation-inducing medium to carry out the main culture. The culture temperature can be 20 to 35°C, and the culture is performed with shaking for about 1 to 7 days.

[0020] In the method for accumulating fats and oils using the first fat-accumulating yeast mutant, preliminary culture is carried out at 23 to 26°C, followed by main culture at 32 to 35°C, thereby enabling synchronous arrest at the G1 phase. In the method for accumulating fats and oils using the second fat-accumulating yeast mutant, synchronization arrest at the G2 / M phase can be achieved by carrying out preliminary culture at 20 to 23° C. and then main culture at 30 to 32° C. These preliminary cultures can be carried out using, for example, a YPD medium.

[0021] 《Fish》 The fish that are fed the fish feed of the present invention may be freshwater fish or saltwater fish. Although there is no particular limitation, farmed fish are preferred. Specifically, salmonids (Atlantic salmon (Salmo salar), Chinook salmon (Oncorhynchus tshawytscha), Coho salmon (Oncorhynchus kisutsh), Brown trout (Salmo trutta), Salmon trout (Oncorhynchus mykiss), Rainbow trout (Oncorhynchus mykiss), Iwana char (Salvelinus leucomaenis), etc.), Perciformes (Red sea bream (Pagrus major), Tuna (Thunnus orientalis), Japanese sea bass (Lateolabrax japonicus), Flounder (Paralichthys olivaceus), Yellowtail (Seriola quinqueradiata), Amberjack (Seriola dumerili), Yellowtail kingfish (Seriola lalandi), Suma (Euthynnus affinis), Chub mackerel (Scomber japonicus, grouper (Epinephelinae), grouper (Epinephelus bruneus), grouper (Epinephelus lanceolatus), etc.), Tetraodontiformes (tiger puffer (Takifugu rubripes), filefish (Stephanolepis cirrhifer), etc.), Sculpiniformes (rockfish (Sebastes inermis), scorpionfish (Sebastiscus marmoratus), etc.), Smeliniformes (sweetfish (Plecoglossus altivelis), etc.), Anguilliformes (Japanese eel (Anguilla japonica), etc.), Cypriniformes (carp (Cyprinus carpio), etc.), Siluriformes (white catfish (Silurus asotus), goldfish, pangasius (Pangasius bocourti), etc.). Although not limited to, goldfish or Anguilliformes are preferred.

[0022] [2] Fish production method The method for producing fish of the present invention includes a step of feeding the fish feed of the present invention to fish. In the method for producing fish of the present invention, the fish feed described in the above section "(1) Fish feed" can be used without limitation. In addition, "oil-producing yeast," "fish," and "oils and fats" are as described in the above section "(1) Fish feed."

[0023] In the fish production method of the present invention, the amount of feed to be fed to fish is not particularly limited as long as the effects of the present invention are obtained, but the upper limit is, for example, 20 g / 100 g body weight / day or less, in one embodiment 10 g / 100 g body weight / day or less, in one embodiment 5 g / 100 g body weight / day or less, and in one embodiment 3 g / 100 g body weight / day. The lower limit is, for example, 0.5 g / 100 g body weight / day or more, in one embodiment 1 g / 100 g body weight / day or more, and in one embodiment 2 g / 100 g body weight / day or more. The upper and lower limits can be combined as appropriate. By keeping the amount within the above range, a superior weight gain rate can be obtained compared to conventional fish feed.

[0024] Feeding method The feeding method can be a method commonly used in the art, for example, feeding 2 to 3 g of feed per 100 g in 2 to 3 divided feedings.

[0025] The method for producing fish of the present invention exhibits an excellent survival rate, as shown in the examples below. One reason for this is thought to be, but is not limited to, the improvement in the quality of the water used for fish farming. Furthermore, the number of bacteria in the water was reduced compared to when conventional fish feed was used, which is thought to be due to the improvement in water quality.

[0026] 《Action》 The reason why feeding the fish feed of the present invention results in a superior growth rate has not been investigated in detail, but can be assumed as follows: However, the present invention is not limited to this assumption. Typically, fish feed contains feed oil, and fish oil such as Alaska pollock oil is used as the feed oil. As described above, the oil contained in the fish oil contains ω-3 fatty acids (DHA, EPA, etc.). On the other hand, in the fish feed of the present invention, the oil accumulated in the oil-producing yeast is, as described above, rich in triacylglycerol (neutral fat). It is presumed that the content ratio of this triacylglycerol (neutral fat) is more effective for the growth rate of fish than fish oil with a high ratio of ω-3 fatty acids. [Example]

[0027] The present invention will be specifically described below with reference to examples, but these examples are not intended to limit the scope of the present invention.

[0028] Example 1 and Comparative Example 1 In this example, the weight gain and waist circumference gain rates of eels fed fish feed supplemented with lipid-containing Lipomyces yeast were examined. In a comparative example, the weight gain and waist circumference gain rates of eels fed fish feed supplemented with a wild-type strain that does not accumulate lipids were examined. Five Japanese eels weighing approximately 100g were kept in aquaria at a temperature of 28°C. The rearing water was maintained at a pH of 7.0 and a nitrite concentration of 0.5mg / mL. The amount of food given was 1.5% of the eel's body weight in the aquaria, and was given three times a week. Lipomyces yeast was mixed into the feed so that it accounted for 4% of the normal feed by weight. The lipid content of the Lipomyces yeast was approximately 40% by weight. The control group was a diet supplemented with yeast that did not accumulate lipids. The basic diet supplemented with Lipomyces yeast contained approximately 4% crude fat. Body length and girth were measured every two weeks. As shown in Figure 1, the fish feed containing the oil-containing Lipomyces yeast showed excellent gains in body weight and girth.

[0029] Example 2 and Comparative Example 2 In this example, the survival rate of eels fed fish feed supplemented with lipomyces yeast containing fats and oils was investigated. In a comparative example, the survival rate of eels fed only fish feed was investigated. Five Japanese eels weighing approximately 70g were kept in aquaria at a temperature of 28°C. The rearing water was maintained at a pH of 7.0 and a nitrite concentration of 0.5mg / mL. The amount of feed was 1.5% of the eel's body weight in the tank, and they were given three times a week. Lipomyces yeast was fed at 4% by weight of the normal diet. The fat and oil content of the Lipomyces yeast was approximately 40% by weight. A control group was fed a diet without added yeast. The basic diet containing Lipomyces yeast contained approximately 4% crude fat. The number of survivors was checked every two weeks. The eels fed the diet containing Lipomyces yeast showed solidified powder and less water contamination. [Industrial Applicability]

[0030] The fish feed of the present invention can be used as feed for cultivating freshwater fish and saltwater fish. [Accession number]

[0031] Lipomyces starkeyi ( Lipomyces starkeyi The Ls66 strain was deposited internationally on July 11, 2023, at the National Institute of Technology and Evaluation (NPMD) Patent Microorganisms Depositary (Room 122, 2-5-8 Kazusa Kamatari, Kisarazu City, Chiba Prefecture, 292-0818) under the accession number NITE BP-03940. Lipomyces starkeyi ( Lipomyces starkeyi The Ls76 strain was deposited internationally on July 11, 2023, at the National Institute of Technology and Evaluation (NPMD) Patent Microorganism Depositary (Room 122, 2-5-8 Kazusa Kamatari, Kisarazu City, Chiba Prefecture, 292-0818) under the accession number NITE BP-03941. Lipomyces starkeyi ( Lipomyces starkeyi The Ls63 strain was deposited internationally on July 11, 2023, at the National Institute of Technology and Evaluation (NPMD) Patent Microorganism Depositary (Room 122, 2-5-8 Kazusa Kamatari, Kisarazu City, Chiba Prefecture, 292-0818) under the accession number NITE BP-03942. Lipomyces starkeyi ( Lipomyces starkeyiThe Ls93 strain was deposited internationally on July 11, 2023, at the National Institute of Technology and Evaluation (NPMD) Patent Microorganism Depositary (Room 122, 2-5-8 Kazusa Kamatari, Kisarazu City, Chiba Prefecture, 292-0818) under the accession number NITE BP-03943.

Claims

1. A fish feed containing an oil-producing yeast.

2. The fish feed according to claim 1, wherein the oil-producing yeast contains 30% by weight or more of oils.

3. The fat / oil-producing yeast is Lipomyces starkeyi or Ls100 strain having accession number NITE BP-03940, accession number NITE BP-03941, accession number NITE BP-03942, or accession number NITE BP-03943. The fish feed according to claim 1 or 2.

4. The fish feed according to claim 1 or 2, which is for eels.

5. A method for producing fish, comprising a step of feeding the fish feed according to claim 1 or 2 to fish.

6. The method for producing fish according to claim 5, wherein the fish is an eel.

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