A feed for promoting metamorphosis of tadpoles, a preparation method and application thereof

Abstract

The application discloses a feed for promoting metamorphosis of tadpoles, a preparation method and application thereof, and comprises the following raw materials in percentage by weight: fish meal 8-13%, chicken meal 15-25%, soybean meal 8-15%, soybean protein concentrate 16-25%, rice bran meal 3-8%, flour 20-30%, soybean oil 1.5-2.5%, and enzymatic fish small peptide 2.5-6.5%. Due to the addition of the enzymatic fish small peptide, the feed has obvious effects of promoting metamorphosis of tadpoles under the same feeding conditions and time, can obviously accelerate the metamorphosis speed of the tadpoles, and effectively improves the metamorphosis rate and survival rate of the tadpoles.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aquaculture, and particularly relates to a feed for promoting metamorphosis of tadpoles, a preparation method and application thereof. BACKGROUND

[0002] The metamorphosis of tadpoles is affected by multiple factors, among which the protein source and the nutritional level in the feed have a greater impact on the metamorphosis of tadpoles, and animal protein sources are generally superior to plant protein sources. When tadpoles are fed with fish meal, the tadpoles can accumulate more energy, have a larger body size at metamorphosis, and can improve their survival potential and reproductive capacity, so fish meal is an important protein source in the feed of tadpoles. However, due to cost reasons, plant protein raw materials such as cottonseed meal and rapeseed meal are commonly used to replace fish meal in aquaculture today, and both of them are widely available, but these plant proteins are rich in a large number of anti-nutritional factors, which can damage the digestive tract of animals and reduce the immunity of animals. The existing feed has the problems of low metamorphosis rate and slow metamorphosis speed in tadpole cultivation.

[0003] Enzymatic fish small peptides are a protein raw material obtained by enzymolysis, separation, concentration and drying of processing waste of sea-capturing low-quality fish or cod, salmon and mackerel. It has not been applied to tadpole breeding at present. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the deficiencies and defects mentioned in the above background, and to provide a feed for promoting the metamorphosis of tadpoles, a preparation method and application thereof, so as to improve the metamorphosis rate and speed of tadpoles.

[0005] To solve the above technical problems, the technical solution provided by the present application is as follows:

[0006] A feed for promoting the metamorphosis of tadpoles comprises the following raw materials in percentage by weight: fish meal 8-13%, chicken meal 15-25%, soybean meal 8-15%, soy protein concentrate 16-25%, rice bran meal 3-8%, flour 20-30%, soybean oil 1.5-2.5%, and enzymatic fish small peptides 2.5-6.5%.

[0007] As a further improvement, the raw materials further comprise: microcrystalline cellulose 0.45-2.5%, mineral and vitamin premix 1-3%, calcium dihydrogen phosphate 1-2%, and choline chloride 0.1-1%.

[0008] As a further improvement, the raw materials further comprise: antioxidants and mildewproof agents 0.01-0.1%, and all the raw materials are 100%.

[0009] As a further improvement, the mass fractions of the fish meal and the enzymatic fish small peptides are 8-10% and 2.5-5%, respectively.

[0010] As a further improvement, the following raw materials are included by weight percentage: fish meal 8-10%, chicken meal 18-22%, soybean meal 8-13%, soy protein concentrate 16-20%, rice bran meal 5-7%, wheat flour 20-28%, soybean oil 1.5-2%, microcrystalline cellulose 0.45-2.5%, mineral and vitamin premix 1.5-2.5%, calcium dihydrogen phosphate 1-2%, choline chloride 0.1-1%, antioxidant and mildewproof agent 0.01-0.1%, enzymatic fish small peptide 2.5-5%, and all the raw materials total 100%.

[0011] The application also provides a preparation method of the feed for promoting metamorphosis of tadpoles, comprising premixing raw materials, and then crushing, mixing, granulating, drying and crushing to prepare powder feed.

[0012] The application also provides application of enzymatic fish small peptide in preparation of the feed for promoting metamorphosis of tadpoles, and the amount of the enzymatic fish small peptide added accounts for 2.5-6.5% of the weight of the feed.

[0013] As a further improvement, the amount of the enzymatic fish small peptide added accounts for 2.5-5% of the weight of the feed.

[0014] Compared with the prior art, the application has the following beneficial effects:

[0015] The enzymatic fish small peptide is obtained by enzymatic hydrolysis process, and protein raw materials are degraded into small peptides and free amino acids which are more easily digested and absorbed by tadpoles by using protease. The content and utilization rate of the protein and free amino acids are much higher than those of imported fish meal, the utilization efficiency of low-quality protein is greatly improved, and the enzymatic fish small peptide has the potential to replace fish meal and promote metamorphosis of tadpoles.

[0016] Due to the addition of the enzymatic fish small peptide, the feed of the application has the effect of promoting metamorphosis of tadpoles under the same feeding conditions and time, can significantly accelerate the metamorphosis speed of tadpoles, and effectively improve the metamorphosis rate and survival rate of tadpoles. In addition, the addition of the enzymatic fish small peptide can improve the antioxidant capacity and digestive capacity of bullfrog tadpoles.

[0017] Since the enzymatic fish small peptide is prepared in the feed in advance, the purpose of promoting metamorphosis can be achieved by feeding the feed every day, and complex operations are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0019] Figure 1is survival rate and metamorphosis rate data of tadpoles;

[0020] Figure 2 is digestion capacity detection data of tadpoles;

[0021] Figure 3 is antioxidant capacity detection data of tadpoles. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present application, the following will be a more comprehensive and detailed description of the present application in conjunction with the drawings of the specification and the preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0023] Unless otherwise defined, all the professional terms used in the following have the same meaning as that generally understood by the skilled in the art. The professional terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the protection scope of the present application.

[0024] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0025] The feed for promoting metamorphosis development of tadpoles in some specific embodiments of the present application has raw materials in accordance with the mass percentage of 8-13% of fish meal, 15-25% of chicken meal, 8-15% of soybean meal, 16-25% of soybean protein concentrate, 3-8% of rice bran meal, 20-30% of flour, 1.5-2.5% of soybean oil, 0.45-2.5% of microcrystalline cellulose, 1-3% of mineral and vitamin premix, 1-2% of calcium dihydrogen phosphate, 0.1-1% of choline chloride, 0.01-0.1% of antioxidant and mildew-proof agent, 2.5-6.5% of enzymatic fish small peptide, and all the raw materials accounting for 100%.

[0026] In some preferred embodiments, the raw materials have components in accordance with the mass percentage of 8-10% of fish meal, 18-22% of chicken meal, 8-13% of soybean meal, 16-20% of soybean protein concentrate, 5-7% of rice bran meal, 20-28% of flour, 1.5-2% of soybean oil, 0.45-2.5% of microcrystalline cellulose, 1.5-2.5% of mineral and vitamin premix, 1-2% of calcium dihydrogen phosphate, 0.1-1% of choline chloride, 0.01-0.1% of antioxidant and mildew-proof agent, 2.5-5% of enzymatic fish small peptide, and all the raw materials accounting for 100%.

[0027] The enzymatic fish small peptide is a protein raw material obtained by enzymatic hydrolysis of processing waste of low-quality fish (cod, salmon, and mackerel) using protease and spray drying. The enzymatic hydrolysis process makes the product more easily digested. In some specific embodiments, the preparation method of the enzymatic fish small peptide is as follows: the fish processing solution is transferred into an enzymatic hydrolysis reactor, and is subjected to enzymatic hydrolysis using a complex protease at 50-55°C for 2h, and then is transferred into a termination reactor for enzyme inactivation and sterilization at 105°C for 1h to obtain an enzymatic hydrolysis solution. The enzymatic hydrolysis solution is subjected to spray drying at 120-140°C to obtain the product used in the following tests.

[0028] The fish meal, chicken meal, soybean meal, and soybean protein concentrate provide the main protein.

[0029] The mineral and vitamin premix mainly includes KCl, KI (1%), CoCl2·6H2O (1%), CuSO4·5H2O, FeSO4·H2O, ZnSO4·H2O, MnSO4·H2O, Na2SeO3·5H2O (1%), MgSO4·H2O, VB1, riboflavin, VB6, VB 12 , VK3, inositol, pantothenic acid, nicotinic acid, folic acid, biotin, VA, VD, VE, and VC, which provide essential minerals and vitamins.

[0030] The preparation method of the feed for promoting metamorphosis of tadpoles can adopt a conventional feed preparation process, for example, the raw materials are premixed, and then are subjected to crushing, uniform mixing, granulation, drying, and crushing to prepare a powder feed.

[0031] Example: Effect of adding enzymatic fish small peptides in feed on metamorphosis, growth, digestive capacity, and antioxidant capacity of bullfrog tadpoles

[0032] 1. Test site: a tadpole breeding factory in Changtang Town, Qingxiu District, Nanning City, Guangxi Zhuang Autonomous Region.

[0033] 2. Test feed and grouping: 0 g / kg, 25 g / kg, and 50 g / kg of enzymatic fish small peptides (Rongcheng Hongde Marine Biological Technology Co., Ltd.) are added to the basic feed of bullfrog tadpoles to prepare three kinds of feed, which are marked as F15E0, F10E2.5, and F10E5. The specific composition of the feed is shown in Table 1. The test is used to compare the difference in the effect of adding or not adding enzymatic fish small peptides and the content of enzymatic fish small peptides on the metamorphosis of tadpoles.

[0034] The preparation method of the feed is as follows: the raw materials are premixed according to the feed formula, and then are subjected to crushing, uniform mixing, granulation, drying, and crushing to prepare a powder feed that can pass through an 80-mesh screen.

[0035] Table 1. Composition and nutrient level of test feed (dry basis, %)

[0036]

[0037]

[0038] 3. Breeding and feeding method: The tadpoles of bullfrog were acclimated in canvas pool for one week, and then the tadpoles with initial weight of about 0.04 g were used for the test. 2880 tadpoles were randomly and evenly divided into 9 net cages, divided into 3 groups, and fed with 3 different feeds prepared in advance respectively. The feeding time was 8 weeks, and the feeding amount was 5% to 7% of the body weight of the tadpoles. During the feeding period, the average air temperature was 32.9℃, the average water temperature was 29.5℃, the water dissolved oxygen was ≥4.0 mg / L, and the pH was 7.0 to 7.6. After the feeding test, the tadpoles were weighed, counted and sampled after anesthesia for 24 hours. The metamorphosis and related indexes of tadpoles fed with different contents of enzymatic fish small peptides were compared.

[0039] 4. Test results:

[0040] (1) As shown in Table 1, compared with the F15E0 group, the addition of enzymatic fish small peptides increased the survival rate and metamorphosis rate of tadpoles. After 8 weeks of feeding, the metamorphosis rate of the F15E0 group was about 43.75%, the metamorphosis rate of the F10E2.5 group increased by about 4.69%, and the metamorphosis rate of the F10E5 group increased by 9.53% (53.28%). Figure 1 Note: Metamorphosis rate (MR, %) = metamorphosed frogs / total number of initial tadpoles × 100%; Survival rate (SR, %) = number of surviving frogs / total number of initial tadpoles × 100%.

[0041] (2) Preparation of intestinal tissue homogenate: about 1 g of tissue sample was weighed and homogenized according to the homogenate matrix of the corresponding kit. After homogenization, the supernatant was obtained by centrifugation (3 000 r / min, 10 min, 4℃). The trypsin, lipase (LPS) and amylase (AMS) were determined by the kit of Nanjing Jiancheng Biological Engineering Institute.

[0042] As shown in Table 2, the addition of enzymatic fish small peptides can improve the digestive capacity of tadpoles. Compared with the F15E0 group, the lipase of the F10E2.5 and F10E5 groups increased by 6.19 and 11.28 U / gprot (up to 62.42 U / gprot) respectively; the amylase of the F10E2.5 and F10E5 groups increased by 0.04 and 0.06 U / mgprot (up to 0.20 U / mgprot) respectively.

[0043] Figure 2

[0044] ​​Note: AMS amylase (U / mg prot); LPS lipase (U / g prot); trypsin trypsin (U / mg prot).

[0045] (3) Preparation of intestinal tissue homogenate: weigh about 1 g of tissue sample, homogenize according to the homogenate matrix of the corresponding kit, and centrifuge (3 000 r / min, 10 min, 4℃) after homogenization. Take the supernatant. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), the content of malondialdehyde (MDA), and the total antioxidant capacity (T-AOC) were determined using the kit from Nanjing Jiancheng Biological Engineering Institute.

[0046] As shown in Figure 3 , the addition of enzymatic fish small peptides can improve the antioxidant capacity. Compared with the F15E0 group, the CAT of the F10E2.5 and F10E5 groups increased by 0.41 and 2.16 U / mg prot (up to 7.06 U / mg prot), respectively; the SOD of the F10E2.5 and F10E5 groups increased by 31.18 and 65.00 U / mg prot (up to 185.67 U / mg prot), respectively; and the GSH-Px of the F10E2.5 and F10E5 groups increased by 91.19 and 150.45 U / mg prot (up to 373.66 U / mg prot), respectively.

[0047] Note: SOD superoxide dismutase (U / mg prot); GSH-Px glutathione peroxidase (U / mg prot); MDA malondialdehyde (U / mg); GSH reduced glutathione (μmol / g prot); CAT catalase (U / mg prot).

[0048] In summary, the addition of enzymatic fish small peptides in feed can enhance the survival rate and metamorphosis rate of tadpoles, improve the digestive capacity of tadpoles, and significantly increase the activities of lipase and amylase and promote the antioxidant stress capacity when the addition amount is 50 g / kg.

[0049] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Therefore, any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the present application, which does not deviate from the technical scheme of the present application, shall fall within the protection scope of the technical scheme of the present application.

Claims

1. Use of a feed to promote metamorphosis of tadpoles, characterized in that, The feed for promoting metamorphosis of tadpoles comprises the following raw materials in percentage by weight: fish meal 8-10%, chicken meal 18-22%, soybean meal 8-13%, soybean protein concentrate 16-20%, rice bran meal 5-7%, flour 20-28%, soybean oil 1.5-2%, microcrystalline cellulose 0.45-2.5%, mineral and vitamin premix 1.5-2.5%, calcium dihydrogen phosphate 1-2%, choline chloride 0.1-1%, antioxidants and antifungal agents 0.01-0.1%, and enzymatic fish small peptide 2.5-5%, and all the raw materials amount to 100%.

2. Use of the feed for promoting metamorphosis of tadpoles according to claim 1, characterized in that, The preparation method of the feed for promoting metamorphosis of tadpoles comprises pre-mixing the raw materials, and then crushing, uniformly mixing, granulating, drying and crushing to obtain powder feed.

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