Bullfrog feed composition added with vitamin A and application of bullfrog feed composition

Abstract

The invention provides a bullfrog feed composition added with vitamin A and application of the bullfrog feed composition. The bullfrog feed composition comprises the following components: 40-60% of a protein source, 30-40% of a carbon water source, 6-12% of a fat source and the balance of an additive, in the additives, a mineral supplement accounts for 1-7% of the total weight of the bullfrog feed composition, and a vitamin supplement accounts for 0.1-5% of the total weight of the bullfrog feed composition; the vitamin A level of the bullfrog feed composition is 2,000 IU / kg to 16,000 IU / kg. The bullfrog feed composition is used for bullfrog breeding, can accelerate growth and metamorphosis development of bullfrog tadpoles, shorten the breeding period and improve the uniformity and yield of seedlings on the premise of guaranteeing basic nutrition supply and health maintenance, so that the overall production efficiency and economic benefits are improved, and the bullfrog feed composition has definite practical value and wide popularization prospects.

Description

Technical Field

[0001] This invention belongs to the field of animal nutrition and feed science, specifically relating to a bullfrog feed composition and its application, and more particularly to a bullfrog feed composition with finely regulated vitamin A levels and its method for promoting the growth and metamorphosis of bullfrog tadpoles. Background Technology

[0002] As an important economically farmed frog species, the length of the bullfrog's farming cycle directly affects its economic benefits. Within the bullfrog farming cycle, the growth rate of the tadpole stage and the synchronicity and uniformity of metamorphosis are crucial in determining overall farming efficiency. Slow tadpole metamorphosis and a prolonged cycle not only increase farming costs and risks but also lead to uneven adult frog sizes, impacting market returns.

[0003] Currently, the industry typically employs a comprehensive strategy to promote frog growth and development, including optimizing feed protein levels and adding compound vitamins and functional additives. For example, patent document CN118716463A discloses a composition for promoting healthy growth in bullfrogs, containing compound traditional Chinese medicine, compound vitamins, and compound trace elements, which provides antibacterial and anti-inflammatory effects, enhances immunity, and promotes digestion, thereby reducing the morbidity rate of adult bullfrogs and promoting weight gain. Patent document CN119498453A provides a feed for spiny-breasted frog tadpoles during metamorphosis, utilizing compound vitamins to improve the tolerance of tadpoles to high-protein feed, thereby reducing tadpole mortality, enhancing protein absorption and utilization, and promoting metamorphosis.

[0004] Vitamin A, an essential fat-soluble vitamin, is a key signaling molecule for hormone activity and a crucial substrate for retinol metabolism. It can influence tadpole metamorphosis by regulating thyroid hormone synthesis. However, vitamin A supplementation in frogs exhibits high species specificity and dose sensitivity. Tazawa et al. (Develop. Growth Differ. 2017, 59, 688-700) treated tailless Japanese red frog tadpoles with high concentrations of vitamin A (1-20 IU / mL) far exceeding physiological levels, resulting in ectopic formation of hind limbs from tail tissue, indicating that excessively high doses of vitamin A can completely disrupt normal development. Arkin et al. (Zoo Biology, 2024, 43, 169-177) tested the effects of adding vitamin A (0.033-0.066 µg / mL retinyl acetate) to fish fillet feed on the growth and development of poison dart frog tadpoles, finding a high tadpole mortality rate and smaller body size in successfully metamorphosed individuals.

[0005] In aquaculture practice, although vitamin A is commonly added as a premix ingredient, precise experimental data to support the optimal dosage range for promoting growth and driving metamorphosis have been lacking. Insufficient vitamin A supplementation in feed may lead to stunted growth and metamorphosis, while excessive supplementation may result in waste, potential toxicity, or even deformities. Conventional frog feeds lack vitamin A supplementation strategies specifically designed for bullfrogs.

[0006] To solve the above problems, it is necessary to develop a new type of bullfrog feed composition containing vitamin A. Summary of the Invention

[0007] This application aims to provide a bullfrog feed composition with finely regulated vitamin A levels, which can promote the healthy and rapid growth of bullfrog tadpoles and significantly accelerate their metamorphosis.

[0008] To achieve the above objectives, this application provides the following technical solution:

[0009] A bullfrog feed composition, the formula of which is as follows: Protein source: 40-60%, carbohydrate source: 30-40%, fat source: 6-12%, and the balance of additives; among the additives, mineral supplements account for 1-7% of the total weight of the bullfrog feed composition, and vitamin supplements account for 0.1-5% of the total weight of the bullfrog feed composition; the vitamin A level of the bullfrog feed composition is 2000-16000 IU / kg.

[0010] This application also provides the following technical solutions: A bullfrog feed, using the aforementioned bullfrog feed composition as dry matter.

[0011] This application also provides the following technical solutions: The aforementioned application of bullfrog feed in bullfrog farming.

[0012] The technical solution provided in this application has the following beneficial effects: (1) Based on the unique nutritional needs and physiological characteristics of bullfrog tadpoles, this application systematically proportions and synergistically designs proteins, fats, carbohydrates, minerals and vitamins to provide a high-performance feed composition that has extremely high safety and nutritional utilization efficiency for bullfrog tadpoles (survival rate greater than 99% and feed conversion ratio close to 1), which can fully meet the metabolic needs of bullfrog tadpoles and promote their rapid and healthy growth.

[0013] (2) This application utilizes the mechanism of action of vitamin A on the growth and metamorphosis of bullfrog tadpoles to design a safe, economical, and efficient optimal addition level. Conventional feeds often add vitamin A as part of a compound vitamin raw material, resulting in a fixed ratio of vitamin A to other vitamins, thus making it impossible to specifically regulate the vitamin A level in the feed. In contrast, the feed composition provided in this application controls the vitamin A level at 2000-16000 IU / kg, which can efficiently accelerate the growth of bullfrog tadpoles (73-day weight gain rate of about 25%). In particular, at a vitamin A level of 2360-4160 IU / kg, the feed composition provided in this application can also effectively promote the synthesis and release of thyroid hormones (T4 and T3) in bullfrog tadpoles and the conversion of T4 to T3, thereby efficiently promoting the metamorphosis process of bullfrog tadpoles from the endocrine level and achieving a dual optimization effect of synergistically promoting growth and development.

[0014] (3) Applying the feed composition provided in this application to bullfrog farming can significantly shorten the breeding cycle and improve the uniformity of hatching and yield by accelerating the growth and metamorphosis of bullfrog tadpoles, while ensuring basic nutrition supply and health maintenance. This is beneficial to improving overall production efficiency and economic benefits, and has clear practical value and broad prospects for promotion. Attached Figure Description

[0015] Figure 1 The effect of dietary vitamin A levels on the weight gain rate of bullfrog tadpoles.

[0016] Figure 2 The effect of dietary vitamin A levels on the survival rate of bullfrog tadpoles.

[0017] Figure 3 The effect of vitamin A levels in feed on feed conversion ratio.

[0018] Figure 4 The effect of dietary vitamin A levels on the metamorphosis rate of bullfrog tadpoles at stage 40.

[0019] Figure 5 The effect of dietary vitamin A levels on the metamorphosis rate of bullfrog tadpoles at stage 41.

[0020] Figure 6 The effect of dietary vitamin A levels on plasma T4 levels in bullfrog tadpoles.

[0021] Figure 7 The effect of dietary vitamin A levels on plasma T3 levels in bullfrog tadpoles.

[0022] Figure 8 The effect of dietary vitamin A levels on the plasma T4 / T3 ratio of bullfrog tadpoles. Invention Details 1. Terminology Explanation All patents and other publications cited herein are incorporated herein in their entirety. In the event of any conflict between any description of terminology herein and any document incorporated herein by reference, this document shall prevail.

[0023] Numerical ranges can be represented by a hyphen "-" or a tilde "~", and their endpoints are included by default. Unless otherwise specified, the numerical types within the range include, but are not limited to, integers, non-integers, percentages, fractions, etc., and the numerical types are not limited by the specific representation of the endpoints.

[0024] The terms “including,” “containing,” and similar expressions have a non-restrictive meaning.

[0025] The term "combination" of an enumeration item means any two or more of the enumeration items used together, unless the context explicitly excludes it or the combination is technically impossible.

[0026] A “composition” refers to a substance consisting of two or more components.

[0027] "Balance" refers to the amount used to bring the composition to 100%.

[0028] In feed, "additives" refer to primary and / or auxiliary functional components other than basic nutrients (such as protein sources, carbohydrate sources, and fat sources). Types of additives in feed compositions include, but are not limited to, mineral supplements, vitamin supplements, amino acid supplements, antimicrobial agents, and antioxidants.

[0029] "Mineral supplements" refer to inorganic salts and / or organic chelates that provide essential mineral elements to target animals. They are designed to supplement macroelements (such as calcium, phosphorus, magnesium, potassium, and sodium) and microelements (such as iron, zinc, copper, manganese, selenium, iodine, and cobalt) to maintain the body's structure, electrolyte balance, and normal function of enzyme systems.

[0030] "Vitamin supplements" refer to compounds or preparations used to provide essential vitamins to target animals. Their main function is to supplement vitamins in feed that the target animal cannot synthesize on its own or whose synthesis is insufficient to meet its physiological needs. In animal nutrition, vitamins can be classified according to their solubility into fat-soluble vitamins (e.g., vitamins A, D, E, and K) and water-soluble vitamins (e.g., B vitamins and vitamin C). For the purposes of this application, vitamins also include their derivatives or precursors, which can be converted into vitamin active substances through metabolism in the target animal.

[0031] "Antioxidants" refer to additives that can delay or prevent oxidation reactions, used to improve the antioxidant stability of feed or enhance the stability of nutrients. These include, but are not limited to, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), ethoxyquin, and natural antioxidants. Antioxidants can also be added as components of other additives (such as vitamin supplements).

[0032] Some raw materials possess two or more additive functions. Their classification depends first on this application, and secondly on the common understanding of their main role in feed compositions by those skilled in the art.

[0033] "Vitamin A" refers to a class of fat-soluble substances and their precursors with all-trans-retinol biological activity, encompassing the following two main forms: (i) preformed vitamin A, referring to compounds that can exert retinol activity directly or after hydrolysis and metabolism, mainly including retinol and its esterified derivatives (such as retinyl acetate, retinyl palmitate, etc.); (ii) provitamin A, referring to compounds that can be metabolized into retinol in animals, thereby indirectly providing vitamin A activity, such as β-carotene. The "vitamin A level" of a feed composition refers to a quantitative indicator used to measure the equivalent biological activity of vitamin A in the composition. Vitamin A levels can be expressed by converting the amount of various forms of vitamin A raw materials added into equivalent International Units (IU) according to a common nutritional conversion system or raw material labeling.

[0034] In this application, the nutritional level of the feed (including protein level, fat level, and vitamin level) is assumed to be the actual content (measured value), unless otherwise specified (e.g., predicted value or theoretical value).

[0035] Fishmeal refers to a high-protein animal feed ingredient prepared from fish or fish processing by-products through processes such as cooking, pressing, drying, and grinding. Fishmeal can be whole fishmeal, by-product fishmeal, or a mixture thereof. Whole fishmeal is made from small, whole-caught fish, such as anchovy meal and sardine meal. By-product fishmeal is made from fish processing residues such as fish heads, bones, and viscera. Fishmeal can be white fishmeal, red fishmeal, or a mixture thereof. White fishmeal comes from white-fleshed fish (such as cod), while red fishmeal comes from red-fleshed fish (such as anchovies, sardines, and bonito). Fishmeal can be processed into whole-fat fishmeal, defatted fishmeal, steam-dried fishmeal, and roasted fishmeal, depending on the processing method.

[0036] 2. Implementation Plan One embodiment of this application is as follows: A bullfrog feed composition, the formula of which is as follows: Protein source: 40-60%, carbohydrate source: 30-40%, fat source: 6-12%, and the balance of additives; among the additives, mineral supplements account for 1-7% of the total weight of the bullfrog feed composition, and vitamin supplements account for 0.1-5% of the total weight of the bullfrog feed composition; the vitamin A level of the bullfrog feed composition is 2000-16000 IU / kg.

[0037] In some specific implementation schemes, the protein source is selected from any one of animal protein raw materials, plant protein raw materials, and combinations thereof.

[0038] In some specific implementation schemes, the protein source components in the bullfrog feed composition are as follows: fish meal, corn gluten meal, and soybean protein concentrate.

[0039] In some specific implementations, the fishmeal is any one of anchovy meal, bonito meal, basa fish meal, sardine meal, tuna meal, and combinations thereof.

[0040] In some specific embodiments, the fishmeal content in the bullfrog feed composition is 10-50%, preferably 30%.

[0041] In some specific embodiments, the content of corn gluten powder in the bullfrog feed composition is 1-20%, preferably 10%.

[0042] In some specific embodiments, the content of soybean protein concentrate in the bullfrog feed composition is 1-20%, preferably 10%.

[0043] In some specific implementations, the carbohydrate source is selected from any one of corn flour, wheat flour, wheat bran, brown rice flour, and combinations thereof, preferably high-gluten flour.

[0044] In some specific implementations, the fat source is selected from any one of vegetable oils, animal fats, lecithin, and combinations thereof.

[0045] In some specific implementations, the fat source components in the bullfrog feed composition are as follows: soybean oil and lecithin.

[0046] In some specific embodiments, the content of soybean oil in the bullfrog feed composition is 1-10%, preferably 4.3%.

[0047] In some specific embodiments, the content of lecithin in the bullfrog feed composition is 1-10%, preferably 4.3%.

[0048] In some specific implementations, the additive is selected from any one of mineral supplements, vitamin supplements, amino acid supplements, antimicrobial agents, antioxidants, and combinations thereof.

[0049] In some specific implementations, the additive consists of mineral supplements and vitamin supplements.

[0050] In some specific implementations, the mineral supplement contains inorganic salts that provide mineral elements, and optionally also contains a carrier.

[0051] In some specific implementations, the inorganic salt is selected from any one of calcium salts, phosphate salts, potassium salts, sodium salts, magnesium salts, iron salts, zinc salts, copper salts, manganese salts, cobalt salts, iodine salts, selenium salts, and combinations thereof.

[0052] In some specific implementations, the carrier in the mineral supplement is zeolite powder.

[0053] In some specific implementation schemes, the mineral supplement components in the bullfrog feed composition are as follows: multi-mineral premix, calcium dihydrogen phosphate, and calcium carbonate; the multi-mineral premix components are as follows: potassium chloride, potassium iodide, cobalt sulfate, copper sulfate, ferrous sulfate monohydrate, zinc sulfate monohydrate, manganese sulfate monohydrate, magnesium sulfate heptahydrate, sodium selenite, and zeolite powder.

[0054] In some specific implementations, the content of the polymineral premix in the bullfrog feed composition is 0.1-1%, preferably 0.5%.

[0055] In some specific embodiments, the content of calcium dihydrogen phosphate in the bullfrog feed composition is 1-5%, preferably 3.3%.

[0056] In some specific embodiments, the content of calcium carbonate in the bullfrog feed composition is 1-5%, preferably 2.3%.

[0057] In some specific embodiments, the multi-mineral premix components in the bullfrog feed composition are as follows: 100-300 parts by weight of potassium chloride, 20-100 parts by weight of potassium iodide, 50-150 parts by weight of cobalt sulfate, 10-40 parts by weight of copper sulfate, 300-500 parts by weight of ferrous sulfate monohydrate, 100-300 parts by weight of zinc sulfate monohydrate, 50-100 parts by weight of manganese sulfate monohydrate, 500-1000 parts by weight of magnesium sulfate heptahydrate, 20-80 parts by weight of sodium selenite, and 2000-4000 parts by weight of zeolite powder.

[0058] In some specific embodiments, the vitamin supplement contains vitamins, and optionally also contains antioxidants and / or carriers; the vitamins are selected from any one of vitamin A, vitamin D, vitamin E, vitamin K, vitamin C, B vitamins, and combinations thereof.

[0059] In some specific implementations, the carrier in the vitamin supplement is flour.

[0060] In some specific implementations, the antioxidant in the vitamin supplement is ethoxyquinoline.

[0061] In some specific implementation schemes, the vitamin supplement components in the bullfrog feed composition are as follows: multivitamin premix, choline chloride, vitamin C, and vitamin A; wherein, the multivitamin premix components are as follows: vitamin B1, riboflavin, pyridoxine hydrochloride, vitamin B12, vitamin K3, inositol, calcium pantothenate, niacin, folic acid, biotin, vitamin D3, vitamin E, ethoxyquinoline, and flour.

[0062] In some specific implementations, the content of the multi-dimensional premix in the bullfrog feed composition is 0.1-1%, preferably 0.2%.

[0063] In some specific embodiments, the content of choline chloride in the bullfrog feed composition is 0.1-1%, preferably 0.5%.

[0064] In some specific embodiments, the content of vitamin C in the bullfrog feed composition is 0.1-1%, preferably 0.1%.

[0065] In some specific embodiments, the content of vitamin A in the bullfrog feed composition is 0.0001-0.01%, preferably 0.0006-0.0049%.

[0066] In some specific embodiments, the protein level of the bullfrog feed composition is 38-50%.

[0067] In some specific embodiments, the fat level of the bullfrog feed composition is 7-12%.

[0068] In some specific embodiments, the multivitamin premix components in the bullfrog feed composition are as follows: 5-15 parts by weight of vitamin B1, 5-15 parts by weight of riboflavin, 5-15 parts by weight of pyridoxine hydrochloride, 0.1-0.5 parts by weight of vitamin B12, 5-15 parts by weight of vitamin K3, 50-150 parts by weight of inositol, 10-30 parts by weight of calcium pantothenate, 30-80 parts by weight of niacin, 1-5 parts by weight of folic acid, 1-5 parts by weight of biotin, 2-8 parts by weight of vitamin D3, 50-150 parts by weight of vitamin E, 100-200 parts by weight of ethoxyquinoline, and 8000-12000 parts by weight of flour.

[0069] In some specific embodiments, the vitamin A is selected from any one of retinol, retinol propionate, retinol acetate, retinol palmitate, and combinations thereof, preferably retinol acetate.

[0070] In some specific embodiments, the bullfrog feed composition comprises the following components: Bonito flakes: 30%, Corn gluten meal: 10%, Soy protein concentrate: 10%, High-gluten flour: 34.5%, Soybean oil: 4.3%, Lecithin: 4.3%, Calcium dihydrogen phosphate: 3.3%, Calcium carbonate: 2.3%, Choline chloride: 0.5%, Multi-mineral premix: 0.5%, Multi-vitamin premix: 0.2%, Vitamin C: 0.1%, Vitamin A: 0.0006-0.0049%.

[0071] In some specific embodiments, the vitamin A level of the bullfrog feed composition is 2360-4160 IU / kg.

[0072] One embodiment of this application is as follows: A bullfrog feed, wherein any of the aforementioned bullfrog feed compositions is used as the dry matter.

[0073] In some specific implementations, the bullfrog feed is obtained by the following preparation method: a) Weigh each ingredient according to the formula of the bullfrog feed composition, and mix all ingredients except for the fat source ingredients; b) Add water to the mixture obtained in step a) for conditioning; c) The conditioned material is then expanded and granulated; d) The expanded granules are then dried; e) Apply the fat source material to the surface of the particles to obtain the bullfrog feed.

[0074] In some specific implementation schemes, the lumpy raw materials are individually crushed and sieved before use to obtain powdered raw materials.

[0075] In some specific implementations, the particle size of the powdered raw material does not exceed 60 mesh, preferably not exceeding 80 mesh.

[0076] In some specific implementation plans, the amount of water used for conditioning is 30-35% of the dry matter in the feed.

[0077] In some specific implementations, the puffing is carried out under conditions of 2-4 MPa, preferably under conditions of 3 MPa.

[0078] In some specific implementations, the puffing is carried out at 130-150°C.

[0079] In some specific implementations, the puffing time is 20-40 seconds, preferably 30 seconds.

[0080] In some specific implementations, the drying process is a baking process.

[0081] In some specific implementations, the drying process is carried out at 100-110°C, preferably at 105°C.

[0082] In some specific implementations, the drying process lasts for 12-36 hours, preferably 24 hours.

[0083] In some specific implementations, the fat source material is mixed and then sprayed onto the surface of the particles.

[0084] One embodiment of this application is as follows: The application of any of the aforementioned bullfrog feeds in bullfrog farming.

[0085] In some specific implementations, the bullfrog feed is used to feed bullfrog tadpoles.

[0086] In some specific implementations, the daily feeding amount of bullfrog feed is 5-8% of the tadpole's body weight, preferably 6.5%. 3. Detailed Implementation The raw materials used in this application can be purchased or synthesized in-house. The following specific embodiments are used to further describe the implementation of the present invention and do not limit the scope of the invention.

[0088] Example 1 In this embodiment, five groups of feeds with vitamin A (VA) levels ranging from 0 to 16,000 IU / kg were formulated using bonito flakes, soy protein concentrate, and corn gluten meal as protein sources, and soybean oil and lecithin as fat sources.

[0089] Bonito flakes, soy protein concentrate, and corn gluten powder are separately fed into a grinder and ground to approximately 80 mesh. The ground materials are then sieved to remove any uncrushed coarse particles, and the qualified powder is collected for later use.

[0090] Weigh each ingredient according to Formula IV (as shown in Table 1) and add them to the mixing container in sequence. First, add high-gluten flour, bonito flakes, soy protein concentrate, and corn gluten powder and premix. Then, add calcium dihydrogen phosphate, calcium carbonate, choline chloride, multi-mineral premix, multi-vitamin premix, vitamin C, and vitamin A (retinyl acetate) and mix thoroughly. Next, add an appropriate amount of water (approximately 30-35% of the dry matter) and continue mixing until the material has a uniform color and no local color differences.

[0091] The conditioned material is poured into an extruder for extrusion (approximately 3 MPa, 130-150℃, 30 seconds) and pelleted. The extruded pellets are promptly loaded into trays and sent to a drying device for drying (105℃, 24 hours). The dried feed is then transferred to a cool, dry place for storage. A predetermined amount of soybean oil and lecithin are mixed and sprayed onto the surface of the feed pellets to obtain the finished feed.

[0092] The raw material composition and nutrient levels of each feed formulation are shown in Table 1. The measured VA levels are as follows: 220 IU / kg (Formula I), 2360 IU / kg (Formula II), 4160 IU / kg (Formula III), 7380 IU / kg (Formula IV), and 15000 IU / kg (Formula V).

[0093] Table 1. Raw material composition and nutrient levels of feed formulation IV (on dry weight)

[0094] Note: Multi-mineral premix 1 The ingredients are as follows: 200 parts by weight of potassium chloride, 60 parts by weight of potassium iodide, 100 parts by weight of cobalt sulfate, 24 parts by weight of copper sulfate, 400 parts by weight of ferrous sulfate monohydrate, 174 parts by weight of zinc sulfate monohydrate, 78 parts by weight of manganese sulfate monohydrate, 800 parts by weight of magnesium sulfate heptahydrate, 50 parts by weight of sodium selenite, and 3114 parts by weight of zeolite powder. Multi-dimensional premix 2 The ingredients are as follows: 10 parts by weight of vitamin B1, 8 parts by weight of riboflavin, 10 parts by weight of pyridoxine hydrochloride, 0.2 parts by weight of vitamin B12, 10 parts by weight of vitamin K3, 100 parts by weight of inositol, 20 parts by weight of calcium pantothenate, 50 parts by weight of niacin, 2 parts by weight of folic acid, 2 parts by weight of biotin, 5 parts by weight of vitamin D3, 100 parts by weight of vitamin E, 150 parts by weight of ethoxyquinoline, and 9520.3 parts by weight of flour.

[0095] Example 2 This embodiment involves a bullfrog tadpole feeding experiment.

[0096] Bullfrog tadpoles with an initial average weight of approximately 0.004 g were randomly divided into 5 groups and fed with five different experimental diets (Formula IV) with different levels of vitamin A. Each group had 3 replicates, with each replicate containing 35 tadpoles.

[0097] The experimental feed was given to the tadpoles for 73 consecutive days, with a daily feed amount of 6.5% of their body weight. The tadpoles were weighed weekly, and the feed amount was adjusted accordingly for the following week. In the early stages of the experiment, if the tadpoles were too small to be fed pelleted feed, the pelleted feed was ground into powder using a grinder before feeding.

[0098] Survival status was recorded during the experiment, and the weight of each tadpole was measured at the end of the experiment. The final average weight (FBW), weight gain (WG), survival rate (SR), specific growth rate (SGR), and feed conversion ratio (FCR) of each replicate group were calculated according to the following formulas, and the results were recorded as “mean ± standard deviation” in Table 2.

[0099]

[0100] Among them, W f The final weight (g) of a single tadpole, N f The number of surviving tadpoles at the end of the experiment;

[0101] Wherein, IBW is the initial average weight (0.004 g);

[0102] Where, N i The number of surviving tadpoles at the start of the experiment (35);

[0103] Where T is the number of days of the experiment (73 days);

[0104] Where FI is the total feeding amount (g) during the experiment, and BW is the total feeding amount (g) during the experiment. g The total weight gain of the tadpole group (g).

[0105] Table 2. Effects of dietary vitamin A levels on the growth performance of bullfrog tadpoles

[0106] Note: In the same row of data, different superscript letters indicate significant differences (P<0.05), while the same letter indicates no significant differences (P>0.05).

[0107] The results showed that the survival rate of bullfrog tadpoles in each group of experiments was greater than 99%. Figure 2 The feed conversion ratio is close to 1. Figure 3 This indicates that the feed composition provided in this application has extremely high safety and utilization rate. Specifically, the specific growth rate (10.79-10.94%) of the experimental groups fed with formulation II-V (VA level 2360-15000 IU / kg) was significantly higher than that of the experimental group fed with formulation I (10.68%). The weight gain rate of bullfrog tadpoles showed a trend of first increasing and then decreasing with increasing VA level in the feed. Figure 1When the feed VA level was 2360 IU / kg (Formula II), the weight gain rate (25.26%) was not significantly different from the higher VA level groups (Formula III, 26.42%; Formula IV, 24.95%), indicating that this dosage could basically meet the normal growth requirements of bullfrog tadpoles. The weight gain rate of tadpoles reached its maximum when the feed VA level was 4160 IU / kg (Formula III). These results demonstrate that the feed composition provided in this application can achieve rapid and healthy growth of bullfrog tadpoles.

[0108] Example 3 This embodiment evaluates the effect of dietary vitamin A levels on metamorphosis in bullfrog tadpoles.

[0109] In Example 2, after the feeding experiment, bullfrog tadpoles were fasted for 24 hours and anesthetized with MS-222 (200 mg / kg, Aladdin, Shanghai, China). Developmental stages of all bullfrog tadpoles in each tank were statistically analyzed. Blood samples were collected from the tails of 15 bullfrog tadpoles (randomly selected from 35 tadpoles) in each tank using a 75 μL anticoagulant capillary micropipette. The samples were transferred to sterile 1.5 mL tubes, centrifuged (3000 rpm, 10 minutes, 4°C), and the plasma was separated and stored at -80°C for the determination of plasma T3 and T4 levels. The levels of triiodothyronine (T3) and thyroid hormone (T4) were determined using a competitive assay with an amphibian-specific enzyme-linked immunosorbent assay (ELISA) kit (Nanjing Jiancheng Bioengineering Institute).

[0110] Table 3. Effects of dietary vitamin A levels on metamorphosis in bullfrog tadpoles

[0111] Note: In the same column of data, different superscript letters indicate significant differences (P<0.05), while the same letter indicates no significant differences (P>0.05).

[0112] The results (Table 3) showed that as the dietary VA level increased, the metamorphosis rates at stages 40 and 41, as well as the plasma T4 and T3 levels of bullfrog tadpoles, all exhibited a trend of first increasing and then decreasing. Figure 4-7Among them, the metamorphosis rates in stages 40 and 41 and the plasma T4 level both reached their maximum values ​​when the dietary VA level was 4160 IU / kg, while the plasma T3 level reached its maximum value when the dietary VA level was 2360 IU / kg. This indicates that the feed composition of this application can more efficiently promote the synthesis and release of thyroid hormones (T4 and T3) in bullfrog tadpoles under conditions of VA level of 2360-4160 IU / kg. T3 is a key active hormone regulating tadpole metamorphosis, mainly derived from T4 by deiodinase in peripheral tissues. At a VA level of 2360 IU / kg, the T4 / T3 ratio was the lowest, while the T3 level was the highest. Figure 7-8 This indicates that under these conditions, the activity of deiodinase may be optimally regulated by retinoic acid (VA metabolite) signaling, significantly improving the conversion efficiency of T4 to T3, thereby efficiently promoting the metamorphosis process of bullfrog tadpoles.

Claims

1. A bullfrog feed composition, characterized in that, Its formula is as follows: Protein source: 40-60%, carbohydrate source: 30-40%, fat source: 6-12%, and the balance of additives; among the additives, mineral supplements account for 1-7% of the total weight of the bullfrog feed composition, and vitamin supplements account for 0.1-5% of the total weight of the bullfrog feed composition; the vitamin A level of the bullfrog feed composition is 2000-16000 IU / kg.

2. The bullfrog feed composition according to claim 1, characterized in that, The protein source is selected from any one of animal protein raw materials, plant protein raw materials, and combinations thereof; Preferably, the protein source components in the bullfrog feed composition are as follows: fish meal, corn gluten meal, and soybean protein concentrate; wherein the fish meal is preferably any one of anchovy meal, bonito meal, basa meal, sardine meal, tuna meal, and combinations thereof; wherein the content of fish meal in the bullfrog feed composition is preferably 10-50%, more preferably 30%; the content of corn gluten meal in the bullfrog feed composition is preferably 1-20%, more preferably 10%; and the content of soybean protein concentrate in the bullfrog feed composition is preferably 1-20%, more preferably 10%.

3. The bullfrog feed composition according to claim 1, characterized in that, The carbohydrate source is selected from any one of corn flour, wheat flour, wheat bran, brown rice flour, and combinations thereof, preferably high-gluten flour.

4. The bullfrog feed composition according to claim 1, characterized in that, The fat source is selected from any one of vegetable oils, animal fats, lecithin, and combinations thereof; Preferably, the fat source components in the bullfrog feed composition are as follows: soybean oil and lecithin; wherein, the content of soybean oil in the bullfrog feed composition is preferably 1-10%, more preferably 4.3%; and the content of lecithin in the bullfrog feed composition is preferably 1-10%, more preferably 4.3%.

5. The bullfrog feed composition according to claim 1, characterized in that, The mineral supplement contains inorganic salts that provide mineral elements, and optionally also contains a carrier; preferably, the inorganic salts are selected from any one of calcium salts, phosphate salts, potassium salts, sodium salts, magnesium salts, iron salts, zinc salts, copper salts, manganese salts, cobalt salts, iodine salts, selenium salts, and combinations thereof; the carrier in the mineral supplement is preferably zeolite powder; Preferably, the mineral supplement components in the bullfrog feed composition are as follows: multi-mineral premix, calcium dihydrogen phosphate, and calcium carbonate; wherein, the content of the multi-mineral premix in the bullfrog feed composition is preferably 0.1-1%, more preferably 0.5%; the content of calcium dihydrogen phosphate in the bullfrog feed composition is preferably 1-5%, more preferably 3.3%; the content of calcium carbonate in the bullfrog feed composition is preferably 1-5%, more preferably 2.3%; wherein, the multi-mineral premix components are as follows: potassium chloride, potassium iodide, cobalt sulfate, copper sulfate, ferrous sulfate monohydrate, zinc sulfate monohydrate, and zinc sulfate monohydrate. Manganese sulfate, magnesium sulfate heptahydrate, sodium selenite, and zeolite powder; preferably, the multi-mineral premix composition of the bullfrog feed composition is as follows: 100-300 parts by weight of potassium chloride, 20-100 parts by weight of potassium iodide, 50-150 parts by weight of cobalt sulfate, 10-40 parts by weight of copper sulfate, 300-500 parts by weight of ferrous sulfate monohydrate, 100-300 parts by weight of zinc sulfate monohydrate, 50-100 parts by weight of manganese sulfate monohydrate, 500-1000 parts by weight of magnesium sulfate heptahydrate, 20-80 parts by weight of sodium selenite, and 2000-4000 parts by weight of zeolite powder.

6. The bullfrog feed composition according to claim 1, characterized in that, The vitamin supplement contains vitamins, and optionally also contains antioxidants and / or a carrier; the vitamins are selected from any one of vitamin A, vitamin D, vitamin E, vitamin K, vitamin C, B vitamins, and combinations thereof; the carrier in the vitamin supplement is preferably flour; the antioxidant is preferably ethoxyquinoline; Preferably, the vitamin supplement components in the bullfrog feed composition are as follows: multivitamin premix, choline chloride, vitamin C, and vitamin A; wherein, the content of the multivitamin premix in the bullfrog feed composition is preferably 0.1-1%, more preferably 0.2%; the content of choline chloride in the bullfrog feed composition is preferably 0.1-1%, more preferably 0.5%; the content of vitamin C in the bullfrog feed composition is preferably 0.1-1%, more preferably 0.1%; and the content of vitamin A in the bullfrog feed composition is preferably 0.0001-0.01%, more preferably 0.0006-0.0049%; wherein, the multivitamin premix components are as follows: vitamin B1, riboflavin, pyridoxine hydrochloride, vitamin B12, and vitamin K.

3. Inositol, calcium pantothenate, niacin, folic acid, biotin, vitamin D3, vitamin E, ethoxyquinoline, and flour; preferably, the multivitamin premix components in the bullfrog feed composition are as follows: 5-15 parts by weight of vitamin B1, 5-15 parts by weight of riboflavin, 5-15 parts by weight of pyridoxine hydrochloride, 0.1-0.5 parts by weight of vitamin B12, 5-15 parts by weight of vitamin K3, 50-150 parts by weight of inositol, 10-30 parts by weight of calcium pantothenate, 30-80 parts by weight of niacin, 1-5 parts by weight of folic acid, 1-5 parts by weight of biotin, 2-8 parts by weight of vitamin D3, 50-150 parts by weight of vitamin E, 100-200 parts by weight of ethoxyquinoline, and 8000-12000 parts by weight of flour; Preferably, the vitamin A is selected from retinol, retinyl propionate, retinyl acetate, retinyl palmitate, and combinations thereof; more preferably, the vitamin A is retinyl acetate.

7. The bullfrog feed composition according to claim 1, characterized in that, The vitamin A level of the bullfrog feed composition is 2360-4160 IU / kg; Optionally, the protein level of the bullfrog feed composition is 38-50%; Optionally, the fat level of the bullfrog feed composition is 7-12%.

8. A bullfrog feed, characterized in that, Using the bullfrog feed composition of claim 1 as the dry matter; the bullfrog feed is preferably obtained by the following preparation method: a) Weigh each raw material according to the formula of the bullfrog feed composition according to claim 1, and mix all raw materials except for the fat source raw material; b) Add water to the mixture obtained in step a) for conditioning; c) The conditioned material is then expanded and granulated; d) The expanded granules are then dried; e) Apply the fat source material to the surface of the particles to obtain the bullfrog feed.

9. The application of the bullfrog feed according to claim 1 in bullfrog farming.

10. The application of the bullfrog feed according to claim 9 in bullfrog farming, characterized in that, The bullfrog feed is used to feed bullfrog tadpoles; Preferably, the daily feeding amount of the bullfrog feed is 5-8% of the tadpole's body weight, more preferably 6.5%.

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