Water temperature-hormone synergistically regulated aquaculture population breeding and hatching method and application

Abstract

The application belongs to the technical field of aquaculture, and particularly relates to a water temperature-hormone synergistically regulated aquaculture population breeding and hatching method and application. The growth regulator is butyric acid or sodium butyrate. The growth regulator is used to enhance the breeding promotion effect of luteinizing hormone-releasing hormone or its analogs. The breeding promotion refers to promoting the growth of oocytes, promoting yolk accumulation, shortening the ovarian development cycle, and improving the egg production rate. It is found and verified for the first time that butyric acid and its sodium salt can enhance the breeding promotion effect of luteinizing hormone-releasing hormone.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, specifically relating to a method and application of aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones. Background Technology

[0002] In aquaculture, water temperature and hormone regulation are core technologies for inducing synchronized reproduction and seedling production in aquatic organisms. The core of water temperature regulation lies in simulating seasonal signals of natural reproduction. The reproductive activities of most aquatic animals are strictly physiologically linked to changes in water temperature. For example, in cyprinid fish, when the water temperature rises to 15℃~20℃ in spring, the hypothalamus secretes luteinizing hormone-releasing hormone, triggering the pituitary gland to secrete luteinizing hormone, ultimately inducing oocyte maturation and sperm release. In artificial breeding, gradient heating or constant temperature control can break the hibernation state of animals, promoting synchronized gonadal development and thus enabling mass seedling production. The advantage of this regulation method is that it closely follows natural physiological laws and reduces drastic interference with the internal environment of the organisms.

[0003] Hormonal regulation directly intervenes in the reproductive axis system through exogenous substances. Commonly used hormones include luteinizing hormone-releasing hormone analogues (LHRHa) and human chorionic gonadotropin (HCG). Their mechanism of action bypasses the limitations of environmental signals such as water temperature, directly stimulating the pituitary gland to secrete gonadotropins and accelerating gonadal maturation. For example, in shrimp breeding, injecting LHRHa can shorten the ovarian development cycle of female shrimp from the natural 30 days to 15 days, and increase the spawning rate to over 80%.

[0004] However, both water temperature regulation and hormone regulation have significant drawbacks when used alone. Water temperature regulation alone is not effective in promoting reproduction, while hormone regulation alone carries the risk of residues. Excessive use of hormones can accumulate in the bodies of broodstock fish and pose a potential threat to human health through the food chain.

[0005] Therefore, how to balance the conditions of water temperature regulation and hormone regulation, and reduce the defects of these two regulatory methods, is a problem that needs to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method and application for aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones.

[0007] The purpose of this invention is to provide an application of a growth regulator in aquatic population reproduction and seedling raising based on water temperature-hormone synergistic regulation. The growth regulator is butyric acid or sodium butyrate. The growth regulator is used to enhance the effect of luteinizing hormone-releasing hormone or its analogues in promoting aquatic reproduction. Promoting aquatic reproduction refers to promoting the growth of aquatic oocytes, promoting yolk accumulation, shortening the ovarian development cycle, and increasing the egg production rate.

[0008] This invention also provides a method for aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones, comprising:

[0009] Select fish that reproduce in spring as parent fish;

[0010] Configure the breeding environment to provide basic nutritional conditions for the reproduction of parent fish;

[0011] Water temperature-hormone synergistic regulation: At the beginning of spring, broodstock are introduced into the aquaculture environment to raise the water temperature in the pond. The daily temperature increase rate is 0.5℃~2.5℃. Starting from the second day of temperature increase, growth regulators are introduced. When the water temperature in the pond is 8℃~30℃, the temperature is kept constant. During the process of maintaining the constant temperature, exogenous hormones are injected. Basic feed is provided during the breeding period until spawning and reproduction are completed.

[0012] Among them, the exogenous hormone is luteinizing hormone-releasing hormone, and the injection dose of exogenous hormone shall not exceed 4 μg / kg based on the fresh weight of the parent fish at the time of injection.

[0013] The growth regulator is butyric acid or sodium butyrate, and the daily dosage is 2 μg / kg to 3 μg / kg, based on the average fresh weight of the broodstock at the time of release. The average fresh weight of the broodstock is calculated by randomly selecting 10 fish, weighing them, and taking the average value.

[0014] Preferably, the parent fish for warm water breeding maintain a constant temperature of 15℃~20℃;

[0015] For parent fish that reproduce in cold water, the temperature range should be maintained between 8°C and 14°C.

[0016] Preferably, the parent fish is a bream.

[0017] Preferably, the injection dose of the luteinizing hormone-releasing hormone is 2 μg / kg.

[0018] Preferably, the exogenous hormone is administered via a single injection.

[0019] Preferably, the growth regulator is applied continuously for 3 to 5 days.

[0020] Preferably, growth regulators are mixed into the basal feed.

[0021] Preferably, the basic feed is composed of the following ingredients in weight percentage:

[0022] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, CMC (sodium carboxymethyl cellulose) 2.00%, cellulose 0.50%.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention is the first to discover and verify that growth regulators can enhance the reproductive-promoting effect of luteinizing hormone-releasing hormone in fish. The growth regulator is butyric acid or sodium butyrate; the reproductive promotion refers to promoting oocyte growth, promoting yolk accumulation, shortening the ovarian development cycle, and increasing the spawning rate, providing a novel application.

[0025] The aquatic group breeding and seedling raising method of the present invention affects the hypothalamic-pituitary-gonadal axis signaling of parent fish by raising the water temperature, stimulating the pituitary gland to synthesize and secrete gonadotropins (GtH), including follicle-stimulating hormone (FSH) and luteinizing hormone (LH). By injecting exogenous hormones, the effects of the aquatic animals' own hormones can be simulated or enhanced, accelerating gonadal development and ovulation. In order to reduce the dosage of exogenous hormones, the present invention introduces a growth regulator before injecting exogenous hormones. The growth regulator is composed of butyric acid or sodium butyrate. Butyric acid and sodium butyrate are used to enhance the function of exogenous hormones, promote GtH secretion, promote oocyte growth and yolk accumulation, accelerate gonadal development and ovulation, and ultimately shorten the ovarian development cycle and increase the spawning rate. Detailed Implementation

[0026] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0027] Unless otherwise specified, all reagents used in this invention are commercially available, and all methods used are conventional techniques in the art.

[0028] The inventive concept of this invention is as follows:

[0029] To reduce the impact of water temperature fluctuations on aquatic animal growth, and to reduce the amount of hormones used, their accumulation and residue in broodstock, thus improving the safety of broodstock, this invention provides the application of a growth regulator in aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones. The growth regulator is butyric acid or sodium butyrate; the promotion of reproduction refers to promoting oocyte growth, promoting yolk accumulation, shortening the ovarian development cycle, and increasing the spawning rate. This invention is the first to discover and verify that butyric acid and its sodium salt (sodium butyrate) can enhance the effect of luteinizing hormone-releasing hormone on promoting fish reproduction.

[0030] Based on the above findings, this invention has conducted further research and provides a method for aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones, comprising the following steps:

[0031] (1) Selection of broodstock

[0032] Healthy individuals with good physical condition, free from disease, well-developed gonads, and excellent genetic traits should be selected as broodstock. Due to significant differences in physiological morphology and growth habits among different species, the method of this invention is applicable to fish that reproduce in spring, such as bream, crucian carp, common carp, grass carp, or black carp.

[0033] (2) Configure the breeding environment to meet the basic nutritional requirements of the broodstock.

[0034] (3) Co-regulation of water temperature and hormones

[0035] At the beginning of spring, parent fish are released into the pond to raise the water temperature by 0.5℃ to 2.5℃ per day. Starting from the second day of temperature increase, growth regulators are introduced. At this time, the gonads of the parent fish gradually develop, preparing for reproduction. When the water temperature in the pond is between 8℃ and 30℃, the temperature is kept constant. At this time, the gonads of the parent fish mature rapidly and quickly reach the reproduction standard.

[0036] It should be noted that different types of parent fish have different requirements for a constant water temperature. Some fish are suitable for breeding in warm water, such as carp, so the temperature range for maintaining a constant temperature is 15℃~30℃. Some fish are suitable for breeding in cold water, such as salmon, so the temperature range for maintaining a constant temperature is 8℃~14℃.

[0037] During the process of maintaining a constant temperature, exogenous hormones are injected. After the injection of exogenous hormones, growth regulators are added. Basic feed is provided during the breeding period until the egg-laying and reproduction are completed.

[0038] The mechanism of this invention is as follows: By increasing the water temperature, the hypothalamic-pituitary-gonadal axis signaling of the broodstock is affected, stimulating the neurosecretory cells of the hypothalamus and causing them to secrete luteinizing hormone-releasing hormone (GnRH). GnRH is transported to the pituitary gland via the bloodstream, where it binds to GnRH receptors and stimulates the pituitary gland to synthesize and secrete gonadotropins (GtH), including follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH further act on the gonads, promoting the proliferation and differentiation of gonadal cells, inducing oocyte growth, maturation, and spermatogenesis. By injecting exogenous hormones, the effects of the aquatic animal's own hormones can be simulated or enhanced, accelerating gonadal development and ovulation. The exogenous hormone selected in this invention is luteinizing hormone-releasing hormone or its analogue LRH-A2 (ovulation-inducing hormone 2). After the exogenous hormone stimulates the pituitary gland to secrete GtH, the FSH in GtH can promote oocyte growth and yolk accumulation, leading to oocyte maturation. Meanwhile, LH plays a crucial role in the late maturation stage of oocytes, stimulating the theca cells to synthesize and secrete steroid hormones. These steroid hormones further induce oocytes to complete meiosis and ovulate. Furthermore, to reduce the dosage of exogenous hormones, this invention administers a growth regulator before injecting exogenous hormones. The growth regulator consists of butyric acid or sodium butyrate. Butyric acid and sodium butyrate enhance the function of exogenous hormones, promote GtH secretion, promote oocyte growth and yolk accumulation, accelerate gonadal development and ovulation, ultimately shortening the ovarian development cycle and increasing the egg production rate.

[0039] The innovations of this invention are illustrated below with specific embodiments and data. It should be noted that, except for the differences described in the embodiments below, other aquaculture methods and the amount of basic feed administered are carried out according to conventional methods in the art, and the same measures are adopted, such as: the basic daily ration is 2% of the fresh body weight of the broodstock each time, fed twice a day; oxygen is increased daily to maintain the dissolved oxygen level in the water at 5 mg / L.

[0040] The sources of raw materials for the basic feed are as follows, as illustrated in the specific embodiments below:

[0041] Fishmeal: Pakistani fishmeal, Tianjin Haiwei International Trade Co., Ltd. Soybean Meal: Soybean meal, Lvshui (Jinan) Chemical Co., Ltd. Rapeseed Meal: Shandong Huachen Biotechnology Co., Ltd., product name: Rapeseed Meal Feed. Cottonseed Meal: Lingshou County Xinde Agricultural Products Co., Ltd. Fish Oil: Shandong Baiqianhui Biotechnology Co., Ltd. Soybean Oil: Jinan Xinyimin Chemical Technology Co., Ltd., product name: Crude Soybean Oil. Corn Starch and Wheat Flour: Purchased from local farmers' markets. Corn Mid-Grain: Yuncheng Jinhui Biological Feed Co., Ltd. Choline: Hebei Chuangzhiyuan Biotechnology Co., Ltd., product name: Choline Chloride. Aquaculture Vitamin Premix: Shandong Qilu Chemical Technology Co., Ltd., product name: Electrolyzed Multivitamin. Sodium Carboxymethyl Cellulose: Xi'an Lavia Biotechnology Co., Ltd. Cellulose: Hebei Yufei Chemical Co., Ltd., product name: Carboxymethyl Cellulose.

[0042] To investigate the effects of different growth regulator dosages on the reproduction of aquatic populations, this invention includes Examples 1 to 4 and Control Groups 1 to 5.

[0043] Example 1

[0044] A method for aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones includes the following steps:

[0045] (1) Selection of broodstock

[0046] Three-year-old blunt snout bream individuals with robust body shape, no disease, well-developed gonads, and excellent genetic traits were selected as parent fish.

[0047] (2) Configure the breeding environment

[0048] After winter ends, around the beginning of spring, female blunt snout bream enter the third stage of ovarian development. Water is added to the pond to increase oxygen levels and maintain the dissolved oxygen level at 5 mg / L. Basic feed is also added to meet the basic nutritional needs of the broodstock.

[0049] The basic feed is composed of the following ingredients in the indicated weight percentages:

[0050] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, cellulose 0.50%.

[0051] (3) Co-regulation of water temperature and hormones

[0052] After setting up the breeding environment, broodstock are released into the pond, and the water temperature is increased by 0.5℃ per day. Starting from the second day of temperature increase, butyric acid growth regulator is added for 3 consecutive days. During the temperature increase period, the gonads of the broodstock gradually develop, preparing for reproduction. When the water temperature in the pond reaches 24℃, the temperature is kept constant. At this time, the gonads of the broodstock mature rapidly and reach the breeding standard.

[0053] Inject exogenous hormones at a dose of 2 μg / kg, and add growth regulators at a dose of 2 μg / kg per day. Mix the growth regulators with the basal feed and add them with the basal feed. Add the basal feed during the breeding period until the egg-laying and reproduction are completed.

[0054] Among them, the exogenous hormone is Fish Ovulation Inducing Agent No. 2 (hereinafter referred to as Ovulation Inducing Agent No. 2), which is injected once, that is, once at the base of the pectoral fin when the ovary develops to the end of stage IV, to initiate final maturation and ovulation. The signs of the ovary developing to the end of stage IV are: the ovary volume is significantly increased, filling the entire abdominal cavity, and is light gray or light yellow; the oocyte develops to stage IV oocyte, the cell diameter is large and transparent, the yolk granules are filled with cytoplasm, the cell nucleus is marginalized, and it is about to complete meiosis.

[0055] Example 2

[0056] A method for aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones, wherein the dosage of growth regulator is 3 μg / kg per day, and the rest of the operation is the same as in Example 1.

[0057] Example 3

[0058] A method for aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones, wherein the growth regulator is sodium butyrate, the dosage is 2 μg / kg per day, and the rest of the operation is the same as in Example 1.

[0059] Example 4

[0060] A method for aquatic population reproduction and seedling raising based on the synergistic regulation of water temperature and hormones, wherein the growth regulator is sodium butyrate, the dosage is 3 μg / kg per day, and the rest of the operation is the same as in Example 1.

[0061] Control group 1

[0062] A method for breeding and raising aquatic populations, in which growth regulators are not added, and all other operations are the same as in Example 1.

[0063] Control group 2

[0064] A method for breeding and raising aquatic populations, wherein the dosage of growth regulator butyric acid is 1 μg / kg per day, and the remaining operations are the same as in Example 1.

[0065] Control group 3

[0066] A method for breeding and raising aquatic populations, wherein the dosage of growth regulator butyric acid is 4 μg / kg per day, and the remaining operations are the same as in Example 1.

[0067] Control group 4

[0068] A method for breeding and raising aquatic populations, wherein the growth regulator is sodium butyrate, and the dosage is 1 μg / kg per day, and the rest of the operation is the same as in Example 1.

[0069] Control group 5

[0070] A method for breeding and raising aquatic populations, wherein the growth regulator is sodium butyrate, and the dosage is 4 μg / kg per day, and the remaining operations are the same as in Example 1.

[0071] The reproductive performance of the broodstock is shown in Table 1. The results showed that, compared with control group 1 (without growth regulators), the time required for ovarian development to the end of stage IV was shortened by up to 33.33%, the spawning rate increased by up to 18.99%, the absolute number of eggs per female increased by up to 61.54%, the fertilization rate increased by up to 43.33%, the hatching rate increased by up to 18.84%, and the fry emergence rate increased by up to 42.5%. Control groups 2-4 represented cases where the growth regulator dosage was too high or too low, and all reproductive performances were inferior to those in the examples. The broodstock reproductive performance of examples 1-4 was the best, indicating that the dosage of growth regulators has a significant impact on the reproductive performance of broodstock. Therefore, the dosage of growth regulators should be carefully considered during breeding.

[0072] Table 1. Effects of different growth regulator dosages on aquatic population reproduction

[0073]

[0074] To investigate the synergistic effect of water temperature, growth regulators and exogenous hormones, this invention set up Example 1 and control groups 1, 6 to 11.

[0075] Control group 6

[0076] A method for breeding and raising aquatic populations includes the following steps:

[0077] (1) Selection of broodstock

[0078] Three-year-old blunt snout bream individuals with robust body shape, no disease, well-developed gonads, and excellent genetic traits were selected as parent fish.

[0079] (2) Configure the breeding environment

[0080] After winter ends, around the beginning of spring, female blunt snout bream enter the third stage of ovarian development. Water is added to the pond to increase oxygen levels and maintain the dissolved oxygen level at 5 mg / L. Basic feed is also added to meet the basic nutritional needs of the broodstock.

[0081] The basic feed is composed of the following ingredients in the indicated weight percentages:

[0082] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, cellulose 0.50%.

[0083] (3) Provide basic feed during the breeding period until the egg-laying and reproduction are completed.

[0084] Control group 7

[0085] A method for breeding and raising aquatic populations includes the following steps:

[0086] (1) Selection of broodstock

[0087] Three-year-old blunt snout bream individuals with robust body shape, no disease, well-developed gonads, and excellent genetic traits were selected as parent fish.

[0088] (2) Configure the breeding environment

[0089] After winter ends, around the beginning of spring, female blunt snout bream enter the third stage of ovarian development. Water is added to the pond to increase oxygen levels and maintain the dissolved oxygen level at 5 mg / L. Basic feed is also added to meet the basic nutritional needs of the broodstock.

[0090] The basic feed is composed of the following ingredients in the indicated weight percentages:

[0091] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, cellulose 0.50%.

[0092] (3) Water temperature control

[0093] After setting up the breeding environment, broodstock fish are introduced into the pond to raise the water temperature by 0.5℃ per day. When the water temperature reaches 20℃, the temperature is kept constant until the breeding standard is met.

[0094] Basic feed is provided during the breeding period until the eggs are laid and reproduced.

[0095] control group 8

[0096] A method for breeding and raising aquatic populations includes the following steps:

[0097] (1) Selection of broodstock

[0098] Three-year-old blunt snout bream individuals with robust body shape, no disease, well-developed gonads, and excellent genetic traits were selected as parent fish.

[0099] (2) Configure the breeding environment

[0100] After winter ends, around the beginning of spring, female blunt snout bream enter the third stage of ovarian development. Water is added to the pond to increase oxygen levels and maintain the dissolved oxygen level at 5 mg / L. Basic feed is also added to meet the basic nutritional needs of the broodstock.

[0101] The basic feed is composed of the following ingredients in the indicated weight percentages:

[0102] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, cellulose 0.50%.

[0103] (3) Regulation by growth regulators

[0104] After setting up the aquaculture environment, broodstock fish are introduced into the pond. On the second day, butyric acid growth regulator is introduced at a dosage of 2 μg / kg per day for 3 consecutive days. Basic feed is provided during the aquaculture period until spawning and reproduction are completed.

[0105] Control group 9

[0106] A method for breeding and raising aquatic populations includes the following steps:

[0107] (1) Selection of broodstock

[0108] Three-year-old blunt snout bream individuals with robust body shape, no disease, well-developed gonads, and excellent genetic traits were selected as parent fish.

[0109] (2) Configure the breeding environment

[0110] After winter ends, around the beginning of spring, female blunt snout bream enter the third stage of ovarian development. Water is added to the pond to increase oxygen levels and maintain the dissolved oxygen level at 5 mg / L. Basic feed is also added to meet the basic nutritional needs of the broodstock.

[0111] The basic feed is composed of the following ingredients in the indicated weight percentages:

[0112] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, cellulose 0.50%.

[0113] (3) Regulation by exogenous hormones

[0114] After setting up the breeding environment, broodstock fish are released into the pond and basic feed is provided during the breeding period until they complete spawning and reproduction.

[0115] The exogenous hormone is ovulation-inducing hormone 2, which is injected once at the base of the pectoral fin when the ovary develops to the end of stage IV to initiate final maturation and ovulation. The signs of the ovary developing to the end of stage IV are: the ovary volume is significantly increased, filling the entire abdominal cavity, and it is light gray or light yellow; the oocyte develops to stage IV oocyte, the cell diameter is large and transparent, the yolk granules are full of cytoplasm, the cell nucleus is marginalized, and it is about to complete meiosis.

[0116] control group 10

[0117] A method for breeding and raising aquatic populations includes the following steps:

[0118] (1) Selection of broodstock

[0119] Three-year-old blunt snout bream individuals with robust body shape, no disease, well-developed gonads, and excellent genetic traits were selected as parent fish.

[0120] (2) Configure the breeding environment

[0121] After winter ends, around the beginning of spring, female blunt snout bream enter the third stage of ovarian development. Water is added to the pond to increase oxygen levels and maintain the dissolved oxygen level at 5 mg / L. Basic feed is also added to meet the basic nutritional needs of the broodstock.

[0122] The basic feed is composed of the following ingredients in the indicated weight percentages:

[0123] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, cellulose 0.50%.

[0124] (3) Regulation

[0125] After setting up the breeding environment, broodstock fish are introduced into the pond, and the water temperature is increased by 0.5℃ per day. Starting from the second day of temperature increase, butyric acid growth regulator is introduced at a dosage of 2μg / kg per day for 3 consecutive days. During the temperature increase period, the gonads of the broodstock fish gradually develop, preparing for reproduction. When the water temperature in the pond reaches 20℃, the temperature is kept constant. At this time, the gonads of the broodstock fish mature rapidly and reach the breeding standard.

[0126] Control group 11

[0127] A method for breeding and raising aquatic populations includes the following steps:

[0128] (1) Selection of broodstock

[0129] Three-year-old blunt snout bream individuals with robust body shape, no disease, well-developed gonads, and excellent genetic traits were selected as parent fish.

[0130] (2) Configure the breeding environment

[0131] After winter ends, around the beginning of spring, female blunt snout bream enter the third stage of ovarian development. Water is added to the pond to increase oxygen levels and maintain the dissolved oxygen level at 5 mg / L. Basic feed is also added to meet the basic nutritional needs of the broodstock.

[0132] The basic feed is composed of the following ingredients in the indicated weight percentages:

[0133] Fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn middlings 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, cellulose 0.50%.

[0134] (3) Regulation

[0135] After setting up the aquaculture environment, broodstock fish are introduced into the pond. On the second day, butyric acid growth regulator is introduced at a dosage of 2 μg / kg per day for 3 consecutive days. Basic feed is provided during the aquaculture period until spawning and reproduction are completed.

[0136] Inject exogenous hormones at a dose of 2 μg / kg.

[0137] Among them, the exogenous hormone is ovulation-inducing hormone No. 2, which is injected once, that is, once at the base of the pectoral fin when the ovary develops to the end of stage IV, to initiate final maturation and ovulation. The signs of the ovary developing to the end of stage IV are: the ovary volume is significantly increased, filling the entire abdominal cavity, and is light gray or light yellow; the oocyte develops to stage IV oocyte, the cell diameter is large and transparent, the yolk granules are full of cytoplasm, the cell nucleus is marginalized, and it is about to complete meiosis.

[0138] In the groups listed in Table 2, control group 6, which received no water temperature adjustment, no exogenous hormone injection, and no growth regulators, had the slowest ovarian development and the worst egg production rate and absolute fecundity per female. Control group 7, which received only water temperature adjustment, shortened ovarian development time and improved egg production rate and absolute fecundity per female to some extent compared to control group 6. Control group 8, which received only growth regulators, showed similar results to control group 7 in terms of egg production rate and also improved egg production rate to some extent compared to control group 6. Control group 9, which received only exogenous hormones, did not significantly shorten ovarian development time because treatment began at the end of ovarian stage IV. Control group 10 was the experimental group regulated by water temperature and growth regulator, control group 11 was the experimental group regulated by growth regulator and exogenous hormone, and control group 1 was the experimental group regulated by water temperature and exogenous hormone. The results showed that, compared with control group 7 and control group 9, the addition of growth regulator improved indicators such as egg production rate and shortened ovarian development time.

[0139] In summary, the results in Table 2 show that water temperature, exogenous hormones, and growth regulators all promote the reproductive performance of broodstock. However, the effects of single-factor and two-factor combinations are not as good as the combined effect of water temperature, exogenous hormones, and growth regulators.

[0140] Table 2 Comparison Results of Synergistic Effects

[0141]

[0142] To investigate the effect of exogenous hormone concentration on the reproductive performance of parent fish, this invention set up Example 1 and control groups 12-13.

[0143] control group 12

[0144] A method for breeding and raising aquatic populations, wherein the injection dose of exogenous hormone ovulation-inducing hormone No. 2 is 5 μg / kg, and the remaining operations are the same as those in control group 1.

[0145] Control group 13

[0146] A method for breeding and raising aquatic populations involves injecting exogenous hormone ovulation-inducing hormone No. 2 at a dose of 5 μg / kg, along with injecting human chorionic gonadotropin (hCG) at a dose of 1000 IU / kg. All other procedures are the same as those in control group 1.

[0147] Control groups 12 and 13 represent existing water temperature and exogenous hormone regulation schemes, with exogenous hormone injection doses exceeding the 2 μg / kg of the present invention. However, comparative experimental results revealed that the present application, using growth additives, achieved excellent reproductive performance even with low doses of exogenous hormones. This indicates that the method of the present invention can reduce the amount of exogenous hormones used, thereby reducing hormone residues in aquatic organisms and lowering safety risks. The butyric acid and sodium butyrate used in this invention are relatively safe feed additives and degrade over time in water, eliminating concerns about long-term residues. Sodium butyrate, in particular, is a highly safe substance.

[0148] Table 3 Comparison Results of Synergistic Effects

[0149]

[0150] To investigate the effects of other growth regulators on the reproductive performance of parent fish, this invention included Example 1 and Control Group 14.

[0151] Control group 14

[0152] A method for breeding and raising aquatic populations, wherein the growth regulator is poly-β-hydroxybutyrate, and the remaining operations are the same as in Example 1.

[0153] Control group 14 was an experimental group containing other growth regulators commonly used in the art. The results in Table 4 show that the effects of other existing growth regulators are not as good as those in Example 1 of this invention. The spawning rate, absolute number of eggs per female, and fertilization rate of control group 14 were the same as those of control group 1, indicating that β-hydroxybutyrate could not improve these key reproductive indicators.

[0154] Table 4. Effects of other growth regulators on the reproductive performance of broodstock.

[0155]

[0156] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the inventive concept of this invention, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.

[0157] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If such modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method, characterized in that, The method comprises the following steps: selecting spring-spawning fish as parent fish; configuring a breeding environment to provide basic nutritional conditions for the reproduction of the parent fish; water temperature-hormone synergistic regulation: in the spring, the parent fish is put into the breeding environment, the water temperature in the pond is increased, the daily temperature increasing speed is 0.5-2.5℃, on the second day of temperature increasing, a growth regulator is put in, when the water temperature in the pond is 8-30℃, the temperature is kept constant, in the process of keeping the temperature constant, an exogenous hormone is injected, basic feed is put in during the breeding period until spawning and reproduction are completed; wherein the exogenous hormone is luteinizing hormone-releasing hormone or an analogue thereof, and the injection dose of the exogenous hormone is not more than 4 μg / kg; the growth regulator is butyric acid or sodium butyrate, and the daily put-in dose is 2-3 μg / kg.

2. The water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method according to claim 1, characterized in that, For the parent fish for warm water reproduction, the constant temperature value is 15-30℃; for the parent fish for cold water reproduction, the constant temperature value is 8-14℃.

3. The water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method according to claim 1, characterized in that, The parent fish is a bream.

4. The water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method according to claim 1, characterized in that, The injection dose of the luteinizing hormone-releasing hormone is 2 μg / kg.

5. The water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method according to claim 1, characterized in that, The exogenous hormone is injected once.

6. The water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method according to claim 1, characterized in that, The growth regulator is continuously put in for 3-5 days.

7. The water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method according to claim 6, characterized in that, The growth regulator is mixed in the basic feed.

8. The water temperature-hormone synergistically regulated aquaculture population breeding and larviculture method according to claim 1, characterized in that, The basic feed is mixed by the following raw materials with the mass percentage: fish meal 12.00%, soybean meal 11.00%, rapeseed meal 10.00%, cottonseed meal 24.10%, fish oil 1.80%, soybean oil 1.80%, corn starch 14.00%, wheat flour 16.00%, corn meal 4.80%, choline 0.50%, aquaculture vitamin premix 1.50%, sodium carboxymethyl cellulose 2.00%, and cellulose 0.50%.

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