Method for increasing survival rate of pelteobagrus fulvidraco female parent in breeding process

Abstract

The invention discloses a method for increasing the survival rate of a pelteobagrus fulvidraco female parent in the breeding process, and relates to the technical field of methods for increasing the survival rate of the pelteobagrus fulvidraco female parent in the breeding process. S2, according to the fish body length of the pelteobagrus fulvidraco female parent, determining the length of the part, inserted into the fish body, of a needle of an injector, and then injecting an oxytocin compound solution into the pelteobagrus fulvidraco female parent through the injector for spawning induction. The problems that in the prior art, body injury and infection are caused by injection and manual egg squeezing, viscera are damaged due to improper operation during injection, and the survival rate of female parents is low are solved.

Description

Technical Field

[0001] This invention relates to the field of artificial breeding technology for yellow catfish, and in particular to a method for improving the survival rate of female yellow catfish during breeding. Background Technology

[0002] Yellow catfish is an important freshwater economic fish in my country, prized for its delicious flesh and rich nutritional value, and holds a significant position in the aquaculture industry. Its hybrid varieties (female yellow catfish × male yellow catfish) have also become a popular aquaculture species due to their superior traits. In the artificial breeding of yellow catfish and its hybrid varieties, the survival rate of the maternal parent has a crucial impact on reproductive efficiency and economic benefits, and is one of the key constraints on the large-scale development of the industry.

[0003] Currently, artificial breeding of yellow catfish involves two main steps: artificial injection of oxytocin and artificial egg extraction. However, the existing operating methods have significant technical drawbacks, easily causing multiple damages to the mother fish and inducing a chain of risks, mainly manifested in the following ways: When oxytocin is artificially injected, the needle punctures the fish's body, creating an exposed puncture site. The subsequent mechanical compression of the ovary during artificial egg extraction further exacerbates the tissue damage. This double damage makes the parent fish highly susceptible to pathogens (such as Aeromonas hydrophila and Vibrio), leading to various diseases and a certain mortality rate in the postpartum mothers. Data shows that the infection rate of the injection site caused by this type of operation is as high as 28%. Manual injection relies on experience. If the needle is inserted too deeply, it can easily damage the internal organs of the parent fish, leading to a significant increase in the risk of death of the mother. According to statistics, without effective protective measures, the mortality rate of the mother during the breeding process can be as high as 20% or more. After induced labor, the mother's immune system is significantly weakened due to stress and tissue damage. Even if no obvious infection occurs in the early stages, the weakened state makes her resistance to pathogens in the environment continuously decrease, and the probability of subsequent secondary infections increases significantly.

[0004] Therefore, it is of great practical significance to develop a method that can effectively improve the survival rate of female yellow catfish during breeding. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a method to improve the survival rate of female catfish during the breeding process, which solves the problems of low survival rate of female catfish caused by bodily damage and infection due to injection and artificial egg squeezing, as well as internal organ damage caused by improper operation during injection.

[0006] This invention discloses a method for improving the survival rate of female yellow catfish during reproduction, the method steps of which are as follows: S1: Preparation of oxytocin compound solution; S2: Determine the length of the syringe needle to be inserted into the fish body based on the length of the female yellow catfish, and then inject the female yellow catfish with an oxytocin compound solution to induce spawning.

[0007] The oxytocin compound solution is composed of oxytocin, antibiotics, polyethylene glycol, chitosan, glacial acetic acid and water, and the pH of the oxytocin compound solution is 6.

[0008] Preferably, the oxytocin compound solution contains 6-8 mg / mL of antibiotic, 4-5% polyethylene glycol, 2% chitosan, and 1-2% glacial acetic acid.

[0009] Preferably, the antibiotic is enrofloxacin and / or florfenicol.

[0010] Preferably, the method for determining the length of the needle that can be inserted into the fish body is as follows: When the fish's body length is 10cm < L 鱼 When <15cm: , When the fish length is 15cm or less L 鱼 When ≤20cm: , In the formula, L 插 The length of the needle inserted into the fish's body, in cm; L 针 The effective length of the needle is in centimeters. L 鱼 The length of the fish is in cm.

[0011] Preferably, the syringe needle is provided with a limiting sleeve to limit the length of the needle inserted into the fish body, and the limiting sleeve can be made of rubber or the like.

[0012] Beneficial technical effects of the present invention: This invention solves the problems of low survival rate of female catfish caused by bodily damage and infection due to injection and artificial egg squeezing, as well as internal organ damage caused by improper injection operation, by controlling the needle depth and designing the oxytocin compound solution. It significantly improves the survival rate of female catfish during the breeding process.

[0013] The oxytocin compound solution of the present invention not only improves the solubility of antibiotics such as enrofloxacin in water and the slow release rate in yellow catfish, thus improving the duration of efficacy; but also significantly improves solution stability, extends shelf life, solves the problem of easy reduction in oxytocin efficacy, and reduces usage costs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the syringe proposed in this invention.

[0015] In the diagram: 1-syringe body, 2-needle, 3-limiting sleeve. Detailed Implementation

[0016] The present invention will be further explained below with reference to specific embodiments. Example 1

[0017] Add glacial acetic acid and chitosan to a conventional oxytocin solution (composed of luteinizing hormone-releasing hormone analog (LRH), human chorionic gonadotropin (HCG), and domperidone (DOM) in a specific ratio), and shake to dissolve (ensuring complete clarity); then add enrofloxacin, a fishery antibiotic, and stir until completely dissolved; then add polyethylene glycol directly to the above compound solution and stir for 5 minutes to prepare an oxytocin compound solution. If a precipitate forms in the solution, add glacial acetic acid to ensure the solution pH is 6.

[0018] Then, the length of the syringe needle inserted into the fish body is determined according to the length of the female yellow catfish. Then, the female yellow catfish is injected with oxytocin compound solution through the syringe to induce spawning. After spawning, the female yellow catfish is placed in a temporary holding tank for postpartum care.

[0019] The oxytocin compound solution contains 7 mg / mL of antibiotic, 4.5% polyethylene glycol, 2% chitosan, and 1.5% glacial acetic acid.

[0020] Reference Figure 1 The method for determining the length of the needle inserted into the fish's body is as follows: When the fish's body length is 10cm < L 鱼 When <15cm: , When the fish length is 15cm or less L 鱼 When ≤20cm: , In the formula, L 插 The length of the needle inserted into the fish's body, in cm; L 针 The effective length of the needle is in centimeters. L 鱼 The length of the fish is in cm.

[0021] To facilitate control over the length of the needle inserted into the fish, the syringe needle is fitted with a limiting sleeve to limit the length of the needle inserted into the fish. The limiting sleeve can be made of rubber.

[0022] The in vivo sustained-release effect of enrofloxacin under different conditions can be directly reflected by HPLC analysis of the blood of parent yellow catfish injected with oxytocin. Blood samples were collected at different time points after injection to determine the drug concentration. The experimental results are shown in Table 1.

[0023] Table 1. Enrofloxacin concentration in blood at different time points Time (h) Yellow catfish oxytocin solution (containing enrofloxacin) (μg / mL) Yellow catfish oxytocin compound solution (containing enrofloxacin / polyethylene glycol / chitosan) (μg / mL) Concentration ratio 0.5 4.75 ± 0.30 3.21 ± 0.25 0.68 2 3.58 ± 0.23 4.24 ± 0.35 1.18 8 1.57 ± 0.12 2.97 ± 0.24 1.89 24 0.31 ± 0.04 1.29 ± 0.10 4.16 As shown in Table 1, at the initial stage of the experiment (0.5 h), the concentration of enrofloxacin in the blood of the yellow catfish oxytocin solution without polyethylene glycol and chitosan was 4.75 ± 0.30 μg / mL; while the concentration of the yellow catfish oxytocin compound solution with polyethylene glycol and chitosan was only 3.21 ± 0.25 μg / mL. This indicates that in the initial stage of administration, the compound solution released enrofloxacin in the body at a slower rate than the ordinary oxytocin solution, resulting in a lower initial drug concentration in the blood.

[0024] At 2 hours, the concentrations of the two types of solutions showed a "reversal" trend. The enrofloxacin concentration in the ordinary yellow catfish oxytocin solution decreased to 3.58±0.23 μg / mL, a decrease of about 24.6% compared to 0.5 hours; while the concentration in the yellow catfish oxytocin compound solution increased to 4.24±0.35 μg / mL, an increase of about 32.1% compared to 0.5 hours. At this point, the concentration ratio reached 1.18, and the concentration ratio continued to increase over time, indicating that the compound components effectively delayed the metabolic process of enrofloxacin, prolonged the duration of drug action in yellow catfish, and improved the long-term efficacy of the drug.

[0025] The stability of oxytocin under different storage conditions was determined, and the results are shown in Table 2.

[0026] Table 2 Comparison of Oxytocin Stability Storage conditions Yellow catfish oxytocin solution Yellow catfish oxytocin compound solution (containing enrofloxacin / polyethylene glycol / chitosan) Key Explanation Normal temperature (20-30℃) The efficacy of the drug decreases significantly within 1-4 hours. The efficacy of the drug is relatively stable within 8 hours. After 8 hours, the effect of labor induction decreases by more than 50%, and the effect is poor. Refrigerate (2-8℃, sealed and protected from light) The drug's effects are generally maintained within 8-12 hours. The drug's efficacy is well maintained within 48 hours. Refrigeration only slows down the decline; after 48 hours, the labor-inducing effect is poor. Room temperature + light / pollution The drug's effects wear off rapidly within 1.5 hours. The efficacy of the drug is relatively stable within 4 hours. Oxytocin with added polyethylene glycol and chitosan has a shelf life 2-3 times longer than oxytocin alone. As shown in Table 2, the combined use of enrofloxacin, polyethylene glycol, and chitosan in this invention significantly improves solution stability, extends shelf life, solves the problem of easily reduced efficacy of oxytocin, and lowers usage costs. Compared to conventional yellow catfish oxytocin solutions, under the same storage conditions, the shelf life of the compound solution can be extended by 2-3 times, reducing efficacy loss during on-site use.

[0027] On June 12, 2024, 200 healthy female yellow catfish with well-developed gonads and an average body length of 12.8 cm were selected from an experimental base of a certain aquatic research institute and randomly divided into two groups of 100 fish each. A conventional oxytocin solution was prepared containing: LRH-A 220 μg / kg + HCG 1000 IU / kg + DOM 2 mg / kg. Enrofloxacin, chitosan, polyethylene glycol, and glacial acetic acid were added according to the method in Example 1 to obtain a compound oxytocin solution. After spawning, the female yellow catfish were placed in a temporary holding tank for postpartum care. On June 17, 2024, the number of dead or near-death female yellow catfish was counted, and the results are shown in Table 3. The control group was injected with the conventional oxytocin solution.

[0028] Table 3 Comparison of mortality rates in broodstock fish supplemented with oxytocin and enrofloxacin Group Number of female fish Postpartum mortality mortality rate control group 100 22 22% experimental group 100 7 7% In addition, the effect of the length of the syringe needle inserted into the fish body on the postpartum survival rate of the female yellow catfish was studied, and the experimental results are shown in Table 4.

[0029] Table 4 Comparison of broodstock mortality rates after adding oxytocin and enrofloxacin compound solution, and after equipping needles with rubber sheaths. Group Number of female fish Death count mortality rate Remark Control group 1 100 23 23% \ Experimental group 1 100 11 11% Needle equipped with rubber sheath Experimental group 2 102 3 2.9% The needle is equipped with a rubber sheath, and the oxytocin contains an enrofloxacin compound solution. Example 2

[0030] Add glacial acetic acid and chitosan to a conventional oxytocin solution (composed of luteinizing hormone-releasing hormone analog (LRH), human chorionic gonadotropin (HCG), and domperidone (DOM) in a specific ratio), and shake to dissolve (ensuring complete clarity); then add enrofloxacin, a fishery antibiotic, and stir until completely dissolved; then add polyethylene glycol directly to the above compound solution and stir for 5 minutes to prepare an oxytocin compound solution. If a precipitate forms in the solution, add glacial acetic acid to ensure the solution pH is 6.

[0031] The oxytocin compound solution contains 6 mg / mL of antibiotic, 4% polyethylene glycol, 2% chitosan, and 1% glacial acetic acid.

[0032] Example 3 Add glacial acetic acid and chitosan to a conventional oxytocin solution (composed of luteinizing hormone-releasing hormone analog (LRH), human chorionic gonadotropin (HCG), and domperidone (DOM) in a specific ratio), and shake to dissolve (ensuring complete clarity); then add enrofloxacin, a fishery antibiotic, and stir until completely dissolved; then add polyethylene glycol directly to the above compound solution and stir for 5 minutes to prepare an oxytocin compound solution. If a precipitate forms in the solution, add glacial acetic acid to ensure the solution pH is 6.

[0033] The oxytocin compound solution contains 8 mg / mL of antibiotic, 5% polyethylene glycol, 2% chitosan, and 2% glacial acetic acid.

[0034] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.

Claims

1. A method for improving the survival rate of female yellow catfish during reproduction, characterized in that, The steps are as follows: S1: Preparation of oxytocin compound solution; S2: Determine the length of the syringe needle to be inserted into the fish body based on the length of the female yellow catfish, and then inject the female yellow catfish with an oxytocin compound solution to induce spawning. The oxytocin compound solution is composed of oxytocin, antibiotics, polyethylene glycol, chitosan, glacial acetic acid and water, and the pH of the oxytocin compound solution is 6.

2. The method for improving the survival rate of female yellow catfish during reproduction according to claim 1, characterized in that, The oxytocin compound solution contains 6-8 mg / mL of antibiotics, 4-5% polyethylene glycol, 2% chitosan, and 1-2% glacial acetic acid.

3. The method for improving the survival rate of female yellow catfish during reproduction according to claim 1 or 2, characterized in that, The antibiotic is enrofloxacin or florfenicol.

4. The method for improving the survival rate of female yellow catfish during reproduction according to claim 1, characterized in that, The method for determining the length of a needle that can be inserted into a fish is as follows: When the fish's body length is 10cm < L 鱼 When <15cm: , When the fish length is 15cm or less L 鱼 When ≤20cm: , In the formula, L 插 The length, in cm, into which the needle can be inserted into the fish's body. L 针 The effective length of the needle, in cm; L 鱼 The length of the fish is in cm.

5. The method for improving the survival rate of female yellow catfish during reproduction according to claim 1, characterized in that, The syringe needle is fitted with a limiting sleeve to limit the length of the needle inserted into the fish.

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