Application of capsaicin in resistance of grass carp to hypoxia stress

Abstract

The invention discloses application of capsaicin to resistance of grass carp to hypoxia stress, and belongs to the technical field of agricultural cultivation. Aiming at the problems of red blood cell function damage, liver and gill tissue damage and the like of grass carps under hypoxia stress, a trace amount of capsaicin is added into the grass carp feed, so that the feed formula is optimized, the reduction of red blood cell quantity and brittleness increase of grass carps in the later growth period caused by hypoxia stress are relieved, liver damage is relieved, and the growth period of grass carps is prolonged. The death rate of the grass carp in a low-oxygen environment is reduced, the culture risk is reduced, and the method has the characteristics of being green, safe, low in cost and remarkable in economic benefit and is suitable for large-scale grass carp culture industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural aquaculture, and particularly relates to the application of capsaicin in grass carp's resistance to hypoxia stress. Background Art

[0002] Grass carp is an important economically cultured fish in China. Its aquaculture volume and output have ranked first in China and the world for many consecutive years. As one of the "four major Chinese carps", it is rich in nutrition and has a high feed conversion rate, and is a common fish on the tables of ordinary people. Grass carp has the characteristics of fast growth, wide feed sources, and high yield. Intensive and high-density aquaculture has become the main aquaculture method in today's aquaculture industry. Under this aquaculture method, hypoxia stress has become one of the most common forms of environmental stress. At the same time, extreme weather occurs frequently in China. Sudden changes in weather will cause rapid and massive death of green plants, algae, etc. in the water body, resulting in a sudden drop in dissolved oxygen in the water body and causing hypoxia stress. Under normal circumstances, fish have a large food intake, a high feed conversion rate, and a fast growth rate in a water environment with an appropriate concentration of dissolved oxygen. Under hypoxia stress, the food intake and feed conversion efficiency of fish are greatly reduced, and the growth is slow. Compared with other fish, grass carp is more sensitive to low-oxygen environments. For example, when the dissolved oxygen content is lower than 2.72 mg / L, its growth rate will decrease by 98%. Large-sized grass carp has a high oxygen consumption, and the problem of hypoxia stress is particularly serious. When staying in a low-oxygen environment for a long time, grass carp is prone to diseases due to metabolic disorders and decreased immunity, especially under the conditions of high temperature or deteriorated water quality, and the mortality rate increases significantly. Under hypoxia stress, the gill, as the main respiratory organ of fish, bears the brunt, and the liver, as the main metabolic organ of fish, will also be affected. It is urgent to improve the resistance of fish to hypoxia stress and alleviate the problems of gill and liver damage. Summary of the Invention

[0003] In view of the above-mentioned prior art, the present invention provides the application of capsaicin in grass carp's resistance to hypoxia stress, and solves the problem that grass carp has low resistance to hypoxia stress when the dissolved oxygen content in the water body is low.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: to provide the application of capsaicin in grass carp's resistance to hypoxia stress.

[0005] Further, capsaicin is added as an additive to the grass carp feed for feeding grass carp.

[0006] Further, the addition amount of capsaicin is 0.00006% or 0.00012% of the quality of the grass carp feed.

[0007] Furthermore, the grass carp feed with added capsaicin includes the following components in parts by mass: 2.5-3.5 parts of fish meal, 2.5-3.5 parts of rapeseed meal, 13-15 parts of soybean meal, 21.5-22.5 parts of dephenolized cottonseed protein, 26-30 parts of α-starch, 17-17.1 parts of flour, 2.5-2.7 parts of fish oil, 1.3-1.5 parts of soybean oil, 1.2-1.7 parts of monocalcium phosphate, 1.99988 or 1.99994 parts of microcrystalline cellulose, 0.00006 or 0.00012 parts of capsaicin, 0.015 parts of hydroxyanisole, 0.22 parts of L-threonine and 5 parts of composite premix.

[0008] Furthermore, the grass carp feed with added capsaicin includes the following components in parts by mass: 3 parts of fish meal, 3 parts of rapeseed meal, 14 parts of soybean meal, 22.15 parts of dephenolized cottonseed protein, 28 parts of α-starch, 17.085 parts of flour, 2.650 parts of fish oil, 1.380 parts of soybean oil, 1.5 parts of calcium dihydrogen phosphate, 1.99988 parts of microcrystalline cellulose, 0.00012 parts of capsaicin, 0.015 parts of hydroxyanisole, 0.22 parts of L-threonine and 5 parts of composite premix.

[0009] Furthermore, the preparation method of the grass carp feed with added capsaicin is as follows: the feed raw materials are crushed until all of them pass through a 40-mesh sieve, and then mixed evenly according to the mass fraction to form particles with a diameter of 2 mm and a length of 3 mm, and the grass carp feed with added capsaicin is obtained after air-drying at room temperature.

[0010] The beneficial effects of the present invention are as follows: the present invention effectively improves the anti-stress ability of grass carp in a hypoxic environment by adding a specific amount of capsaicin to grass carp feed; capsaicin can completely alleviate the decrease in the number of red blood cells and the increase in fragility caused by hypoxia, maintain the stability of red blood cell function, significantly reduce the negative impact of hypoxia stress on the liver of grass carp, inhibit the abnormal increase of serum alanine aminotransferase (GPT), aspartate aminotransferase (GOT) and lactate dehydrogenase (LDH) activities, and capsaicin effectively reduces liver cell damage caused by hypoxia stress; the present invention can significantly reduce breeding costs and increase output by alleviating the decrease in the number of red blood cells and the increase in fragility of grass carp caused by hypoxia stress in the late growth stage, and alleviates liver damage, and has wide industrial application value. Moreover, as a natural active ingredient, capsaicin has an extremely low dosage and no risk of drug residues, and meets the requirements of ecological breeding and food safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The gill appearance and histological structure of the fish in the basal diet-normoxia group in Example 2; Figure 2 The gill appearance and histological structure of the fish in the basal diet-hypoxia group in Example 2; Figure 3 This is the appearance and tissue structure of the gills of fish in the hypoxia group of the present invention's diet in Example 2. Detailed implementation mode

[0012] The following combines examples to make a detailed description of the specific implementation mode of the present invention.

[0013] Example 1 Select 180 healthy grass carps with an average weight of 317 g, randomly divide them into two treatment groups, namely the control group and the capsaicin addition group. Each group has 3 replicates, with 30 tails in each replicate, and they are fed with the basal diet and the grass carp diet added with capsaicin of the present invention respectively.

[0014] The basal diet includes the following components in parts by mass: 3 parts of fish meal, 3 parts of rapeseed meal, 14 parts of soybean meal, 22.15 parts of defatted cottonseed protein, 28 parts of α-starch, 17.085 parts of flour, 2.650 parts of fish oil, 1.380 parts of soybean oil, 1.5 parts of calcium dihydrogen phosphate, 2 parts of microcrystalline cellulose, 0.015 parts of butylated hydroxyanisole, 0.22 parts of L-threonine and 5 parts of compound premix; The grass carp diet added with capsaicin includes the following components in parts by mass: 3 parts of fish meal, 3 parts of rapeseed meal, 14 parts of soybean meal, 22.15 parts of defatted cottonseed protein, 28 parts of α-starch, 17.085 parts of flour, 2.650 parts of fish oil, 1.380 parts of soybean oil, 1.5 parts of calcium dihydrogen phosphate, 1.99988 parts of microcrystalline cellulose, 0.00012 parts of capsaicin, 0.015 parts of butylated hydroxyanisole, 0.22 parts of L-threonine and 5 parts of compound premix.

[0015] The preparation methods of the basal diet and the grass carp diet added with capsaicin are both: crush the feed raw materials until all pass through a 40-mesh sieve, then mix evenly according to the parts by mass, make into particles with a diameter of 2 mm and a length of 3 mm, and air-dry at room temperature to obtain.

[0016] The feeding method of this example is: the experimental grass carps are respectively raised in (2.0 m×2.0m×2.0 m) net cages for 63 days. Feed regularly 4 times a day at 7:00, 11:00, 15:00, and 19:00. After feeding for ten minutes each time, collect, dry and weigh the remaining feed, and calculate the feed intake (FI). And observe the health status of the grass carps every day. During the test, the water temperature and pH value are 25.8±2.1°C and 7.5±0.2 respectively, and the dissolved oxygen is maintained at ≥6 mg / L. After the feeding test is over, stop feeding for 24 h, anesthetize with ethyl aminobenzoate, and weigh by cage unit.

[0017] The test results are shown in Table 1. After the grass carps are fed with the diet added with capsaicin of the present invention, the final weight increases by 14%, the feed intake increases by 3%, the feed utilization rate increases by 15%, and the weight gain rate increases by 19%. It shows that capsaicin can significantly promote the feeding of grass carps, improve the feed conversion and utilization efficiency, and promote the growth of grass carps.

[0018] Table 1 Effects of capsaicin on the growth performance of grass carp Item Basic feed group Feed group of the present invention Average initial weight (g / tail) 317.11±0.84 317.22±0.69 Average final weight (g / tail) 1164.67±61.34 1325.67±179.89 Average feed intake (g / tail) 1269.13±13.21 1304.61±39.17 Feed efficiency 0.67±0.04 0.77±0.12 Weight gain rate (%) 267.30±19.90 317.98±57.53 Example 2 Effect of capsaicin on the ability of grass carp to resist hypoxia stress: On the basis of Example 1, the experiment was continued. 24 fish were selected from each treatment (12 in the hypoxia group and 12 in the normoxia group). The dissolved oxygen in the normoxia group was ≥6 mg / L, and the dissolved oxygen in the hypoxia group was 1 mg / L. The dissolved oxygen concentration of the water body was monitored with a YSI dissolved oxygen meter, and the test period was 96 hours.

[0019] After the hypoxia test, the grass carp blood was centrifuged for 10 min and the supernatant (i.e., blood sample) was taken to measure the hematological indexes. After blood collection, the fish in each treatment were slaughtered, and the gills and livers were separated, and enzyme activity samples, molecular samples, HE section samples, and transmission electron microscope samples were taken respectively.

[0020] The effects of capsaicin on the related indexes of grass carp blood red blood cells are shown in Table 2. Hypoxia stress led to a decrease in the number of red blood cells and a significant increase in the minimum and maximum fragility of red blood cells. Compared with the basal diet-normoxia group (N-N), the increase amplitudes of the minimum and maximum fragility of red blood cells in the basal diet-hypoxia group (N-H) were 12% and 31% respectively. After adding capsaicin to the diet of the present invention-hypoxia group (capsaicin-H), it could completely relieve the decrease in the number of red blood cells and the increase in red blood cell fragility caused by hypoxia, indicating that capsaicin could relieve the decrease in the number of red blood cells and the increase in fragility of grass carp in the late growth stage caused by hypoxia stress.

[0021] Table 2 Effects of capsaicin on the related indexes of grass carp blood red blood cells under hypoxia stress

[0022] The activities of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), and lactate dehydrogenase (LDH) in serum are key indexes of hepatocyte damage. When hepatocytes are damaged, their permeability changes, and a large amount of GOT, GPT, and LDH are transported from hepatocytes to serum, resulting in an increase in their activities in serum. Table 3 shows the changes in the related indexes of grass carp serum in each treatment group. From the data in the table, it can be seen that hypoxia stress led to a significant increase in GOT, GPT, and LDH in serum. Compared with the basal diet-normoxia group (N-N), the increase amplitudes of serum GOT, GPT, and LDH in the basal diet-hypoxia group (N-H) were 15%, 29%, and 14% respectively. After adding capsaicin to the diet of the present invention-hypoxia group (capsaicin-H), it could completely relieve the increase in hypoxia serum GOT, GPT, and LDH, indicating that capsaicin could relieve the liver damage of grass carp in the late growth stage caused by hypoxia stress.

[0023] Table 3 Effects of capsaicin on the related indexes of grass carp serum under hypoxia stress

[0024] Gills are important respiratory organs of fish and play an important role in regulating the hypoxic stress response. When fish are under long-term hypoxic conditions, the gill tissue structure will be damaged. In this embodiment, the gills and HE section results of the basal diet-normoxia group, the basal diet-hypoxia group, and the diet of the present invention-hypoxia group are as Figures 1-3 shown. The gills of the basal diet-normoxia group are rosy, while the gills of the basal diet-hypoxia group are blackened, which is caused by insufficient oxygen carrying. The diet of the present invention-hypoxia group added with capsaicin completely alleviates the symptom of blackened gill color; the HE results show that compared with the basal diet-normoxia group, the gill lamellae of the basal diet-hypoxia group show serious detachment, disappearance, and even necrosis of respiratory epithelial cells, the shape of the gill lamellae is bent, and the gill structure is severely damaged. However, the diet of the present invention-hypoxia group can completely alleviate the abnormal oxygen carrying and appearance of the gills caused by hypoxia.

[0025] Although the specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative work still fall within the protection scope of this patent.

Claims

1. Application of capsaicin in grass carp's resistance to hypoxia stress.

2. The application according to claim 1, characterized in that Use capsaicin as an additive and add it to the grass carp feed to feed grass carp.

3. The application according to claim 1, wherein: The addition amount of the capsaicin is 0.00006% or 0.00012% of the quality of the grass carp feed.

4. The application according to claim 1, wherein The grass carp feed added with capsaicin comprises the following components in parts by mass: fish meal 2.5 - 3.5 parts, rapeseed meal 2.5 - 3.5 parts, soybean meal 13 - 15 parts, defatted cottonseed protein 21.5 - 22.5 parts, α - starch 26 - 30 parts, flour 17 - 17.1 parts, fish oil 2.5 - 2.7 parts, soybean oil 1.3 - 1.5 parts, calcium dihydrogen phosphate 1.2 - 1.7 parts, microcrystalline cellulose 1.99988 or 1.99994 parts, capsaicin 0.00006 or 0.00012 parts, BHA 0.015 parts, L - threonine 0.22 parts and compound premix 5 parts.

5. The application according to claim 4, wherein The grass carp feed added with capsaicin comprises the following components in parts by mass: fish meal 3 parts, rapeseed meal 3 parts, soybean meal 14 parts, defatted cottonseed protein 22.15 parts, α - starch 28 parts, flour 17.085 parts, fish oil 2.650 parts, soybean oil 1.380 parts, calcium dihydrogen phosphate 1.5 parts, microcrystalline cellulose 1.99988 parts, capsaicin 0.00012 parts, BHA 0.015 parts, L - threonine 0.22 parts and compound premix 5 parts.

6. The application according to claim 1, characterized in that The preparation method of the grass carp feed added with capsaicin is as follows: crush the feed raw materials until all pass through a 40 - mesh sieve, then mix evenly according to the parts by mass, make into particles with a diameter of 2mm and a length of 3mm, and obtain the grass carp feed added with capsaicin after air - drying at room temperature.

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