Fish are temperature-changing animals, and their growth and reproduction are closely related to climatic factors such as temperature, light, and air pressure. Among them, environmental temperature is the most important climatic factor for fish growth and development. Within a certain temperature range, higher temperatures make fish grow faster, and lower temperatures grow slower. In the cultured fish, when the water temperature is 15-32℃, most carps are suitable for survival, while the four major home fish enter the obvious growth period at 15-20℃, and enter the optimal growth period at 25-30℃, exceeding this temperature , It will produce heat stress. 1. The effect of heat stress on fish 1.1 The effect of heat stress on fish’s nerve and endocrine system In the process of fish’s heat stress response, a large amount of catecholamine hormones stored in cells can be released and the blood cortisol content is significant Elevated. Changes in catecholamines and cortisol will affect the immune function of fish. In the process of stress, catecholamines mainly accelerate the decomposition of glycogen and raise blood sugar to meet the body’s energy needs during stress. In addition, it can also promote adrenocorticotropic hormone, growth hormone, triiodothyronine and thyroxine, etc. Secretion, thereby coordinating more defense mechanisms to counter the stress response. However, too much catecholamines can also lead to decreased feed intake, increased energy consumption, increased oxygen consumption, and tissue ischemia. Cortisol can promote fat mobilization, leading to reduced fat synthesis, weight loss, and growth arrest. 1.2 The effect of heat stress on the anti-oxidation regulation ability of fish The spleen is one of the important immune organs of fish and contains a large number of macrophages. When macrophages are under stress by external stimuli, they will burst into respiration, produce a large number of free radicals, complete the physiological functions of phagocytosis and sterilization, and induce inflammation. When the body is abnormally stimulated, the balance of the production and elimination of free radicals in the body is broken, and the concentration of Phenibut powder wholesale free radicals will increase abnormally. High concentrations of free radicals will attack DNA and RNA, break the main chain, destroy and degrade bases, cause base mutations, change their thermal stability, and also cause protein denaturation and autoimmune diseases. Strong oxidizing free radicals will damage the plasma membrane, causing lipid peroxidation and producing lipid peroxides. Among them, malondialdehyde is a class of substances produced after the decomposition of lipid peroxides that has a strong toxic effect on organisms. 1. 3 Heat stress leads to up-regulation of HSP gene expression. Heat stress protein (HSP) is a non-specific production of fish under stress conditions and can enhance the body’s ability to adapt to high and low temperatures, trauma, bacterial and viral infections, etc. Defensive product. The main physiological function of HSP is to promote and maintain the correct folding of new polypeptide chains, regulate cell growth, division, differentiation, and death, participate in cell resistance to damage, repair and heat tolerance processes, and help cells restore normal structure and function. , And play an important role in the treatment of many diseases. At the same time, HSP has an antioxidant effect. Its antioxidant effect is manifested in: HSP can inhibit the production of key enzymes of oxygen free radicals, and reduce the production of oxygen free radicals through feedback; HSP can increase the level of endogenous antioxidant enzymes to maintain cell function and survival; HSP can Affect the release and metabolism of glucocorticoids. 2. The role of eucommia leaf extract in anti-heat stress. Eucommia leaf extract is produced from eucommia leaves using modern advanced extraction technology. It has superior anti-oxidation, scavenging free radicals, anti-heat stress, antibacterial and anti-bacterial properties. It improves immunity and is a green feed additive with high efficiency, environmental protection, safety, and non-toxic side effects. The anti-heat stress effect of Eucommia leaf extract is mainly manifested in the following aspects China Phenibut . 2. 1 The effect of Eucommia leaf extract on blood hormones has found that the chlorogenic acid in Eucommia leaf extract can inhibit the contraction of fibroblast collagen framework caused by fibroblasts and inhibit adrenal glands caused by stress response. Elevated corticosteroids. 2.2 Effect of Eucommia Leaf Extract on the Antioxidant Function of Fish Body Eucommia Leaf Extract can remove free radicals generated by heat stress in the body and protect fish body tissues from oxidative damage. The chlorogenic acid and its derivatives in eucommia leaf extract have a stronger free radical elimination effect than ascorbic acid, caffeic acid and tocopherol, and can effectively remove DPPH free radicals, hydroxyl free radicals and superoxide anion free radicals, chlorogenic acid It has anti-oxidation effect because it contains a certain amount of R-OH group, which can form hydrogen free radicals with anti-oxidation effect to eliminate the activity of hydroxyl free radicals and super anions and other free radicals, so as to protect tissues from oxidation. purpose. The polysaccharides and flavonoids in the extract of Eucommia ulmoides also have significant free radical scavenging ability. The mechanism of action includes: Scavenge free radicals by transferring electrons to free radicals; Block the generation of free radicals by chelating with metal ions; Activate antioxidant enzyme activity; Inhibit enzyme oxidation. 2.3 The effect of Eucommia leaf extract on HSP70 Existing studies have shown that the thermal tolerance and immune function of aquatic animals are closely related to the expression of HSP70 gene. Studies have shown that HSP70 can maintain intracellular homeostasis, and its increase or high expression in cells can significantly improve cell viability and increase cell tolerance to heat stress. Many Chinese herbal medicines or plant extracts with immune enhancement effects can not only significantly improve the non-specific immune function of farmed fish, but also induce the expression of HSP70 in various immune tissues. According to reports, anti-stress granules of traditional Ch Buy Phenibut Online inese medicine can increase the heat tolerance of the body’s cells by increasing the content of HSP70 in pig liver. The heat-clearing compound Chinese herbal medicine can induce the increase of HSP70 expression in the liver tissue of heat-stressed rats and improve the tolerance of tissue cells. Lei Aiying et al. reported that the HSP70 gene mRNA expression in the liver tissue of Litopenaeus vannamei was significantly higher than that in the control group after feeding Litopenaeus vannamei with 1% Chinese herbal feed for 10 days. Ellen et al. injected 1ml (2 mg/ml tail) zymosan into the carp intraperitoneally. At 24 h after the injection, the expression of HSP70 gene was significantly increased in the head and kidney, and then decreased rapidly. Tang Jufen and others studied the effect of plant polysaccharides on the expression of tilapia heat stress protein genes, and showed that injection of a certain dose of plant polysaccharides can significantly increase the expression of HSP70 gene in gills, head kidney, liver and spleen tissues. It can be seen that plant polysaccharides can By inducing the expression of HSP70 gene in gills, head kidney, liver and spleen tissues, tilapia can reach the heat-adapted state earlier. It has been reported that plant extracts have the dual effects of nutrition and medicine, especially heat-clearing, relieving heat, qi and detoxification, etc., which can improve the immunity of aquatic animals and promote their blood circulation, maintain the stability of the endocrine system, and make the body’s health The normal metabolism provides a material basis for the body to resist high temperature, thereby alleviating the adverse effects of high temperature on aquatic animals. Eucommia ulmoides leaf extract can also effectively promote the high-level expression of HSP70 in the liver of farmed fish under heat stimulation, and is an effective additive that can be used to relieve heat stress in fish. It can be seen that the extract of Eucommia ulmoides mainly eliminates the increase of free radicals caused by heat stress and increases the expression of HSP 70 gene in the liver, so as to alleviate various problems caused by heat stress. The article is compiled and published by Shandong Longchang Animal Health Products Co., Ltd. (www.sdlcdb.com). Please indicate the source for reprinting. Contact number: 18396824491