Research and Application of Growth Promoters in Aquaculture
Research on Aquatic Growth Promoters
1. Growth Promoters
The main function of fish growth promoters is to stimulate the endocrine system of fish, regulate metabolism, and improve feed utilization, thereby promoting the growth of farmed fish.
1.1 Olaquindox
Olaquindox is a broad-spectrum antibacterial chemical drug with an obvious growth-promoting effect, and is the most widely used growth promoter in animal feed. Its action is to affect metabolism, promote synthesis, improve the utilization of energy and nitrogen in fish feed, and promote nitrogen deposition. Wang Shengneng et al. added 150 mg/kg of olaquindox to the diets of carp and tilapia, and the growth rate increased by 75% and 65% compared with the control; Ye Jinyun added 50 mg/kg of olaquindox to the diet to feed 1-year-old grass carp. The growth rate increased by 53.82%, and the survival rate increased by 22.7%; Wen Yinliang et al.'s experiment on carp proved that adding 200 mg/kg of olaquindox promoted growth, with the relative growth rate increasing by 53.88% compared with the control group, and the fish body's tolerance to low oxygen was enhanced, and the meat quality was also improved; Zhang Liang et al. believed that adding 100 mg/kg of olaquindox to channel catfish had a good growth-promoting effect. Geng Yi et al. reported that for long-term addition of olaquindox to carp feed, the dose should be controlled below 50 mg/kg, otherwise there is a risk of poisoning in the fish body (ascites and hemorrhagic symptoms appear, intolerance to transport, and mass death during severe fishing).
1.2 Antibiotics
Antibiotics are fermentation products of microorganisms. Their mechanism of action is mainly to change the structure of pathogenic microorganisms and interfere with their metabolic processes, such as hindering cell wall synthesis, affecting the permeability of the cytoplasmic membrane, hindering protein synthesis, and changing nucleic acid metabolism. In addition, some scholars believe that after animals consume antibiotics, their intestinal wall becomes thinner and healthier, thereby improving intestinal absorption efficiency. However, whether antibiotics have a growth-promoting effect on fish is still somewhat controversial. Hashimoto (1956) and Aoe (1961), after reviewing the research results of Woef et al. on the effects of penicillin, oxytetracycline, chlortetracycline and other antibiotics on fish growth, pointed out that antibiotics basically have no effect on promoting fish growth. Cao Weimin et al. (1993) added 18 mg of erythromycin to every 100 kg of basal feed and raised 40-60 g juvenile Feng carp in tanks for 40 days, and also reached the same conclusion. It is believed that this is because the digestive tract of healthy fish is in a sterile state due to lack of food. However, some scholars hold the opposite view. Ye Yuantu (1994) added tetracycline medicinal residue at a ratio of 1.3% to compound feed to feed carp. After 50 days, the average weight gain rate of the experimental group was 33.27% higher than that of the control group, and the feed coefficient was 22.05% lower than that of the control group. He believed that the growth-promoting effect of the medicinal residue mainly depended on the tetracycline in it, and the mechanism of action was to inhibit the growth of microorganisms unfavorable to carp growth.
Flavomycin is an antibiotic feed additive developed in the early 1970s. A large number of studies on pigs, broilers and meat ducks have confirmed that flavomycin can promote the growth and reproduction of beneficial microorganisms in the animal intestinal tract, inhibit harmful microorganisms, maintain the microbial ecological balance in the digestive tract, and facilitate the absorption of nutrients. In recent years, studies have shown that flavomycin is also a relatively ideal additive in fish feed. Flavomycin is a macromolecular substance with a relative molecular mass of 1582, and is not easily digested and absorbed by fish. Its main function is to purify the internal environment of the digestive tract, promote thinning of the intestinal tract, and improve the absorption rate of nutrients. Flavomycin can also promote various biochemical reactions in the fish body, regulate metabolism, and enhance the protein conversion rate in the fish body. Wang Xuehong and Xia Changqing confirmed through research that flavomycin has a growth-promoting effect on slow-growing European eels; Ren Zelin reported that adding flavomycin to feed can promote the growth of carp; Zhou Xiaoqiu's research concluded that adding flavomycin to feed has no negative impact on the transport tolerance of carp. The optimal amount of flavomycin in the feed for carp in the early growth stage is 3 mg/kg, and the combined effect of flavomycin and olaquindox on carp growth promotion is not obvious.
1.3 Hormones
Research on growth promoters for fish and shrimp began in the 1960s. Because fish and shrimp are aquatic organisms, their digestion and metabolic mechanisms are different from those of mammals and poultry, so many antibiotics and antibacterial agents used to promote the growth of livestock and poultry have no effect in fish and shrimp bait. The growth promoter commonly used in fish and shrimp bait now is olaquindox. Since the 1980s, the most eye-catching growth promoter studied internationally has been growth hormone. Growth hormone is secreted by acidophilic cells in the anterior pituitary gland of vertebrates. Pickfold and Atz (1957) pointed out that growth hormone is a single-chain polypeptide hormone composed of 200 amino acid residues and can promote fish growth. Y. Eitomoite (1964), R. Smift et al. (1965) added pituitary growth hormone to bait and found that it had a significant promoting effect on the growth of rainbow trout and river perch. The development of genetic engineering has opened a path for the mass production of the proteinaceous trace active substance growth hormone. Takahashi Akiyoshi et al. (1985) used an improved isolation method to isolate 50 micrograms of growth hormone from about 1000 chum salmon pituitaries, and together with the Tokyo Research Institute of Kyowa Hakko Kogyo, which has the latest bioengineering technology, analyzed the amino acid sequence and the base sequence of the gene, and developed technology for mass production of growth hormone using genetic engineering. At present, the world can already produce growth hormones for cattle, pigs, sheep, chickens, fish and many other animals, and excellent results have been obtained through feeding. The Institute of Hydrobiology, Chinese Academy of Sciences is conducting this research work on fish.
However, there is also a view that growth hormone is a protein and is easily decomposed and destroyed by digestive enzymes, so it is not suitable for use as an additive. Experiments at the National University of Singapore confirmed that adding 0.01 mg/kg of thyroxine to feed can enhance the appetite of carp and accelerate the growth rate.
Steroid hormones currently include more than 20 kinds of steroid hormones, which have been used in more than 20 species of fish including salmon, trout, carp, crucian carp, and tilapia, all of which take effect orally as non-nutritive growth promoters. However, due to side effects such as carcinogenic residues and effects on sex, growth promoters mainly based on steroid hormones have never formed commercial production. Among them, androgens have a significant promoting effect on fish growth, while whether estrogens have a growth-promoting effect on fish remains controversial. Another role of applying steroid hormones to fish is to change sex differentiation, promote sex reversal, and produce large numbers of monosex fish. For example, producing all-male tilapia can also achieve the purpose of improving economic benefits.
1.4 Chinese Herbal Medicines
As a natural resource, Chinese herbal medicines contain trace components beneficial to organisms and have no toxic side effects. Yang Shifan (1994) believed that any substance with one of the following functions can promote fish growth and enhance disease resistance: (1) those that can excite the circulatory system and respiratory center, activate and improve blood circulation, enhance cell membrane activity, and regulate digestive tract and endocrine functions, including henbane, motherwort, and angelica; (2) those that can promote digestion and strengthen the stomach, stop fermentation and remove stagnation, strengthen gastrointestinal functional activity, and promote digestion, including hawthorn, tangerine peel, green tangerine peel, and bitter orange; (3) those that can excite the nerve center, stimulate gastrointestinal peristalsis, resist bacteria and inflammation, and eliminate sores and toxins, including bupleurum, wild chrysanthemum, dandelion, rhubarb, and coptis; (4) those that can strengthen the stomach, eliminate accumulation, kill parasites, detoxify, and excite gastrointestinal peristalsis, including pumpkin seeds and areca nut. Compound Chinese herbal medicine additives are a hot spot in the research and development of fish growth promoters. Wang Yongling reported that adding 1% garlic to feed can increase the weight gain rate of crucian carp by 7.99%, while reducing the feed coefficient by 10.37%; Chen Weiyan et al. added 0.5% mugwort leaf to feed to feed carp, and the weight gain rates of summer fry, 1-year-old carp, and 2-year-old carp increased by 11.65%, 22.46%, and 12.55% respectively compared with the control group; Wu Wen et al. added 0.3% gynostemma to feed to feed grass carp, which could increase weight gain by 31.25%. Duan Ming et al. used a formula of codonopsis, astragalus, and fennel, adding 1% to feed crucian carp, which could increase weight gain by 21.77%; Chen Tielang et al. used a formula of Polygonum multiflorum, astragalus, etc., adding 1% to feed, and the weight gain rate of Oreochromis niloticus increased by 95.40%, and the weight gain rate of catfish increased by 42.20%; Zhang Zhaohua et al. added a compound Chinese herbal medicine additive composed of 30 Chinese herbal medicines such as mugwort leaf, bitter orange, and medicated leaven to turtle feed. The results showed that the experimental animals gained more than 30% in weight compared with the end of the same period of the previous year. Wu Defeng et al. (2001) used a prescription composed of Chinese herbal medicines such as astragalus, codonopsis, Atractylodes macrocephala, Poria cocos, licorice, medicated leaven, hawthorn, angelica, rhubarb, Scrophularia, Isatis root, and Scutellaria as a disease-resistant and growth-promoting additive for European eels. The experimental results showed that European eels with Chinese herbal medicines added to the daily feed gained significantly more weight than the control group, and also had varying degrees of resistance to several common infectious diseases, indicating that Chinese herbal medicine feed additives improved the breeding effect of European eels. Liu Hongbai et al. (2004) found that adding Scutellaria and astragalus to feed can significantly promote the growth of carp and improve feed conversion efficiency, and adding Poria cocos, Houttuynia cordata, and Isatis root also had certain effects. Yan Youli et al. (1994) reported that using a prescription composed of Chinese herbal medicines such as rhubarb, Sophora flavescens, tangerine peel, astragalus, and licorice to protect the liver and promote gallbladder function, replenish qi and blood, and clear heat and detoxify, adding 0.3% to carp basal feed, the results showed that the daily growth rate of the experimental group was 30.6% higher than that of the control group, and the feed coefficient was 18.91% lower. Similar conclusions were also obtained by adding Chinese herbal medicine additives such as garlic, codonopsis, fennel, and licorice to the feed of crucian carp, tilapia, grass carp, silver carp, carp, fry, and prawns. This shows that Chinese herbal medicines have an obvious growth-promoting effect on aquatic animals.
Research on Chinese herbal medicines as fish growth-promoting additives is still not mature enough. Current research mainly focuses on comparing additive effects, and issues such as medication and formula, dosage, active ingredients, mechanism of action, and safety testing still need to be further explored.
--------------------------------------
Except for Chinese herbal medicines, the others should be used less or not at all, especially olaquindox, which is prohibited.
--------------------------------------
Olaquindox is indeed prohibited. Now there are not many options for things that can be added to fish feed to promote growth.
--------------------------------------
Chinese herbal medicines need much more research. Currently they are used very little.
--------------------------------------
Personally, I think olaquindox can be used in aquaculture. Although the state does not allow it, as long as its purity is sufficient, there is no major problem!
--------------------------------------
Current laws are relatively complete for livestock and poultry, but there are quite a few loopholes in the regulations for aquatic animals. Whether to use it or not is indeed highly controversial!!
--------------------------------------
Olaquindox is prohibited. I think that by controlling its added amount well, safe and effective results can be achieved.
--------------------------------------
It would be best if hormones could be used.
--------------------------------------
Olaquindox indeed has a very obvious growth-promoting effect on fish. Some feed companies should still be using it secretly now. The key is to control the amount well.
--------------------------------------
Just passing by, learning a bit.
--------------------------------------
In aquatic feed, olaquindox is the best antibacterial growth promoter. There is currently nothing better to replace it.
--------------------------------------
For the food safety of aquatic products, formulators have a responsibility.
The main function of fish growth promoters is to stimulate the endocrine system of fish, regulate metabolism, and improve feed utilization, thereby promoting the growth of farmed fish.
1.1 Olaquindox
Olaquindox is a broad-spectrum antibacterial chemical drug with an obvious growth-promoting effect, and is the most widely used growth promoter in animal feed. Its action is to affect metabolism, promote synthesis, improve the utilization of energy and nitrogen in fish feed, and promote nitrogen deposition. Wang Shengneng et al. added 150 mg/kg of olaquindox to the diets of carp and tilapia, and the growth rate increased by 75% and 65% compared with the control; Ye Jinyun added 50 mg/kg of olaquindox to the diet to feed 1-year-old grass carp. The growth rate increased by 53.82%, and the survival rate increased by 22.7%; Wen Yinliang et al.'s experiment on carp proved that adding 200 mg/kg of olaquindox promoted growth, with the relative growth rate increasing by 53.88% compared with the control group, and the fish body's tolerance to low oxygen was enhanced, and the meat quality was also improved; Zhang Liang et al. believed that adding 100 mg/kg of olaquindox to channel catfish had a good growth-promoting effect. Geng Yi et al. reported that for long-term addition of olaquindox to carp feed, the dose should be controlled below 50 mg/kg, otherwise there is a risk of poisoning in the fish body (ascites and hemorrhagic symptoms appear, intolerance to transport, and mass death during severe fishing).
1.2 Antibiotics
Antibiotics are fermentation products of microorganisms. Their mechanism of action is mainly to change the structure of pathogenic microorganisms and interfere with their metabolic processes, such as hindering cell wall synthesis, affecting the permeability of the cytoplasmic membrane, hindering protein synthesis, and changing nucleic acid metabolism. In addition, some scholars believe that after animals consume antibiotics, their intestinal wall becomes thinner and healthier, thereby improving intestinal absorption efficiency. However, whether antibiotics have a growth-promoting effect on fish is still somewhat controversial. Hashimoto (1956) and Aoe (1961), after reviewing the research results of Woef et al. on the effects of penicillin, oxytetracycline, chlortetracycline and other antibiotics on fish growth, pointed out that antibiotics basically have no effect on promoting fish growth. Cao Weimin et al. (1993) added 18 mg of erythromycin to every 100 kg of basal feed and raised 40-60 g juvenile Feng carp in tanks for 40 days, and also reached the same conclusion. It is believed that this is because the digestive tract of healthy fish is in a sterile state due to lack of food. However, some scholars hold the opposite view. Ye Yuantu (1994) added tetracycline medicinal residue at a ratio of 1.3% to compound feed to feed carp. After 50 days, the average weight gain rate of the experimental group was 33.27% higher than that of the control group, and the feed coefficient was 22.05% lower than that of the control group. He believed that the growth-promoting effect of the medicinal residue mainly depended on the tetracycline in it, and the mechanism of action was to inhibit the growth of microorganisms unfavorable to carp growth.
Flavomycin is an antibiotic feed additive developed in the early 1970s. A large number of studies on pigs, broilers and meat ducks have confirmed that flavomycin can promote the growth and reproduction of beneficial microorganisms in the animal intestinal tract, inhibit harmful microorganisms, maintain the microbial ecological balance in the digestive tract, and facilitate the absorption of nutrients. In recent years, studies have shown that flavomycin is also a relatively ideal additive in fish feed. Flavomycin is a macromolecular substance with a relative molecular mass of 1582, and is not easily digested and absorbed by fish. Its main function is to purify the internal environment of the digestive tract, promote thinning of the intestinal tract, and improve the absorption rate of nutrients. Flavomycin can also promote various biochemical reactions in the fish body, regulate metabolism, and enhance the protein conversion rate in the fish body. Wang Xuehong and Xia Changqing confirmed through research that flavomycin has a growth-promoting effect on slow-growing European eels; Ren Zelin reported that adding flavomycin to feed can promote the growth of carp; Zhou Xiaoqiu's research concluded that adding flavomycin to feed has no negative impact on the transport tolerance of carp. The optimal amount of flavomycin in the feed for carp in the early growth stage is 3 mg/kg, and the combined effect of flavomycin and olaquindox on carp growth promotion is not obvious.
1.3 Hormones
Research on growth promoters for fish and shrimp began in the 1960s. Because fish and shrimp are aquatic organisms, their digestion and metabolic mechanisms are different from those of mammals and poultry, so many antibiotics and antibacterial agents used to promote the growth of livestock and poultry have no effect in fish and shrimp bait. The growth promoter commonly used in fish and shrimp bait now is olaquindox. Since the 1980s, the most eye-catching growth promoter studied internationally has been growth hormone. Growth hormone is secreted by acidophilic cells in the anterior pituitary gland of vertebrates. Pickfold and Atz (1957) pointed out that growth hormone is a single-chain polypeptide hormone composed of 200 amino acid residues and can promote fish growth. Y. Eitomoite (1964), R. Smift et al. (1965) added pituitary growth hormone to bait and found that it had a significant promoting effect on the growth of rainbow trout and river perch. The development of genetic engineering has opened a path for the mass production of the proteinaceous trace active substance growth hormone. Takahashi Akiyoshi et al. (1985) used an improved isolation method to isolate 50 micrograms of growth hormone from about 1000 chum salmon pituitaries, and together with the Tokyo Research Institute of Kyowa Hakko Kogyo, which has the latest bioengineering technology, analyzed the amino acid sequence and the base sequence of the gene, and developed technology for mass production of growth hormone using genetic engineering. At present, the world can already produce growth hormones for cattle, pigs, sheep, chickens, fish and many other animals, and excellent results have been obtained through feeding. The Institute of Hydrobiology, Chinese Academy of Sciences is conducting this research work on fish.
However, there is also a view that growth hormone is a protein and is easily decomposed and destroyed by digestive enzymes, so it is not suitable for use as an additive. Experiments at the National University of Singapore confirmed that adding 0.01 mg/kg of thyroxine to feed can enhance the appetite of carp and accelerate the growth rate.
Steroid hormones currently include more than 20 kinds of steroid hormones, which have been used in more than 20 species of fish including salmon, trout, carp, crucian carp, and tilapia, all of which take effect orally as non-nutritive growth promoters. However, due to side effects such as carcinogenic residues and effects on sex, growth promoters mainly based on steroid hormones have never formed commercial production. Among them, androgens have a significant promoting effect on fish growth, while whether estrogens have a growth-promoting effect on fish remains controversial. Another role of applying steroid hormones to fish is to change sex differentiation, promote sex reversal, and produce large numbers of monosex fish. For example, producing all-male tilapia can also achieve the purpose of improving economic benefits.
1.4 Chinese Herbal Medicines
As a natural resource, Chinese herbal medicines contain trace components beneficial to organisms and have no toxic side effects. Yang Shifan (1994) believed that any substance with one of the following functions can promote fish growth and enhance disease resistance: (1) those that can excite the circulatory system and respiratory center, activate and improve blood circulation, enhance cell membrane activity, and regulate digestive tract and endocrine functions, including henbane, motherwort, and angelica; (2) those that can promote digestion and strengthen the stomach, stop fermentation and remove stagnation, strengthen gastrointestinal functional activity, and promote digestion, including hawthorn, tangerine peel, green tangerine peel, and bitter orange; (3) those that can excite the nerve center, stimulate gastrointestinal peristalsis, resist bacteria and inflammation, and eliminate sores and toxins, including bupleurum, wild chrysanthemum, dandelion, rhubarb, and coptis; (4) those that can strengthen the stomach, eliminate accumulation, kill parasites, detoxify, and excite gastrointestinal peristalsis, including pumpkin seeds and areca nut. Compound Chinese herbal medicine additives are a hot spot in the research and development of fish growth promoters. Wang Yongling reported that adding 1% garlic to feed can increase the weight gain rate of crucian carp by 7.99%, while reducing the feed coefficient by 10.37%; Chen Weiyan et al. added 0.5% mugwort leaf to feed to feed carp, and the weight gain rates of summer fry, 1-year-old carp, and 2-year-old carp increased by 11.65%, 22.46%, and 12.55% respectively compared with the control group; Wu Wen et al. added 0.3% gynostemma to feed to feed grass carp, which could increase weight gain by 31.25%. Duan Ming et al. used a formula of codonopsis, astragalus, and fennel, adding 1% to feed crucian carp, which could increase weight gain by 21.77%; Chen Tielang et al. used a formula of Polygonum multiflorum, astragalus, etc., adding 1% to feed, and the weight gain rate of Oreochromis niloticus increased by 95.40%, and the weight gain rate of catfish increased by 42.20%; Zhang Zhaohua et al. added a compound Chinese herbal medicine additive composed of 30 Chinese herbal medicines such as mugwort leaf, bitter orange, and medicated leaven to turtle feed. The results showed that the experimental animals gained more than 30% in weight compared with the end of the same period of the previous year. Wu Defeng et al. (2001) used a prescription composed of Chinese herbal medicines such as astragalus, codonopsis, Atractylodes macrocephala, Poria cocos, licorice, medicated leaven, hawthorn, angelica, rhubarb, Scrophularia, Isatis root, and Scutellaria as a disease-resistant and growth-promoting additive for European eels. The experimental results showed that European eels with Chinese herbal medicines added to the daily feed gained significantly more weight than the control group, and also had varying degrees of resistance to several common infectious diseases, indicating that Chinese herbal medicine feed additives improved the breeding effect of European eels. Liu Hongbai et al. (2004) found that adding Scutellaria and astragalus to feed can significantly promote the growth of carp and improve feed conversion efficiency, and adding Poria cocos, Houttuynia cordata, and Isatis root also had certain effects. Yan Youli et al. (1994) reported that using a prescription composed of Chinese herbal medicines such as rhubarb, Sophora flavescens, tangerine peel, astragalus, and licorice to protect the liver and promote gallbladder function, replenish qi and blood, and clear heat and detoxify, adding 0.3% to carp basal feed, the results showed that the daily growth rate of the experimental group was 30.6% higher than that of the control group, and the feed coefficient was 18.91% lower. Similar conclusions were also obtained by adding Chinese herbal medicine additives such as garlic, codonopsis, fennel, and licorice to the feed of crucian carp, tilapia, grass carp, silver carp, carp, fry, and prawns. This shows that Chinese herbal medicines have an obvious growth-promoting effect on aquatic animals.
Research on Chinese herbal medicines as fish growth-promoting additives is still not mature enough. Current research mainly focuses on comparing additive effects, and issues such as medication and formula, dosage, active ingredients, mechanism of action, and safety testing still need to be further explored.
--------------------------------------
Except for Chinese herbal medicines, the others should be used less or not at all, especially olaquindox, which is prohibited.
--------------------------------------
Olaquindox is indeed prohibited. Now there are not many options for things that can be added to fish feed to promote growth.
--------------------------------------
Chinese herbal medicines need much more research. Currently they are used very little.
--------------------------------------
Personally, I think olaquindox can be used in aquaculture. Although the state does not allow it, as long as its purity is sufficient, there is no major problem!
--------------------------------------
Current laws are relatively complete for livestock and poultry, but there are quite a few loopholes in the regulations for aquatic animals. Whether to use it or not is indeed highly controversial!!
--------------------------------------
Olaquindox is prohibited. I think that by controlling its added amount well, safe and effective results can be achieved.
--------------------------------------
It would be best if hormones could be used.
--------------------------------------
Olaquindox indeed has a very obvious growth-promoting effect on fish. Some feed companies should still be using it secretly now. The key is to control the amount well.
--------------------------------------
Just passing by, learning a bit.
--------------------------------------
In aquatic feed, olaquindox is the best antibacterial growth promoter. There is currently nothing better to replace it.
--------------------------------------
For the food safety of aquatic products, formulators have a responsibility.