China is currently the world's largest aquaculture aquaculture, and its aquaculture species and production rank first, and the aquaculture industry is developing at an unprecedented rate. With the enormous abundance of social materials and the continuous improvement of people’s living standards, people are increasingly concerned about the quality of daily food consumption. Aquatic products, which are irreplaceable as one of the main sources of protein in daily consumer products, are the focus of attention. Compared with the early 20-30 years, the environmental pollution is becoming more and more serious, the variety and usage of pesticides are increasing sharply, the abuse of other antibiotics in antibiotics, the disorderly addition of feed additives (including adhesives) in aquaculture species, etc. There are worrying phenomena in the aquatic products supplied by the market: that meat quality is not as delicious as before, accumulation of heavy metals, residues of pesticides and antibiotics, individuals are getting smaller, and strange smells appear from time to time. Consumers continue to raise doubts that the demand for quality of aquatic products is growing louder and louder. Green pollution-free products or organic products are required. This is a major concern worldwide, especially after the accession to the WTO, with the integration of global economic and trade, The requirements for the quality of aquatic products are not only domestic quality issues, but also placed on a globally recognized quality issue. Zhejiang Province is a national economic province, and Hangzhou is a provincial capital of Zhejiang Province. It is known as the "land of fish and rice, the home of silk." At present, provincial and municipal people of all walks of life and fisheries administrative departments have recognized this problem and have referred it to the agenda to prepare for the establishment of the “Aquatic Quality Monitoring Centerâ€. Its purpose is to formulate standards that require water The products are produced, processed and sold in accordance with standards. The quality of the aquatic products is monitored and tested. The Ningbo City of Zhejiang has taken the lead in establishing the “Aquatic Product Quality Monitoring Centerâ€. The Shanghai Bureau of Quality and Technical Supervision has already established “safety. “Local standards for high-quality aquatic products†are the trend of the times. Hangzhou City tests the meat (pork), vegetables, and tofu in daily consumer products, and conducts sampling inspections by specialized agencies. The same applies to aquatic products. Healthy breeding has become imminent, but it is limited to the special situation of the aquaculture industry in the city, namely state-owned units, collective units, and more specialized households for breeding, from breeding species, aquaculture forms, breeding cycles, aquaculture techniques, breeding environment The average weight difference is large, and the previous quality problems of aquatic products have not been given corresponding attention. Kang also implement a breeding experiment, summary, promotion process must recognize the urgency of providing pollution-free food, changing production technology to meet product standards.
Here are some of the major aspects and technical issues concerning the healthy breeding of aquatic products expressed as follows, I hope to play an important role.
I. Seedlings of seed problems are the basis of the aquaculture industry. The emergence of a good breeding species can raise an industry upsurge (such as turtles, turtles, river crabs, giant prawn, shrimp, prawns, etc.). The opposite is a poor one. Variety will bring greater losses to the industry. Variety refers to a species with good germplasm gene, no degradation, strong disease resistance, rapid growth, high feed utilization, good meat quality, certain genetic stability, and should be derived from the original species. Generation - improved species. In order to make the cultivated species healthy and less harmful and reduce the use of drugs, the residues of various drugs and heavy metal ions can be minimized. However, breeding of seedlings often takes a long time and costs a lot and needs to be completed by specialized scientific research institutes. Hangzhou has invested some effort in this area. The main measures for improving the quality of seedlings include:
1. Crossbreeding Breeding of superior varieties or strains by means of artificial crossbreeding, and directional breeding of species with fast growth, strong resistance to disease and resistance to stress, for the majority of farmers to breed. This is one of the most important breeding methods in China. Such as silver squid, Feng Yu and so on.
2. Bioengineering techniques are obtained through gynogenetic development, pedigree breeding, combined with multilineage crossbreeding, or by artificial induction (temperature, pressure, biological factors) to double the chromosomes of aquatic product species. For example, Jian 鲤 (purple purpurea and Yuanjiang 鲤 as original parent), unisexual tilapia grade. For example, the engineering triploid (triploid) and triploid species have the characteristics of fast growth and large individuals. Now people know more and more clearly about DNA, and their molecular breeding techniques will gradually improve. We believe that in the near future there will be more and more healthy varieties that are cultivated using DNA technology.
3. The production of disease-free seedlings is becoming more and more intensive. Today, the diseases of farmed species are also increasing, especially viral diseases. Therefore, in the cultivation of conventional seedlings, the promotion of “healthy seedlings†and “viral-free or sterile seedlings†is to strictly select the parents throughout the seedling raising process and strictly control the number of bacterial viruses and other harmful organisms in the water, so as to minimize the The degree is conducive to future breeding. For example, many shrimps are now cultivated using this method, such as SPF without specific virus. In the future, it will also increase its disease resistance from the genetic level.
4. Genetic characteristics of aquaculture germplasm The current aquaculture industry in China tests only the introduction, development and domestication of cultured species. With the development of the aquaculture industry, due to the long-term inbreeding and the genetic characteristics of many good varieties have changed, they must be tested regularly to ensure that they have a good idea. The developed countries, especially the United States, have done relatively well. China has done less work in this area and has a certain degree of blindness in aquaculture production.
5. The rejuvenation of good germplasm is the rejuvenation of germplasm on large-scale farmed species. The current main approach is to introduce the origin or natural germplasm on a regular basis to improve the decline in the growth characteristics of the culture due to the long cultivation time. Variations in individuals become smaller. This problem exists in many species cultivated in our province, such as the mixing of shrimp and crab strains and inbreeding, so that the specifications of commodities are generally smaller than the original in the same culture conditions, and many fishes also have this phenomenon. In the future, we will solve problems by applying improved seed and artificial breeding.
6. Strictly controlling blind introductions The increase in the number of farmed species in China in recent years is greater than that at that time and in that country. This has also brought serious consequences. Regardless of whether it is introduced from abroad or from outside the province (including trans-regional), strict quarantine (especially the former) must be carried out to clarify the original diseases of the district and the status of the disease and the disease caused by the species. The impact of the pathogenic flora and the evaluation of the hazards to the major local economical culture species; the identification of the impact of the introduction of the species on ecological balance and germplasm resources will be introduced. Blind introduction has caused a lot of damage to our original breeding and introduced varieties, especially the diseases in the breeding of shrimp, crab, and crab. The “Administrative Measures on Aquatic Seed Production†issued by the Ministry of Agriculture should be strictly implemented.
II. Environmental issues Aquaculture water environment With the great development of industry, pollution is becoming more and more serious. This is a worldwide environmental problem, including direct pollution of water bodies, pollution of land, and pollution of the atmosphere, but it will eventually pollute water bodies. surroundings. As for the development of aquaculture, its own biological pollution is also increasing. Deterioration of environmental conditions will surely increase the diseases of cultured species and increase the use of drugs by farmers. The higher the accumulation of heavy metals and pesticides, the higher the residue of antibiotics, thus affecting the quality of products. The main measures to improve the aquaculture water environment are:
1. Selection of site and water source The excavation of Xintang must consider the choice of site. There are not many ponds newly excavated after the release of grain in Zhejiang Province. It is also necessary to consider this issue (only the new fish ponds were added in 2001 in Hangzhou area. Thousands of acres). Open ponds must be selected from sources that have sufficient water, fresh water, and little or no pollution. To understand the situation of industrial pollution and pesticide pollution around the year, if necessary, carry out water quality tests to meet the fishery water quality standards in China.
2. The removal of excessive silt is particularly important for old ponds. Silt is often the site for the proliferation of pathogens, and excessive silt can cause excessive oxygen consumption in the breeding process, and can also cause outbreaks in disease seasons. Generally only about 20 centimeters of mud can be left.
3. Improvement of sediment (1) In addition to removing excess silt every year, it is best to allow it to dry in winter, and to kill a large number of harmful pathogens and their spores, spores, resting eggs, etc. through freezing and sunlight to reduce the number of The number of episodes. And after cracking the substrate, air and soil can be fully contacted, the organic matter in the substrate can be fully oxidized, minerals can be mineralized into inorganic salts, and can become the nutrient source of food organisms in the pond in the coming year. (2) Before stocking each year, use sufficient amount of quicklime to fully mix with the sludge. A stable and slightly alkaline water environment that can maintain the pH of the water will be conducive to the breeding of beneficial microorganisms and reduce the disease. Second, the bottom silt can be loosened. , increase the permeability.
4. Clear ponds Clear ponds can be dried at the end of the year or before stocking in the coming year. The main purpose is to remove the wild fish, shrimp and pathogens in the pond, which will help the survival rate of the culture and reduce the incidence of the breeding process.
5. Water quality treatment (1) Chemical treatment In order to avoid large-scale disease outbreaks in culture, many water treatment ponds are set up to sterilize the cited water sources in advance to ensure that they are added to the pool. The water in the pathogen is not pathogenic, reducing the incidence of disease and improving the survival rate. For example, the pretreatment of shrimp in high-level pond culture. (2) Biological treatment mainly applies and controls the growth of beneficial microbial communities. When the beneficial microorganisms multiply, the growth of pathogenic bacteria and harmful bacteria will be inhibited and the occurrence of diseases will be reduced. In addition, beneficial bacteria can decompose organic substances under aerobic conditions and reduce self-pollution in the breeding process. Biological treatment of higher levels of biological rotation, bio-packaging, etc., in industrial or recirculating aquaculture, etc.; lower level of treatment is the regular addition of beneficial microorganisms, such as PSB, digestive bacteria, viable bacteria, etc., in general culture ponds. (3) Physical treatment is mainly through pre-sterilization or filtration of influent water by UV or ozone.
6. Simulating the natural ecological environment In the cultured water body, as many species as possible are added to habitats, hidden sites and activities. For example, additional nets for three-dimensional culture of green shrimp and hanging nets for the cultivation of greenhouse turtles are all aimed at increasing the sheltered sites for farmed species; planting aquatic plants in shrimp and crab farming can increase their hidden sites to reduce mutual mistreatment and absorb Some organic matter and other nutrients improve the water quality; the food table in the soft-shelled turtle farm has the function of drying and back. This is to increase the survival rate and benefit in the breeding, but at the same time, it can reduce the occurrence of diseases by simulating the natural ecological environment.
Third, the feed problem Feed is the material basis for aquaculture, each breed because of its different characteristics of the nutritional requirements of feed are also different, and the same species in different growth stages of the nutritional requirements of feed are not the same. Under the conditions of numerous aquaculture species, the basic research on nutrient requirements of major aquaculture species in China has so far been insufficient, and the management of feed production industry is not sound enough. Therefore, each feed manufacturer has its own governance and different standards, with different ingredients and raw materials. Ultra-standard use of synthetic growth promoters. As a result, the nutrients may not necessarily meet the needs, the raw materials or feeds may be deteriorated, or the added adhesives and other chemical substances may not meet the standards, or the added drugs may not be standardized. The impact on production is: (1) First, it is a nutritional disease, liver disease such as fatty liver, high-sugar liver, or excessive accumulation of body fat, or many vitamin deficiencies, or poor growth, etc. Wait. (2) Decreased constitution of cultured species, vulnerability to infection by pathogens, and impaired survival rate. As a result, farmers increased their drug use and caused an increase in residual levels. (3) The final product contains substances that are harmful to the human body.
In order to ensure healthy breeding, the following measures must be taken in the feed sector:
1. First of all, the nutrient needs of the cultured species must be clearly understood, and the corresponding feed formulation must be determined based on the cultured species and the nutritional needs at different stages. The formula should be scientific and reasonable. At the same time, it calls for the need to increase basic research on feed and nutrition in aquaculture.
2. Raw materials for feed production should be strictly controlled, and raw materials that are deteriorating, contaminated, and do not meet the requirements should be rejected.
3. The use of additives (nutritional and non-nutrient additives such as vitamins, mineral salts, antibiotics, adhesives, natural growth promoters) must be compliant, especially the latter three. Chemically synthesized adhesives, which contain a lot of impurities or do not meet health standards, must not be used. Antibiotics used in pharmaceutical baits should not be abused. To understand their residual characteristics and compliance with the Veterinary pharmacopoeia, there must be sufficient withdrawal periods (15-20 days) before marketing.
4. The storage of finished feed should be used within the specified time, and can not be used after expiration or deterioration.
5. For some substances that need to be added at the time of feeding (such as oils), the product description should clearly indicate: the amount, type, ratio, and requirement of addition cannot be arbitrarily added.
6. Animal or vegetable feeds used to reduce feed costs, or to increase feed efficiency, or to make full use of local natural resources in aquaculture must be guaranteed to be non-destructive, non-polluting and suitable for use.
7. Local fishery or agricultural authorities and feed inspection and supervision departments shall strictly regulate and manage local feed manufacturers in accordance with national or local standards and conduct management according to law. The same must be regulated management of sales businesses, the sale of counterfeit products is strictly prohibited.
8. Scientific feed feeding: From the perspective of breeding, it is still necessary to adhere to a reasonable scientific feeding method (“Four Dingâ€) in order to reduce the disease, increase the survival rate, and reduce the use of drugs to ensure the health status of cultured species.
IV. Disease Prevention and Medication Problems There are many kinds of aquatic products. The culture environment is divided into seawater, freshwater and brackish water. In the whole breeding process, due to factors such as seedlings, feed, management, technology, water quality, temperature and climate, or There are more or fewer diseases, serious ones affect the survival rate and yield, or even out of production, so the prevention and treatment of diseases is an important task in aquaculture. In order to increase production and efficiency and improve the quality of aquatic products, the principle of prevention shall be advocated for the aquatic products cultivated. Once the disease needs to be correctly diagnosed, drugs should be selected for treatment, and the drugs used should be used to maximize the effectiveness of the drugs. Residue is reduced to the lowest level. From the perspective of healthy breeding, the following measures should be implemented:
1. Correctly diagnose the cause, select drugs reasonably, and strictly control the adaptability and physical and chemical characteristics of the drug. The correct diagnosis is the successful treatment and the first condition. Infectious diseases include: bacterial, viral, and parasitic diseases. Diagnosis is based on symptoms and pathogens. It should be noted that it takes a certain amount of time for the drug to exert its effect, and it cannot be expected that the day of drug use will be rapid and effective. Sometimes, deaths will increase after one or two days of drug use. If the drug dose is within the safe range, it may be due to The drug kills pathogenic bacteria in the animal body and prompts the bacterial cell to release endotoxin at the same time, causing animal death from acute poisoning. In this case, the mortality rate will generally decline after 3-4 days; otherwise, the drug dose should be considered too large. In the later stages of the disease, mixed infections of multiple pathogens often occur. Clinically, there are rotting diseases caused by the combined infection of trichoderma and bacteria, and enteritis caused by mixed infection of viruses and bacteria. At this time, there must be treatment programs for different pathogens. After the correct diagnosis, drugs are selected according to the adaptation of the drug, and a reasonable method of administration is adopted.
2, the use of drugs should not be as soon as possible Delay in the first appearance of the animal is generally the symptoms of loss of appetite, it can not eat baits, oral drugs do not work on the diseased animals, the disease has been difficult to cure. The drugs used for the prevention of animal disease has not yet played a protective role, so the real treatment of farmed animals is very small, so the prevention of aquaculture is more important than the importance of treatment. After the onset of the disease, the good fruit is treated too late and the incidence rate will increase rapidly, which will bring difficulties to the treatment.
3. Oral administration of external medications in combination with two administrations has different effects. For bacterial diseases, whether it is a body surface infection or a systemic infection, it should be combined with oral administration and external use. For surface parasitic infections, generally only topical drugs can be used, but sometimes oral administration can also be effective.
4. It is necessary to emphasize the importance of comprehensive therapeutic measures in the application of antibacterial drugs in the treatment of bacterial diseases. It is necessary to fully recognize the importance of the animal's own immunity. Over-reliance on the efficacy of antibiotics, neglecting feeding management and improving the water quality environment are often the main factors of failure.
5. Pay attention to the selection of various types of drugs The selected drugs should be listed in the Veterinary Pharmacopoeia and use Chinese Medicine as much as possible, or use drugs that have been clinically tested, have good safety, quality assurance, low residue, and short residue time. The residue standard and degree of drugs should be known, and the characteristics of commonly used drugs in aquaculture should be better understood. If necessary, there is a withdrawal period to avoid blind drug use.
Here are some of the major aspects and technical issues concerning the healthy breeding of aquatic products expressed as follows, I hope to play an important role.
I. Seedlings of seed problems are the basis of the aquaculture industry. The emergence of a good breeding species can raise an industry upsurge (such as turtles, turtles, river crabs, giant prawn, shrimp, prawns, etc.). The opposite is a poor one. Variety will bring greater losses to the industry. Variety refers to a species with good germplasm gene, no degradation, strong disease resistance, rapid growth, high feed utilization, good meat quality, certain genetic stability, and should be derived from the original species. Generation - improved species. In order to make the cultivated species healthy and less harmful and reduce the use of drugs, the residues of various drugs and heavy metal ions can be minimized. However, breeding of seedlings often takes a long time and costs a lot and needs to be completed by specialized scientific research institutes. Hangzhou has invested some effort in this area. The main measures for improving the quality of seedlings include:
1. Crossbreeding Breeding of superior varieties or strains by means of artificial crossbreeding, and directional breeding of species with fast growth, strong resistance to disease and resistance to stress, for the majority of farmers to breed. This is one of the most important breeding methods in China. Such as silver squid, Feng Yu and so on.
2. Bioengineering techniques are obtained through gynogenetic development, pedigree breeding, combined with multilineage crossbreeding, or by artificial induction (temperature, pressure, biological factors) to double the chromosomes of aquatic product species. For example, Jian 鲤 (purple purpurea and Yuanjiang 鲤 as original parent), unisexual tilapia grade. For example, the engineering triploid (triploid) and triploid species have the characteristics of fast growth and large individuals. Now people know more and more clearly about DNA, and their molecular breeding techniques will gradually improve. We believe that in the near future there will be more and more healthy varieties that are cultivated using DNA technology.
3. The production of disease-free seedlings is becoming more and more intensive. Today, the diseases of farmed species are also increasing, especially viral diseases. Therefore, in the cultivation of conventional seedlings, the promotion of “healthy seedlings†and “viral-free or sterile seedlings†is to strictly select the parents throughout the seedling raising process and strictly control the number of bacterial viruses and other harmful organisms in the water, so as to minimize the The degree is conducive to future breeding. For example, many shrimps are now cultivated using this method, such as SPF without specific virus. In the future, it will also increase its disease resistance from the genetic level.
4. Genetic characteristics of aquaculture germplasm The current aquaculture industry in China tests only the introduction, development and domestication of cultured species. With the development of the aquaculture industry, due to the long-term inbreeding and the genetic characteristics of many good varieties have changed, they must be tested regularly to ensure that they have a good idea. The developed countries, especially the United States, have done relatively well. China has done less work in this area and has a certain degree of blindness in aquaculture production.
5. The rejuvenation of good germplasm is the rejuvenation of germplasm on large-scale farmed species. The current main approach is to introduce the origin or natural germplasm on a regular basis to improve the decline in the growth characteristics of the culture due to the long cultivation time. Variations in individuals become smaller. This problem exists in many species cultivated in our province, such as the mixing of shrimp and crab strains and inbreeding, so that the specifications of commodities are generally smaller than the original in the same culture conditions, and many fishes also have this phenomenon. In the future, we will solve problems by applying improved seed and artificial breeding.
6. Strictly controlling blind introductions The increase in the number of farmed species in China in recent years is greater than that at that time and in that country. This has also brought serious consequences. Regardless of whether it is introduced from abroad or from outside the province (including trans-regional), strict quarantine (especially the former) must be carried out to clarify the original diseases of the district and the status of the disease and the disease caused by the species. The impact of the pathogenic flora and the evaluation of the hazards to the major local economical culture species; the identification of the impact of the introduction of the species on ecological balance and germplasm resources will be introduced. Blind introduction has caused a lot of damage to our original breeding and introduced varieties, especially the diseases in the breeding of shrimp, crab, and crab. The “Administrative Measures on Aquatic Seed Production†issued by the Ministry of Agriculture should be strictly implemented.
II. Environmental issues Aquaculture water environment With the great development of industry, pollution is becoming more and more serious. This is a worldwide environmental problem, including direct pollution of water bodies, pollution of land, and pollution of the atmosphere, but it will eventually pollute water bodies. surroundings. As for the development of aquaculture, its own biological pollution is also increasing. Deterioration of environmental conditions will surely increase the diseases of cultured species and increase the use of drugs by farmers. The higher the accumulation of heavy metals and pesticides, the higher the residue of antibiotics, thus affecting the quality of products. The main measures to improve the aquaculture water environment are:
1. Selection of site and water source The excavation of Xintang must consider the choice of site. There are not many ponds newly excavated after the release of grain in Zhejiang Province. It is also necessary to consider this issue (only the new fish ponds were added in 2001 in Hangzhou area. Thousands of acres). Open ponds must be selected from sources that have sufficient water, fresh water, and little or no pollution. To understand the situation of industrial pollution and pesticide pollution around the year, if necessary, carry out water quality tests to meet the fishery water quality standards in China.
2. The removal of excessive silt is particularly important for old ponds. Silt is often the site for the proliferation of pathogens, and excessive silt can cause excessive oxygen consumption in the breeding process, and can also cause outbreaks in disease seasons. Generally only about 20 centimeters of mud can be left.
3. Improvement of sediment (1) In addition to removing excess silt every year, it is best to allow it to dry in winter, and to kill a large number of harmful pathogens and their spores, spores, resting eggs, etc. through freezing and sunlight to reduce the number of The number of episodes. And after cracking the substrate, air and soil can be fully contacted, the organic matter in the substrate can be fully oxidized, minerals can be mineralized into inorganic salts, and can become the nutrient source of food organisms in the pond in the coming year. (2) Before stocking each year, use sufficient amount of quicklime to fully mix with the sludge. A stable and slightly alkaline water environment that can maintain the pH of the water will be conducive to the breeding of beneficial microorganisms and reduce the disease. Second, the bottom silt can be loosened. , increase the permeability.
4. Clear ponds Clear ponds can be dried at the end of the year or before stocking in the coming year. The main purpose is to remove the wild fish, shrimp and pathogens in the pond, which will help the survival rate of the culture and reduce the incidence of the breeding process.
5. Water quality treatment (1) Chemical treatment In order to avoid large-scale disease outbreaks in culture, many water treatment ponds are set up to sterilize the cited water sources in advance to ensure that they are added to the pool. The water in the pathogen is not pathogenic, reducing the incidence of disease and improving the survival rate. For example, the pretreatment of shrimp in high-level pond culture. (2) Biological treatment mainly applies and controls the growth of beneficial microbial communities. When the beneficial microorganisms multiply, the growth of pathogenic bacteria and harmful bacteria will be inhibited and the occurrence of diseases will be reduced. In addition, beneficial bacteria can decompose organic substances under aerobic conditions and reduce self-pollution in the breeding process. Biological treatment of higher levels of biological rotation, bio-packaging, etc., in industrial or recirculating aquaculture, etc.; lower level of treatment is the regular addition of beneficial microorganisms, such as PSB, digestive bacteria, viable bacteria, etc., in general culture ponds. (3) Physical treatment is mainly through pre-sterilization or filtration of influent water by UV or ozone.
6. Simulating the natural ecological environment In the cultured water body, as many species as possible are added to habitats, hidden sites and activities. For example, additional nets for three-dimensional culture of green shrimp and hanging nets for the cultivation of greenhouse turtles are all aimed at increasing the sheltered sites for farmed species; planting aquatic plants in shrimp and crab farming can increase their hidden sites to reduce mutual mistreatment and absorb Some organic matter and other nutrients improve the water quality; the food table in the soft-shelled turtle farm has the function of drying and back. This is to increase the survival rate and benefit in the breeding, but at the same time, it can reduce the occurrence of diseases by simulating the natural ecological environment.
Third, the feed problem Feed is the material basis for aquaculture, each breed because of its different characteristics of the nutritional requirements of feed are also different, and the same species in different growth stages of the nutritional requirements of feed are not the same. Under the conditions of numerous aquaculture species, the basic research on nutrient requirements of major aquaculture species in China has so far been insufficient, and the management of feed production industry is not sound enough. Therefore, each feed manufacturer has its own governance and different standards, with different ingredients and raw materials. Ultra-standard use of synthetic growth promoters. As a result, the nutrients may not necessarily meet the needs, the raw materials or feeds may be deteriorated, or the added adhesives and other chemical substances may not meet the standards, or the added drugs may not be standardized. The impact on production is: (1) First, it is a nutritional disease, liver disease such as fatty liver, high-sugar liver, or excessive accumulation of body fat, or many vitamin deficiencies, or poor growth, etc. Wait. (2) Decreased constitution of cultured species, vulnerability to infection by pathogens, and impaired survival rate. As a result, farmers increased their drug use and caused an increase in residual levels. (3) The final product contains substances that are harmful to the human body.
In order to ensure healthy breeding, the following measures must be taken in the feed sector:
1. First of all, the nutrient needs of the cultured species must be clearly understood, and the corresponding feed formulation must be determined based on the cultured species and the nutritional needs at different stages. The formula should be scientific and reasonable. At the same time, it calls for the need to increase basic research on feed and nutrition in aquaculture.
2. Raw materials for feed production should be strictly controlled, and raw materials that are deteriorating, contaminated, and do not meet the requirements should be rejected.
3. The use of additives (nutritional and non-nutrient additives such as vitamins, mineral salts, antibiotics, adhesives, natural growth promoters) must be compliant, especially the latter three. Chemically synthesized adhesives, which contain a lot of impurities or do not meet health standards, must not be used. Antibiotics used in pharmaceutical baits should not be abused. To understand their residual characteristics and compliance with the Veterinary pharmacopoeia, there must be sufficient withdrawal periods (15-20 days) before marketing.
4. The storage of finished feed should be used within the specified time, and can not be used after expiration or deterioration.
5. For some substances that need to be added at the time of feeding (such as oils), the product description should clearly indicate: the amount, type, ratio, and requirement of addition cannot be arbitrarily added.
6. Animal or vegetable feeds used to reduce feed costs, or to increase feed efficiency, or to make full use of local natural resources in aquaculture must be guaranteed to be non-destructive, non-polluting and suitable for use.
7. Local fishery or agricultural authorities and feed inspection and supervision departments shall strictly regulate and manage local feed manufacturers in accordance with national or local standards and conduct management according to law. The same must be regulated management of sales businesses, the sale of counterfeit products is strictly prohibited.
8. Scientific feed feeding: From the perspective of breeding, it is still necessary to adhere to a reasonable scientific feeding method (“Four Dingâ€) in order to reduce the disease, increase the survival rate, and reduce the use of drugs to ensure the health status of cultured species.
IV. Disease Prevention and Medication Problems There are many kinds of aquatic products. The culture environment is divided into seawater, freshwater and brackish water. In the whole breeding process, due to factors such as seedlings, feed, management, technology, water quality, temperature and climate, or There are more or fewer diseases, serious ones affect the survival rate and yield, or even out of production, so the prevention and treatment of diseases is an important task in aquaculture. In order to increase production and efficiency and improve the quality of aquatic products, the principle of prevention shall be advocated for the aquatic products cultivated. Once the disease needs to be correctly diagnosed, drugs should be selected for treatment, and the drugs used should be used to maximize the effectiveness of the drugs. Residue is reduced to the lowest level. From the perspective of healthy breeding, the following measures should be implemented:
1. Correctly diagnose the cause, select drugs reasonably, and strictly control the adaptability and physical and chemical characteristics of the drug. The correct diagnosis is the successful treatment and the first condition. Infectious diseases include: bacterial, viral, and parasitic diseases. Diagnosis is based on symptoms and pathogens. It should be noted that it takes a certain amount of time for the drug to exert its effect, and it cannot be expected that the day of drug use will be rapid and effective. Sometimes, deaths will increase after one or two days of drug use. If the drug dose is within the safe range, it may be due to The drug kills pathogenic bacteria in the animal body and prompts the bacterial cell to release endotoxin at the same time, causing animal death from acute poisoning. In this case, the mortality rate will generally decline after 3-4 days; otherwise, the drug dose should be considered too large. In the later stages of the disease, mixed infections of multiple pathogens often occur. Clinically, there are rotting diseases caused by the combined infection of trichoderma and bacteria, and enteritis caused by mixed infection of viruses and bacteria. At this time, there must be treatment programs for different pathogens. After the correct diagnosis, drugs are selected according to the adaptation of the drug, and a reasonable method of administration is adopted.
2, the use of drugs should not be as soon as possible Delay in the first appearance of the animal is generally the symptoms of loss of appetite, it can not eat baits, oral drugs do not work on the diseased animals, the disease has been difficult to cure. The drugs used for the prevention of animal disease has not yet played a protective role, so the real treatment of farmed animals is very small, so the prevention of aquaculture is more important than the importance of treatment. After the onset of the disease, the good fruit is treated too late and the incidence rate will increase rapidly, which will bring difficulties to the treatment.
3. Oral administration of external medications in combination with two administrations has different effects. For bacterial diseases, whether it is a body surface infection or a systemic infection, it should be combined with oral administration and external use. For surface parasitic infections, generally only topical drugs can be used, but sometimes oral administration can also be effective.
4. It is necessary to emphasize the importance of comprehensive therapeutic measures in the application of antibacterial drugs in the treatment of bacterial diseases. It is necessary to fully recognize the importance of the animal's own immunity. Over-reliance on the efficacy of antibiotics, neglecting feeding management and improving the water quality environment are often the main factors of failure.
5. Pay attention to the selection of various types of drugs The selected drugs should be listed in the Veterinary Pharmacopoeia and use Chinese Medicine as much as possible, or use drugs that have been clinically tested, have good safety, quality assurance, low residue, and short residue time. The residue standard and degree of drugs should be known, and the characteristics of commonly used drugs in aquaculture should be better understood. If necessary, there is a withdrawal period to avoid blind drug use.
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