Since the 1980s, the domestic aquaculture industry has developed rapidly and has formed a certain scale of breeding. At the same time, it has brought serious diseases and has affected the sustainable development of aquaculture. Now the author put forward the following points on how to strengthen Yan's own resistance to disease.
I. Screening and cultivating varieties with strong disease resistance Breeding varieties with strong disease resistance can be carried out by artificial hybridization or seed selection methods. Cell engineering or genetic engineering techniques can also be used for breeding. However, these tasks have certain difficulties. In order to improve the disease resistance of alfalfa germplasm, the breeding industry can work hard from the following aspects at this stage:
1, equipped with appropriate wild quail as a parent.
2, pro-gaze should be physically robust, complete shape, normal body color, smooth skin, skirt, hypertrophy, firm, do not have wrinkles on the back edge of the carapace, strong disease resistance; if found injury, disease, residual, deformity, should be Clear, can not be used as a pro-sister.
3, to avoid inbreeding and improve the genetic quality of earthworms.
4, try not to reproduce with the old age.
Second, to strengthen the management of feeding and feeding The purpose of feeding and management is to create a good environment and nutritional conditions suitable for the growth of loquat, to cultivate healthy and robust loquat, to obtain the highest economic benefits. Undoubtedly, the strength of cricket disease resistance is closely related to the quality of feeding and management, and the feeding and management technologies directly related to strengthening cricket's disease resistance are:
1. As far as possible, on-site cultivation of juveniles, cubs, and breeding of cockroaches can ensure their types, specifications, quantity, and quality. It can also avoid the introduction of pathogens when introduced from outside the country, or the introduction of injured cockroaches, resulting in pathogens. Secondary infection.
2, a reasonable stocking is a reasonable density. A reasonable stocking density will not only reduce the breeding efficiency, but will also ease the conflicts between individuals competing for space, competing for oxygen and striving for feed, slowing down the speed of water pollution, and enhancing the constitution of the cockroach, which in turn will increase economic efficiency. Under normal temperature culture conditions, the densities of juveniles, juveniles, adults, and relatives can be referred to the data provided in the attached table.
The second is to classify the pools according to different specifications and avoid the occurrence of weak meats and strong foods.
Third, in the juvenile breeding stage, after breeding for a period of time, it is necessary to adjust the culture density and re-classify the size.
3. The contents of “Four Sets†for “Four Ding†feedings are timed: 2 times a day, 9–10 a.m., 1–4 p.m. one time each; the number of feedings is too low and the feed utilization rate is low. After finishing, the residual bait is easy to be corrupted; the number of feedings is too high, and frequent access to Dianchi Lake interferes with the normal life activities of paralysis. Positioning, set up a fixed bait station, which is conducive to inspection of food intake, timely removal of residual bait, avoid feed waste and water pollution. The bait is often fed on the feed table near the water line, and live fresh feed can also be fed. Qualitative: Feeding fresh, non-corrupted, nutritious and palatable feed. Quantitative: The feeding amount is generally the best amount after feeding for two hours, and the daily feeding amount (dry matter) for juvenile and young larvae is generally 3% to 5% of its body weight, up to no more than 6%. Feeding volume: The dry matter is about 1% to 1.5% of the body weight and fresh feed is about 5% to 10% or more. "Four Ding" feeding is not always the same, and it is necessary to make appropriate adjustments according to the season, climate, water quality, and the growth and health status of earthworms.
I. Screening and cultivating varieties with strong disease resistance Breeding varieties with strong disease resistance can be carried out by artificial hybridization or seed selection methods. Cell engineering or genetic engineering techniques can also be used for breeding. However, these tasks have certain difficulties. In order to improve the disease resistance of alfalfa germplasm, the breeding industry can work hard from the following aspects at this stage:
1, equipped with appropriate wild quail as a parent.
2, pro-gaze should be physically robust, complete shape, normal body color, smooth skin, skirt, hypertrophy, firm, do not have wrinkles on the back edge of the carapace, strong disease resistance; if found injury, disease, residual, deformity, should be Clear, can not be used as a pro-sister.
3, to avoid inbreeding and improve the genetic quality of earthworms.
4, try not to reproduce with the old age.
Second, to strengthen the management of feeding and feeding The purpose of feeding and management is to create a good environment and nutritional conditions suitable for the growth of loquat, to cultivate healthy and robust loquat, to obtain the highest economic benefits. Undoubtedly, the strength of cricket disease resistance is closely related to the quality of feeding and management, and the feeding and management technologies directly related to strengthening cricket's disease resistance are:
1. As far as possible, on-site cultivation of juveniles, cubs, and breeding of cockroaches can ensure their types, specifications, quantity, and quality. It can also avoid the introduction of pathogens when introduced from outside the country, or the introduction of injured cockroaches, resulting in pathogens. Secondary infection.
2, a reasonable stocking is a reasonable density. A reasonable stocking density will not only reduce the breeding efficiency, but will also ease the conflicts between individuals competing for space, competing for oxygen and striving for feed, slowing down the speed of water pollution, and enhancing the constitution of the cockroach, which in turn will increase economic efficiency. Under normal temperature culture conditions, the densities of juveniles, juveniles, adults, and relatives can be referred to the data provided in the attached table.
The second is to classify the pools according to different specifications and avoid the occurrence of weak meats and strong foods.
Third, in the juvenile breeding stage, after breeding for a period of time, it is necessary to adjust the culture density and re-classify the size.
3. The contents of “Four Sets†for “Four Ding†feedings are timed: 2 times a day, 9–10 a.m., 1–4 p.m. one time each; the number of feedings is too low and the feed utilization rate is low. After finishing, the residual bait is easy to be corrupted; the number of feedings is too high, and frequent access to Dianchi Lake interferes with the normal life activities of paralysis. Positioning, set up a fixed bait station, which is conducive to inspection of food intake, timely removal of residual bait, avoid feed waste and water pollution. The bait is often fed on the feed table near the water line, and live fresh feed can also be fed. Qualitative: Feeding fresh, non-corrupted, nutritious and palatable feed. Quantitative: The feeding amount is generally the best amount after feeding for two hours, and the daily feeding amount (dry matter) for juvenile and young larvae is generally 3% to 5% of its body weight, up to no more than 6%. Feeding volume: The dry matter is about 1% to 1.5% of the body weight and fresh feed is about 5% to 10% or more. "Four Ding" feeding is not always the same, and it is necessary to make appropriate adjustments according to the season, climate, water quality, and the growth and health status of earthworms.
Foldable Stretcher,Folding Stretcher,Emergency Folding Stretcher,Foldable Ambulance Stretcher
jiangyin chenyi medical technology co.,ltd , https://www.chenyimed.com