Large-scale Artificial Breeding Of All-male And Hybrid Pelteobagrus Fulvidraco And The Key Disease Control Technologies Research

In the study, large-scale artificial breeding of wholly male yellow-head catfish and hybrid yellow-head catfish(Pelteobagrus fulvidraco), the optimum low permeability concentration of artificial insemination, the optimal incubation mode,the application technology of wholly male yellow-head catfish breeding with three times a year, the key calibration method of “yellow egg seeding” and diagnosis and treatment of "crack head" disease in the middle and later farming period were researched. We attempted to lay a solid theoretical basis on the rapid development of all-male and hybrid yellow-head catfish industry through our study.In the first part of the paper, we conducted the tests of optimum low permeability concentration of artificial insemination and the optimal incubation mode, according to the key technology of large-scale artificial all-male and hybrid yellow-head catfish breeding. First of all, vachelli sperm motility at seven different concentrations of sodium chloride and distilled water hypotonic solution configuration were measured at water temperature 28 + 1 ℃.The result showed that the strongest sperm motility was under the hypotonic solution of 0.25%. Further study indicated that the highest artificial fertilization rate(reaching 75.1%) was displayed in the 0.20 percent hypotonic solution and the top hatching rate(as high as73.1%) was occurred in the 0.25% hypotonic solution. In addition, the optimal incubation way was selected via the four hatching devices(three different incubation barrels and a kind of 60 nylon mesh, mesh size is 80 cm * 60 cm) determination ofthe effects on the fertilization and hatching rate for all-male and hybrid catfish. The results show that the optimal incubation for the hybrid yellow-head catfish is in incubation barrel 3. When put the fertilized egg 4 kg per barrel, the fertilization rate can still be above 80%. The all-male yellow-head catfish have higher fertilization rate both in the second incubation barrel and the third incubation barrel, the fertilization rate as high as 80%.In the second part, the acute toxicity effects of two kinds of pesticides(Cypermethrin and Ivermectin) on Pelteobagrus fulvidraco in different developmental stages(5days of age, 10 days of age and 20 days of age) were studied with static toxicity test. The results showed that the 24h-LC50 and 48h-LC50 of Cypermethrin were 0.017mg/L-0.053mg/L-0.133mg/L and0.013mg/L-0.035mg/L-0.112mg/L in the developmental stages. The safety concentrations of Cypermethrin were 0.0023mg/L, 0.0046mg/L and 0.0238mg/L during the three stages respectively. The 24h-LC50 and 48h-LC50 of the Ivermectin were 0.295mg/L-0.339mg/L-0.356mg/L and 0.263mg/L-0.3mg/L-0.323mg/L. The safety concentrations of the Ivermectin were 0.0627mg/L,0.0705mg/L and0.0798mg/L separately. Five ponds(total areas of 41 acres) were randomly selected for clinical experiment with 14 billion 2-3-day fry. Clinical application demonstrated that yellow catfish larvae survival rate could reach more than 40%, a 20% increase compared with conventional breeding methods when processed with 0.1-0.2 ppm of Cypermethrin 2-3 days before the pond breeding, treated with 0.02-0.03 ppm of Ivermectin9-11 days later after pond breeding or conducted with 0.05- 0.07 ppm of Ivermectin for 18-20 days pond breeding before lamp domestication.In the last part, a therapeutic treatment for crack head was analyzed in detail.Through the determination of physical and chemical indicators of water quality and the investigation of pond farming situation, we ruled out the reason of water quality and farming. Clinical examination by the onset of symptoms, yellow catfish was diagnosed with the “crack head” disease complicated by wheel worm disease.Sensitive drugs(doxycycline hyclate and enrofloxacin) were screened by the medicine sensitive experiment.We developed a set of treatment methods which included insecticide, vitro disinfectio, water quality control and oral antibiotics.After 14 days of treatment, we successfully cured the “crack head” by a comprehensive treatment, and highlighted several issuesin the clinical treatment course, which provided a reference for the clinical treatment of crack head desease.This experiment materials and experiment were finished in in Jiangsu provincial aquatic breeding farm-Sheyang Kang Yu Fisheries Technology Limited Company.