鲇人工催产药物筛选及其精子生理特性与胚胎发育研究OA

During the 10-Year Fishing Ban in the Yangtze River,the lower-utilisation problem of germplasm resources and the unsound technology of large-scale fry breeding of fish seriously affect the protection and ra-tional development and utilisation of Yangtze River fisheries resources.Silurus asotus is a vital germplasm re-source,but the research on its reproductive and breeding biology was relatively scarce.It is highly prized by con-sumers for its tender,low-spiky meat,delicious flavour,and rich nutritional value.However,the current re-ported oviposition stimulants and their combinations have poor oviposition effects on S.asotus,with low fertilisa-tion and hatching rates.It is urgent to screen for efficient oviposition stimulants and their optimal dosages and ratios.This study investigated reproductive physiology,gonadotropin drugs,and incubation conditions in S.aso-tus,aiming to establish a research foundation for breakthroughs in efficient large-scale artificial breeding tech-niques for catfish fry.Therefore,sexually mature S.asotus was chosen as the material in our present study to test its sperm physiology,embryonic development,and hatching water environment,aiming to advance research on efficient,large-scale artificial breeding techniques for S.asotus.Our results showed that after sexual maturity,the testes of S.asotus were relatively regular in shape,indicating that they could be fertilised by manually squee-zing out the semen.The combination of 3 μg/kg LRH-A2,1,500 IU/kg HCG,and 2 mg/kg DM demon-strated optimal spawning induction in S.asotus,achieving 100%of spawning rate,93.23%of fertilisation rate,and 91.3%of hatching rate.And,the pH of the optimal activation solution for sperm ranged from 7 to 8.Addi-tionally,the glucose of the optimal activation solution for sperm was 0.22 mol/L.The highest activation rate,fast movement time and life time of sperm were observed in solution with the only factor of 0.08 mol/L K+,0.015 mol/L Ca2+,0.014 mol/L Na+,and 0.021 mol/L Mg2+,respectively.In addition,the better viability of sperm was tested in solutions containing Na+or K+than in the solutions containing Ca2+or Mg2+.As for the embryonic development of S.asotus,there were 49 hours and 30 minutes for hatching under the water tempera-ture of 23℃.Higher water temperatures can promote the development of fertilisation rates and shorten the hatching time,and the optimal hatching temperature was 25℃.The optimal hatching pH for the S.asotus was 7.0 to 7.5,and the optimal photoperiod was 24 hours(Dark)∶0 hours(Light).The parameters of the drug combination,activation liquid and embryo incubation were determined,which can be directly applied to the large-scale breeding of S.asotus,and provide technical support for the protection and sustainable utilisation of the characteristic fish resources after the fishing ban in the Yangtze River.