| Epinephelus fuscoguttatus is an important aquaculture species in the southeast coast of my country,but its quality,genetic diversity,growth rate and disease resistance are affected due to the degradation of germplasm resources.Gynogenesis as one of the means to obtain excellent varieties is widely used in the development of improved fish varieties.According to reports,the technique of artificially inducing the gynogenesis of E.fuscoguttatus has been successful,but due to the artificial inactivation of the gynogenetic process,the sperm genetic material needs to be inactivated and the chromosomes of the fertilized egg are doubled to make the larval survival rate and malformation rate high.In order to explore the effect of artificially induced gynogenesis on the embryonic development of fertilized eggs of E.fuscoguttatus,this study used UV method and cold shock method as the treatment method of gynogenesis,using ultraviolet lamp,E.fuscoguttatus female parent(♀)and E.polyphekadion(♂)as the research object,the stability range and time of ultraviolet lamp radiation intensity were measured,and the best dilution of sperm of grouper sperm was screened.The exploration of treatment conditions and cold shock treatment conditions of fertilized eggs and the observation of the development of embryos induced by ultraviolet treatment and embryos treated with cold shock are as follows:1.Research on the radiation intensity of different UV lamps shows that the duration of the radiation intensity tends to be stable after different UV lamps are turned on;the radiation intensity at different positions of the same lamp is different;the radiation intensity decreases with the increase of the lamp height,within a certain range,A height increase of 1 cm will cause a significant difference in radiation intensity(P<0.05).2.Five kinds of sperm dilutions(ELS3,EM1,Hank’s,MPRS,and TS-19)were used to dilute the sperm of E.polyphekadion.After observing the sperm activation rate,fast sperm movement time and lifespan,EM1 was measured as the freshwater grouperThe best diluent for sperm.In this study,ultraviolet irradiation conditions,cold shock treatment start time and treatment duration were screened.The results showed that when the radiation intensity was 2 500μW/cm~2and the irradiation time was 2.5min,the embryo survival rate and hatching rate of the fertilized oocyte of E.polyphekadion were the highest;when the cold shock(0～2℃)treatment start time was 6.0 min The embryo hatching rate was the highest after continuous treatment for6.5min.3.Observation of the development of fertilized egg embryos without any treatment,ultraviolet irradiation and cold shock.The result shown that the development of fertilized egg embryos after cold shock treatment takes the longest time,and ultraviolet and cold shock treatment can cause the development of fertilized egg embryos.The cleavage is uneven,and the embryonic cells appear oily balls,and cause different degrees of deformity in the first hatchling. |
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