Studies On Artificial Induction Of Androgenesis In Yellow Catfish (Pelteobagrus Fulvidraco Richardson)

Yellow catfish (Pelteobagrus fulvidraco Richardson) belongs to Siluriformes, Bagridae,Pelteobagrus. It could be found all over the waters of China. Its meat is delicious and nutritious sothat the fish is of high market value. In recent years it has been becoming an important economicspecies for pond cultivation. There were differences in growth velocity between males and females,the growth index of male was 1.7 times as females at age 1, and it was 1.2 times at age 2. With thegonad developed, the growth velocity of females declined. Sex control of Pelteobagrus fulvidracocould be carried out by the technology of androgenesis, so the successful production of all maleindividuals could bring high market value. Up to now, no reports have been published on theinduction ofandrogenesis of Pelteobagrus fulvidraeo.In this study the eggs of yellow catfish were irradiated by UV light, and found out the suitablecondition of inactivation by UV irradiated; Androgenetic diploid could be induced by heat shock.The result of test was that:The synthetic ovarian fluid (OF) or TC-199 were used as conserving liquor of eggs. Eggs werespread on a 9.0-cm-diameter plastic petri dish with OF or TC-199. The dish was placed on a shakerbelow a 30 w UV germicidal light, which provided a UV intensity of 2 mw/cm~2 measured by adigital radiometer. There were 10 treatments in the test, and the irradiation duration of treatmentswas 40 s～130 s. Then hatched (26±1℃). Malformed fries were found in every treatment. With thedosage of irradiation increased, the rate of malformed rose, but the rate of fertilization and thehatching rate declined. When the dosage of irradiation was at 220 mJ/cm~2, the rate of malformedfries was up to 100％, the oocytes were inactivated. So it was the suitable condition of inactivation.The malformed fries were haploid with the analysis by flow cytometry.Under the same dosage of irradiation, two kinds of preserving fluids were effective. But therate of malformed in OF was higher than TC-199, so the effect of OF was better than TC-199.Eggs were eggs were spread on a 9.0-cm-diameter plastic petri dish with OF, and the dosage ofirradiation was 220 mJ/cm~2. Eggs were hatched in pond water of 40℃, and the treatment lasted 2min or 3 rain, at 15～37 min after the fertilization, the interval of every two groups was 2 min. Theresult showed that heat shock with 2 rain was better than 3 min; There were two apices of inductionin 17～21 min and 27～31 rain after fertilization. The highest hatching rate was 3.30％at 29 min afterfertilization, and the difference between two apices of induction was unobvious.