The Early Development And Vitellin Levels Of The Crayfish, Procambarus Clarkii

The early development of crayfish was observed. Refering to existing documents and according to their characteristics embryonic development can be divided in to eight period: fertilized egg stage, cleavage stage, blastula stage, gastrul stage, early stage nauplius, late stage of nauplius, the zoea stage and incubative prepare stage. The morphological characteristics of embryos and larva in different developmental periods were studied respectively in detail.Vitellin was purified from mature ovary of female crayfish via electrophoresis method. Specific antiserum against purified vitellin was raised from rabbit. It was proved that the antiserum was specific by means of immunoprecipitation reaction.An indirect competitive enzyme-linked immunosorbent assay (ELISA) for detecting vitellin content of Procambius clarkii was established. The optimum concentration of antiserum and antigen coating were 1:40000 and 31.25 ng/ml vitellin respectively. The linear detection ranged from10ng/ml to 1000ng/ml, which has good linearity and repeatability, with mean intra-and inter-assay coefficients of variation less than 10%. The content of vitellin was determined rapidly and accurately.ELISA was used to detect the change of vitellin in the crayfish early developmental stage. It was found that nauplius vitellin was increased in early stage. The content can reach 0.1888 mg/ml. Then it declined. Vitellin only left 0.0022 mg/ml in the third instar. The larval already can feed in this period.