Studies On The Utility Of Vitellin In Larval Of The Prawn, Fenneropenaeus Chinensis

This experiment established a method firstly, which vitellin was precipitated by EDTA-MgCl₂.The vitellin was isolated and purified with chromatography (SephadexG-150, DEAE-Cellulose-52) . According to a routine method, a specific antiserum against purified vitellin was raised from rabbit. Immunological characteristics of the female specific protein were studied with the antiserum. By the means of immunoprecipitation reaction and Western-blotting, it was proved that the antiserum was specific.An indirect competitive enzyme-linked immunosorbent assay (ELISA) for detecting Vitellin content of Fenneropenaeus chinensis was established. The optimum concentration of antiserum and antigen coating were 1:10000 and 125 ng/mL Vitellin , respectively. The linear detection ranged from 10 ng/mL to 500 ng/mL, with mean intra- and inter-assay coefficients of variation were 5.0 % and 6.2 %, respectively.By the means of ELISA to detect the change of Vitellin content in the eggs and larva of different stage of F.chinesis, the content of Vitellin decreased along with the development of larval prawn, Vitellin was digested very quickly from N_3⁴ to N_5⁶ and from N_5⁶ to Z₁, the decrease of Vitellin were 1322 ng/mL and 1213 ng/mL, it occupied gross of Vitellin content of eggs 38.9% and 35.7%, respectively. After the stage of Z₁, the content of Vitellin was not detected.Activities of several digestive enzymes from nauplius of Fenneropenaeus chinensis were analyzed during its ontogenesis. The results showed that there were 3 different patterns in the activities of 4 digestive enzymes from larval prawn. At the early stage of larval development, protease kept high activities. Each of enzymes increased greatly in the stage of N_3⁴ and N_5⁶, which was associated with liver differentiation. It was considered that the activities of digestive enzymes had close relation to the decomposion of the Vitellin.