Research Of The Oral IgY Of WSSV

WSS(White Spot Syndrome) ,which the global shrimp farming industry currently face , is the greatest harmful disease affecting the widest range, and become one of the main bottlenecks in the development of shrimp farming. That is why the world aquatic disease experts invested great concern to WSS. According to actual needs, our research dedicate to develop the oral anti-WSSV IgY preparations for the foundation of a simple and effective new methods to prevent WSS.First, the experiments used the improved simple and effective centrifugation named differential-speed centrifugation to separate and purify the WSSV with the gills of sick shrimps. Compared with the Ultra-speed centrifugation which is widely using currently, a conclusion was made that the differential-speed centrifugation can absolutely replace the Ultra-speed centrifugation. Then the virus was mixed with Equivalent volume Freud's Adjuvant,and then immunize hens with different doze.use indirect-elisa to observe the generation of antibodies, ensure that the suitable immune procedure was 100ug WSSV at the first immunization, and a double doze at the strengthening immunization every two weeks .After three immunizations we can test an high price-IgY ,and its price remains for more than two months.Next we researched the separation and purification of IgY and the suitable large-scale production processes .By water dilution and salting out process these two simple steps, we gained IgY solution of about 80% purity. In further Sephadex G-25 and DEAE cellulose collum chromatography process, the purity of IgY was rised to 97.3% ,then we adopted different ways of spray drying experiments , confirmed that the IgY remains a majority of price after a direct spray drying, and in addition, the IgY remains a higher price when mixed with protectives proportionally . So the result of the experiments condicted the spray drying is a simple and easy methods for large-scale production. Finally we added IgY powder that prepared by spray drying to the shrimp basis feed, and take a deep study in its protective effect of different doses to the artifical attack of the WSSV, our animal model was Procambarus Clarkii. The conclusion is that the adding volume of 20% yolk delayed the shrimp death time in a certain extent, but 40% of the yolk adding reduced the mortality from 100% to 30%, besides there is no differece between pre-feeding group and nonpre-feeding group.Through a series of experiments steps on anti-WSSV IgY generation, production processes and exploration of its applicable effect against to WSS, thus provided critical technical platform and theoretical basis for the development of anti-WSSV...