Effects Of High Salinity On Growth Performance,Physiology And Chemical Factor,Gene Expression Of Litopenaeus Vannamei

1.The effects of salinity stress on growth,feeding and feed translation rate of Litopenaeus vannameiIn this study,Litopenaeus vannamei was used as the research material,and four salinity gradients of 30,40,50 and 60 were set,survival rate,weight gain,specific growth rate,feeding rate,feed translation rate(FCE)were tested.The results showed that with the increase of salinity,the survival rate,weight gain,specific growth rate and feed translation rate of Litopenaeus vannamei decreased gradually,but the feeding rate increased gradually.2.The effect of high salt stress time on osmotic pressure,digestion and immune related enzyme activity of Litopenaeus vannameiIn this study,Litopenaeus vannamei was used as the research material,four salinity gradients of 30,40,50 and 60 were set.Osmotic pressure,Na+-K+-ATPase,superoxide dismutase(SOD),catalase(CAT),Alkaline phosphatase(AKP),acid phosphatase(ACP),protease,lipase,amylase activit were determined in the 0?5?10?15?20 days.The results showed that with the extension of time,the plasma osmotic pressure increased gradually and the Na+-K+-ATPase activity decreased gradually.The enzymes associated with digestive showed a tendency to increase gradually on the whole.The AKP activity is highest in the haemolymph and showed a tendency to decrease gradually.The ACP activity is highest in muscles and showed a tendency to increase gradually.The SOD and CAT activity changes mainly in hepatopancreas and showed a tendency to increase gradually.3.The long-term effects of high salinity on osmotic pressure,digestion and immune related enzyme activity of Litopenaeus vannameiIn this study,Litopenaeus vannamei was used as the research material,four salinity gradients of 30.40,50 and 60 were set and raise 30 days,osmotic pressure,Na+-K+-ATPase,superoxide dismutase(SOD),catalase(CAT),Alkaline phosphatase(AKP),acid phosphatase(ACP),protease,lipase,amylase activities were determined.The results showed that with the increase of salinity,the osmotic pressure and Na+-K+-ATPase decreased gradually,the digestion-related enzyme activity increased gradually(P<0.05);in haemolymph,the AKP activity increased gradually,the ACP,CAT and SOD activities increased first and then decreased;in muscle,the AKP,ACP and SOD activities showed the trend of increased first and then decreased;in hepatopancreas,the activity of AKP showed a trend of decrease after risen,but there was no significant difference in ACP activity after salt stress treatment(P>0.05),the activity of CAT decreased first and then increased,and the SOD activity decreased gradually after 40 salinity.4.The effects of high salinity on gene expression of Litopenaeus vannameiIn order to have a knowledge of the molecular mechanism enhanced by high salinity stress,the expression quantity of Litopenaeus vannamei raised in high salinity in different tissues have been analyzed comparing to that raised in normal salinity of sea water.The research result shows that there are 1659 significant differentially expressed genes.Through the differential analysis on patterns of expression for Litopenaeus vannamei raised in high salinity and that raised in normal salinity,it is found that:the osmoregulation,ion transport and antioxidant related genes were high-expression in gill,the immune defense,bacteriolysis and apoptosis related genes were high-expression in hepatopancreas,and the development and nutrition metabolism related genes were low-expression in muscle.