Effects Of Two Main Environmental Factors On The Immune Function Of Macrobrachium Rosenbergii

In the world shrimp culture suffered great damage from environmental pollution and diseases. Environmental factor is the one of three reasons resulted in diseases outbreak. Attach important to the farming condition, emphasis was transferred to research the relation between the immune system of shrimp and external environmental. Ammonia-N and nitrite-N that is the main pollutions in the culture system became the research point. Effect of Ammonia-N and nitrite-N on immune function of Macrobrachium rosenbergii was systematical studied by means of the total hemocyte counts, the ultrastructure of hemocyte, four kinds of enzymes related with immunity and the soluble protein analysis. The results clearly showed that 0.1 mg/L ammonia-N and nitrite-N had obvious effect on M. rosenbergii, and show as follow:1. Exposure to 0.1 mg/L ammonia-N and 0.1 mg/L nitrite-N, the total hemocyte counts of M. rosenbergii decreased significantly and the impact of nitrite-N was stronger. The changes of ultrastructural features of hemocyte after 10 days exposure to ammonia-N and nitrite-N were well observed and the quantities of rough endoplasmic reticulum, ribosome and mitochondrion were reduced respectively. The greater alterations of hemocytes were observed exposure to ammonia-N.2. Phenoloxidase (PO) activity in hemolymph and muscle decreased significantly when the prawns were exposed to ammonia-N and nitrite-N in 10 days, but the phenoloxidase activity in hepatopancreas increased appreciably. Superoxide dismutase (SOD) activity increased at beginning and decreased after 10 days. Alkaline phosphatase (ALP) and acid phosphatase (ACP) activities increased significantly.3. The concentration of soluble protein in hemolymph, hepatopancreas and muscle decreased when the prawns were exposed to ammonia-N and nitrite-Nin 10 days. SDS-PAGE of the hemolymph, hepatopancreas and muscle of test prawn revealed different polypeptides. It indicated that ammonia-N and nitrite-N interfered protein biosynthesis in M. rosenbergii.The conclusion was that the immune functions of M. rosenbergii were affected significantly exposure to O.lmg/L ammonia-N and nitrite-N. The total hemocyte counts, the ultrastructure of hemocyte, PO, SOD and the soluble protein concentration can act as indexes of immunocompetence of prawns.