Effects Of Changes In Salinity On The Nonspecific Immune Factors Of Japanese Flounder And Antioxidant Enzymes Activities In Amphioxus

This study deals with the effects of changes in salinity on the nonspecific immune function of the Japanese flounder Paralichthys olivaceus are studied. The tested salinities are 30%(control), 40 % (hyper-osmotic) and 20%o(hypo-osmotic) respectively. It is shown from the study that the serum haemagglutination activity for the fish incubated in 20% or 40% seawater increased by 4-folds compared with the control on day 3 after the salinity changed, and the high haemagglutination activity was maintained till the end of the experiments (12 days); the concentration of lysozyme in the sera rose slightly on day 3 after the salinity change, reached a peak in day 5 and then decreased to the level lower than the control; C3 concentration increased markedly on day 1 after the salinity was changed, remained high on day 7, and then decreased to the control level.Study on antioxidant enzymes remains open in amphioxus. The superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities were determined in the different gender and tissues of amphioxus Branchiostoma belcheri tsingtauense. It was found that (1) CuZn-SOD, CAT and GPX activities in the whole amphioxus B. belcheri tsingtauense were basically at the same levels in male and female amphioxus, while both T-SOD and Mn-SOD activities in male amphioxus was significantly higher than that in the female (p<0.05); (2) The testis had significantly higher T-SOD and CuZn-SOD activities than the ovary (p<0.05); (3) CuZn-SOD activity was undetectable in the guts of male and female amphioxus; (4) For both male and female amphioxus, the activities of CAT and GPX in the gonads including testis and ovary were lowest (p<0.05) among the tissues examined; (5) The gut andgill had the same level GPX activities while the gut had a higher CAT activity; (6)There was no marked difference in CAT and GPX activities in the corresponding tissues between male and female amphioxus. This is the first report on SOD, CAT and GPX activities in the different gender and tissues of the protochordate, providing data for future comparison of amphioxus antioxidant enzymes with those of both invertebrates and vertebrates.