Basic Research Of Osmoregulation Physiology Of Larvae And Postlarvae Of Marsupenaeus Japonicus And Fenneropenaeus Chinensis

The paper studies basic research of osmoregulation physiology of larvae and postlarvae of Penaeus Japonicus and Fenneropenaeus chinensis and discussed mainly the following these:â‘ Effect of salinity on development and Na⁺-K⁺-ATPase activity of Marsupenaeus Japonicus postlarvae;â‘¡Effects of ratio of Na⁺/K⁺ and Mg²⁺/Ca²⁺ in saline groundwaters on Na⁺-K⁺-ATPase activity, survival and growth of Marsupenaeus japonicus postlarvae;â‘¢Effect of pH on ion-transport enzyme in body of Marsupenaeus japonicus postlarvaeâ‘£Research on change of ion-transport enzyme in larvae and postlarvae of Marsupenaeus Japonicus and Fenneropenaeus chinensis1.Effect of salinity on development and Na⁺-K⁺-ATPase activity of Marsupenaeus Japonicus postlarvaeSalinity had significant effects on survival rate, daily body weight gain and Na⁺-K⁺-ATPase activity of Marsupenaeus japonicus postlarve(p<0.05).Survival rate and growth rate of postlarve decreased significantly with salinity decrease, while had no significant difference with salinity increased. The Na⁺-K⁺-ATPase activities of seawater groups had no significant difference from groups of salinity of 30. And along with the salinity change increasing within 48h, the change of Na⁺-K⁺-ATPase activities of postlarves increased, activites of each treated group presented wave change, and was up to maximum in hyposaline-treated groups but up to minimum in hypersaline-treated groups till 24h. The Na⁺-K⁺-ATPase activity of postlarves tended to be stable from 48h to 72h, and was higher while salinity was lower. From above, it suggested that the feasible salinity of Marsupenaeus japonicus postlarve in hyposaline water was 20-24.2.Effects of ratio of Na⁺/K⁺and Mg²⁺/Ca²⁺ in saline groundwaters on Na⁺-K⁺-ATPase activity, survival and growth of Marsupenaeus japonicus postlarvaeThe results suggest that the Na+-K+-ATPase activity, survival rate and weigh gain of Marsupenaeus japonicus postlarvae were significantly affected by the ratios of Na+/K+ and Mg2+/Ca2+ (PO.05). The changing extent of Na+-K+-ATPase activity positively accorded with the changing extent of Na+/K+and Mg2+/Ca2+ ratios. The Na-K+-ATPase activity of postlarvae of every treatment groups came to a stable level after 24h. Moreover there was a negative correlation between Na+-K+-ATPase activity and Na+/K+ ratio, while a positive correlation between Na+-K+-ATPase activity and Mg2+/Ca2T ratio. Compared with seawater (the Na+/K+ ratio is 27.8 and the Mg2+/Ca2+ ratio is 4.64), the Na+-K+-ATPase activity of the Na+/K+ ratio 30 treatment showed indistinctive diflference, while the Mg2+/Ca2+ ratio 4.5 treatment showed significant difference. Both the survival rate and weight gain of the postlarvae decreased when the Na7K+and Mg2+/Ca2+ ratios were too high or too low, and reached their maximum with Na+/K+ ratio ranging between 20 and 30 and Mg2+/Ca2+ ratio 4.5. We suggest that the ratios of Na+/KT and Mg^VCa2* of the saline groundwaters in Marsupenaeus japonicus postlarvae culture were modulated to 30 and 4.5 respectively, of which the absolute concentration of Mg + and Ca2+ are 1312mg/L and 291 mg/L, respectively. 3. Effect of pH on ion-transport enzyme in body oli Marsupenaeus japonicus postlarvaeThe effects of the suddenly changed pH on ATPase, Na+-K+-ATPase,V-ATPase and HCO3—ATPase of Marsupenaeus japonicus postlarvae were studied in this paper. The results showed that there was a significant effect on the activities of ATPase^ Na+-K+-ATPase> V-ATPase $J HCOf-ATPase (F>F0.05).During the 72h the activities of ATPase and Na+-K+-ATPase appeared peak changes with the sample times and reached their maximum at 24h, then turned to be stable at 72h in each treatments. No significant differences of the Na+-K+-ATPase activites were found between of controls(pH=8) and each treatments after the stabilization (F