Effect of ambient ammonia on ammonia-N excretion and ATPase activity of Penaeus chinensis

Abstract

Ammonia-N excretion, total ATPase and Na+, K+-ATPase activities of Penaeus chinensis (10.38 ± 0.30 g) which were individually exposed to 0.037, 5.043, 10.106 and 20.093 mg/l ammonia-N (un-ionized plus ionized ammonia as nitrogen) were determined every 4 h up to 24 h. Ammonia-N excretion of shrimp exposed to control (0.037 mg/l ammonia-N) increased with time elapsed. Ammonia-N excretion of shrimp increased with ambient ammonia-N in the range of 0.037 to 5.043 mg/l, but decreased in the range of 5.043-20.093 mg/l. Ammonia-N excretion was inhibited as shrimp were exposed to higher than 10.106 mg/l ammonia-N after 4 h. Shrimp exposed to 20.093 mg/l ammonia-N had higher ammonia-N uptake than those exposed to 10.106 mg/l ammonia-N. The shrimp exposed to 5.043 mg/l ammonia-N had higher total ATPase and Na+, K+-ATPase activities in the gill than controls after 4, 8, 16 and 24 h. However, total ATPase and Na+, K+-ATPase activities of shrimp exposed to 10.106 and 20.093 mg/l ammonia-N were significantly lower than those exposed to 5.043 and 0.037 mg/l ammonia-N after 8 h.