Effects of acute nitrite stress on oxidative stress, energy metabolism and osmotic regulation of Penaeus monodon

Penaeus monodon (African group) accommodates industrial aquaculture and has promising market prospects. But the deterioration of water quality causes frequent occurrence of diseases. Nitrite is a common pollutant, and the experiment was conducted to observe its effect on oxidative stress, energy metabolism and osmotic regulation. Four gradients of nitrite concentrations (0.1, 5, 10 and 15 mg/L) were set for 4 groups, and three parallels were set for each group. After the acute stress experiment for 72 hours, enzyme activities or substance content were assayed. ① As for oxidative stress factors in gill, activities of SOD, GSH-Px, CAT and NOS increased initially and decreased subsequently. At 24 h, the activities of SOD, GSH-Px and NOS reached maximum. The activities of SOD and GSH-Px in the 10 mg/L group and NOS activity in 15 mg/L group were significantly higher than other groups. On the contrary, MDA content in stress groups was the lowest at 24 h, and the 10 mg/L group was significantly lower than other groups. At 48 h, CAT activity reached the maximum, and the CAT activity of 10 mg/L group was significantly higher than other groups. At 72 h, the NO content reached maximum, and 15 mg/L group was significantly higher than other groups. ②The indicator of serum energy metabolism, LPS, increased at first and decreased then. The activities of HK, PFK, PK or TG content, decreased obviously during stress process. At 48 h, LPS activity reached maximum, and 10 mg/L group was significantly higher than other groups. At 72 h, the activities of HK, PFK, PK and TG content reached minimum, 15 mg/L group were significantly lower than those of other groups. ③The gill osmotic regulation parameters, Na⁺, K⁺ -ATPase, decreased during whole process. At 72 h, the Na⁺, K⁺ -ATPase activity reached the minimum, and the 15 mg/L stress group was significantly lower than other groups. Results showed that P. monodon could improve antioxidant capacity, enhance lipid absorption and utilization, and disturb osmotic balance when exposed to acute nitrite stress. But only within certain concentration or time limits can it come into play. The result will provide data support for the further exploration of molecular mechanisms and also provide theory support for healthy prawn farming.