The impact of elevated nitrite levels on the digestive system of Micropterus salmoides
To investigate the effects of a high nitrite aquaculture environment on the digestive system of the largemouth bass Micropterus salmoides,histological observations and analyses were conducted on the liver,stomach,and intestinal tissues of M.salmoides cultured in environments with elevated ni-trite levels(>0.15 mg/L)compared to normal nitrite levels(≤0.005 mg/L).The findings revealed that in high-nitrite environments,the liver and intestinal tissue structures of M.salmoides were sig-nificantly compromised,with liver cell nuclei exhibiting vacuolation and enlargement,and a marked difference in the length of intestinal villi(P<0.05).In conclusion,excessive nitrite concentrations have a profound impact on the digestive system of M.salmoides.Under the current aquaculture mod-el,controlling nitrite concentration is essential for enhancing fish immunity.