Abstract:

Tissue section staining observation technology and physiological and biochemical detection methods were used to study the hepatopancreas histopathological and blood biochemical indicators of acute poisoning of Eriocheir sinensis under high concentration nitrite farming conditions, five experimental concentrations were set: 10.16, 21.13, 30.06, 41.11, and 51.04 mg/L. The results showed that acute intoxication caused shrinkage of the basement membrane of the hepatopancreatic tubules in crabs, with severe cases resulting in rupture. The hepatopancreatic cells were separated from the basement membrane to form a large gap. The cell boundary was not obvious, and the arrangement was disordered and fell off to the lumen. Some hepatic tubules were broken, the tissue dissolved, and the stromal cells infiltrated; the hemocyte density (DHC) in the blood increased. In haemolymph of acute poisoning crabs, glutamic oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT) and the glucose content (GLU) increased, the activities of triglyceride (TG) decreased. Immunological indexes showed that superoxide dismutase (SOD) and catalase (CAT) decreased but the activity of galkaline phosphatase (ALP) increased. The research indicated that acute high concentration nitrite poisoning caused great damage to the hepatopancreas and reduced the immunity of the crab, ultimately affecting the normal feeding and activities of the crab. When the concentration of nitrite in the water of Eriocheir sinensis aquaculture is 41.11 mg/L, the mortality rate is 50% at 20 hours and 60% at 24 hours; when the concentration of nitrite is 51.04 mg/L, the mortality rate is 50% at 8 hours and 80% at 24 hours.

Key words: Eriocheir sinensis, hepatopancreas, nitrite, poisoning, histopathology, biochemical indexes