Pathological effects of Aspergillus toxicity on gill structure of Litopenaeus vannamei in Iran by two different toxicological investigations

This histological study was conducted to discover the response of Litopenaeus vannamei to various levels of aflatoxigenic fungi (Aspergillus) toxicity. For this purpose, 400 specimens of live shrimp were gathered from a shrimp culture site in Iran. According to the results of the high-pressure liquid chromatography (HPLC) analysis, Aspergillus parasiticus had a higher production capability of total aflatoxin (TAF) (1073.804 ng g-1) compared to Aspergillus flavus (292.349 ng g-1). Two experiments with different toxicities of Aspergillus were assayed. In both experiments, the shrimps in 6 experimental groups were exposed to 0, 1, 5, 10, 15, and 20 ml of fungal spore suspension (FSS) in the feed (E1) and culture medium water (E2) in triplicate in each group for 4 weeks. The histopathology results of the gill tissue in the control group were normal. However, the inflammation, hemocytic infiltration, melanization, edema, and necrosis (as the main histopathological changes in the gill tissue) were observed after 28 days of the experiment when the toxicity of both experiments reached 18 µg kg-1 total aflatoxin and 1 ml FSS in E1 and E2, respectively. Furthermore, it was recognized that the histological alterations index (HAI) of gill was higher in E2 (0-130) than in E1 (0-74).