β-Glucan improved the immunity, hepato-renal, and histopathology disorders induced by chlorpyrifos in Nile tilapia

This study aimed at investigating the potential role of β-glucan in improving the immunity, anti-inflammatory and histopathology disorders induced by chlorpyrifos in Nile tilapia. Fish were allocated in four group where the control fed the basal diet without chlorpyrifos toxicity and chlorpyrifos group fed the basal diet and subjected to chlorpyrifos (15 μg/L water). The third group fed dietary β-glucan (1 g/kg diet) without chlorpyrifos toxicity and the fourth group fed dietary β-glucan and exposed to chlorpyrifos (β-glucan/chlorpyrifos). Results revealed that the exposure to chlorpyrifos tended to decrease final body weight (FBW), weight gain (WG), specific growth rate (SGR), and survival but increased the feed intake (FI) and feed conversion ratio (FCR). Administration of β-glucan tended to increase FBW, WG, SGR, survival, and FI but did not change the FCR. Exposure to chlorpyrifos did not change the blood alkaline phosphatase (ALP) but increased aspartate aminotransferase (AST), alkaline phosphatase (ALP), and cortisol levels whereas β-glucan administration markedly decreased ALP, AST, ALT, and cortisol levels and β-glucan/chlorpyrifos treatment declined the levels of these variable close to the baseline values. Compared to the control, chlorpyrifos administration tended to decrease the lysozyme and phagocytic index but no change was observed in phagocytic activity. β-Glucan administration greatly increased the levels of lysozyme, phagocytic activity and phagocytic index, and β-glucan tended to alleviate the negative effect of chlorpyrifos on the mentioned parameters. The chlorpyrifos exposure caused congestion and telangiectasia in gills, catarrhal enteritis followed by degeneration and sloughing of the apical part of the intestinal villi with diffused lymphocytic infiltration, and fatty degeneration and vacuolation of hepatocytes in addition to congestion of blood sinusoids in liver. However, the histopathological structure of these organs was normal with dietary β-glucan. In conclusion, β-glucan administration alleviated the adverse effects of chlorpyrifos on the immune and anti-inflammatory response as well as histopathology of gills, liver, and intestine of Nile tilapia.