Growth and hepatic lesions of Nile tilapia ( Oreochromis niloticus) fed diets containing aflatoxin B 1

Abstract

Responses of Nile tilapia to varying concentrations of aflatoxin B 1 (AFB) were investigated under controlled laboratory conditions. Nile tilapia (2.7 g) were fed semipurified diets containing 0, 0.25, 2.5, 10, or 100 mg AFB/kg of diet for 8 weeks. Weight gain and hematocrit of fish fed with 0.25 mg AFB/kg were not significantly different from that of the control; however, diets containing higher levels of AFB had significantly ( P<0.05) reduced weight gain and hematocrit. Histologically, livers of fish fed with diets containing 10 mg AFB/kg contained excess lipofuscin and irregularly sized hepatocellular nuclei. Diets containing 100 mg AFB/kg caused weight loss and severe hepatic necrosis; 60% of the fish in this treatment died by the end of the 8-week feeding period. No lesions were observed in the spleen, stomach, pyloric intestine, head kidney, or heart of fish in all treatments. These results indicate that acute and subchronic effects of AFB to Nile tilapia are unlikely if dietary concentrations are 0.25 mg/kg or less.