Evaluation of growth performance, hematological, biochemical and histopathological parameters of Rhamdia quelen fed with a feed artificially contaminated with aflatoxin B1

•Different levels of aflatoxin B1 (AFB1) in the diet do not cause changes in zootechnical performance in Rhamdia quelen.•AFB1 in the diet may cause hematological changes in Rhamdia quelen.•AFB1 in diet may cause changes in liver histological parameters of Rhamdia quelen. Contamination by aflatoxin B1 (AFB1) in fish is related to several non-specific signs, including immunosuppression, inadequate growth, histological and behavioral changes. Hematological, biochemical and histopathological parameters can be important diagnostic tools to evaluate metabolic and cellular processes in fish. The objective of this study was to determine the effects of diets containing different levels of AFB1 fed to silver catfish (Rhamdia quelen). A total of 624 silver catfish juveniles (mean weight of 7.44 g ± 2.18) were distributed into 4 different treatments (T1, T2, T3 and T4 containing 0, 45, 90 and 180 μg.kg−1 AFB1, respectively). Fish were randomly divided into 24 aquaria (n = 26 per aquarium) and fed for 56 consecutive days with pelleted feed. Growth, hematological, serum biochemistry and histopathological parameters were evaluated on days 28, 42 and 56 of the experimental period. There were no significant differences (p > 0.05) in the growth parameters when comparing the treatments exposed to AFB1 with the control treatment. AFB1 was able to induce hematological and biochemical changes consistent with metabolic disorders in the silver catfish and these were found in liver, gill and renal tissue. Different concentrations of dietary AFB1 had no effect on growth performance of silver catfish in a linear way, nor do they cause histological alterations in the evaluated organs. Nonetheless, fish fed AFB1 containing diets showed hematological and biochemical changes consistent with immunosuppression and hepatoxicity, which are commonly reported in animals exposed to AFB1.