Response and recovery of gibel carp from subchronic oral administration of aflatoxin B1

A 16-week feeding trial was conducted to evaluate the effect of dietary aflatoxin B1 (AFB1) on growth, physiological responses, histological changes, and accumulation in gibel carp (Carassius auratus gibelio), and the recovery when the fish were fed basal diet without supplemental chemical AFB1. Triplicate groups of gibel carp with initial body weight of 10.33 ± 0.19 g were fed seven semipurified diets (Diets 1 to 7) designed to contain 0, 10, 20, 50, 100, 200, 1000 μg AFB1 kg−1 diet (determined level was 3.2, 11.3, 20.2, 55.2, 95.8, 176.0, 991.5 μg AFB1 kg−1 diet, respectively) for 12 weeks. Subsequently, all fish were fed Diet 1 for another 4 weeks. The results showed that, after 12 weeks of AFB1 exposure, average body weight in fish fed Diet 4 was 112.3% of that of the control group (Diet 1), but there was no significant difference between other groups and the control group. No external changes, unusual behavior or significant difference in mortality were observed in the fish fed with various levels of AFB1. There was no significant difference in feeding rate (FR) between the control and experimental groups. Specific growth rate (SGR) and feed efficiency (FE) of the fish fed with Diet 4 was significantly higher than that fed the control diet during the first exposure period (weeks 0–4) while there were no significant difference during the second exposure period (weeks 5–12). Fish fed with various levels of AFB1 showed no significant differences in activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), superoxide dismutase (SOD), total protein, total serum cholesterol, and hematocrit compared to the control group. No significant histological lesions were identified between the control and increasing AFB1 treatments. Low AFB1 residues were found in muscles, whereas high residues of AFB1 were determined in hepatopancreas (above the safety limitation of 5 μg kg−1), which was logarithmically related to the dietary AFB1 levels. Our results indicate that gibel carp is a less susceptible species to AFB1 exposure up to approximately 1000 μg AFB1 kg−1 diet, at least for 12 weeks. The fish also showed strong clearance ability of AFB1 during recovery period.