Growth and aflatoxin B1 accumulation of gibel carp adult fed with diets of different levels of aflatoxin B1

A 56-day 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) adult. Triplicate groups of gibel carp (122.3 ± 0.7) g were fed with five semi-purified diets (Diet 1 to 5) containing0, 5, 20, 50 and 500 μg/kg AFB (determined level was 2.59, 4.12, 12.39, 46.23 and 454.07 μg AFB1/kg diet, respectively). During the experiment, photoperiod was 12D∶12L with the light period from 09:00 to 21:00, dissolved oxygen was above 6 mg/L, ammonia-N was less than 0.4 mg/L and pH was about 6.8. The results showed that during the 56-day of AFB1 exposure, no external changes and unusual behavior were observed in the fish fed with various levels of AFB1. The survival rate in all groups attained 100%. There was no significant difference in final body weight, feeding rate (FR), specific growth rate (SGR) and feed efficiency (FE) between the control and the other groups. Fish fed with various levels of AFB1 showed no significant differences in total cholesterol, activities of serum alanine aminotransferase (ALT), asparitic aminotransferase (AST), alkaline phosphatase (ALP) and superoxide dismutase (SOD) compared to the control group. No significant histological lesions in hepatopancreasand ovary were identified between the control and increasing AFB1 treatments. Low AFB1 residues were found in muscles and ovary, and were below the safety limitation of 5 mg/kg. Accumulation of AFB1 in hepatopancreas was logarithmically correlated to the dietary AFB1 level. Our results indicated that gibel carp was a less susceptible species to AFB1 exposure up to approximately 500 μg/kg diet (determined level was 454.07 μg/kg diet), at least for 56 days.