Aflatoxin B1 (AFB1) reduces growth performance, physiological response, and disease resistance in Tra catfish (Pangasius hypophthalmus)

Triplicate groups of one hundred Tra catfish (8 g ± 0.2) were fed seven test diets containing increasing levels of AFB1 (0, 50, 100, 250, 500, and 1000 μg AFB1 kg−1). Additionally Mycofix® Secure was added at 1.5% to one diet containing 500 μg AFB1 kg−1. Results showed that Tra catfish are sensitive to AFB1. Reduction in weight gain (P < 0.05) was observed for fish fed 50 μg AFB1 kg−1 and declined further with increasing levels of AFB1 in the diets. Fish fed diets contaminated with 500 and 1000 μg AFB1 kg−1 showed increased (P > 0.05) hepatosomatic index (HIS), while an increase in adipose somatic index (ASI) was observed in fish fed 50 μg AFB1 kg−1 and above when compared to the control and Mycofix® diets. After 12 weeks, blood serum analysis revealed higher alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in fish fed the 50, 100, and 250 μg AFB1 kg−1 suggesting occurrence of liver damage. Disease resistance of fish exposed to Edwardsiella ictaluri was also compromised by the presence of AFB1 in the feed and was directly related to the contamination level. Seven days after Edwardsiella ictaluri exposure, survival rates were 50, 41.7, 31.7, and 8.3% for fish fed control, 50, 100, and 250 μg AFB1 kg−1, respectively. This trial shows that AFB1 at a level of 50 μg AFB1 kg−1 and above can affect fish performance and disease resistance. Application of an effective mycotoxin management in the feed seems to be useful to prevent the negative effects of AFB1.