Ochratoxin A fed to channel catfish (Ictalurus punctatus) causes reduced growth and lesions of hepatopancreatic tissue

Ochratoxins are a group of secondary metabolites produced by fungal organisms belonging to Aspergillus and Penicillium genera. Ochratoxin A (OA) is the most abundant of this group of mycotoxins and is more toxic than other ochratoxins. It contaminates corn cereal grains and oilseeds that have been infected with certain species of molds of the two previously indicated genera. Ochratoxin A can adversely affect animal performance. The effects of OA on channel catfish have not been documented. An experiment was conducted in aquaria with juvenile channel catfish to evaluate the effect of feeding graded levels of OA in a semipurified diet for 8 weeks on growth, feed conversion ratio (FCR), hematology, survival, and histopathology of liver and kidney. Channel catfish, initial body weight 6.1 g/fish, were fed diets containing 0, 0.5, 1.0, 2.0, 4.0, or 8.0 mg OA/kg diet supplied from culture material containing 80 mg OA/kg. Significant (Pless than or equal to0.05) reductions in body weight gain were observed after only 2 weeks and at each successive 2-week weighing interval for catfish fed diets containing 2.0 mg OA/kg diet or above. At week 8, weight gain was significantly reduced in catfish fed diets containing 1.0 mg OA/kg or above. Feed conversion ratio was significantly poorer for catfish fed diets containing 4.0 or 8.0 mg OA/kg of diet. Hematocrit was significantly lower for catfish fed 8.0 mg OA/kg, but no significant (P>0.05) differences in white blood cell (WBC) count were observed for catfish at any dietary levels of OA. Survival was high for catfish fed diets containing 0-4 mg; OA/kg, but fish fed the diet containing 8.0 mg OA/kg had significantly lower survival compared with those of the other treatments. Histopathological examination of liver and posterior kidney at 8 weeks revealed that there was increased incidence and severity of melanomacrophage centers in hepatopancreatic tissue and posterior kidney for catfish fed dietary concentrations of 2.0 mg OA/kg or above. Exocrine pancreatic cells that normally surround the hepatic portal veins of channel catfish were reduced in number or absent in livers of fish fed 1.0 mg OA/kg diet or greater. (C) 2003 Elsevier Science B.V. All rights reserved.