SPHINGOLIPID LEVELS IN CATFISH CONSUMING FUSARIUM-MONILIFORME CORN CULTURE MATERIAL CONTAINING FUMONISINS

Fumonisin, a secondary metabolite of Fusarium moniliforme, is frequent ly found in foods and feeds of humans and animals. Fumonisins are spec ific inhibitors of sphinganine (sphingosine) N-acyltransferase, a key enzyme in the pathway for de novo sphingolipid biosynthesis and reacyl ation of sphingosine derived from dietary sources or complex sphingoli pid turnover. The objective of this study was to evaluate the effect o f F. moniliforme toxins on sphingolipids in year-2 channel catfish. In a 12-week feeding trial, four groups of catfish per treatment were fe d pelleted balanced diets containing F. moniliforme cultured corn. The fumonisin B-1 (FB1) concentrations in diets were 0.3 (control), 2.5, 5, 10, 20, 40, 80 and 240 mg/kg. The free sphinganine to free sphingos ine ratio was significantly (P < 0.05) elevated (with exception of bra in) at 10, 20, 40 and 80 mg FB, per kg diet in kidney, serum, liver an d muscle, respectively. The increase in free sphingolipid ratios obser ved were found to be due to increases in the levels of free sphinganin e in tissues. These results demonstrate that a mode of action of F. mo niliforme toxins in catfish is similar to other species (ponies, pigs, rats), and is suggestive of fumonisin toxicity. It also demonstrated the potential diagnostic value of ratios of free sphingolipids in catf ish.