Effects of Fusarium moniliforme and corn associated with equine leukoencephalomalacia on rat neurotransmitters and metabolites.

Fusarium moniliforme (FM) is associated with equine leukoencephalomalacia (ELEM) and hepatotoxicities in horses and rats. The neurochemical effects of ELEM-associated corn naturally infected with FM and FM strain MRC 826 were studied in rats. Increases in brain 5-hydroxyindoleacetic acid (5-HIAA, major metabolite of serotonin, 5-HT) and 5-HIAA/5-HT ratios were observed in rats fed the ELEM-FM corn. These rats had reduced body weights (17%, P less than 0.01) and increased brain weight/body weight ratios (14%, P less than 0.01) as compared with controls that were fed commercial corn. Rats fed a rodent chow supplemented (16%, w/w) with corn cultures of FM (MRC 826) had brain 5-HT and 5-HIAA increased (11% and 60%, P less than 0.01, respectively). At 20% FM (MRC 826)-chow diet, the 5-HIAA levels were increased (18%, P less than 0.01). In both the 16% and 20% diets, brain 5-HIAA/5-HT ratios were increased (45%, P less than 0.01 and 10%, P less than 0.05), body weights reduced (30% and 18%, P less than 0.01) and brain weight/body weight ratios increased (40% and 16%, P less than 0.01), respectively. The incidences of microscopic liver lesions (particularly bile duct proliferations, hepatocellular hyperplasia, and focal necrosis) were consistent with rats fed the FM contaminated and FM-fortified diets. These results suggest a possible FM (ELEM-associated)-induced dysfunction in either 5-HT metabolism or 5-HIAA elimination in rat brains.