Effects of Fusarium moniliforme and Corn Associated with Equine Leukoencephalomalacia on Rat Neurotransmitters and Metabolites

Abstract

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 < 0.01) and increased brain weight/body weight ratios (14%, P < 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 < 0.01, respectively). At 20% FM (MRC 826)-chow diet, the 5-HIAA levels were increased (18%, P < 0.01). In both the 16% and 20% diets, brain 5-HIAA/5-HT ratios were increased (45%, P < 0.01 and 10%, P < 0.05), body weights reduced (30% and 18%, P < 0.01) and brain weight/body weight ratios increased (40% and 16%, P < 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.