Characterization and prevention of Fusarium mycotoxicoses in the horse

Abstract

Deoxynivalenol (DON), vomitoxin), zearalenone and fusaric acid are the most commonly found Fusarium mycotoxins in Ontario-grown feedstuffs. A survey was conducted to examine the degree of Fusarium mycotoxin and mold contamination of hay found on Ontario performance horse farms. Half of the hay sampled showed potentially significant levels of mycotoxins and mold contamination. The farm owner, trainer or manager’s subjective opinion o f the hay did not correlate to analysis results. The feeding of Fusarium mycotoxin-contaminated grains adversely affects the production of swine and poultry. Very little information is available, however, on adverse effects of feeding these mycotoxin-contaminated grains on the athletic or reproductive performance of horses. Trials were conducted, therefore, to determine the effects of feeding diets naturally-contaminated with Fusarium mycotoxins on horses. The contaminated diets were formulated by replacing com and wheat of the control diet with grains naturally-contaminated with Fusarium mycotoxins. A polymeric glucomannan mycotoxin adsorbent (GM polymer) was also tested for its ability to prevent Fusarium mycotoxicoses. Trials examined both exercising and non-exercising horses. Feed intake of horses fed contaminated grains was reduced compared to controls in each trial. Supplementation o f 0.2% GM polymer to the contaminated diet did not alter feed intake of exercising horses compared with those fed the unsupplemented contaminated diet. Supplementation of 0.2% GM polymer to the contaminated diet improved feed intake of non-exercising horses compared with those fed the unsupplemented contaminated diet. Serum activities of gamma-glutamyltransferase were higher (P = 0.047 and P - 0.027) in nonexercising horses fed the diet containing contaminated grain compared to those fed the control diet on d 7 and 14, but not on d 21 (P = 0.273). Supplementation of GM polymer to the contaminated diet reduced (P < 0.05) serum gamma-glutamyltransferase activities of nonexercising horses compared with those fed unsupplemented contaminated diet on d 7 and 14. All hay was consumed regardless o f concentrate fed. Weight loss from 0 to 21 d was observed in exercising horses fed contaminated grains as compared to controls (P < 0.05). No effect of diet was seen on variables used to measure athletic ability although the results showed an expected response to exercise for a fit horse. It was concluded that both non-exercising and exercising horses are susceptible to Fusarium mycotoxicoses as indicated by appetite suppression and weight loss.