AN INVESTIGATION OF THE ROLE OF FUSARIUM-MONILIFORME IN DUODENITIS PROXIMAL JEJUNITIS OF HORSES

Duodenitis/proximal jejunitis syndrome (DPJ) is a small intestinal dis ease of horses that is associated with depression and copious gastric reflux. Since an infectious cause for DPJ remains unsubstantiated, the se studies were designed to Investigate the possible role of Fusarium moniliforme toxins In this disease. Fusarium moniliforme was isolated by culturing 2 samples of feed that had been fed to horses with clinic al signs of DPJ. These isolates (AU 2/3) were subsequently grown concu rrently on autoclaved corn and their toxicity evaluated In a feeding t rial utilizing horses; Isolates of F moniliforme known to be low and h igh producers (RRC 415 and MRC 826, respectively) of fumonisin B-1 (FB 1) were cultured individually on corn and each fed separately to other groups of horses. Control horses were fed autoclaved corn that was no t inoculated with fungus. Production of FB1 by isolates RRC 415, MRC 8 26 and AU 2/3 were 19 4360 and 1455 ppm respectively. Each group conta ined 2 horses and the test diets were prepared by diluting culture mat erial with sweet feed and clean corn. The test diets consisted of cont rol corn that contained <1 ppm FB1, RRC 415 diluted to <1 ppm FB1, MRC 826 diluted to 200 ppm FB1, and AU 2/3 culture material duluted to co ntain 65 ppm FB1 on days 1-10 and 130 ppm on days 11-27. Horses fed ei ther MRC 826 or AU 2.3 had elevated serum gamma-glutamyltransferase af ter 7 to 21 d exposure and elevated serum L-iditol dehydrogenase activ ity after 7 to 19 d exposure to test diets. All horses in these 2 grou ps had elevated serum sphinganine/sphingosine ratios. The 2 horses fed MRC 826 died with signs of neurologic disease after 13 and 16 d of di et feeding. The 2 horses fed AU 2/3 died with signs of neurologic dise ase after 25 and 27 d of feeding. All horses that died bad liquefactiv e necrosis of cerebral white matter characteristic of equine, leukoenc ephalomalacia. The severity of lesions was directly related to duratio n of treatment. Horses fed MRC 826 had intestinal lesions consistent w ith DPJ.