In vitro ruminal disappearance of fumonisin B1 and its effects on in vitro dry matter disappearance.

Fumonisins were produced by inoculating corn with Fusarium moniliforme M-1325 and incubating for 5 w. Fumonisin B1 (FB1) concentration determined by high performance liquid chromatography was 5,087 ppm. Ruminal fluid inoculum obtained from 2 ruminally cannulated steers and tubes containing 0, 50 or 100 ppm of FB1 were incubated in vitro with ruminal fluid and artificial saliva for 72 h in a 39 C oscillating incubator. Supernatant was analyzed for FB1 concentration, and in vitro dry matter disappearance (IVDMD) was calculated in the remaining precipitates. There was minimal degradation of FB1 by ruminal microbes (about 10%) irrespective of concentration of FB1 used when incubated for the 72 h. No differences in IVDMD rates, were found between treatments, and the rates were normal, indicating that microbial efficiency was unaffected by the presence of FB1 at diet concentrations up to 100 ppm.