Author
SCHNEIDER, IAN - IOWA STATE UNIV., AMES | |
AMES, MICHAEL - IOWA STATE UNIV., AMES | |
Rasmussen, Mark | |
REILLY, PETER - IOWA STATE UNIV., AMES |
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/30/2002 Publication Date: 4/1/2002 Citation: N/A Interpretive Summary: Bovine rumen fluid was fermented anaerobically over 48 h with cottonseed, corn, alfalfa, or a mixture of these substrates in a buffered medium. Samples taken at different times were subjected to gas chromatography and mass spectroscopy. No unusual fermentation end products from the cottonseed substrate were detected. Cottonseed supported fermentation at levels comparable to those of other substrates. Samples containing cottonseed, subjected to high performance liquid chromatography, indicated that gossypol concentrations did not decrease during the microbial fermentation. This plant toxin appears to be resistant to fermentation. This work is of interest to rumen microbiologists and nutritionists interested in basic research regarding rumen metabolism and function. Technical Abstract: Bovine rumen fluid was fermented anaerobically over 48 h with cottonseed, corn, alfalfa, or a mixture of these substrates in anaerobic mineral buffer. Samples taken at different incubation times were derivatized with n-butanol and subjected to gas chromatography and mass spectroscopy. No unusual fermentation end-products from the cottonseed substrate were detected. Cottonseed supported rumen fermentation at levels comparable to those of the other substrates. Major components were usually found in the decreasing order of acetate, propionate, butyrate, and valerate, although acetate and propionate concentrations decreased late in the alfalfa and mixed-feed fermentations, eventually allowing butyrate concentrations to exceed those of propionate. As expected, lactate was produced in high concentrations when corn was fermented. The minor components 2- methylpropionate, 2- and 3-methylbutyrate, phenylacetate, phenylpropionate, and caproate also accumulated, their relative concentrations varying with the substrate. Succinate was produced in substantial amounts only when corn and alfalfa were fermented, not accumulating when cottonseed was the substrate. Samples containing cottonseed were derivatized and subjected to reversed-phase, high- performance liquid chromatography, revealing that gossypol concentrations did not change during fermentation. |