Rumen volatile fatty acids x dietary supplementation with live yeast and yeast cell wall in feedlot beef cattle

This study assessed the effect of dietary supplementation of yeast cell wall (YCW) and live cell yeast (LCY) at different dosages on rumen's metabolites. Sixty steers were divided into two groups on the basis of their feeding phase: growing and finishing. Growing and finishing groups were each randomly divided into equal three subgroups (n = 10): no supplement (growing control), supplemented with YCW, and supplemented with LCY + YCW, no supplement (finishing control), supplemented with LCY and supplemented with LCY + YCW. Ruminal fluid has been collected before, after 21 and 42 days of experimental period in order to evaluate the volatile fatty acids concentrations and pH values. Statistical analysis showed a significant effect of time (P<.05) on all studied parameters except iso-valeric acid both in growing and finishing groups. Changes among growing subgroups (P<.05) on propionic acid, acetic acid, iso-butyric acid and n-butyric acid were found, whereas no statistical significances were found among finishing subgroups.