Effect of ADY and YC on Concentration of Ruminal Medium Chain Fatty Acid, Lactic Acid, Ethanol and Relative Abundance of Bacteria in Beef Cattle

The aim of this study was to evaluate the effect of two typical yeast preparation (ADY and YC) supplementation on the concentration of ruminal medium chain fatty acid, lactic acid, ethanol and the abundance of relative rumen bacteria in finishing beef cattle. The results showed that ADY supplementation significantly increased the concentration of caproate (C6:0) (P < 0.05) and tended to increase the content of total medium chain fatty acids (P = 0.094), while had no significant effect on concentration of caprylate (C8:0) and caprate (C10:0) (P > 0.1). YC supplementation did not show a significant effect on the content of total medium chain fatty acids and the concentration of individual volatile acids (P > 0.1); ADY supplementation significantly decreased the concentration of lactic acid (P < 0.05) and has a tendency to decrease the ethanol concentration (P = 0.057). YC did not affect significantly the concentration of lactic acid and ethanol (P > 0.1); Both ADY and YC supplementation significantly decreased relative abundance of B. fibrisolvens (P < 0.05) and increased relative abundance S. ruminantium (P < 0.05), and YC rather than ADY tended to increase relative abundance of S. bovis (P= 0.053). Furthermore, both ADY and YC did not show the significant effect on relative abundance of M. elsdenii and C. kluyveri (P > 0.1). These data suggested that there are significant differences between ADY and YC in the effects on rumen metabolites including MCFAs, ethanol and lactic acid, and increased concentration of caproate (C6:0) in rumen may be responsible for the increment of circulating ghrelin caused by ADY supplementation finishing bull. © 2021 Friends Science Publishers