Effect of yeast culture and its combination with direct-fed microbials on growth performance and rumen fermentation of weaned lambs

Abstract

Thirty-two lambs weighing 22.20 (± 0.75) kg were randomly assigned to one of four treatments: No additive (control), yeast culture (YEC), YEC plus B. licheniformis (YBL) or YEC plus C. butyricum (YCB). Diet consisted of grass hay ad libitum and concentrate (300 g/head/day). Average daily gain was 102, 114, 90, and 89 g/d in control, YEC, YBL, and YCB, respectively, with no significant difference (P>0.05) among treatments, but the carcass weight of YEC lambs was significantly higher (P<0.05) than that of other treatments. Total volatile fatty acids and acetate to propionate ratio were uninfluenced, although the butyric acid concentration was higher (P<0.05) in the rumen fluid of YCB lambs compared to YEC lambs and slightly higher (P>0.05) than in controls and YBL lambs. Solid-associated fungi population relative to total rumen bacteria 16S ribosomal DNA was significantly lower (P<0.05) in YBL lambs (3.55) compared to YCB (23.12). There was little difference in blood glucose and plasma urea-N concentrations among the treatments. Blood concentrations of creatinine and globulin were significantly higher (P<0.05) in YBL and YCB lambs compared to the control and YEC-fed animals. Results indicated that yeast culture improved growth performance with little advantage expected from combining yeast culture with either B. licheniformis or C. butyricum. More research using adjusted diet formulations and doses of B. licheniformis or C. butyricum in combination with yeast culture is recommended.

Keywords: Direct fed microbials, ruminant nutrition, sheep