Effects of Saccharomyces cerevisiae supplementation on growth rate and nutrient digestibility in Awassi lambs fed diets with different roughage to concentrate ratios

Abstract

Thirty two Awassi male lambs with initial body weight (27 ± 1.78 kg), and four to five months old, were allocated into four equal groups in factorial experiment to study the effect of two roughage to concentrate rations (R:C, 60:40 and 40:60) supplemented with two levels of Saccharomyces cerevisiae (0 and 5 g SC/head/day) on daily intake, weight gain and digestion of nutrients. The diets were offered in quantity to achieve 150 g daily gain. Results revealed that R:C ratios had no significant effect on daily nutrients intake of dry matter (DM), organic matter (OM), nitrogen free extract (NFE), neutral detergent fiber (NDF) and hemicelluloses, while crude protein(CP), ether extract (EE) and metabolizable energy (ME) increased significantly (P < 0.01). Results showed significant (P < 0.01) decrease in crude fiber (CF), acid detergent fiber (ADF) and cellulose intake with high concentrate ration. DM, OM, CP, EE, NFE, ME, NDF, cellulose, and hemicelluloses intake were not affected by S. cerevisiae supplementation; whereas, CF and ADF increased significantly (P < 0.01) with S. cerevisiae supplementation. Results also indicated that final body weight (FBW), total BW gain (TBWG), daily body weight gain (DBG) and feed conversion ratio of lambs were not significantly affected by R:C ratios. FBW and TBWG were not affected by addition of S. cerevisiae, whereas, DBG was significantly (P < 0.05) affected, where, higher values were achieved by a group of lambs fed diet with added S. cerevisiae. The digestibility coefficients of DM, OM,CP, EE, NFE and TDN and DCP values increased significantly (P < 0.05) with increasing level of concentrate in the rations, while no effect on CF digestibility was observed. In contrast, the digestibility coefficients of all nutrients and nutritive values of experimental rations increased significantly (P < 0.05) with S. cerevisiae supplementation. Consequently, S. cerevisiae supplementation may improve DBG and nutrients digestibility of CP and CF in diets meant for lambs.

Keywords: Saccharomyces cerevisiae, Intake, growth, digestibility, lambs.