Effect of yeast culture supplementation level on the growth performance of growing goats

Abstract

Twelve growing Egyptian Baladi male goats aged seven months old and averaging 9.2 kg ± 1.18 were stratified by weight and randomly assigned to three experimental rations in a feeding trial lasted 84 days. The dry yeast culture (YC)- containing 108 cells of Saccharomyces cerevisiae per gram was mixed with ground concentrates mixture (CM) at 0.1 and 2 g YC/Kg CM. Unsupplemented or YC-supplemented CM were fed Individually and offered at 2.5% of the body weight along with ad-libitum berseem (Trifolium alexandrinum) hay The results exhibit that supplementation with YC did not increase roughage (hay) intake, however, it increased (P<0.05) CF digestibility and insignificantly increased nutrient digestibilities. Ruminal pH, total VFA production and molar proportions of acetate, propionate and butyrate (after 4 hrs of feeding) were resembling in all groups. Molar proportions of isobutyric, valeric and isovaleric fatty acids were higher (P<0.01, 0.05 and 0.01, respectively) in YC rations. Densities of ruminal nicrobes (Ruminococcus sp. and yeast) were insignificantly influenced by YC supplementation levels, while the density of cellulolytic rods bacteria was increased (P<0.05) for animals fed the 1 g YC supplemented ration. Concentration of rumen HN3-N was lower (P<0.05) in YC-fed groups, meanwhile, increasing the level of YC in ration to 2 CM was associated with an increase (P<0.05) in plasma urea-N concentration and urinary N loss. Average daily gam and feed conversion in terms of TDN (kg/kg gam) were improved in YC groups, but the statistical difference from the control was only obtained (P<0.05) on animals fed 1 g YC ration. The study demonstrates that inclusion of YC in the daily ration of growing goats at the rate of 1 g/Kg concentrates or 0.25 g YC/d/10 kg BW is safe and possibly economical in feeding practices.