Feed intake, digestibility, rumen fermentation and growth performance of camels fed diets supplemented with a yeast culture or zinc bacitracin

Twelve Maghraby camel calves (185.2 ± 0.7 kg body weight, BW) were utilized in a – 14 weeks – completely randomized design experiment to evaluate the effects of feeding a probiotic yeast culture (YC; Diamond V® “XP” YC containing Saccharomyces cerevisiae) or zinc bacitracin (ZnB) on feed intake, growth performance, nutrient digestibility, N utilization, rumen fermentation, and water balance. Treatments were: (1) a basal diet (control) consisted of peanut hay (400 g/kg) and concentrates (600 g/kg) on dry matter (DM) basis. (2) The basal diet supplemented with 5 g/kg (DM basis) of an YC. (3) The basal diet supplemented with 2 g/kg (DM basis) of ZnB. Diets were offered individually at 0.03 of BW per day. Feed intake (DM) was not affected by treatments. Total weight gain for YC supplemented group was higher (P<0.05), while average daily gain (ADG), final body weight and feed (DM) conversion tended to be better (0.05<P<0.10) compared to the control or ZnB supplemented groups. Digestibility of ADF of YC supplemented diet was higher (P<0.05), while digestibilities of dry matter, organic matter and crude protein tended (0.05<P<0.10) to be higher than the control or ZnB supplemented diets. Retained N in YC supplemented animals, either as absolute values or as proportions of intake N was higher (P<0.05) than in the control or ZnB supplemented animals. Rumen pH was not affected by treatments, while rumen ammonia and total volatile fatty acids concentrations were higher for YC group compared to the control or ZnB groups. Insensible water loss was not affected by treatments. Results indicate that YC supplementation of dites of Maghraby camel calves at 5 g/kg (DM basis) improves weight gain, ADG and feed utilization, while supplementation with ZnB at 2 g/kg (DM basis) has no effect on the same traits.