Effects of sodium bicarbonate and yeast on productive performance and carcass characteristics of light-weight lambs fed finishing diets

This experiment was conducted to study productive performance and carcass characteristics of finishing lambs fed diets containing yeast culture (YC) and/or sodium bicarbonate (SB). Twenty male Pelibuey lambs, weighing 11.4 kg, were assigned to one of four groups according to a completely randomized design, with a 2 × 2 factorial arrangement of treatments. Each group received a basal diet with one of the following four treatments: (1) no additives (NA); (2) 0.12% yeast culture (YC; Yea Sacc® 1026; All-Tech, Lexington, Kentucky) containing 2.8 × 104 cfu of yeast/g; (3) 0.5% sodium bicarbonate (SB); and (4) both, 0.12% YC and 0.5% SB. Lambs were individually confined to 1.5 m2 metabolic cages. Dry matter (DM) intake, on a live weight basis, was not different among treatments (P > 0.05) during the entire 60-day period. However, when expressed on an empty body weight basis, SB in the diet significantly increased (P < 0.05) DM intake. Similarly, weight gain was not affected (P > 0.05) by the inclusion of YC or SB. Although feed efficiency was not affected (P > 0.05) by YC, more feed was required per unit gain when SB was added to the ration (P < 0.05). Cold and hot carcass weights (kg) were not different (P > 0.05) among treatments. Full gastrointestinal tract weight was not affected by YC or SB supplementation. Neither YC or SB affected marbling score, external fat, or longissimus muscle (ribeye) area. However, SB increased (P < 0.05) degree of finishing of lamb carcasses. No effect of YC or SB in the diet was observed on weight of skin, liver, lungs, testicles or blood. Heart weight was greater (P < 0.05) for lambs consumed diets with YC. First and second yield carcass grade were not affected (P > 0.05) by YC or SB.