EFFECTS OF FEEDING DIFFERENT LEVELS OF BAKER’S YEAST (Saccharomyces cerevisiae) AS AN ADDITIVE ON PERFORMANCE AND HAEMATOLOGICAL PARAMETERS OF BROILER CHICKS

Abstract

The effect of feeding different levels of baker’s yeast on feed intake, daily body weight gain (ADG), feed conversion ratio (FCR), blood constituents, carcass characteristics and profitability of the rations of Cobb 500 broiler chicks was studied. Four nearly isocaloric and isonitrogenous starter and finisher rations were prepared according to the recommendation of National Research Council (NRC). Unsexed 240 Cobb 500 chicks with an average initial body weight of 42.75±0.71g were randomly divided into 12 groups of 20 chicks each and assigned randomly to 4 treatments with 3 replications. The chicks were offered starter and finisher rations for 21 and 24 days, respectively. Treatments were rations containing 0% baker’s yeast (T1), 0.5% baker’s yeast (T2), 1.5% baker’s yeast (T3) and 2.5% baker’s yeast (T4). At the end of the trial, 3 male and 3 female chickens from each replication were slaughtered for carcass parameters evaluation. The crude protein (CP) and metabolizable energy (ME) contents of baker’s yeast were 48% and 3615kcal/kg DM, respectively. The CP content of the rations during the starter and finisher phases were about 22% and 20%, respectively. The ME content of the rations during the starter and finisher phases were about 3100 kcal/kg and 3200 kcal/kg. Intake of feed during the starter phase (46.6, 45.8, 45.7 and 45.1 g/bird/day) and the entire trial period (96.4, 95.0, 95.9 and 94.2 g/bird/day was lower for T4, whereas feed intake during the finisher phase (140.7, 140.0, 138.1 and 137.2 for T1, T2, T3 and T4, respectively) was affected by treatment (P<0.05) and feeding control diet showed highest feed intake than the other supplemental groups. Highest (P<0.05) ADG was recorded in broilers fed T4 rations during starter phase (20.7, 21.5, 21.5 and 23.1 g/day), finisher phase (54.42, 54.48, 56.39 and 55.67g/day) and the entire experimental period (38.7, 39.1, 40.1 and 40.5 g/day for T1, T2, T3 and T4, respectively). Feed conversion ratio of T4 (2.33±0.02) and T3 (2.37±0.02) was better (P<0.05) than that of T2 (2.45±0.02) and T1 (2.5±0.02). Group fed with T3 and T4 had higher (P<0.05) eviscerated percentages (71.43±0.8 and 70.13±0.8 respectively) than T1 (67.93±0.8) and T2 (67.67±0.8). There was no significant difference (P>0.05) in mortality among the treat ments. At the end of experiment RBC, WBC, PCV and Hb in chick’s blood were evaluated. Res ults showed that fed broilers yeast containing ration had higher (P<0.05) WBC, PCV and Hb. Partial budget analysis indicated that the highest net income, marginal rate of return and chicks’ sale to feed cost were obtained for T3 followed by T4. Baker’s yeast can be an important feed additive, which can included up to 2.5% of the total ration improve the overall performance of broilers without compromising the hematological indices of broiler chickens.