ABSTRACT

The physiological responses of broilers fed diet supplemented with yeast (Saccharomyces cerevisiae) was investigated. Ninety (90) unsexed day old chicks were randomly allocated to 3 treatment, each having 3 replications of 10 chicks in a completely randomized design (CRD). I was the control without yeast while T2 and T3 contained yeast at 1.5g/kg and 2.5g/kg inclusion, respectively. Each diet was given ad-libitum to the birds. Data were collected for daily weight gain, final weight gain, daily feed intake, total feed intake and feed conversion ratio during the experimental period. Carcass percentage of breast, wing, head, backcut, thigh, shank, neck, drumstick, kidney, intestine, crop, gizzard, liver, lungs were recorded. On 28 days, concentration of packed cell volume (PCV), white blood cell (WBC), mean corpuscular volume (MCV) and mean corpuscular haemoglohin concentration (MCHC) in chicks blood were evaluated. Kidney and liver were also collected for histopathological examination. Results showed that in growth parameters, final weight gain showed significant difference (P<O.05) where T3 (9O1.33g gave the best weight gain compared with Ti (871.67g), T2 (871.67g). Daily weight gain followed the same trend whereT3 (32.].9g) was the highest, compared to Ti (31.60g) and T2 (31.12g). Total feed intake showed significant difference (P<0.05) where T1 (36 14.00g) was the highest while T2 and T3 were comparable. Daily feed intake followed the same trend as total feed mt ke where T 1 (129.03g) was the highest compared to T2 and T3. For haematological indices, PCV, RBC, WBC and MCHC showed no significant difference (P>O.05). In the Hb, T3 (7.13) showed the highest while T1 and T2were comparable. In MCV, T2 (143. 14g) showed the highest increase compared with T1 and T 3 respectively. In WBC, T3 (1.99%) has the lowest compared with T2 (2.33) and T3 (2.36). In the organ proportion, there was no significant difference (P>0.05) in the kidney, intestine, spleen, heart, gizzard, crop and liver. However in the kidney T3 (0.69) showed an increase compared to T 1 and T2 0.65g and 0.55 respectively. In the liver, T 1 (3.3 lg) observed to increase them T2 (2.44g) and T3 (2.22g) respectively. The proventriculus and lungs showed significant difference (P<0.05). In the cut parts, the head drumstick, neck and back cut, showed no significant effect (P>0.05). Yeast (Saccharomyces cereviasiae) showed no significant effect (P<0.05) on the histology of both liver and kidney of the birds. There was no toxic effect observed.