Effect of yeast culture supplementation on carcass yield and humoral immune response of broiler chicks

Aim: A study was conducted to evaluate the effect of supplemental yeast culture (Diamond V XPC Yeast Culture; YC) in broiler diets on carcass characteristics and humoral immune response. Materials and Methods: A total of 240 one-day-old broiler chicks (Ross 308) were randomly assigned to four YC dietary treatments of 60 birds each. The dietary treatments were 0 (control), 1, 1.25 and 1.5 g YC/kg diet over 42 d. Results and Discussion: The results revealed that the birds fed yeast cultures had statistically increased (P < 0.05) body weight from control birds only at 5-6 weeks of age. The highest inclusion level (1.5g/kg) recorded the best weight. The broiler chicks fed a diet supplemented with 1.25g/kg had the lowest mortality rate over the whole period of the experiment. The birds given the highest level of yeast (1.5g/kg) had significantly (P < 0.05) higher percentage of major and minor breast muscles compared with the others that fed a basal diet. A significantly (P < 0.01) increase in IgM titer was noticed in birds fed diet containing YC levels more than 1g/kg at 7 days post-injection with sheep red blood cells. Likewise, broilers fed a diet containing 1.25g/kg exhibited a higher level of antibody titer against Newcastle disease virus at latter age (on d 42) compared with the other groups. Conclusion: The data suggest improvement in growth performance, carcass yield and humoral immunity of broilers fed yeast culture supplementation diet.