Probiotic on Performance, Immune Response, Serum Lipids and Microbial Population of Broilers

This study was conducted to investigate the effects of the medicinal plant yarrow (Achillea millefolium L.), a probiotic (Primalac) and an antibiotic (virginiamycin) on gastrointestinal tract (GIT) characteristics, microbial populations, immune response, serum lipids and growth performance of broiler chickens. A total of 250 one-day old male broilers (Ross 308) were randomly allocated to 5 treatments, 5 replicates with 10 birds in each in a completely randomized design. Experimental treatments included the control, yarrow powder at two different concentrations (1.5 and 3 % of diet), Primalac (0.1 % of diet) and virginiamycin (15 ppm). The highest feed conversion ratio (FCR) was observed in the control while the lowest FCR was seen in the virginiamycin group at 42 days of age (P< 0.05). Moreover, the highest body weight gain (BWG) was observed in the virginiamycin group while the lowest value was related to the control animals (P< 0.05). Carcass yields were not different between treatments (P> 0.05). Relative weights of breast and thigh were similar among all treatments (P> 0.05). Relative weights of bursa Fabricius, spleen and primary immune response (total titer, IgG and IgM) against sheep red blood cells (SRBC ) were not affected by treatments. The seru