Abstract

A total number of 192 male one-day-old broilers chickens were randomly divided into four treatment groups of 48 chickens. Chickens of group one fed a plain diet without any supplement (control), while the diets ib groups two, three, and four were supplemented with Whole Yeast (WY, Saccharomyces cerevisiae, 0.1%), Yeast Cell Wall (YCW, 0.3 %), and Yeast Extract (YE, 0.07 %), respectively. At the end of the experimental period (35 days), the bodyweight of chickens and the feed intake of each cage were measured, and then the feed conversation ratio was calculated. Blood samples were also collected to measure the serum components and relative spleen, bursa of Fabricius, and thymus gland. The results obtained indicated that all productive performance parameters improved in response to the feeding supplementation. Blood parameters indicated that the treated groups had a significantly higher level of serum total protein and albumin as well as significantly lower serum total lipids and cholesterol. The enzyme activities of ALT, AST, and ALP were significantly reduced by WY, YCW, and YE supplementation. The relative organ weights of the spleen, bursa of Fabricius, and thymus increased significantly in broilers fed with WY, YCW, and YE, and the highest values were observed in the chickens fed with WY. It can be demonstrated that the supplementation of WY or its derivatives in the diet of broiler chickens improves the production performance as well as the physiological and immunological parameters, and consequently produce a healthier chicken.