Two hundred and eight one-day broiler chicks (ROSS 500) were divided into 4 treatments till 35 days old, each group fed on corn-soybean starter diet (S) from 1-21 days old and grower diet (G) from 22-35 days old. Control treatment received un-supplemented S and G diets, S1G0 group fed on S supplemented with 1 g Bio-Mos kgG 1 then un-supplemented G, S1G0.5 group received S supplemented with 1 g Bio-Mos kgG
INTRODUCTIONMannan oligosaccharides (MOS) and its commercial product form (Bio-Mos, product of Alltech Inc., Nicholasville, KY, USA) is one of prebiotics that derived from the outer layer of yeast cell walls (Saccharomyces cerevisiae). The main idea to use yeast MOS in poultry feeds evolved from the following two concepts about involved mannose, which could be: (1) it is used largely to block the colonization of intestinal pathogenic bacteria, especially E. coli and Salmonella which are the most common pathogenic bacteria hosted in intestinal tract of poultry and enhance growth of beneficial bacteria such as Lactobacillus in intestinal gut, therefore, supporting growth performance of bird as reported by Cavazzoni et al. (1998), Brzoska et al. (1999), Joerger (2003 and Patterson and Burkholder (2003). (2) Some research workers including Spring (1996), Shane (2001) and Markovic et al. (2009), reported a beneficial alteration effect of Bio-Mos and yeast cell wall (as a source of MOS) inclusion in broiler diets on microvillus length and crypt depth of which are the basic absorbent elements of nutrients in intestinal mucosa.