Effect of Probiotic supplementation on intestinal micro flora in poultry, especially with lactobacillus Sp. showed beneficial effects on resistance to infections agents such as Escherichia coli [6]. The early use of the intestinal contents of normal adult birds as a probiotic, orally administered to one day old chicks , altered their sensevity to infection by Salmonella spp [7] the intestinal micro biota play a major role in growth as well as maintenance of the health of animals.
Probiotics prescription is a good alternative for antibiotics for several reasons: suitable function, nonexistence of residue in poultry productions, environmental protection and prohibition of antibiotics usage in Europe union [8].
Yogurt is a product of the lactic acid fermentation of milk by addition of a starter culture containing Streptococcus thermophilus and Lactobacillus delbrueckii. Bulgaricu ssps. Although fermented milk products such as yogurts were originally developed simply as a means of preserving the nutrients in milk . Yogurt contains mainly lactobacilli and other beneficial bacteria's that have strong positive health effect. Yogurt could aid digestion and inhibit the development of pathogens by improving the balance of microbial living in the digestive tract. Due to its probiotical potential, yogurt can be used instead of commercial antibiotic [9].
The objective of this study was to investigate the effects of supplementation of probiotic and dry yogurt powder on the productive performance and intestinal microbial micro flora of broiler chickens under commercial conditions.