Effects of Probiotics on Performance, Intestinal Morphologic and Gut Microbiota Responses in Local and Commercial Strain of Chickens.

Omani chickens represent local breeds of chickens that have long been established in the Sultanate of Oman. They are raised under the traditional system and are well known for their adaptation to harsh environmental conditions. In a series of our previous studies we demonstrated that local Omani chickens exhibited inferior growth performance compared to Cobb500 Broilers when these birds were maintained under closed housing management system. This inferior growth performance was demonstrated to be directly associated with delayed small intestinal villi development during the critical growth period at an early age. Furthermore, using ribosomal DNA based molecular techniques it was shown that the inferior villi development was associated with significantly different microbial populations in the small intestine during this same time period. Alterations in the gut microbiota can have adverse effects on feed efficiency, productivity, and health of chickens. It is well documented in the literature the benefits of probiotics utilization on productive indexes. In addition, administered probiotic in adequate amounts can confer a beneficial physiological effect on the host, improve intestinal structure and above mentioned improve growth performance. The use of probiotics could represent a major opportunity to achieve mutual benefit for both the industry and consumers. To our knowledge, there are no studies however available to evaluate the effects of probiotics on growth performance, intestinal development or microbial populations of various intestinal segments of slow-growing chickens such the local Omani birds. Analysis of chicken gut bacteria has usually been carried out using conventional culture techniques, but these techniques have been found to be inefficient in identifying and classifying certain groups of bacteria. Recent advances in ribosomal DNA based molecular techniques allow identification of different bacterial populations in environmental samples without cultivation. The objective of the current study will be to evaluate the effect of probiotics on growth performance, gut morphology and the biodiversity of the bacterial community in the gastrointestinal tract of two strain of chickens using 16S rDNA- based analysis. This will be the first study to evaluate the effect of dietary probiotics on Omani chicken bacteria populations using molecular techniques with 16S rDNA and the effect of these probiotics on the growth performance and intestinal development.