Performance and Cecal Bacteria Counts of Broilers Fed Low Protein Diets With and Without a Combination of Probiotic and Prebiotic

A total of 360 one-day-old Cobb 500 chicks were randomly distributed in a completely randomized design according to a 3×2 factorial arrangement, consisting of three levels of dietary crude protein (100, 90 and 85% of NRCrecommended levels) and a feed additive (with or without feed additive). A blend of a commercial probiotic and a prebiotic were used as feed additives. Each treatment had four replicates of 15 birds each. Prebiotic and probiotic were added to the starter (days 1 to 21) and finisher (days 22 to 42) diets according to the manufacturer´s recommendations. The findings indicated that significant differences were not observed between 100 and 90% NRC for broiler performance (body weight, body weight gain, feed intake and feed conversion ratio) throughout the experiment, while the birds fed the diets containing 85% NRC had poorer performance than those fed 100% (p