Effects of Lactobacillus reuteri and Streptomyces coelicolor on Growth Performance of Broiler Chickens

There are well documented complications associated with the continuous use of antibiotics in the poultry industry. Over the past few decades, probiotics have emerged as viable alternatives to antibiotics; however, most of these candidate probiotic microorganisms have not been fully evaluated for their effectiveness as potential probiotics for poultry. Recent evaluation of a metagenome of broiler chickens in our laboratory revealed a prevalence of Lactobacillus reuteri (L. reuteri) and Actinobacteria class of bacteria in their gastrointestinal tract. In this study Lactobacillus reuteri and Streptomyces coelicolor (S. coelicolor) were selected as probiotic bacteria, encapsulated, and added into broiler feed at a concentration of 100 mg/kg of feed. In an 8-week study, 240 one day-old chicks were randomly assigned to four dietary treatments. Three dietary treatments contained two probiotic bacteria in three different proportions (L. reuteri and S. coelicolor individually at 100 ppm, and mixture of L. reuteri and S. coelicolor at 50 ppm each). The fourth treatment had no probiotic bacteria and it functioned as the control diet. L. reuteri and S. coelicolor were added to the feed by using wheat middlings as a carrier at a concentration of 100 ppm (100 mg/kg). Chickens fed diets containing L. reuteri and S. coelicolor mixture showed 2% improvement in body weight gain, 7% decrease in feed consumption, and 6-7% decrease in feed conversion ratios. This research suggests that L. reuteri and S. coelicolor have the potential to constitute probiotics in chickens combined or separately, depending on the desired selection of performance index.