Effects of probiotics on the growth performance and intestinal micro flora of broiler chickens.

Antibiotics have been used in poultry industry for decades to promote growth and protect animals from diseases, followed by various side effects. In efforts of searching for a better alternative, probiotic is of extensive attention. We investigated the effects of Bacillus subtitles, Rhodopseudomonas palustris, Candida utilis and Lactobacillus acidophilus as 0.1% (W/W) feed additives on broiler growth performance and intestinal microflora. The results showed the probiotics treatments significantly improved growth of broilers. Broilers supplemented with B. subtilis and L. acidophilus weighed 18.4% and 10.1% more than birds in control group at 42 days of age. Furthermore the feed conversion ratios of the birds in the two groups were also improved, decreasing 9.1% and 12.9%, respectively. Further study indicated a significant increase of cecal Lactobacilli concentration in briolers supplemented with probiotics, expecially in L. acidophilus treatment group. Meanwhile, the count of cecal Actinomyces in birds treated with probiotics was significantly lower compared with the control group. In conclusion, probiotics such as B. subtitles and L. acidophilus are good alternatives to antibiotics in promoting growth resulting from a beneficial modulation of the intestinal micro flora, which leads to increased efficiency of intestinal digestion in the host animal.