Influence of a dried Bacillus subtilis culture and antibiotics on performance and intestinal microflora in turkeys.

Two experiments, each involving a 3 x 2 factorial design, were conducted with Large White Nicholas turkeys. The first experiment involved three antibiotic treatments: an unmedicated control diet, the diet plus 44 ppm of penicillin-streptomycin (1:3), and the diet plus 44 ppm of Zn bacitracin; each diet was fed in the presence and absence of a dried Bacillus subtilis culture to females 0 to 16 wk of age. Antibiotic supplements increased body weight at 12 (P less than .05) and 16 (P less than .001) wk of age. Body weight and feed efficiency were not significantly affected by feeding the B. subtilis culture in this experiment. The dietary B. subtilis culture significantly increased B. subtilis counts in the crop and cecum but failed to influence intestinal Lactobacillus or Escherichia coli counts. The second experiment also involved three antibiotic treatments: an unmedicated control diet, 44 ppm of Zn-bacitracin, and 2.2 ppm of bambermycins, and each diet was fed in the presence and absence of the dried B. subtilis culture to male birds from 0 to 20 wk of age. Increased body weight gain was observed in birds receiving the B. subtilis culture at 12 wk (P less than .01). Feed efficiency of birds receiving the B. subtilis culture was improved (P less than .05) at 20 wk. Birds receiving bambermycins had greater body weights (P less than .05) at 12 and 16 wk of age than birds receiving Zn bacitracin or the control diet. Livability was not affected by the B. subtilis culture or the antibiotic treatments in either experiment.