In vivo inhibitory effects of Lactobacillus acidophilus against pathogenic Escherichia coli in gnotobiotic chicks.

Chicks were hatched germfree in gnotobiotic isolators to determine the inhibitory effects of Lactobacillus acidophilus towards pathogeneic Escherichia coli in vivo. Twelve trials were conducted in two flexible film isolators utilizing a total of 221 chicks. One treatment consisted of inoculating 2-day-old chicks with L. acidophilus, then challenging with pathogenic E. coli with subsequent dosing with L. acidophilus. The other treatment consisted of challenging with the E. coli at 2 days of age, then subsequently dosing with L. acidophilus. Statistical analysis of the data showed initial dosing with L. acidophilus prevented excessive mortality when chicks were challenged with E. coli. Also, continued dosing with L. acidophilus lowered the pH in the crop, cecum, and rectum whether chicks were initially given L. acidophilus or E. coli. This strain of L. acidophilus was capable of competing with E. coli in the gut of gnotobiotic chicks.