Improvement of Poplar Bark Extract on Physiological Characters of Lactococcus lactis in Intestine of White Feather Broilers.

[Objective] The paper was to study the improvement of poplar bark extract on intestinal Lactococcus lactis of white feather broilers. [Method] Totally 450 Ross 308 white-feather broilers were randomly divided into five groups: control group, low dose group, medium dose group, high dose group, and antibiotic group (oxytetracycline hydrochloride). The feeding duration was 45 d. The probiotics were screened and isolated through homology, and the physiological and biochemical characteristics of chicken intestinal bacteria in different groups were compared to determine the properties of bacterial strain. The drug resistance, antibacterial ability, proliferation ability, acid resistance and bile salt resistance of isolated strain were tested, and a strain of L. lactis was obtained. [Result] The isolated L. lactis was sensitive to other drugs except natural tetracyclines, and there was no significant difference among the four groups except oxytetracycline group; as the concentration of extract increased, the inhibition of L. lactis against Salmonella sp. increased; the medium dose extract had the largest increase in the ability to tolerate the proliferation of L. lactis. [Conclusion] Feeding poplar bark extract will produce positive effects on the physiological characters of intestinal L. lactis in broiler chicken, which will provide potential probiotic strain for chicken production. [ABSTRACT FROM AUTHOR]