This research is aimed to investigate the effects of Lactoplantibacillus plantarum (L. plantarum) on growth performance, oxidation resistance, immunity, as well as cecal microbiota in broilers. This work classed three hundred and sixty 1-day-old broilers as three groups randomly, including control (CON, basal diet), antibiotic (ANT, 75 mg kg-1 chlortetracycline added into basal diet), or probiotic group (LP, 5×108 CFU kg-1 Lactoplantibacillus plantarum HJLP-1 contained within basal diet). Animal were then fed for 42 days, and each group consisted of 15 broilers for 8 replicates. Compared with CON, L. plantarum supplementation significantly improved the average weight daily gain (AWDG) (P < 0.05) while reducing feed-to-gain ratio over the entire supplemental period (P < 0.05). Birds fed L. plantarum had marked lower serum ammonia and xanthine oxidase levels (P < 0.05) than those in ANT and CON. Significant improvements (P < 0.05) of superoxide dismutase, catalase, serum IgM and IgY contents in broilers fed L. plantarum were also observed when compared those in CON and ANT groups. Both L. plantarum and antibiotics decreased the pro-inflammatory factor IL-1β level significantly (P < 0.05), while only L. plantarum promoted the anti-inflammatory factor IL-10 level dramatically in the serum (P < 0.05) compared with CON. The L. plantarum dramatically (P < 0.05) increased acetic acid and butyric acid concentrations in the cecal contents，when compared to those in CON and ANT. Among the differences revealed by 16S rRNA analysis, L. plantarum markedly improved the community richness of cecal microbiota. At the genus level, butyric acid-producing bacteria Ruminococcus and Lachnospiraceae were found in higher relative abundance in samples of L. plantarum treated birds. In conclusion, dietary L. plantarum supplementation promoted the growth and health of broilers, likely by inducing a shift in broiler gut microbiota toward short-chain fatty acid (SCFA)-producing bacteria. Therefore, L. plantarum has tremendous potential as an alternative for antibiotics in poultry breeding.

Lyme disease (LD) is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species which includes B. burgdorferi, B. afzelii, and B. garinii. The majority of patients with early LD can be cured by standard treatment, yet some still suffer from post-treatment Lyme disease syndrome (PTLDS). The presence of Borrelia persisters has been proposed as a contributing factor, which cannnot be completely killed by the currently used antibiotics for Lyme disease. Finding new pharmaceuticals targeting Borrelia persisters is crucial in developing more effective treatment. Here, we first confirmed the existence of persisters in cultures of B. garinii and B. afzelii and then conducted high-throughput screening of a custom drug library against persister-rich stationary-phase cultures of B. garinii and B. afzelii. Among 2427 compounds screened, hypocrellin A (HA), anthracycline class of drugs, and topical antibiotics along with some other natural compounds were identified to have strong potential in killing persisters of B. garinii and B. afzelii. HA was the most active anti-Borrelia compound, capable of eradicating stationary-phase Borrelia persisters, in particular when combined with doxycycline and/or ceftriaxone. Liposoluble antioxidant vitamin E was found to antagonize the activity of HA, indicating HA’s target is the cell membrane where HA-triggered reactive oxygen species (ROS) generation took place in the presence of light. HA was found to have distinct bactericidal activity against Borrelia species but had poor or no activity against Gram-positive and Gram-negative bacteria. Identification of the above-mentioned drug candidates may help to develop more effective therapies for LD.