Animal Health - Growth and Immunity

We evaluated anti-Campylobacter activity among 11,790 isolates of lactic acid bacteria from poultry production environments. We measured zones of C. jejuni inhibition surrounding the candidate strains and observed 279 isolates exhibiting antagonism. A Lactobacillus salivarius strain PVD32, was identified and deposited under provisions of the Budapest Treaty (NRRL B-30514). The cell-free, ammonium sulfate precipitate from the culture was termed the crude antimicrobial preparation (CAP). A zone of C. jejuni growth inhibition surrounding 10 ul of the CAP was observed. C. jejuni growth resumed when the CAP was pre-incubated with protease enzymes, thus demonstrating the peptide characteristic consistent with bacteriocin definition. The bacteriocin was further purified using a combination of ammonium sulfate precipitation, CM-Sepharose, Superose, and ion exchange chromatography. SDS-PAGE electrophoresis provided an estimated molecular weight of 6 KDa. MALDI-TOF analysis refined the molecular weight as 5,123 Da. The isoelectric point of the active fraction was determined at a pH of 9.0. The amino acid sequence of the bacteriocin was determined. The bacteriocin activity was stable following exposure to 90oC for 15 minutes. The moiety was purified and encapsulated in polyvinylpyrrolidone (PVP), and added to feed at levels of 250 mg/Kg feed. Day of hatch chicks were colonized with C. jejuni; log 10 cfu/gm feces mean levels in untreated, 7-day old control chicks was 6.21, while birds provided bacteriocin in feed 3 days prior to sampling was 1.98; untreated, 10-day old control chicks were colonized at a means of 8.99 and treated birds were colonized at 0.61. Among an additional 14 trials, comprised of 290 chickens, of varying ages, with varying amounts of bacteriocin administered, and challenge strains of C. jejuni, we consistently observed at least a one-million fold reduction in cecal levels among treated birds. The bacteriocin from this L. salivarius appears useful to control C. jejuni in poultry.