Pediocin A modulates intestinal microflora metabolism in swine in vitro intestinal fermentations

摘要

The aim of this study was to investigate in vitro the effects of pediocin A [a bacteriocin produced by lactic acid bacteria (LAB) Pediococcus pentosaceus FBB61] on microbial metabolism in the small and large intestine of pigs. Pediocin A was partially purified by ion exchange chromatography and added to an in vitro fermentation system. The intestinal inoculum was collected from pigs immediately after slaughter, diluted with a buffer, and dispensed into fermentation syringes and vessels of the 2 experimental groups: 1) Bac+ = cecal liquor + predigested diet + pediocin A (final concentration 160 activity units/mL); 2) Bac- = cecal liquor + predigested diet + partially purified supernatant of P. pentosaceus FBB61-2. Intestinal microbial growth was monitored using the cumulative gas production technique; the kinetics of fermentation, bacterial counts, VFA, ammonia, polyamines, and p-cresol production were analyzed. Pediocin A had almost no effects on small intestine fermentation parameters, whereas in the cecum pediocin A decreased gas production (-16%; P < 0.05), ammonia, and VFA production (-52 and -21%, respectively, after 24 h; P < 0.001) compared with the control group. Significant inhibition of clostridia and LAB occurred in cecal fermentations: the Bac+ group yielded a decreased number of clostridia and LAB in cecal fermentations (8.19 and 7.80 cfu/mL, respectively) compared with Bac- (9.32 and 8.95 cfu/mL, respectively; P < 0.001). The low clostridia counts in the pediocin-treated group may also explain the reduced concentration of the carcinogenic compound p-cresol (-88%; P < 0.01). Our results suggest that pediocin A could be an alternative to replace antibiotic growth promoters for the prophylaxis of enteric diseases and to improve production of farm animals.