Glucose but Not Polypeptone Reduces the Effect of Probiotic Preparations to Stimulate Carbohydrate Breakdown and Reduce Net Ammonia Production by Pig Cecal Bacteria In Vitro

Abstract

Probiotic preparations are used to prevent or treat diarrhea. Probiotic preparations increase the in vitro breakdown of carbohydrates and decrease that of protein by mixed cecal bacteria in the absence of readily fermentable materials. Diarrhea can increase the influx of readily digestible materials into the large intestine. Therefore, we compared production of organic acids and ammonia in batch cultures using pig cecal contents with or without probiotic preparations (Clostridium butyricum, Lactobacillus casei plus Bifidobacterium breve, or L. casei plus Enterococcus faecalis) and with or without readily fermentable substrates (glucose or polypeptone). Effects of additional substrates appeared earlier than those of probiotic preparations. Both probiotic preparations and glucose increased the production of most short-chain fatty acids and lactic acid but decreased those of ammonia and isovaleric acid. Effects of probiotic preparations and glucose were not additive. Effects of different preparations were alike. Polypeptone increased the production of ammonia and isovaleric acid independent of probiotic preparations. Effects of probiotics and glucose may be to provide either energy or carbon to the microbial ecosystem. Effects of glucose were probably mediated through their direct utilization by indigenous bacteria.