In-vitro assessment of the effects of dietary fibers on microbial fermentation and communities from large intestinal digesta of pigs

Dietary fibers (oat β-glucan, flaxseed gum, and fenugreek gum) can be fermented to short chain fatty acids (SCFAs) in batch cultures by pig intestinal digesta. Lactate in the β-glucan-grown cultures had the highest level among SCFAs produced, whereas flaxseed or fenugreek gum-containing cultures generated a significant amount of acetate, propionate and butyrate over three subcultures tested (p < 0.05). Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA genes in the initial and subcultures revealed that types of fibers impacted pronouncedly on the bacterial community structure. Identified DGGE DNA bands were mainly affiliated with Bacteroidetes, and Firmicutes, in which numbers of butyrate-producing species were widely distributed. The fermentability of dietary fibers to SCFAs and their selection towards the bacterial communities suggest their potential application in promoting animal/human health.