Faeces may be representative of the microbial population present in the large intestine (LI) of monogastric animals, and is being used as the inoculum for in vitro procedures to investigate hindgut fermentation. To test this hypothesis, samples were taken from the caecum, mid-colon, and rectum of three pigs fed a simple diet (no antibiotics or copper). The in vitro cumulative gas production technique (Theodorou et a/., 1994) was used to measure the fermentation characteristics of four standard carbohydrate feedstuffs.

Four feeds representative of certain carbohydrate fractions were used. They were fructo-oligosaccharide (FOS- oligosaccharides), oat hulls (OatH- fibre), potato starch (PST- resistant starch), and wheat bran (WBR- fibre). The entire large intestine was taken to laboratory, where samples were removed from the caecum, mid-colon, and rectum, diluted, and mixed, under strictly anaerobic conditions before being used as inoculum. The cumulative gas data (144 hours) were fitted to the monophasic modified Michaelis-Menten model (Groot et a/., 1996). After fermentation, samples were taken for VFA analysis, and substrate losses and pH measured.