Comparing the Ileal and Hindgut Fermentations in the Pig Model (P08-087-19)

Abstract

Abstract Objectives This study aimed to compare ileal and hindgut fermentations in the pig model using a combined in vivo/in vitro methodology. Methods Pigs (23 kg bodyweight, n = 5) were fed a human-type diet for 15 days. On day 15, pigs were euthanased and the small intestine was immediately dissected out and ligated in three equal lengths. Digesta from the last 50 cm of the second (terminal jejunum) and last (terminal ileum) third sections of the small intestine were collected as substrates. Digesta from the remaining last third (i.e., last third minus 50 cm) of the small intestine (ileum) was collected along with caecal digesta for preparing inocula. Terminal jejunal digesta substrates were fermented in vitro with a pooled ileal digesta inoculum for 2 h (ileal fermentation), while terminal ileal digesta substrates were fermented in vitro with a pooled caecal digesta inoculum for 24 h (hindgut fermentation). Results The ileal organic matter (OM) fermentability (28%) was similar than the hindgut counterpart (35%) (P > 0.05). However, the fermentable OM was 63% higher during ileal fermentation than hindgut fermentation (P < 0.05). The production of acetic, isovaleric and succinic acids was higher during ileal fermentation than caecal fermentation (P < 0.05), but the production of propionic, iso-butyric, butyric, valeric and pyruvic acids was lower (P < 0.05). The SCFAs produced in each gastrointestinal tract location was absorbed in their respective gastrointestinal tract location. Conclusions An important amount of OM is fermented in the ileum producing comparable amounts of short-chain fatty acids and organic acids to hindgut fermentation. This challenge the current paradigm concerning gastrointestinal tract fermentation. Funding Sources Centre of Research Excellence Fund from the Tertiary Education.