Adaptation of gut microbiota to corn physical structure and different types of dietary fibre

An experiment was designed to study the effect of corn physical structure and different types of dietary fibre on pig gut microbiota during growing. Ninety-six animals (15 ± 2.2 kg) were assigned to four different diets: a control diet (CT), a diet with coarse ground corn (CC), and other two with 8% of sugar beet pulp (BP) or 10% of wheat bran (WB). Thirty-two animals (8 per diet) were sacrificed on days 7, 21 and 42 to measure microbial activity in digesta. Other 8 pigs were sacrificed on day 0 before receiving the diets. Enterobacteria and lactobacilli population in colon were quantified by qPCR. With all diets enterobacteria diminished with time and were lower than lactobacilli. Expressed as lactobacilli:enterobacteria ratio we found differences between diets at day 7 and 21 that had disappeared at day 42. Purine bases (PB) concentration indicated an adaptation of the microbiota with time which was reflected in an increasing content in the caecum and a decreasing content in the colon. Time of adaptation of microbiota was also shown by xylanase and cellulase activities that were not detected until day 7 and 42, respectively. Results obtained shows that pig gut microbiota need a relative long time to adapt after a change of diet that could last up to 6 weeks. We were not able to detect a clear effect of dietary fibre content on this process.