Introduction Gut microbiota in the colon ferment undigested dietary fibre to produce short-chain fatty acids (SCFA). SCFA have beneficial effects on colonic health. Differences in microbiota composition and metabolic activity have been described between IBD patients and healthy controls. This project explored the capacity of the gut microbiota of IBD patients to breakdown dietary fibre.
Method Fresh faecal samples were collected from IBD patients in clinical remission and healthy controls (HC). In vitro batch culture fermentations were carried out for 5 carbohydrate/fibres and for a mixture of these 5 fibres together (hi maize, pectin, raftilose, wheat bran, cellulose). Aliquots were taken at 0 and 48 hours. Faecal SCFA (butyrate, propionate and acetate) concentration (umol/g) and their proportional ratio (%) were measured with Gas Chromatography.
Results 25 IBD patients (13 CD and 12 UC) and 14 matched HC were recruited. Following 48 hour batch cultures, total SCFA from hi maize and raftilose in CD patients (median (IQR) HC; 51.76 (22.02) vs. CD; 41.12 (23.28) vs. UC; 41.94 (14.72) p=0.02) and from hi maize in UC patients were significantly lower than in heathy controls (median (IQR) HC; 58.87 (17.69) vs. UC; 44.92 (21.49) p=0.008). The proportional contribution of butyrate to total SCFA following fermentation with mixed fibre was also significantly higher for healthy controls compared to UC patients (median (IQR) HC; 10.76 (8.26) vs. CD; 8.75 (4.74) p=0.044). In no cases were there any significant differences between the SCFA concentration or relative contribution in CD or UC patients.
Conclusion These data suggest that the microbiota of IBD patients has a lower capacity to break down fibre, compared to healthy people. The findings of this work should be complemented with changes in microbiota composition using next generation sequencing.
Disclosure of Interest None Declared
- gut microbiota
- in vitro fermentation
- Inflammatory Bowel Disease
- short-chain fatty acids