Molecular ecological analysis of the pig's intestinal microbiota in response to fermentable carbohydrates and calcium-phosphate in the diet
Final Report Abstract
Two experiments were conducted to evaluate the effect of differently viscous and fermentable non-starch polysaccharides (NSP) in combination with different dietary calcium-phosphate (CaP) levels on the intestinal bacterial community, butyrate-producing bacteria, fermentation end-products and intestinal Ca and P absorption in pigs. In experiment I, growing pigs fitted with a simple T-cannula in the distal ileum were fed comstarch-casein based diets with 5% active NSP ingredient: low viscous, low fermentable cellulose (CEL); high viscous, low fermentable carboxymethylcellulose (CMC); low viscous, high fermentable oat ß-glucan (LG); or high viscous, high fermentable oat ß-glucan (HG). Overall, effects of the NSP fractions were linked to the individual NSP fractions rather than to their shared functional properties, i.e. viscosity and fermentability. The NSP fractions changed the nutrient digestibility in the small intestine in such a way that more fermentable material entered the large intestine for CEL, LG and HG becoming available for bacterial fermentation. Results further indicated that CEL negatively affected ileal absorption and retention of Ca and P suggesting that the daily requirement increases when this CEL is supplemented to the diet. In contrast, CMC resulted in the highest Ca and P retention in comparison with the other NSP fractions tested. Moreover, the present results demonstrate that substantial amounts of Ca can be absorbed from the large intestine in case of decreased absorption in the small intestine and that fermentation influences Ca flux in the large intestine. Changes in intestinal bacterial community, genes of alternative pathways of butyrate production, and E. coli vimlence factors could be attributed to both fermentation of NSP and the altered ileal flow of nutrients into the large intestine. Gene copy numbers of butyryl-CoA CoA transferase were higher than numbers of butyrate kinase genes, indicating that this pathway is the dominant butyrate-production pathway in the large intestine of growing pigs. However, despite the higher digesfibility of nutrients, feeding of CMC may be disadvantageous for the health of growing pigs as it increases the susceptibility of pigs to overgrowth of pathogenic E. coli. In terms of intestinal health, LG may be the most appropriate of the 4 tested NSP fractions, as it resulted in the lowest numbers of Enterobacteriaceae and E. coli virulence factors. In experiment 2, weaning pigs were fed cornstarch-casein based diets with or without LG in combination with a low or high CaP content. Strikingly, bacterial numbers and butyrate fermentation was substantially increased in the stomach by LG. Particularly, LG in combination with the high CaP content stimulated gastric butyrate which can be beneficial for small intestinal development of the young pig. The high dietary CaP content changed bacterial metabolic activity as indicated by reduced gastric lactate and propionate concentrations in the large intestine, whereas the effect of dietary CaP content on bacterial numbers was small. Quantification of butyrate-production pathway genes, however, did not reveal higher gene copy numbers with LG in the diet. In contrast to growing pigs, the butyrate kinase was the dominant butyrate production pathway in weaned pigs. Because LG reduced total tract digestibility of Ca and P, the effect of oat ß-glucan on ileal nutrient digestibility should be first evaluated in further studies to estimate whether oat ß-glucan is a suitable feed supplement for weaned pigs.
Publications
- 2010. Bacterial fermentation affects net mineral flux in the large intestine of pigs fed diets with viscous and fermentable non-starch polysaccharides. Journal of Animal Science
Metzler-Zebeli, B. U., Hooda, S., Mosenthin, R., Gänzle, M. G., and R. T. Zijlstra
(See online at https://doi.org/10.2527/jas.2010-2906) - 2010. Fermentation affects mineral flux in the gastrointestinal tract of pigs fed diets supplemented with differently viscous and fermentable non-starch polysaccharides. Banff Pork Seminar 2010, January 19-22, Banff, AB, Canada, Abstract #18
Metzler-Zebeli, B. U., Hooda, S., Mosenthin, R., Gänzle, M. G., and R. T. Zijlstra
- 2010. Non-starch polysaccharides modulate bacterial microbiota, pathways for butyrate production, and abundance of pathogenic Escherichia coli in the gastrointestinal tract of pigs. Applied and Environmental Microbiology 76: 3692-3701
Metzler-Zebeli, B. U., Hooda, S., Pieper, R., Zijlstra, R. T., van Kessel, A. G., Mosenthin, R., and M. G. Gänzle
- 2010. Quantitative changes in ileal and faecal microbiota and occurrence of Escherichia coli virulence factors in grower pigs fed diets supplemented with purified viscous and fermentable non-starch polysaccharides. 64th Conference of the Society of Nutrition Physiology, March 9-11, Göttingen, Germany, p. 66
Metzler-Zebeli, B. U., Hooda, S., Zijlstra, R. T., Mosenthin, R., and M. G. Gänzle
