title: An arabinoxylan-rich fraction from wheat enhances caecal fermentation and protects colonocyte DNA against diet-induced damage in pigs.
abstract: Population studies show that greater red and processed meat consumption increases colorectal cancer risk, whereas dietary fibre is protective. In rats, resistant starches (a dietary fibre component) oppose colonocyte DNA strand breaks induced by high red meat diets, consistent with epidemiological data. Protection appears to be through SCFA, particularly butyrate, produced by large bowel carbohydrate fermentation. Arabinoxylans are important wheat fibre components and stimulate large bowel carbohydrate SCFA production. The present study aimed to determine whether an arabinoxylan-rich fraction (AXRF) from wheat protected colonocytes from DNA damage and changed colonic microbial composition in pigs fed with a diet high (30 %) in cooked red meat for 4 weeks. AXRF was primarily fermented in the caecum, as indicated by higher tissue and digesta weights and higher caecal (but not colonic) acetate, propionate and total SCFA concentrations. Protein fermentation product concentrations (caecal p-cresol and mid- and distal colonic phenol) were lower in pigs fed with AXRF. Colonocyte DNA damage was lower in pigs fed with AXRF. The microbial profiles of mid-colonic mucosa and adjacent digesta showed that bacteria affiliating with Prevotella spp. and Clostridial cluster IV were more abundant in both the mucosa and digesta fractions of pigs fed with AXRF. These data suggest that, although AXRF was primarily fermented in the caecum, DNA damage was reduced in the large bowel, occurring in conjunction with lower phenol concentrations and altered microbial populations. Further studies to determine the relationships between these changes and the lowering of colonocyte DNA damage are warranted.
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: Damien P
authors: DP
authors: Belobrajdic
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: Anthony R
authors: AR
authors: Bird
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: Michael A
authors: MA
authors: Conlon
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: Barbara A
authors: BA
authors: Williams
authors: CSIRO Livestock Industries, St Lucia, QLD 4067, Australia.
authors: Seungha
authors: S
authors: Kang
authors: CSIRO Livestock Industries, St Lucia, QLD 4067, Australia.
authors: Christopher S
authors: CS
authors: McSweeney
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: Dagong
authors: D
authors: Zhang
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: Wayne L
authors: WL
authors: Bryden
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: Michael J
authors: MJ
authors: Gidley
authors: High Fibre Grains Cluster, CSIRO Food Futures National Research Flagship, Adelaide, SA 5000, Australia.
authors: David L
authors: DL
authors: Topping
mesh_terms: D000821:Animal Feed; D000818:Animals; D002432:Cecum / Q000378:metabolism* / Q000382:microbiology*; D003013:Clostridium; D003106:Colon / Q000166:cytology* / Q000378:metabolism / Q000382:microbiology; D015179:Colorectal Neoplasms / Q000517:prevention & control; D020552:Comet Assay; D004249:DNA Damage; D004032:Diet; D005285:Fermentation; D007413:Intestinal Mucosa / Q000473:pathology; D008297:Male; D008460:Meat; D020411:Oligonucleotide Array Sequence Analysis; D018720:Prevotella; D013552:Swine; D014908:Triticum / Q000737:chemistry*; D014990:Xylans / Q000737:chemistry*
chemical_list: D014990:Xylans; C085118:arabinoxylan