title: Microbial ecosystem and fermentation traits in the caecum of growing rabbits given diets varying in neutral detergent soluble and insoluble fibre levels.
abstract: The effect of the level of neutral detergent fibre (NDF: 0.35, LI and 0.42, HI) and neutral detergent soluble fibre (NDSF: 0.14, LS and 0.17, HS) in the caecal ecosystem was studied in 24 weaned (28 days of age) rabbits, weighing 630 ± 80.2 g in a 2 × 2 factorial design. After 22 days, rabbits were slaughtered and their caecal contents sampled. The caecal pH (on average 6.2) and molar volatile fatty acids (VFA) proportions were not affected by dietary treatments, but total VFA concentration tended to be lower with NDF (84.7 vs. 74.1 mmol/l; P = 0.095). The amount of total bacteria tended (P = 0.075) to increase with NDSF, but only in diets with 0.35 NDF. The caecal proportions of Ruminococcus albus and Fibrobacter succinogenes were not affected by type or level of fibre, but Butyrivibrio fibrisolvens decreased (P = 0.055) with the NDF proportion in LS diets. Denaturing gradient gel electrophoresis (DGGE) analysis showed that bacterial communities clustered according to each combination of NDF and NDSF, but did not greatly differ among diets (similarity indexes between 0.67 and 0.70), nor biodiversity was affected (average Shannon and richness indexes 3.50 and 33.1; P > 0.10). Archaeal population revealed changes in the amount and composition that were particularly evident in HS diets, decreasing in concentration (from 4.37 to 4.12 log10 gene copy number/g) and biodiversity (Shannon index from 3.14 to 2.52 and richness index from 23.7 to 13.9) compared to LS. The type and level of dietary fibre had a minor impact on caecal fermentation traits or caecal bacterial community. However, the increase in NDSF from 0.14 to 0.17 reduced concentration and diversity of methanogenic archaea.
authors: Instituto Universitario de Investigación en Ciencias Ambientales, Departamento de Producción Animal y Ciencia de los Alimentos, Universidad de Zaragoza, Miguel Servet 177, 50013, Zaragoza, Spain. norelysr24@hotmail.com
authors: Norelys
authors: N
authors: Rodríguez-Romero
authors: Leticia
authors: L
authors: Abecia
authors: Manuel
authors: M
authors: Fondevila
mesh_terms: D000818:Animals; D001105:Archaea / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D002432:Cecum / Q000378:metabolism / Q000382:microbiology*; D058645:Denaturing Gradient Gel Electrophoresis; D003902:Detergents; D004032:Diet / Q000379:methods; D004043:Dietary Fiber / Q000008:administration & dosage*; D017753:Ecosystem; D005285:Fermentation; D016133:Polymerase Chain Reaction / Q000379:methods; D011817:Rabbits / Q000382:microbiology*; D014886:Weaning
chemical_list: D003902:Detergents; D004043:Dietary Fiber