title: In situ identification and quantification of starch-hydrolyzing bacteria attached to barley and corn grain in the rumen of cows fed barley-based diets.
abstract: Cereal grains rich in starch are widely used to meet the energy demands of high-producing beef and dairy cattle. Bacteria are important players in starch digestion in the rumen, and thus play an important role in the hydrolysis and fermentation of cereal grains. However, our understanding of the composition of the rumen starch-hydrolyzing bacteria (SHB) is limited. In this study, BODIPY FL DQ starch staining combined with fluorescence in situ hybridization (FISH) and quantitative FISH were applied to label, identify and quantify SHB possessing active cell-surface-associated (CSA) α-amylase activity in the rumen of heifers fed barley-based diets. When individual cells of SHB with active CSA α-amylase activity were enumerated, they constituted 19-23% of the total bacterial cells attached to particles of four different cultivars of barley grain and corn. Quantitative FISH revealed that up to 70-80% of these SHB were members of Ruminococcaceae in the phylum Firmicutes but were not Streptococcus bovis, Ruminobacter amylophilus, Succinomonas amylolytica, Bifidobacterium spp. or Butyrivibrio fibrisolvens, all of whose amylolytic activities have been demonstrated previously in vitro. The proportion of barley grain in the diet had a large impact on the percentage abundance of total SHB and Ruminococcaceae SHB in these animals.
authors.affiliation: Key laboratory of Special Biological Resource Development and Utilization of Universities of Yunnan Province, Kunming University, Kunming 750021, China Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, Alberta T1J 4B1, Canada.
authors.forename: Yun
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Key laboratory of Special Biological Resource Development and Utilization of Universities of Yunnan Province, Kunming University, Kunming 750021, China.
authors.forename: Yunhong
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Department of Microbiology, La Trobe University, Bundoora, VIC 3228, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Seviour
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, Alberta T1J 4B1, Canada.
authors.forename: Hee-Eun
authors.initials: HE
authors.lastname: Yang
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, Alberta T1J 4B1, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Forster
authors.affiliation: Department of Food and Nutritional Sciences, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
authors.forename: Thavaratnam
authors.initials: T
authors.lastname: Vasanthan
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, Alberta T1J 4B1, Canada Tim.McAllister@agr.gc.ca.
authors.forename: Tim
authors.initials: T
authors.lastname: McAllister
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D004032:Diet / Q000662:veterinary; D004063:Digestion; D002523:Edible Grain / Q000378:metabolism*; D005260:Female; D005285:Fermentation; D001467:Hordeum / Q000378:metabolism; D006868:Hydrolysis; D017404:In Situ Hybridization, Fluorescence; D012417:Rumen / Q000382:microbiology*; D045857:Ruminococcus / Q000201:enzymology / Q000378:metabolism*; D013213:Starch / Q000378:metabolism; D003313:Zea mays / Q000378:metabolism; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D013213:Starch; D000516:alpha-Amylases
keywords: BODIPY FL DQTM starch staining combined with FISH; cell-surface-associated amylase activity; in situ identification; ruminal starch-hydrolyzing organisms