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Koike Satoshi

Research Faculty of Agriculture Fundamental AgriScience Research Animal ScienceProfessor
Institute for the Promotion of Business-Regional CollaborationProfessor

Researcher basic information

■ Degree
  • 博士(農学), 北海道大学
  • 修士(生物資源学), 三重大学
■ URL
researchmap URL■ Various IDs
J-Global ID■ Research Keywords and Fields
Research Keyword
  • 消化管微生物
  • 家畜栄養学
  • 分子生態学
  • 植物繊維分解
  • ルーメン
  • 反芻動物
  • molecular ecology
  • Plant fiber degradation
  • Rumen microbes
Research Field
  • Life Science, Animal production science
■ Educational Organization

Career

■ Career
Career
  • Apr. 2022 - Present
    Hokkaido University, Research Faculty of Agriculture, Professor
  • Oct. 2015 - Mar. 2022
    Hokkaido University, Research Faculty of Agriculture, Associate Professor
  • Apr. 2007 - Sep. 2015
    Hokkaido University, Research Faculty of Agriculture, Assistant Professor
  • Jan. 2006 - Mar. 2007
    Hokkaido University, Creative Research Institute Sosei, Assistant Professor
  • Feb. 2003 - Dec. 2005
    University of Illinois at Urbana-Champaign, Postdoctoral fellow
Educational Background
  • 2003, Hokkaido University, 農学研究科, Japan
  • 2003, Hokkaido University, Graduate School, Division of Agriculture
  • 2000, Mie University, 生物資源研究科, Japan
  • 2000, Mie University, Graduate School, Division of Bioresources
  • 1998, Mie University, Faculty of Bioresources, Japan
  • 1998, Mie University, Faculty of Bioresources
Committee Memberships
  • Apr. 2021 - Present
    Animal Science Journal, Associate Editor, Society
  • 2017 - Present
    ルーメン研究会, 評議員
  • 2008 - Present
    ルーメン研究会, 庶務委員, Society
  • 2018 - 2019
    家畜栄養生理研究会, 庶務幹事, Society
  • 2012 - 2013
    北海道畜産草地学会, 庶務幹事, Society
  • 2010 - 2011
    北海道畜産学会, 庶務幹事, Society

Research activity information

■ Awards
  • Mar. 2019, 日本畜産学会, Animal Science Journalレビュアー賞
  • Jan. 2017, AJAS 2016 Best Reviewer Award
    KOIKE Satoshi
  • Mar. 2015, 日本畜産学会, Animal Science Journal Reviewers Award
  • 2011, Animal Science Journal Excellent Paper Award
    Japan
  • 2007, 日本畜産学会奨励賞
    Japan
■ Papers
  • Developmental changes in the capacity for mucosal immunoglobulin production and secretion in the intestines of growing calves.
    Yutaka Suzuki; Mutsumi Oishi; Shoko Hirota; Hideaki Hayashi; Satoshi Haga; Satoshi Koike; Yasuo Kobayashi
    Veterinary research, 56, 1, 220, 220, 19 Nov. 2025, [International Magazine]
    English, Scientific journal, Neonatal calves predominantly rely on colostral IgG for the passive transfer of immunity; however, little is known about their intrinsic capacity for mucosal immunoglobulin production and the developmental changes associated with their growth. To elucidate the developmental trajectory of mucosal immunity, we investigated changes in mucosal immunoglobulin concentrations and the expression levels of genes involved in immunoglobulin production and secretion across different growth stages in calves. The results demonstrated that fecal IgG and IgM levels exhibited transient peaks at 1 week of age according to smooth spline analysis, followed by sharp decreases, whereas IgA levels remained relatively stable and became the predominant isotype after 4 weeks. Gene expression analysis and immunohistochemistry revealed the localized expression of immunoglobulins in the intestinal mucosa, particularly IgA, which gradually increased with calf growth. The secretion of IgA is also thought to be facilitated by the upregulated expression of PIGR, a gene encoding the IgA transporter whose expression levels increase with calf growth. In contrast, the levels of plasma cell-recruiting chemokines and their receptors were not increased. These results suggest an important role for IgA in the mucosal defense system of the calf intestine, indicating its pivotal function in maintaining gut health following the clearance of colostral IgG.
  • Early high nutrition enhances grass-fed beef productivity through epigenetically regulated muscle metabolism, altered early adipogenesis, and rumen fermentation dynamics.
    D Nishino; S Khounsaknalath; K Saito; A Saito; T Abe; E Kobayashi; F Ebara; S Maak; E Albrecht; M W Pfaffl; R Saneshima; S Shimamoto; D Ijiri; S Koike; S Yasuo; T Gotoh
    Animal : an international journal of animal bioscience, 19, 7, 101551, 101551, Jul. 2025, [International Magazine]
    English, Scientific journal, We previously reported that high nutrition early in life enhances the growth and intramuscular fat (IMF; i.e., marbling) content of grass-fattened beef cattle. The objectives of this study were to elucidate the mechanisms determining meat traits through comprehensive investigations from multiple perspectives. Specifically, we evaluated the long-term effects of early high nutrition on IMF adipogenesis, lipid metabolism, myofibre characteristics, rumen fermentation, and epigenetic regulation. Epigenetically mediated metabolism was investigated using integrated multiomics approaches including metabolites, gene expression, and DNA methylation. Wagyu (Japanese Black) steers were allocated to two groups: early roughage (ER, n = 11) steers fed a standard amount of milk replacer until 3 months of age (mo) and only roughage from 4 to 10 mo; and early high overall nutrition (EHN, n = 12) steers provided three times the standard amount of milk replacer until 3 mo and a high-concentrate diet from 4 to 10 mo. From 11 to 31 mo, all of the steers were fed only roughage (final BW, ER: 521.9 kg, EHN: 571.3 kg, P = 0.005; IMF in longissimus thoracis muscle (LM), ER: 9.4%, EHN: 13.2%, P = 0.039). The EHN LM contained larger adipocytes from the early to the finishing period (P < 0.055), with higher expression of adipogenesis-related genes (P < 0.032), including CCAAT/enhancer binding protein alpha (C/EBPα) and peroxisome proliferator-activated receptor gamma (PPARγ). During the finishing period, EHN adipose tissues contained more monounsaturated fatty acid (P < 0.018) and EHN LM contained fewer oxidative and more glycolytic myofibres (P < 0.054). The EHN steers had a higher proportion of rumen propionate and a lower acetate/propionate ratio during the high-nutrition and late fattening periods (P < 0.046). Multiomics analysis of metabolites, mRNA transcripts, and DNA methylation identified mitochondrial β-oxidation and biogenesis declines in EHN LM as candidate epigenetically regulated metabolism. These were indicated by accumulated 9-acylcarnitines and low gene expression of acyl-CoA synthetase medium-chain family member 1 (ACSM1), enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (EHHADH), 3-hydroxybutyrate dehydrogenase 1 (BDH1), and apelin receptor (APLNR; P < 0.059), all of which had differentially methylated DNA regions. These findings suggest that the increase in LM IMF might be the result of early adipocyte hyperplasia, greater nutrient supply through rumen programming of high propionate production, and epigenetic regulation of metabolism, involving decreased muscle mitochondrial function inducing a shift towards myofibres that consume less lipids.
  • Coconut Fatty Acid Distillate Ca-Soap with Different Calcium Sources: Effects of Varied Proportions of Protected and Unprotected Fat Supplementation in Dairy Rations
    Rika Zahera; Mega Indah Pratiwi; Ainissya Fitri; Satoshi Koike; Idat Galih Permana; Despal
    Dairy, 13 Sep. 2024
    English, Scientific journal, This study aimed to compare calcium oxide (CaO) and calcium chloride (CaCl2) as calcium sources for coconut fatty acid distillate (CFAD) calcium soap (Ca-soap) production and to evaluate the supplementation ratios of unprotected and protected CFAD in dairy rations to optimize rumen function. This research included two steps: (1) assessing the protection strength of Ca-soap made with CaO and CaCl2 at mole ratios of Ca to CFAD of 1, 1.5, 2, and 2.5; (2) evaluating CFAD supplementation in an in vitro dairy ration study using a 5 × 4 randomized factorial block design. Factor A compared unprotected and protected CFAD ratios of A1 = 100:0, A2 = 75:25, A3 = 50:50, A4 = 25:75, and A5 = 0:100, and factor B compared supplementation levels of B1 = 0%, B2 = 1%, B3 = 2%, and B4 = 3%. CaCl2 at a 2.5-mole ratio to CFAD produced the lowest acid value and the carboxylic acid (C=O) chemical bond. Complete protection (0:100) exhibited the highest densities of Bacteroides and nutrient digestibility (p < 0.05) without significantly affecting rumen fermentability (p > 0.05). Higher CFAD levels significantly reduced methanogens and protozoa (p < 0.05) without significantly affecting estimated methane production. In conclusion, CaCl2 at a 2.5-mole ratio to CFAD provided the best protection, and its complete protection in CFAD supplementation optimized rumen function.
  • Isolation and characterization of tannin‐degrading bacteria from the rumen of wild Hokkaido sika deer (Cervus nippon yezoensis)
    Yoshihiko Sawabe; Hidehisa Yamano; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, Jan. 2024
    Scientific journal
  • In vitro Effects of Cellulose Acetate on Fermentation Profiles, the Microbiome, and Gamma-aminobutyric Acid Production in Human Stool Cultures
    Hiroaki Yamada; Hiroto Miura; Yutaka Suzuki; Satoshi Koike; Shu Shimamoto; Yasuo Kobayashi
    Current Microbiology, 80, 9, Springer Science and Business Media LLC, 14 Jul. 2023
    Scientific journal
  • Aristaeella hokkaidonensis gen. nov. sp. nov. and Aristaeella lactis sp. nov., two rumen bacterial species of a novel proposed family, Aristaeellaceae fam. nov.
    Sam C. Mahoney-Kurpe; Nikola Palevich; Samantha J. Noel; Dragana Gagic; Patrick J. Biggs; Priya Soni; Peter M. Reid; Satoshi Koike; Yasuo Kobayashi; Peter H. Janssen; Graeme T. Attwood; Christina D. Moon
    International Journal of Systematic and Evolutionary Microbiology, 12 May 2023
    Scientific journal
  • Batch culture analysis to identify potent organic acids for suppressing ruminal methane production
    Kyouko Yamada; Keiichiro Iwamae; Yutaka Suzuki; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, Jan. 2023
    Scientific journal
  • Alterations in rumen microbiota via oral fiber administration during early life in dairy cows
    Heshan Kodithuwakku; Daiki Maruyama; Hisashi Owada; Yuto Watabe; Hiroto Miura; Yutaka Suzuki; Kazuo Hirano; Yasuo Kobayashi; Satoshi Koike
    Scientific Reports, 12, 1, Springer Science and Business Media LLC, Jun. 2022, [Peer-reviewed], [Last author, Corresponding author]
    English, Scientific journal, Abstract

    Bacterial colonization in the rumen of pre-weaned ruminants is important for their growth and post-weaning productivity. This study evaluated the effects of oral fiber administration during the pre-weaning period on the development of rumen microbiota from pre-weaning to the first lactation period. Twenty female calves were assigned to control and treatment groups (n = 10 each). Animals in both groups were reared using a standard feeding program throughout the experiment, except for oral fiber administration (50–100 g/day/animal) from 3 days of age until weaning for the treatment group. Rumen content was collected during the pre-weaning period, growing period, and after parturition. Amplicon sequencing of the 16S rRNA gene revealed that oral fiber administration facilitated the early establishment of mature rumen microbiota, including a relatively higher abundance of Prevotella, Shuttleworthia, Mitsuokella, and Selenomonas. The difference in the rumen microbial composition between the dietary groups was observed even 21 days after parturition, with a significantly higher average milk yield in the first 30 days of lactation. Therefore, oral fiber administration to calves during the pre-weaning period altered rumen microbiota, and its effect might be long-lasting until the first parturition.
  • Application of MinION Amplicon Sequencing to Buccal Swab Samples for Improving Resolution and Throughput of Rumen Microbiota Analysis
    Hiroto Miura; Masayuki Takeda; Megumi Yamaguchi; Yoshihisa Ohtani; Go Endo; Yasuhisa Masuda; Kaede Ito; Yoshio Nagura; Kunihiro Iwashita; Tomohiro Mitani; Yutaka Suzuki; Yasuo Kobayashi; Satoshi Koike
    Frontiers in Microbiology, 13, 783058, 783058, Frontiers Media SA, 24 Mar. 2022, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
    English, Scientific journal, The Illumina MiSeq platform has been widely used as a standard method for studying the rumen microbiota. However, the low resolution of taxonomic identification is the only disadvantage of MiSeq amplicon sequencing, as it targets a part of the 16S rRNA gene. In the present study, we performed three experiments to establish a high-resolution and high-throughput rumen microbial profiling approach using a combination of MinION platform and buccal swab sample, which is a proxy for rumen contents. In experiment 1, rumen contents and buccal swab samples were collected simultaneously from cannulated cattle (n = 6) and used for microbiota analysis using three different analytical workflows: amplicon sequencing of the V3–V4 region of the 16S rRNA gene using MiSeq and amplicon sequencing of near full-length 16S rRNA gene using MinION or PacBio Sequel II. All reads derived from the MinION and PacBio platforms were classified at the species-level. In experiment 2, rumen fluid samples were collected from beef cattle (n = 28) and used for 16S rRNA gene amplicon sequencing using the MinION platform to evaluate this sequencing platform for rumen microbiota analysis. We confirmed that the MinION platform allowed species-level taxa assignment for the predominant bacterial groups, which were previously identified at the family- and genus-level using the MiSeq platform. In experiment 3, buccal swab samples were collected from beef cattle (n = 30) and used for 16S rRNA gene amplicon sequencing using the MinION platform to validate the applicability of a combination of the MinION platform and buccal swab samples for rumen microbiota analysis. The distribution of predominant bacterial taxa in the buccal swab samples was similar to that in the rumen samples observed in experiment 2. Based on these results, we concluded that the combination of the MinION platform and buccal swab samples may be potentially applied for rumen microbial analysis in large-scale studies., 12776927
  • Expression of chemerin in intestinal mucosa of calves with comparable expression level with other antimicrobial proteins
    Yutaka Suzuki; Kanako Kubota; Satoshi Haga; Hideaki Hayashi; Mutsumi Oishi; Hiroto Miura; Sanggun Roh; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 93, 1, Wiley, Jan. 2022
    Scientific journal
  • Rumen microbiota and its relation to fermentation in lactose-fed calves
    S. Koike; M. Ueno; H. Miura; A. Saegusa; K. Inouchi; Y. Inabu; T. Sugino; L.L. Guan; M. Oba; Y. Kobayashi
    Journal of Dairy Science, 104, 10, 10744, 10752, American Dairy Science Association, Oct. 2021, [Peer-reviewed], [Lead author, Corresponding author], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Effects of oral administration of timothy hay and psyllium on the growth performance and fecal microbiota of preweaning calves
    K.A.H.T. Kodithuwakku; H. Owada; H. Miura; D. Maruyama; K. Hirano; Y. Suzuki; Y. Kobayashi; S. Koike
    Journal of Dairy Science, in press, American Dairy Science Association, Sep. 2021, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Cashew nut shell liquid potentially mitigates methane emission from the feces of Thai native ruminant livestock by modifying fecal microbiota
    Chiaki Narabe; Saki Kamiyama; Mizuki Saito; Phoompong Boonsaen; Anchalee Khongpradit; Suriya Sawanon; Yutaka Suzuki; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 92, 1, e13614, Wiley, 18 Aug. 2021, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal, The methane-mitigating potency of cashew nutshell liquid (CNSL) was evaluated by investigating gas production from batch cultures using feces from Thai native ruminants that had been incubated for different periods. Feces was obtained from four Thai native cattle and four swamp buffaloes reared under practical feeding conditions at the Kasetsart University farm, Thailand. Fecal slurry from the same farm was also included in the analysis. CNSL addition successfully suppressed the methane production potential of feces from both ruminants by shifting short chain fatty acid profiles towards propionate production. Methane mitigation continued for almost 150 days, although the degree of mitigation was more apparent from Day 0 to Day 30. Bacterial and archaeal community shifts with CNSL addition were observed in feces from both ruminants; specifically, Bacteroides increased, whereas Lachnospiraceae and Ruminococcaceae decreased in feces to which CNSL was added. Fecal slurry did not show marked changes in gas production with CNSL addition. The findings showed that the addition of CNSL to the feces of ruminants native to the Southeast Asian region can suppress methane emission. Because CNSL can be easily obtained as a byproduct of the local cashew industry in this region, its on-site application might be ideal.
  • Addition of ginkgo fruit to cattle feces and slurry suppresses methane production by altering the microbial community structure
    Risa Shintani; Seongjin Oh; Yutaka Suzuki; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 92, 1, e13620, 17 Aug. 2021, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Growth and morphologic response of rumen methanogenic archaea and bacteria to cashew nut shell liquid and its alkylphenol components
    Makimi Wakai; Shusuke Hayashi; Yuko Chiba; Satoshi Koike; Kyo Nagashima; Yasuo Kobayashi
    Animal Science Journal, 92, 1, e13598, 05 Aug. 2021, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Identification of the core rumen bacterial taxa and their population dynamics during the fattening period in Japanese Black cattle
    Hiroto Miura; Takuya Hashimoto; Yukiko Kawanishi; Hiroki Kawauchi; Ryo Inoue; Noriaki Shoji; Kunihiko Saito; Mario Sekiya; Yosuke Saito; Jumpei Yasuda; Chiemi Yonezawa; Tetsushiro Endo; Hirotaka Kasuya; Yutaka Suzuki; Yasuo Kobayashi; Satoshi Koike
    Animal Science Journal, 92, 1, e13601, 27 Jul. 2021, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Effect of Bacillus subtilis C‐3102 supplementation in milk replacer on growth and rumen microbiota in preweaned calves
    Satoshi Koike; Machiho Ueno; Nobuhisa Ashida; Tomokazu Imabayashi; Yasuo Kobayashi
    Animal Science Journal, 92, 1, e13580, Wiley, 26 Jul. 2021, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
    English, Scientific journal, We aimed to assess the effect of feeding Bacillus subtilis C-3102 on the growth and rumen microbiota in the preweaned calves. Twelve newborn Japanese Black calves were randomly allocated to either the control (n = 6) or the treatment (n = 6) groups in the present study. Calves in the treatment group were offered B. subtilis C-3102 supplemented milk replacer throughout the preweaning period. Rumen fermentation during the first 21 days of life seemed to be slightly suppressed by feeding B. subtilis C-3102. This fermentation shift was probably attributed to the lower abundance of the core members of rumen microbiota until 21 days of age in the calves fed B. subtilis C-3102. However, feeding B. subtilis C-3102 did not influence the abundance of the core members of rumen microbiota at 90 days of age. Distribution of Sharpea spp. and Megasphaera spp., which potentially contribute to low methane production and are regarded as beneficial rumen bacteria, was higher in the rumen of calves fed B. subtilis C-3102 at 90 days of age. These results suggest that B. subtilis C-3102 supplementation in milk replacer could potentially contribute to the improvement of feed efficiency after weaning via the establishment of beneficial rumen bacteria.
  • Feeding cashew nut shell liquid decreases methane production from feces by altering fecal bacterial and archaeal communities in Thai local ruminants
    Koya Tamori; Bungo Matsunaga; Phoompong Boonsaen; Anchalee Khongpradit; Suriya Sawanon; Kyo Nagashima; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 92, 1, e13569, 30 May 2021, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal, The effect of feeding cashew nut shell liquid (CNSL) on fecal fermentation products and microbiota was investigated in Thai native cattle and swamp buffaloes. Four of each animal were fed rice straw and concentrate diet with control pellets without CNSL for 4 weeks, followed by the same diet with pellets containing CNSL for another 4 weeks, so that CNSL was administered at a level of 4 g/100 kg body weight. Feces were collected the last 2 days in each feeding period. CNSL alkyl phenols were recovered from feces (16%-28%) in a similar proportion to those in the diet, indicating that most functional anacardic acid was not selectively removed throughout the digestive tract. In vitro production of gas from feces, particularly methane, decreased with CNSL feeding. The proportion of acetate in feces decreased with CNSL feeding, whereas that of propionate increased, without affecting total short-chain fatty acid concentration. CNSL feeding changed fecal microbial community, particularly in swamp buffaloes, which exhibited decreases in the frequencies of Treponema, unclassified Ruminococcaceae, and Methanomassiliicoccaceae. These results suggest that CNSL feeding alters not only rumen fermentation but also hindgut fermentation via modulation of the microbial community, thereby potentially attenuating methane emission from the feces of ruminant animals.
  • Chemical and microbial characterization for fermentation of water-soluble cellulose acetate in human stool cultures
    Hiroaki Yamada; Yuto Watabe; Yutaka Suzuki; Satoshi Koike; Shu Shimamoto; Yasuo Kobayashi
    Journal of the Science of Food and Agriculture, 101, 7, 2950, 2960, May 2021, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Effect of trehalose supplementation in milk replacer on the incidence of diarrhea and fecal microbiota in preweaned calves.
    Hiroto Miura; Kazuhisa Mukai; Keigo Sudo; Satoshi Haga; Yutaka Suzuki; Yasuo Kobayashi; Satoshi Koike
    Journal of Animal Science, 99, 1, 1, 9, 16 Jan. 2021, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
    English, Scientific journal, Trehalose, a nonreducing disaccharide consisting of d-glucose with α,α-1,1 linkage, was evaluated as a functional material to improve the gut environment in preweaned calves. In experiment 1, 173 calves were divided into two groups; the trehalose group was fed trehalose at 30 g/animal/d with milk replacer during the suckling period, and the control group was fed nonsupplemented milk replacer. Medication frequency was lower in the trehalose group (P < 0.05). In experiment 2, calves (n = 20) were divided into two groups (control group [n = 10] and trehalose group [n = 10]) based on their body weight and reared under the same feeding regimens as in experiment 1. Fresh feces were collected from individual animals at the beginning of the trial (average age 11 d), 3 wk after trehalose feeding (experimental day 22), and 1 d before weaning, and the fecal score was recorded daily. Fecal samples were analyzed for fermentation parameters and microbiota. The fecal score was significantly lower in the trehalose group than in the control group in the early stage (at an age of 14 to 18 d; P < 0.05) of the suckling period. Calves fed trehalose tended to have a higher proportion of fecal butyrate on day 22 than calves in the control group (P = 0.08). Population sizes of Clostridium spp. were significantly lower (P = 0.036), whereas those of Dialister spp. and Eubacterium spp. tended to be higher in the feces of calves in the trehalose group on day 22 (P = 0.060 and P = 0.083). These observations indicate that trehalose feeding modulated the gut environment and partially contributed to the reduction in medication frequency observed in experiment 1., 10810054
  • Microbial community structure of the bovine rumen as affected by feeding cashew nut shell liquid, a methane-inhibiting and propionate-enhancing agent.
    Chisato Su; Takumi Shinkai; Nodoka Miyazawa; Makoto Mitsumori; Osamu Enishi; Kyo Nagashima; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 92, 1, e13503, 04 Jan. 2021, [Peer-reviewed], [International Magazine]
    English, Scientific journal, The effect of cashew nut shell liquid (CNSL) feeding on bacterial and archaeal community of the bovine rumen was investigated by analyzing clone libraries targeting 16S rRNA genes, methyl-coenzyme reductase A-encoding genes (mcrA), and their respective transcripts. Rumen samples were collected from three non-lactating cows fed on a hay and concentrate diet with or without CNSL supplementation. DNA and complementary DNA (cDNA) libraries were generated for investigating rumen microbial communities. MiSeq analysis also was performed to understand more comprehensively the changes in the microbial community structures. Following CNSL supplementation, the number of operational taxonomical unit (OTU) and diversity indices of bacterial and archaeal community were decreased. Bacterial OTUs belonging to Proteobacteria, including Succinivibrio, occurred at a higher frequency with CNSL feeding, especially in cDNA libraries. The methanogenic archaeal community became dominated by Methanomicrobium. A bacterial community shift also was observed in the MiSeq data, indicating that CNSL increased the proportion of Succinivibrio and other genera known to be involved in propionate production. Methanogenic archaeal community shifts to increase Methanoplanus and to decrease Methanobrevibacter also were observed. Together, these results imply the occurrence of significant changes in rumen communities, not only for bacteria but also for methanogens, following CNSL feeding.
  • The bio-surfactant mannosylerythritol lipid acts as a selective antibacterial agent to modulate rumen fermentation.
    Kana Okuhira; Satoshi Koike; Shinji Ito; Yasuo Kobayashi
    Animal Science Journal, 91, 1, e13464, 05 Oct. 2020, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Methyl-mannosylerythritol lipid (MEL), a new sugar esterified lipid synthesized by Pseudozyma aphidis, was assessed for its functionality in modulating rumen fermentation and microbiota toward more propionate and less methane production. A pure culture study using rumen representatives showed that MEL selectively inhibited the growth of most Gram-positive bacteria including Streptococcus bovis, ruminococci, and Fibrobacter succinogenes, but not Gram-negative bacteria such as Megasphaera elsdenii, Succinivibrio dextrinosolvens, and Selenomonas ruminantium. A batch culture study revealed that MEL significantly decreased methane production in a dose-dependent manner with accumulation of hydrogen, while propionate production was enhanced. A continuous culture (Rusitec) study confirmed all of these changes. A feeding study revealed that sheep fed a MEL diet showed an increased proportion of propionate, while proportions of acetate and butyrate were decreased without affecting total VFA level. These changes disappeared after cessation of MEL feeding. Based on these results, dietary application of MEL can favorably modify rumen fermentation in terms of the efficiency of dietary energy utilization.
  • Effect of pineapple stem starch feeding on rumen microbial fermentation, blood lipid profile, and growth performance of fattening cattle.
    Anchalee Khongpradit; Phoompong Boonsaen; Nitipong Homwong; Yutaka Suzuki; Satoshi Koike; Suriya Sawanon; Yasuo Kobayashi
    Animal Science Journal, 91, 1, e13459, 29 Sep. 2020, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal, Pineapple stem starch (PS) was evaluated for its suitability as a new starch source in concentrate for fattening cattle, based on the growth performance, blood profile, and rumen parameters of 36 steers in a 206-day feeding study. PS was formulated as a 40% concentrate and fed with forage in comparison with ground corn (GC) and ground cassava (CA) formulated at the same level. PS feeding improved weight gain and feed conversion ratio without affecting feed intake. PS did not obviously influence blood lipid profiles throughout the experiment. Ruminal concentration of total short-chain fatty acids (SCFA) increased with PS without affecting SCFA composition throughout the feeding study. Rumen amylolytic group, especially Ruminococcus bromii, was dominant in the rumen microbial community, and showed increased abundance by PS feeding throughout the experiment. These results clearly indicate the potential of PS as a useful starch source for fattening cattle in terms of rumen fermentation and growth performance.
  • Comparison of the fecal microbiota of two monogastric herbivorous and five omnivorous mammals
    Rana Kobayashi; Kentaro Nagaoka; Naomichi Nishimura; Satoshi Koike; Eiki Takahashi; Kimie Niimi; Harutaka Murase; Teruo Kinjo; Takamitsu Tsukahara; Ryo Inoue
    Animal Science Journal, 91, 1, e13366, Wiley, 03 Apr. 2020, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Occurrence and expression of genes encoding methyl-compound production in rumen bacteria.
    William J Kelly; Sinead C Leahy; Janine Kamke; Priya Soni; Satoshi Koike; Roderick Mackie; Rekha Seshadri; Gregory M Cook; Sergio E Morales; Chris Greening; Graeme T Attwood
    Animal Microbiome, 1, 15, 14 Nov. 2019, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal, BACKGROUND: Digestive processes in the rumen lead to the release of methyl-compounds, mainly methanol and methylamines, which are used by methyltrophic methanogens to form methane, an important agricultural greenhouse gas. Methylamines are produced from plant phosphatidylcholine degradation, by choline trimethylamine lyase, while methanol comes from demethoxylation of dietary pectins via pectin methylesterase activity. We have screened rumen metagenomic and metatranscriptomic datasets, metagenome assembled genomes, and the Hungate1000 genomes to identify organisms capable of producing methyl-compounds. We also describe the enrichment of pectin-degrading and methane-forming microbes from sheep rumen contents and the analysis of their genomes via metagenomic assembly. RESULTS: Screens of metagenomic data using the protein domains of choline trimethylamine lyase (CutC), and activator protein (CutD) found good matches only to Olsenella umbonata and to Caecibacter, while the Hungate1000 genomes and metagenome assembled genomes from the cattle rumen found bacteria within the phyla Actinobacteria, Firmicutes and Proteobacteria. The cutC and cutD genes clustered with genes that encode structural components of bacterial microcompartment proteins. Prevotella was the dominant genus encoding pectin methyl esterases, with smaller numbers of sequences identified from other fibre-degrading rumen bacteria. Some large pectin methyl esterases (> 2100 aa) were found to be encoded in Butyrivibrio genomes. The pectin-utilising, methane-producing consortium was composed of (i) a putative pectin-degrading bacterium (phylum Tenericutes, class Mollicutes), (ii) a galacturonate-using Sphaerochaeta sp. predicted to produce acetate, lactate, and ethanol, and (iii) a methylotrophic methanogen, Methanosphaera sp., with the ability to form methane via a primary ethanol-dependent, hydrogen-independent, methanogenesis pathway. CONCLUSIONS: The main bacteria that produce methyl-compounds have been identified in ruminants. Their enzymatic activities can now be targeted with the aim of finding ways to reduce the supply of methyl-compound substrates to methanogens, and thereby limit methylotrophic methanogenesis in the rumen.
  • Diverse hydrogen production and consumption pathways influence methane production in ruminants
    Chris Greening; Renae Geier; Cecilia Wang; Laura C. Woods; Sergio E. Morales; Michael J. McDonald; Rowena Rushton-Green; Xochitl C. Morgan; Satoshi Koike; Sinead C. Leahy; William J. Kelly; Isaac Cann; Graeme T. Attwood; Gregory M. Cook; Roderick I. Mackie
    The ISME Journal, 13, 10, 2617, 2632, Springer Science and Business Media LLC, 26 Jun. 2019, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Effect of cashew nut shell liquid feeding on fermentation and microbiota in the rumen of Thai native cattle and swamp buffaloes
    S. Konda; R. Onodera; E. Kanchanasatit; P. Boonsaen; S. Sawanon; K. Nagashima; Y. Suzuki; S. Koike; Y. Kobayashi
    Livestock Science, 226, 99, 106, Elsevier BV, 15 Jun. 2019, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Seasonal differences in rumen bacterial flora of wild Hokkaido sika deer and partial characterization of an unknown bacterial group possibly involved in fiber digestion in winter.
    Hidehisa Yamano; Yasuhiro Ichimura; Yoshihiko Sawabe; Satoshi Koike; Yutaka Suzuki; Yasuo Kobayashi
    Animal Science Journal, 90, 6, 790, 798, Wiley, 14 Apr. 2019, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Rumen digesta was obtained from wild Hokkaido sika deer to compare bacterial flora between summer and winter. Bacterial flora was characterized with molecular-based approaches and enrichment cultivation. Bacteroidetes was shown as a major phylum followed by Firmicutes, with similar proportions in both seasons. However, two phylogenetically unique groups in Bacteroidetes were found in each season: unknown group A in winter and unknown group B in summer. The ruminal abundance of unknown group A was the highest followed by Ruminococcus flavefaciens in winter. Moreover, the abundance of these two was higher in winter than in summer. In contrast, the abundance of unknown group B was higher in summer than in winter. In addition, this group showed the highest abundance in summer among the bacteria quantified. Unknown group A was successfully enriched by cultivating with oak bark and sterilized rumen fluid, particularly that from deer. Bacteria of this group were distributed in association with the solid rather than the liquid rumen fraction, and were detected as small cocci. Accordingly, unknown group A is assumed to be involved in degradation of fibrous materials. These results suggest that wild Hokkaido sika deer develop a rumen bacterial flora in response to changes in dietary conditions.
  • Selection of plant oil as a supplemental energy source by monitoring rumen profiles and its dietary application in Thai crossbred beef cattle.
    Keiji Matsuba; Apirada Padlom; Anchalee Khongpradit; Phoompong Boonsaen; Prayad Thirawong; Suriya Sawanon; Yutaka Suzuki; Satoshi Koike; Yasuo Kobayashi
    Asian-Australasian Journal of Animal Sciences, 32, 10, 1511, 1520, Asian Australasian Association of Animal Production Societies, 14 Feb. 2019, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal, Objective: The present study was conducted to select a plant oil without inhibitory effects on rumen fermentation and microbes, and to determine the optimal supplementation level of the selected oil in a series of in vitro studies for dietary application. Then, the selected oil was evaluated in a feeding study using Thai crossbred beef cattle by monitoring growth, carcass, blood and rumen characteristics. Methods: Rumen fluid was incubated with substrates containing one of three different types of plant oil (coconut oil, palm oil and soybean oil) widely available in Thailand. The effects of each oil on rumen fermentation and microbes were monitored and the oil without a negative influence on rumen parameters was selected. Then, the dose-response of rumen parameters to various levels of the selected palm oil was monitored to determine a suitable supplementation level. Finally, an 8-month feeding experiment with the diet supplemented with palm oil was carried out using 12 Thai crossbred beef cattle to monitor growth, carcass, rumen and blood profiles. Results: Batch culture studies revealed that coconut and soybean oils inhibited the most potent rumen cellulolytic bacterium Fibrobacter succinogenes, while palm oil had no such negative effect on this and on rumen fermentation products at 5% or higher supplementation level. Cattle fed the diet supplemented with 2.5% palm oil showed improved feed conversion ratio (FCR) without any adverse effects on rumen fermentation. Palm oil-supplemented diet increased blood cholesterol levels, suggesting a higher energy status of the experimental cattle. Conclusion: Palm oil had no negative effects on rumen fermentation and microbes when supplemented at levels up to 5% in vitro. Thai crossbred cattle fed the palm oil-supplemented diet showed improved FCR without apparent changes of rumen and carcass characteristics, but with elevated blood cholesterol levels. Therefore, palm oil can be used as a beneficial energy source.
  • Functional modulation of caecal fermentation and microbiota in rat by feeding bean husk as a dietary fibre supplement
    H. Myint; H. Kishi; Y. Iwahashi; W. Saburi; S. Koike; Y. Kobayashi
    Beneficial Microbes, 9, 6, 963, 974, Wageningen Academic Publishers, 07 Dec. 2018, [Peer-reviewed], [International Magazine]
    English, Scientific journal, A feeding study using rats was conducted to evaluate the utility of lablab bean husk and soya bean husk as sources of potential prebiotic fibre. Twenty 5-week-old Sprague Dawley rats were divided into 4 groups and fed one of the following diets for 3 weeks: purified diet (AIN93 G) containing 5% cellulose (CEL), or the same diet in which cellulose was replaced by corn starch (STA), lablab bean husk (LBH), or soya bean husk (SBH). Rats were sacrificed at 8 weeks of age and caecal digesta were collected. Feed intake, body weight, anatomical parameters, and caecal ammonia level did not differ significantly among diets. Rats on LBH and SBH showed higher concentrations of caecal short-chain fatty acid and lactate than those on CEL. Rats on CEL, SBH, and LBH exhibited lower caecal indole and skatole levels. LBH yielded increased caecal abundance of Akkermansia muciniphila and Oscillibacter relatives, as demonstrated by either qPCR, MiSeq, or clone library analysis. SBH favoured the growth of lactobacilli as assessed by both qPCR and MiSeq, and favoured the growth of bifidobacteria as assessed by MiSeq. In comparison with STA, LBH and SBH yielded lower caecal abundance of bacteria related to Dorea massiliensis, as demonstrated by qPCR, MiSeq, and clone library analysis. Both types of bean husk were found to contain oligosaccharides that might selectively stimulate the growth of beneficial bacteria. Based on these results, the two species of bean husk tested are considered potentially functional for promoting the gut health of monogastric animals.
  • Cellulose acetate, a new candidate feed supplement for ruminant animals: In vitro evaluations
    Y. Watabe; Y. Suzuki; S. Koike; S. Shimamoto; Y. Kobayashi
    Journal of Dairy Science, 101, 12, 10929, 10938, American Dairy Science Association, Dec. 2018, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Rumen responses to dietary supplementation with cashew nut shell liquid and its cessation in sheep
    Sungchhang Kang; Ryo Suzuki; Yutaka Suzuki; Satoshi Koike; Kyo Nagashima; Yasuo Kobayashi
    Animal Science Journal, 89, 11, 1549, 1555, Wiley, 05 Sep. 2018, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Cultivation and sequencing of rumen microbiome members from the Hungate1000 Collection
    Rekha Seshadri; Sinead C. Leahy; Graeme T. Attwood; Koon Hoong Teh; Suzanne C. Lambie; Adrian L. Cookson; Emiley A. Eloe-Fadrosh; Georgios A. Pavlopoulos; Michalis Hadjithomas; Neha J. Varghese; David Paez-Espino; Rechelle Perry; Gemma Henderson; Christopher J. Creevey; Nicolas Terrapon; Pascal Lapebie; Elodie Drula; Vincent Lombard; Edward Rubin; Nikos C. Kyrpides; Bernard Henrissat; Tanja Woyke; Natalia N. Ivanova; William J. Kelly; Hungate1000 project collaborators; Nikola Palevic; Peter H. Janssen; Ron S. Ronimus; Samantha Noel; Priya Soni; Kerri Reilly; Todd Atherly; Cherie Ziemer; Andre-Denis Wright; Suzanne Ishaq; Michael Cotta; Stephanie Thompson; Katie Crosley; Nest McKain; John Wallace; Harry J. Flint; Jennifer C. Martin; Robert J. Forster; Robert J. Gruninger; Tim McAllister; Rosalind Gilbert; Diane Ouwerkerk; Rosalind Gilbert; Diane Ouwerkerk; Athol Klieve; Rafat Al Jassim; Stuart Denman; Chris McSweeney; Carly Rosewarne; Satoshi Koike; Yasuo Kobayashi; Makoto Mitsumori; Takumi Shinkai; Silvio Cravero; María Cerón Cucchi
    Nature Biotechnology, 36, 4, 359, 367, Nature Publishing Group, 19 Mar. 2018, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Partial characterization of phylogeny, ecology and function of the fibrolytic bacteriumRuminococcus flavefaciens OS14, newly isolated from the rumen of swamp buffalo
    Phoompong Boonsaen; Madoka Kinjo; Suriya Sawanon; Yutaka Suzuki; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 89, 2, 377, 385, Wiley, Feb. 2018, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Potency of cashew nut shell liquid in rumen modulation under different dietary conditions and indication of its surfactant action against rumen bacteria
    Seongjin Oh; Yasuyuki Suzuki; Shusuke Hayashi; Yutaka Suzuki; Satoshi Koike; Yasuo Kobayashi
    Journal of Animal Science and Technology, 59, 1, 27, 27, Springer Science and Business Media LLC, 24 Nov. 2017, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Background: Cashew nut shell liquid (CNSL) is an agricultural byproduct containing alkylphenols that has been shown to favorably change the rumen fermentation pattern only under experimentally fixed feeding conditions. Investigation of CNSL potency in rumen modulation under a variety of feeding regimens, and evidence leading to the understanding of CNSL action are obviously necessary for further CNSL applications. The objective of this study was to evaluate the potency of CNSL for rumen modulation under different dietary conditions, and to visually demonstrate its surfactant action against selected rumen bacteria. Methods: Batch culture studies were carried out using various diets with 5 different forage to concentrate (F:C) ratios (9:1, 7:3, 5:5. 3:7 and 1:9). Strained rumen fluid was diluted with a buffer and incubated with each diet. Gas and short chain fatty acid (SCFA) profiles were characterized after 18 h incubation at 39 °C. Monensin was also evaluated as a reference additive under the same conditions. Four species of rumen bacteria were grown in pure culture and exposed to CNSL to determine their morphological sensitivity to the surfactant action of CNSL. Results: CNSL supplementation decreased total gas production in diets with 5:5 and 3:7 F:C ratios, whereas the F:C ratio alone did not affect any gas production. Methane decrease by CNSL addition was more apparent in diets with 5:5, 3:7, and 1:9 F:C ratios. An interactive effect of CNSL and the F:C ratio was also observed for methane production. CNSL supplementation enhanced propionate production, while total SCFA production was not affected. Monensin decreased methane production but only in a diet with a 1:9 F:C ratio with increased propionate. Studies of pure cultures indicated that CNSL damaged the cell surface of hydrogen- and formate-producing bacteria, but did not change that of propionate-producing bacteria. Conclusion: CNSL can selectively inhibit rumen bacteria through its surfactant action to lead fermentation toward less methane and more propionate production. As CNSL is effective over a wider range of dietary conditions for such modulation of rumen fermentation in comparison with monensin, this new additive candidate might be applied to ruminant animals for various production purposes and at various stages.
  • Plasma concentrations of glucagon-like peptide 1 and 2 in calves fed calf starters containing lactose
    Y. Inabu; A. Saegusa; K. Inouchi; S. Koike; M. Oba; T. Sugino
    Journal of Dairy Science, 100, 11, 9361, 9371, Nov. 2017, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Effect of soybean husk supplementation on the fecal fermentation metabolites and microbiota of dogs
    Htun Myint; Yu Iwahashi; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 88, 11, 1730, 1736, Nov. 2017, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Effect of ginkgo extract supplementation on in vitro rumen fermentation and bacterial profiles under different dietary conditions
    Seongjin Oh; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 88, 11, 1737, 1743, Nov. 2017, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Potency of ginkgo fruit for modulation of rumen microbiota and fermentation
    OH Seongjin; SUZUKI Yutaka; KOIKE Satoshi; KOBAYASHI Yasuo
    栄養生理研究会報, 61, 2, 33‐41, 41, 家畜栄養生理研究会, Sep. 2017, [Peer-reviewed], [Invited], [Domestic magazines]
    English
  • Bean husk, an agricultural by-product having functionality in animal nutrition and health
    MYINT Htun; KISHI Hiroyuki; IWAHASHI Yu; SUZUKI Yutaka; KOIKE Satoshi; KOBAYASHI Yasuo
    栄養生理研究会報, 61, 2, 13‐19, 19, 家畜栄養生理研究会, Sep. 2017, [Peer-reviewed], [Invited], [Domestic magazines]
    English
  • Effects of partial replacement of corn grain with lactose in calf starters on ruminal fermentation and growth performance
    A. Saegusa; K. Inouchi; M. Ueno; Y. Inabu; S. Koike; T. Sugino; M. Oba
    Journal of Dairy Science, 100, 8, 6177, 6186, Aug. 2017, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Ginkgo fruit extract as an additive to modify rumen microbiota and fermentation and to mitigate methane production
    S. Oh; R. Shintani; S. Koike; Y. Kobayashi
    Journal of Dairy Science, 100, 3, 1923, 1934, Mar. 2017, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Effect of chickpea husk dietary supplementation on blood and cecal parameters in rats
    Htun Myint; Hiroyuki Kishi; Satoshi Koike; Yasuo Kobayashi
    Animal Science Journal, 88, 2, 372, 378, Feb. 2017, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Use of Asian selected agricultural byproducts to modulate rumen microbes and fermentation
    Yasuo Kobayashi; Seongjin Oh; Htun Myint; Satoshi Koike
    Journal of Animal Science and Biotechnology, 7, 1, Dec. 2016, [Peer-reviewed], [Invited], [International Magazine]
    English, Scientific journal
  • Rumen microbial community composition varies with diet and host, but a core microbiome is found across a wide geographical range
    Gemma Henderson; Faith Cox; Siva Ganesh; Arjan Jonker; Wayne Young; Peter H. Janssen
    Scientific Reports, 5, 1, 26 Nov. 2015, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Monitoring of gene expression in Fibrobacter succinogenes S85 under the co-culture with non-fibrolytic ruminal bacteria
    Naoki M. Fukuma; Satoshi Koike; Yasuo Kobayashi
    Archives of Microbiology, 197, 2, 269, 276, Mar. 2015, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, Scientific journal
  • Interaction of rumen bacteria as assumed by colonization patterns on untreated and alkali-treated rice straw
    Koike, S.; Yabuki, H.; Kobayashi, Y.
    Animal Science Journal, 85, 5, 524, 531, May 2014, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal
  • Determination of bacteria constituting ruminal fibrolytic consortia developed on orchard grass hay stem
    Shinkai, T.; Ueki, T.; Koike, S.; Kobayashi, Y.
    Animal Science Journal, 85, 3, 254, 261, Mar. 2014, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Phenotypic and genotypic characterization of antibiotic-resistant soil and manure bacteria adjacent to swine production facilities
    Ekizoglu, M.; Koike, S.; Krapac, I.; Sultan, M.N.; Mackie, R.
    Turkish Journal of Veterinary and Animal Sciences, 37, 5, 504, 511, Aug. 2013, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Involvement of recently cultured group U2 bacterium in ruminal fiber digestion revealed by coculture with Fibrobacter succinogenes S85
    Fukuma, N.; Koike, S.; Kobayashi, Y.
    FEMS Microbiology Letters, 336, 1, 17, 25, Nov. 2012, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, Scientific journal
  • Use of bean husk as an easily digestible fiber source for activating the fibrolytic rumen bacterium Fibrobacter succinogenes and rice straw digestion
    Fuma, R.; Oyaizu, S.; Nukui, Y.; Ngwe, T.; Shinkai, T.; Koike, S.; Kobayashi, Y.
    Animal Science Journal, 83, 10, 696, 703, Oct. 2012, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Bean husks as a supplemental fiber for ruminants: Potential use for activation of fibrolytic rumen bacteria to improve main forage digestion
    Ngwe, T.; Nukui, Y.; Oyaizu, S.; Takamoto, G.; Koike, S.; Ueda, K.; Nakatsuji, H.; Kondo, S.; Kobayashi, Y.
    Animal Science Journal, 83, 1, 43, 49, Jan. 2012, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Agricultural by-products as modulators of rumen microbiota
    Kobayashi Y; Shinkai T; Koike S
    International Colloquium on Rumen Microbiology, 49, 60, 2012, [Peer-reviewed], [Invited], [International Magazine]
  • Evidence for the possible involvement of Selenomonas ruminantium in rumen fiber digestion
    Sawanon, S.; Koike, S.; Kobayashi, Y.
    FEMS Microbiology Letters, 325, 2, 170, 179, Dec. 2011, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Effect of liquid whey feeding on fecal microbiota of mature and growing pigs
    Yasuo KOBAYASHI; Aya ITOH; Kanae MIYAWAKI; Satoshi KOIKE; Osamu IWABUCHI; Yuji IIMURA; Yuri KOBASHI; Tomoyuki KAWASHIMA; Junichi WAKAMATSU; Akihito HATTORI; Hiroshi MURAKAMI; Fumiki MORIMATSU; Takashi NAKAEBISU; Takeshi HISHINUMA
    Animal Science Journal, 82, 4, 607, 615, Aug. 2011, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Phylogenetic diversity and dietary association of rumen Treponema revealed using group-specific 16S rRNA gene-based analysis
    Aschalew Z. Bekele; Satoshi Koike; Yasuo Kobayashi
    FEMS Microbiology Letters, 316, 1, 51, 60, Mar. 2011, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, Scientific journal
  • In vitro evaluation of cashew nut shell liquid as a methane-inhibiting and propionate-enhancing agent for ruminants
    Watanabe, Y.; Suzuki, R.; Koike, S.; Nagashima, K.; Mochizuki, M.; Forster, R.J.; Kobayashi, Y.
    Journal of Dairy Science, 93, 11, 5258, 5267, Nov. 2010, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Molecular ecology of macrolide-lincosamide-streptogramin B methylases in waste lagoons and subsurface waters associated with swine production
    Koike, S.; Aminov, R.I.; Yannarell, A.C.; Gans, H.D.; Krapac, I.G.; Chee-Sanford, J.C.; Mackie, R.I.
    Microbial Ecology, 59, 3, 487, 498, Apr. 2010, [Peer-reviewed], [Lead author], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Molecular Monitoring and Isolation of Previously Uncultured Bacterial Strains from the Sheep Rumen
    S. Koike; Y. Handa; H. Goto; K. Sakai; E. Miyagawa; H. Matsui; S. Ito; Y. Kobayashi
    Applied and Environmental Microbiology, 76, 6, 1887, 1894, 15 Mar. 2010, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Genetic diversity and diet specificity of ruminal Prevotella revealed by 16S rRNA gene-based analysis
    Aschalew Z. Bekele; Satoshi Koike; Yasuo Kobayashi
    FEMS Microbiology Letters, 305, 1, 49, 57, 04 Mar. 2010, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, Scientific journal
  • Molecular Analyses of an Unusual Translesion DNA Polymerase from Methanosarcina acetivorans C2A
    Li-Jung Lin; Aya Yoshinaga; Yuyen Lin; Claudia Guzman; Yi-Hsing Chen; Shou Mei; Angelica M. Lagunas; Satoshi Koike; Shigenori Iwai; M. Ashley Spies; Satish K. Nair; Roderick I. Mackie; Yoshizumi Ishino; Isaac K.O. Cann
    Journal of Molecular Biology, 397, 1, 13, 30, Mar. 2010, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Fate and transport of antibiotic residues and antibiotic resistance genes following land application of manure waste
    Chee-Sanford, J.C.; Mackie, R.I.; Koike, S.; Krapac, I.G.; Lin, Y.-F.; Yannarell, A.C.; Maxwell, S.; Aminov, R.I.
    Journal of Environmental Quality, 38, 3, 1086, 1108, Wiley, May 2009, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Fibrolytic Rumen Bacteria: Their Ecology and Functions
    Satoshi Koike; Yasuo Kobayashi
    ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES, 22, 1, 131, 138, Jan. 2009, [Invited], [Lead author], [International Magazine]
    English
  • Ecological and physiological characterization shows that Fibrobacter succinogenes is important in rumen fiber digestion - Review
    Kobayashi, Y.; Shinkai, T.; Koike, S.
    Folia Microbiologica, 53, 3, 195, 200, Springer Science and Business Media LLC, May 2008, [Peer-reviewed], [Invited], [International Magazine]
    English, Scientific journal
  • Phylogenetic analysis of hindgut microbiota in Hokkaido native horses compared to light horses
    Hidehisa YAMANO; Satoshi KOIKE; Yasuo KOBAYASHI; Hiroshi HATA
    Animal Science Journal, 79, 2, 234, 242, Apr. 2008, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Monitoring and source tracking of tetracycline resistance genes in lagoons and groundwater adjacent to swine production facilities over a 3-year period
    Koike, S.; Krapac, I.G.; Oliver, H.D.; Yannarell, A.C.; Chee-Sanford, J.C.; Aminov, R.I.; Mackie, R.I.
    Applied and Environmental Microbiology, 73, 15, 4813, 4823, Aug. 2007, [Peer-reviewed], [Lead author], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Validation and application of real-time polymerase chain reaction assays for representative rumen bacteria
    Satoshi KOIKE; Hiroyoshi YABUKI; Yasuo KOBAYASHI
    Animal Science Journal, 78, 2, 135, 141, Apr. 2007, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal
  • Tetracycline residues and tetracycline resistance genes in groundwater impacted by swine production facilities
    MacKie, R.I.; Koike, S.; Krapac, I.; Chee-Sanford, J.; Maxwell, S.; Aminov, R.I.
    Animal Biotechnology, 17, 2, 157, 176, Dec. 2006, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Hindgut microbes, fermentation and their seasonal variations in Hokkaido native horses compared to light horses
    Yasuo Kobayashi; Satoshi Koike; Makoto Miyaji; Hiroshi Hata; Keiichi Tanaka
    Ecological Research, 21, 2, 285, 291, Mar. 2006, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Ruminal distribution of the cellulolytic bacterium Fibrobacter succinogenes in relation to its phylogenetic grouping
    Satoshi KOIKE; Jun PAN; Tomoyuki SUZUKI; Toru TAKANO; Chihiro OSHIMA; Yasuo KOBAYASHI; Keiichi TANAKA
    Animal Science Journal, 75, 5, 417, 422, Wiley, Oct. 2004, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal
  • Molecular microbial ecology of the gastrointestinal tract: from phylogeny to function.
    Erwin G Zoetendal; Biao Cheng; Satoshi Koike; Roderick I Mackie
    Current issues in intestinal microbiology, 5, 2, 31, 47, Sep. 2004, [Peer-reviewed], [International Magazine]
    English, Scientific journal, During the past decade it became evident that anaerobic cultivation-based approaches provides an incomplete picture of the microbial diversity in the GI tract, since at present only a minority of microbes can be obtained in culture. The application of molecular, mainly 16S ribosomal RNA (rRNA)-based approaches enables researchers to bypass the cultivation step and has proven its usefulness in studying the microbial composition in a variety of ecosystems, including the gastrointestinal (GI) tract. This critical review summarizes the impact of these culture-independent approaches on our knowledge of the ecology of the GI tract and provides directions for future studies which should emphasize function of specific strains, species and groups of microbes.
  • Partial characterization of structure and function of a xylanase gene from the rumen hemicellulolytic bacterium Eubacterium ruminantium
    Hidenori TAGUCHI; Satoshi KOIKE; Yasuo KOBAYASHI; Isaac K. O. CANN; Shuichi KARITA
    Animal Science Journal, 75, 4, 325, 332, Wiley, Aug. 2004, [Peer-reviewed], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Rumen microbes and fermentation of wild sika deer on the Shiretoko peninsula of Hokkaido Island, Japan
    Yasuhiro ICHIMURA; Hidehisa YAMANO; Toru TAKANO; Satoshi KOIKE; Yasuo KOBAYASHI; Keiichi TANAKA; Nobuo OZAKI; Masatsugu SUZUKI; Hideaki OKADA; Masami YAMANAKA
    Ecological Research, 19, 4, 389, 395, Jul. 2004, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Effect of ammonia treatment on physical strength of rice straw, distribution of straw particles and particle-associated bacteria in sheep rumen
    Selim, A.S.M.; Pan, J.; Takano, T.; Suzuki, T.; Koike, S.; Kobayashi, Y.; Tanaka, K.
    Animal Feed Science and Technology, 115, 1-2, 117, 128, Jul. 2004, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Recent advances in gut microbiology and their possible contribution to animal health and production - A review
    Kobayashi, Y.; Koike, S.; Taguchi, H.; Itabashi, H.; Kam, D.K.; Ha, J.K.
    Asian-Australasian Journal of Animal Sciences, 17, 6, 877, 884, Asian Australasian Association of Animal Production Societies, 01 Jun. 2004, [Peer-reviewed], [Invited], [Internationally co-authored], [International Magazine]
    English, Scientific journal
  • Molecular ecological analysis of the gastrointestinal microbiota: A review
    EG Zoetendal; CT Collier; S Koike; RI Mackie; HR Gaskins
    JOURNAL OF NUTRITION, 134, 2, 465, 472, Feb. 2004, [Invited], [International Magazine]
    English, Scientific journal
  • Molecular detection of verotoxigenic Escherichia coli (VTEC) from animal feces for screening VTEC-shedders
    Kobayashi, Y.; Sato, M.; Taguchi, H.; Koike, S.; Nakatsuji, H.; Tanaka, K.
    Asian-Australasian Journal of Animal Sciences, 17, 3, 423, 427, 01 Jan. 2004, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Phylogenetic analysis of fiber-associated rumen bacterial community and PCR detection of uncultured bacteria
    Koike, S.; Yoshitani, S.; Kobayashi, Y.; Tanaka, K.
    FEMS Microbiology Letters, 229, 1, 23, 30, Dec. 2003, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal
  • Expression and export of aRuminococcus albuscellulase inButyrivibrio fibrisolvensthrough the use of an alternative gene promoter and signal sequence
    Yasuo Kobayashi; Hidenori Taguchi; Takashi N Goto; Satoshi Koike; Kunio Ohmiya
    Canadian Journal of Microbiology, 49, 6, 375, 382, 01 Jun. 2003, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Effect of mastication on degradation of orchardgrass hay stem by rumen microbes: Fibrolytic enzyme activities and microbial attachment
    Pan, J.; Koike, S.; Suzuki, T.; Ueda, K.; Kobayashi, Y.; Tanaka, K.; Okubo, M.
    Animal Feed Science and Technology, 106, 1-4, 69, 79, Apr. 2003, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Kinetics of In Sacco Fiber-Attachment of Representative Ruminal Cellulolytic Bacteria Monitored by Competitive PCR
    S. Koike; J. Pan; Y. Kobayashi; K. Tanaka
    Journal of Dairy Science, 86, 4, 1429, 1435, Apr. 2003, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal
  • Effects of urea infused into the rumen on liquid- and particle-associated fibrolytic enzyme activities in steers fed low quality grass hay
    Pan, J.; Suzuki, T.; Koike, S.; Ueda, K.; Kobayashi, Y.; Tanaka, K.; Okubo, M.
    Animal Feed Science and Technology, 104, 1-4, 13, 27, Feb. 2003, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Development and use of competitive PCR assays for the rumen cellulolytic bacteria: Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens
    Satoshi Koike; Yasuo Kobayashi
    FEMS Microbiology Letters, 204, 2, 361, 366, Nov. 2001, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal
  • Fecal Bacteria in Hokkaido Native Horses as Characterized by Microscopic Enumeration and Competitive Polymerase Chain Reaction Assays.
    Satoshi KOIKE; Yuko SHINGU; Hiroyuki INABA; Masahito KAWAI; Yasuo KOBAYASHI; Hiroshi HATA; Keiichi TANAKA; Masahiko OKUBO
    Journal of Equine Science, 11, 2, 45, 50, Japan Society of Equine Science, 2000, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal
■ Other Activities and Achievements
■ Books and other publications
  • ルーメンの科学
    板橋, 久雄; 小林, 泰男
    農山漁村文化協会, May 2023, 9784540231209, 9,330p, Japanese, [Contributor]
  • 新しい子牛の科学 : 胎生期から初産分娩まで
    家畜感染症学会, 子牛の第一胃発酵と腸内細菌叢
    緑書房, Mar. 2021, 9784895315876, 343p, 152-156, Japanese, [Contributor]
  • Antibiotic Resistance Genes in Natural Environments and Long-Term Effects
    第8章
    Nova Science Publishers (ISBN:978-1-53611-818-6), Feb. 2017, [Internationally co-authored], [Contributor]
  • 肉用牛の科学
    肉用牛研究会, 肉牛の第一胃内微生物群
    養賢堂, 09 Jan. 2015, 4842505311, 398, 104-106, Japanese, Scholarly book, [Contributor]
■ Lectures, oral presentations, etc.
  • ルーメン微生物の制御と反芻家畜生産のSDGs
    小池 聡
    第10回北海道畜産草地学会シンポジウム, 11 Sep. 2021, Japanese, Nominated symposium
    [Invited], [Domestic Conference]
  • 乳牛の常在微生物研究のルーツをたどる〜ルーメン微生物研究のアプローチと乳房炎研究への応用の可能性〜
    小池 聡
    第25回乳房炎研究会座談会, 24 Oct. 2020, Japanese, Nominated symposium
    [Invited], [Domestic Conference]
  • Effect of dietary condition on development of rumen microbiota in newborn calves (update)
    Satoshi Koike
    The 3rd International Symposium on Young Ruminant Rearing, 28 Sep. 2020, English, Nominated symposium
    [Invited], [International presentation]
  • Effect of dietary condition on development of rumen microbiota in newborn calves
    Satoshi Koike
    The 2nd International Symposium on Young Ruminant Rearing, 22 Oct. 2018, English, Nominated symposium
    [Invited], [International presentation]
■ Syllabus
  • 大学院共通授業科目(一般科目):自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
  • 畜産科学特論, 2024年, 修士課程, 農学院
  • 大学院共通授業科目(教育プログラム):One program for Global Goals, 2024年, 修士課程, 大学院共通科目
  • 大学院共通授業科目(教育プログラム):One program for Global Goals, 2024年, 修士課程, 大学院共通科目
  • 大学院共通授業科目(一般科目):自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
  • 胃腸内圏微生物学特論, 2024年, 修士課程, 農学院
  • 環境化学, 2024年, 学士課程, 農学部
  • 環境と人間, 2024年, 学士課程, 全学教育
  • 畜産科学概論, 2024年, 学士課程, 農学部
  • 動物機能栄養科学, 2024年, 学士課程, 農学部
  • 基礎家畜生産学Ⅱ, 2024年, 学士課程, 農学部
  • 動物機能栄養科学実験, 2024年, 学士課程, 農学部
  • 一般教育演習(フレッシュマンセミナー), 2024年, 学士課程, 全学教育
■ Affiliated academic society
  • JAPANESE SOCIETY FOR ANIMAL NUTRITION AND METABOLISM
  • 北海道畜産草地学会
  • 日本微生物生態学会
  • 日本応用糖質科学会
  • ルーメン研究会
  • 日本畜産学会
■ Research Themes
  • 子牛の健全発育に資する消化管微生物の積極的な定着コントロールに関する研究
    科学研究費助成事業
    01 Apr. 2022 - 31 Mar. 2025
    小池 聡
    本研究では自発的な固形飼料摂取が始まる前に粗飼料の早期経口投与を実施し、子牛消化管微生物の積極的な定着コントロールの可能性を探った。
    前年度に開始した新生子牛を対象とした試験では、哺乳期における粗飼料の早期経口投与の有益な効果、すなわち生後21日までの増体の向上ならびに消化管(ルーメンおよび腸内)での有用菌の増加が確認された。
    本年度は試験対象牛を同一農場にて同一の飼料条件で継続飼養し、哺乳期の飼養管理の違いがその後の生産性に及ぼす影響の追跡調査に着手した。これまでのところ、9ヶ月齢時点での体重や飼料摂取量には試験区間で違いが見られなかった。ルーメン内容物の解析を実施したところ、VFA産生量と組成ならびに菌叢構成にも明確な違いは認められなかった。したがって、哺乳期における粗飼料の早期経口投与は、育成期における発育ならびにルーメン発酵に影響を及ぼさないことが確認された。
    前年度の試験において、粗飼料の早期経口投与により、腸内(糞便中)のLactobacillus属細菌が増加することを確認した。本年度はロングリードシーケンサーを用いて、Lactobacillus属細菌の種レベルでの特定を試みた。16S rRNA遺伝子解析より特定されたLactobacillus属細菌の約50%は未培養の細菌種であったが、残り50%はLactobaciilus reuteri、Lactobacillus gasseriおよびLactobacillus johnsoniiであった。これらの3種の乳酸菌はいずれもプロバイオティック効果を持つことが報告されている。したがって、粗飼料の早期経口投与により子牛の腸内では有用な乳酸菌が増殖することを確認した。
    日本学術振興会, 基盤研究(B), 北海道大学, 23K23753
  • 子牛の健全発育に資する消化管微生物の積極的な定着コントロールに関する研究
    科学研究費助成事業 基盤研究(B)
    01 Apr. 2022 - 31 Mar. 2025
    小池 聡
    日本学術振興会, 基盤研究(B), 北海道大学, 22H02488
  • Research on boosting mechanism of fiber digestion in key rumen bacterium by agricultural byproduct
    Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
    Apr. 2020 - Mar. 2022
    小池 聡; LAHRITA LUCY
    本研究ではF. succinogenesが保有する糖質分解酵素遺伝子(以下、GH遺伝子)のうち、機能がわかっている15個のGHに的を絞り、それらの遺伝子発現レベルを検討した。発現変動が見られたGH遺伝子は8つあり、2つは、マメ外皮添加によって発現量が減少した。これらの遺伝子は、GHファミリー8および9に属するエンドグルカナーゼであった。GHファミリー9に属する遺伝子は、結晶セルロースに対してほとんどまたはまったく活性を示さないが、可溶性セルロース誘導体およびさまざまな植物多糖類に対しては活性を示すことが知られている。植物の細胞壁のセルロースは結晶化した構造であるため、これらの遺伝子がコードする酵素はイナワラ消化への貢献度は低い可能性がある。マメ外皮添加によりイナワラ消化への貢献が低い酵素の遺伝子発現が低下するのであれば、酵素合成のコスト節約となり、結果としてF. succinogenesの効率的な繊維消化を促すかもしれない。
    本研究で対象としたGH遺伝子のうち、エンドグルカナーゼ、キシラナーゼまたはセロデキストリンをコードする6つはマメ外皮の添加により発現量が向上した。これらのGH遺伝子の発現向上は、マメ外皮によるイナワラ消化のブースター効果を一部説明するものである。F. succinogenesは、植物細胞壁多糖類のセルロースとヘミセルロースの両方を分解する能力があることが知られている。多様なセルラーゼとヘミセルラーゼの発現向上は、複数の糖質分解酵素が複合的に作用することでF. succinogenesのセルロース分解が効率的に行われることを示唆している。
    以上より、マメ外皮添加によりセルロース分解菌が保有するセルラーゼやキシラナーゼの遺伝子発現向上が認められ、本資材による繊維分解ブースト効果の機序を一部解明した。
    Japan Society for the Promotion of Science, Grant-in-Aid for JSPS Fellows, Hokkaido University, Competitive research funding, 20F20102
  • Methane mitigation from ruminants by wide range application of alkylpenol-containing plants
    Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Apr. 2018 - Mar. 2022
    Kobayashi Yasuo
    Methane mitigation potential of alkylphenol-containing plants such as ginkgo fruit (GF) and cashew nut shell liquid (CL) was evaluated by the application as manure and/or feed additive. Considering local availability of each material, GF was supposed to use for Japanese cattle, while CL was for native cattle and swamp buffaloes in Thailand. The evaluations were made by monitoring changes of fermentation products and microbiota in in vitro culture systems and also in feeding studies.
    Both materials decreased methane production potential by the direct addition to feces with significant alteration of fecal microbial community, based on the selective anti-microbial actions. CL was further evaluated by feeding studies using Thani animals and was found to decrease methane production not only from the rumen fluid but also from feces. This accompanied with apparent changes in fecal microbiota.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Coinvestigator, 18H02322
  • Exploration of microbial marker for prediction of metabolic disorder in ruminants
    Grants-in-Aid for Scientific Research Challenging Research (Exploratory)
    Jun. 2017 - Mar. 2019
    Koike Satoshi
    Rumen microbes play a pivotal role in cattle productivity. The aim of this study was to identify the microbe(s) showing positive correlation with host productivity as a biomarker for prediction of productivity. As the first step, buccal swab as a proxy of rumen digesta was validated. This alternative sample enable to avoid laborious and time consuming sample collection by using stomach tube. Then, buccal swab samples were collected from Japanese Black cattle and employed for microbial analyses. Population size of Prevotella spp. seemed to have a positive correlation with the body weight of Japanese Black cattle . Therefore, Prevollta spp. can be used as a biomarker for prediction of body weight gain in the future.
    Japan Society for the Promotion of Science, Challenging Research (Exploratory), Hokkaido University, Principal investigator, 17K19315
  • 黒毛和種牛の安定生産を保障するルーメン発酵と微生物機能の特定
    科学研究費補助金(基盤C)
    2014 - 2016
    小池 聡
    日本学術振興会, Principal investigator, Competitive research funding
  • 黒毛和牛のルーメン微生物相と産肉成績の関連探索
    科学研究費補助金若手研究(B)
    2012 - 2013
    小池 聡
    日本学術振興会, Principal investigator, Competitive research funding
  • 低メタン産生牛の特定をめざしたルーメン菌叢プロファイリング指標の確立
    科学研究費補助金基盤研究(B)
    2011 - 2013
    小林泰男
    日本学術振興会, Competitive research funding
  • 遺伝子発現調節による和牛肉の不飽和度向上技術の開発
    新たな農林水産政策を推進する実用技術開発事業
    2008 - 2012
    庄司則章
    農林水産省, Competitive research funding
  • Identification of high risk bacterial strains in rumen acidosis for the prevention of metabolic disorder in ruminants
    Grants-in-Aid for Scientific Research
    2010 - 2011
    KOIKE Satoshi
    The present research revealed that genotypically and physiologically heterogeneous strains of S. bovis were distributed in the rumen. The specific genotypes of S. bovis strains are predominant when the animal is fed a high-grain diet. In addition, the balance of lactate producer/utilizer was altered by high-grain diet. This bacterial community shift might result in lactate accumulation and lower pH.
    Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Principal investigator, Competitive research funding, 22780238
  • Development of innovative rumen modifier to reduce methane production
    Grants-in-Aid for Scientific Research
    2008 - 2010
    KOBAYASHI Yasuo; KOIKE Satoshi; ENISHI Osamu; TAKENAKA Akio
    Cashew nut shell liquid, a novel rumen modifier, was evaluated for its potential to reduce methane from ruminant animals and possible mechanisms involved in it. The shell liquid selectively inhibited growth of several species of rumen bacteria to lead a dramatic shift of rumen microbiota. This resulted in rumen fermentation changes with less methane and more propionate production but without adverse effects on feed digestion and animal health. The feeding of shell liquid allowed more than 20% reduction of methane that had not been realized by any other modifiers. Therefore, future application of the shell liquid is highly expected.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Competitive research funding, 20380146
  • 草食動物消化管内での繊維分解において真に重要な細菌群の特定
    科学研究費補助金若手スタートアップ
    Apr. 2007 - Mar. 2008
    小池 聡
    本課題の平成19年度における達成目標は、1)標的グループのルーメン内での挙動モニタリング、2)各種草食動物消化管内における標的グループの分布量把握および3)未知菌の培養化の3点であった。
    1および2点目については平成18年度の試験で繊維分解に深く関与する可能性を示したPrevotella属に着目し、rea1-time PCRによる定量を行った。その結果、本属はルーメン内で10〜20%程度の密度で存在することを確認した。さらに、ルーメン内繊維片上に15%程度の密度で付着することを突き止め、Prevotella属が繊維片上で量的にメジャーであることを明らかにした。
    3点目についてはこれまでに確立されている古典的培養法を基礎として、易分解性繊維成分に富む天然植物を培養基質として用いることで新規細菌の分離培養に成功した。新規に分離した繊維分解性細菌3菌株および非繊維分解性細菌4菌株はこれまでDNA情報でのみ存在が確認されてきた未培養細菌と91〜99%の16S rDNA塩基配列相同性を示し、本研究ではじめて分離に成功した菌株であった。新規株の繊維分解酵素活性を測定したところ、いずれの株もキシラナーゼやアラビノフラノシダーゼと言ったヘミセルロース分解に関与する酵素を保有し、その活性は既知のキシラン分解菌Butyrivibrio fibrisolvensの活性よりも高かった。したがって、本研究で初めて分離した新規菌株はルーメン内においてヘミセルロース分解に関与するものと考えられた。また、新規の非繊維分解性菌株を繊維分解菌と2菌共培養すると繊維分解率が向上することを確認した。
    以上の結果はルーメン内での繊維分解において既知の繊維分解菌以外にも重要な細菌が存在することを示すものであり、草食動物消化管内での繊維分解を最適化する上で必要不可欠な情報を得ることができたものと確信している。
    日本学術振興会, 若手研究(スタートアップ), 北海道大学, Principal investigator, Competitive research funding, 18880002