1996 Fiscal Year Final Research Report Summary
Studies on rumen methanogens associated with ciliates
| Project/Area Number |
07660364
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Zootechnical science/Grassland science
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| Research Institution | Kyoto Prefectural University |
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Principal Investigator |
USHIDA Kazunari Kyoto Prefectural University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (50183017)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAZAKI Kouji Kyoto Prefectural University, Faculty of Agriculture, Assistant, 農学部, 助手 (60254322)
KOJIMA Yoichi Kyoto Prefectural University, Faculty of Agriculture, Professor, 農学部, 教授 (80046490)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Rumen / Methanogens / ciliate |
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| Research Abstract |
Roles and niche or ruminal methanogens were investigated with special reference to their relation to rumen ciliate protozoa. Following points were clarified.(1) Number of methanogens associated with ciliates significantly increased after feeding, then declined to pre-feeding level 3 h after feeding. Rapid increases and decrease in numbers suggested the presence of methanogenic population which attaches on and leaves from ciliate surfaces according to the metabolic activity of ciliates. Difference in ammonia tolerance and sodium chloride dependence of methanogens was observed between ciliate associated and non-associated populations. (2) Apparent methane productions from ciliate protozoa were apparently genus-dependent. Isotricha spp. produced the largest amount of methane among genera tested. While Polyplastron spp. and Epidinium spp. produced small amount of methane. (3) Relation between methanogens and ciliate is characterized as interspecies hydrogen transfer. It was tested if this
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relation could be replaced by other hydrogenotrophic bacteria. Desulfovibrio sp. SR3 and ruminal acetogen Ser 5 established cocultures with rumen ciliates in consuming hydrogen. Substrate degradation by ciliate was not significantly stimulated, however. (4) More than 11 methanogens were isolated from ciliates, most of them had similar morphological features. One gram positive cocoid and one gram positive rod were further tested their substrates and some physiological characteristics. Both isolates used hydrogen and formate as electron donors. Sodium chloride dependence and ammonia tolerance of both isolates were similar and differed from those observed in ciliate associated methanogenic population. These isolates may not be endosymbiotic methanogens but the methanogens attached on the ciliate surfaces. DNA analysis on these isolates as well as ciliate associated methanogenic population by PCR using the primer sets for 16Sr DNA of alchaea suggested the genetical difference of methanogen on and in ciliate from known alchaea, because no amplified product was obtained with this alchaea specific primer set. Less
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