저지종 젖소의 반추위 내 미생물 균총 변화와 고창증 발병간의 상관관계 연구 = The Study on the Relationship between Changes of Rumen Microflora and Bloat in Jersey Cow

국문 초록 (Abstract)

본 연구는 고창증 발병으로 폐사된 저지종 젖소의 반추위액과 캐놀라가 장착한 저지종 젖소의 반추위액을 샘플링하여 반추위 내 미생물 균총의 급작스런 변화에 따른 반추위 발효와 고창증 발병간에 연관성을 알아보고자 진행되었다. 채취한 반추위액 샘플은 PowerMax Soil DNA Isolation Kit (MO BIO Inc., CA, USA)를 이용하여 DNA를 추출한 후 PicoGreen (Turner BioSystems, Inc., CA, USA)과 Nanodrop spectrophotometer (ND-1000, NanoDrop Technologies Inc., DE, USA)를 이용하여 260/280 nm와 260/230 nm 흡광도 값을 측정하였다. DNA를 정량분석하고 $MiSeq^{TM}$ platform (Illumina, CA, USA)을 이용한 장내 미생물 균총의 다양성 분석을 마크로젠(Macrogen Inc., Seoul)에 의뢰하여 실시하였다. 반추위액 내 미생물 균총 분석 결과, 전분 분해균의 경우 고창증 발병으로 인한 폐사우의 반추위 내에서 R. bromii가 우점 하였으며, R. bromii, B. pseudolongum, B. merycicum 및 B. fibrisolvens 등과 같은 전분 분해균들이 정상우 대비 36배 높았다. 반면 반추위 발효와 밀접한 관련이 있는 F. succinogenes, R. albus 및 R. flavefaciens 등과 같은 대표적인 섬유소 분해균 비율은 정상우에서 고창증 발병으로 인한 폐사우 대비 12배 높았다. 이와 같은 결과를 볼 때, 반추위 내 균총 가운데 R. bromii, B. pseudolongum, B. merycicum 및 B. fibrisolvens 등과 같은 전분 분해균들의 급격한 증가가 반추위 내 pH 저하 및 가스 생성 증가를 초래했고 이는 저지종 젖소의 고창증 발병으로 인한 폐사와 밀접한 연관이 있었을 것으로 판단된다.

다국어 초록 (Multilingual Abstract)

This study was conducted to investigate the relationship between changes of rumen microflora and bloat in Jersey cow. Jersey cows (control age: 42 months, control weight: 558kg; treatment age: 29 months, treatment weight 507kg) were fed on the basis of dairy feeding management at dairy science division in National Institute of Animal Science. The change of microbial population in rumen was analyzed by using next generation sequencing (NGS) technologies due to metabolic disease. The diversity of Ruminococcus bromii, Bifidobacterium pseudolongum, Bifidobacterium merycicum and Butyrivibrio fibrisolvens known as major starch fermenting bacteria was increased more than 36-fold in bloated Jersey, while cellulolytic bacteria community such as Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens was increased more than 12-fold in non-bloated Jersey. The proportion of bacteroidetes and firmicutes was 33.4% and 39.6% in non-bloated Jersey's rumen, while bacteroidetes and firmicutes were 24.9% and 55.1% in bloated Jersey's. In conclusion, the change of rumen microbial community, in particular the increase in starch fermenting bacteria, might have an effect to occur the bloat in Jersey cow.

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