學 術 報 告
題 目：ECOLOGY, PATHOGENESIS,
報告人：龔建華（Joshua Gong）首席科學家（Principal Research Scientist）
加拿大農業與食品安全部食品研究中心（Agriculture and Agri-Food Canada，Food Research Program, Guelph, Ontario, Canada）
研究領域：
1. Gut microbial ecology of domestic animals and fowls and interactions between gut bacteria and animal hosts.
2. Pre/probiotics to mitigate the use of dietary antibiotics and food-borne pathogens in food animal production.
3. Biotechnology of gut bacteria to enhance food safety and quality.
地 點：2號樓302室
時間：9：00 – 11：00
日期：
地點：動科院2號樓302室
動物科技學院
科 研 處
專家簡介
Joshua Gong
Agriculture and
E-mail: gongj@agr.gc.ca
Education: Ph.D. in Microbiology (1994),
M.Sc. in Microbiology (1983),
B.Sc. in Industrial Fermentation (1980),
Employment History:
1999 - Present Principal Research Scientist
Agriculture and
Food Research Program,
Research area: Animal gut microbiology and food safety/quality
1997 - 1999 Senior Research Associate
Department of Cell Biology, Neurobiology, and Anatomy
Research area: Signal transduction and
1995 - 1997 Research Associate
Department of Medical and Molecular Genetics
Research area: Opioid receptor mediated signal transduction and functions
1994 - 1995 Postdoctoral Fellow
Center for Food and Animal Research, Agriculture
Research area: Molecular ecology and phylogeny of ruminal bacteria
1988 – 1994 Research Assistant
Department of Microbiology,
Research area: Physiology of cellulose digestion and bacterial adhesion
Professional Appointments:
2004 - Present Member of the Scientific Advisory Committee
2002 - Present Adjunct Professor
Department of Animal & Poultry Science
2002 - Present Adjunct Professor
Institute of Subtropical Agriculture,
Current Research Interests:
1. Gut microbial ecology of domestic animals and fowls and interactions between gut bacteria and animal hosts
2. Pre/probiotics to mitigate the use of dietary antibiotics and food-borne pathogens in food animal production
3. Biotechnology of gut bacteria to enhance food safety and quality
Publications and Conference Presentations:
More than 50 peer-reviewed publications in internationally renowned scientific journals. More than 100 conference presentations.
報告摘要
ECOLOGY, PATHOGENESIS,
Joshua Gong
Guelph Food Research Centre, Agriculture & Agri-Food Canada,
Clostridium perfringens (CP) causes necrotic enteritis (NE) in chickens, which has been the major target of prophylactic use of antibiotics in feed. We have studied microbial ecology and chicken response to CP infection with an experimental infection chicken model, in order to enhance our knowledge for control of the disease. Chickens were fed antibiotic-medicated (bacitracin, 55 mg/kg) or non-medicated diets, and were challenged with CP (107 CFU/ml) through the diets at 18 days of age. Digesta and tissue samples were collected daily before and after the challenge, and were examined for cell proliferation of CP, gene expression of alpha-toxin, changes in the composition of ileal bacterial microbiota, and gene expression profiles in the spleens and ileum, in addition to recording animal performance. The cell proliferation of CP was highly correlated to alpha-toxin production during the development of necrotic enteritis (NE). The average CP counts in the ileal digesta of 5 log10 CFU/g was shown to be a threshold for developing NE disease. While major bacterial groups, such as Enterococcus genus and Enterobacteriaceae family, exhibited no change in their populations, the abundance of lactobacilli in the ileum was significantly reduced. In particular, the change of L. avarius correlated negatively with the CP counts. The analysis of gene expression profiles indicated that many immune-associated genes were significantly up-regulated in CP-infected chickens. These genes encode members of the Toll-like receptor pathway, antibody response, T cell markers, and inflammatory cytokines. The expression of a subset of functionally relevant genes was validated through quantitative RT-
