追踪沙门菌病暴发的起源     

Billy M.Hargis  Renee M.Tsolis  徐仕忠 《中国家禽》2008,30(21)

在1980年代,欧洲和美洲的卫生官员们就注意到由肠炎沙门菌（SE）引起的人类食物源性疾病明显增加,发现这种沙门菌存在于鸡胴体、鸡蛋和蛋产品中。这提示,作为公共卫生问题,SE的出现可能是现代家禽养殖实践和家禽遗传多样性下降的结果。但是,这些假设没有说明为什么其它沙门菌血清型,如鼠伤寒沙门菌（ST）,感染人的数量没有增加。  相似文献   

Zooplanktivore fish body growth responses to browning-induced light limitation vary over ontogeny,but not with fish density     

Renee M. van Dorst  Anna Grdmark  Richard Svanbck  Magnus Huss 《Ecology of Freshwater Fish》2022,31(1):17-28

Ongoing climate change is leading to browning of many lakes and coastal areas, which can impair fish body growth and biomass production. However, whether and how effects of light limitation caused by browning on fish body growth vary over early ontogeny is unknown. In this study, we set up a mesocosm experiment to test whether roach (Rutilus rutilus) body growth responses to browning depend on body size, and if findings are robust over roach densities. We also studied a potential mechanism for size-specific responses by conducting an aquaria experiment to test if size-specific prey selectivity in roach changes with browning. We found that roach body growth responses to browning-induced light limitation vary over ontogeny (independent of roach density), negatively affecting body growth of young-of-the-year (YOY) but not of 1-year-old individuals. We also show that this difference in growth response is likely a consequence of browning-induced alterations in zooplankton community composition and variation in prey selectivity between YOY and 1-year-old fish. This suggests that we should account for the diverse effects of browning over fish ontogeny, mediated via altered prey composition and ontogenetic changes in prey preference, when assessing overall impacts of browning on aquatic ecosystems.  相似文献