Gast Richard K, Guraya Rupa, Jones Deana R, Anderson Kenneth E, Karcher Darrin M
USDA Agricultural Research Service, U. S. National Poultry Research Center, Athens, Georgia 30605
USDA Agricultural Research Service, U. S. National Poultry Research Center, Athens, Georgia 30605.
Poult Sci. 2016 Jun 1;95(6):1363-9. doi: 10.3382/ps/pew037. Epub 2016 Mar 4.
Epidemiologic analyses have linked the frequency of human infections with Salmonella enterica subspecies enterica serovar Enteritidis to the consumption of contaminated eggs and thus to the prevalence of this pathogen in commercial egg-laying flocks. Contamination of the edible contents of eggs by Salmonella Enteritidis is a consequence of the colonization of reproductive tissues in systemically infected hens. The animal welfare implications of laying hen housing systems have been widely debated, but no definitive consensus has yet emerged about the food safety significance of poultry housing options. The present study sought to determine the effects of two different bird stocking densities on the invasion of internal organs by Salmonella Enteritidis in groups of experimentally infected laying hens housed in colony cages enriched with perching and nesting areas. In two trials, groups of laying hens were distributed at two different stocking densities into colony cages and (along with a group housed in conventional cages) orally inoculated with doses of 1.0 × 10(7) cfu of Salmonella Enteritidis. At 5 to 6 d post-inoculation, hens were euthanized and samples of internal organs were removed for bacteriologic culturing. For both trials combined, Salmonella Enteritidis was recovered at a significantly (P < 0.05) greater frequency from hens in enriched colony cages at the higher stocking density than at the lower density from livers (75.0% vs. 51.4%) and ovaries (51.4% vs. 30.6%). However, spleens from hens in enriched colony cages at the higher stocking density were significantly less often positive for Salmonella Enteritidis than from hens in conventional cages at that same density (90.3% vs. 68.1%). These results suggest that stocking density can influence the susceptibility of hens to Salmonella Enteritidis, but other housing systems parameters may also contribute to the outcome of infections.
流行病学分析已将人类感染肠炎沙门氏菌肠炎亚种肠炎血清型的频率与食用受污染的鸡蛋联系起来，进而与这种病原体在商业产蛋鸡群中的流行率联系起来。肠炎沙门氏菌污染鸡蛋的可食用内容物是系统感染母鸡生殖组织定植的结果。蛋鸡饲养系统对动物福利的影响已得到广泛辩论，但关于家禽饲养方式对食品安全的重要性尚未形成明确共识。本研究旨在确定两种不同的饲养密度对实验感染的蛋鸡群中肠炎沙门氏菌侵入内脏的影响，这些蛋鸡饲养在配备栖木和巢区的群养笼中。在两项试验中，将蛋鸡群以两种不同的饲养密度分布到群养笼中，并（与饲养在传统笼中的一组一起）口服接种1.0×10⁷ cfu的肠炎沙门氏菌。接种后5至6天，对母鸡实施安乐死，并取出内脏样本进行细菌培养。综合两项试验来看，在较高饲养密度的配备栖木和巢区的群养笼中，肠炎沙门氏菌从肝脏（75.0%对51.4%）和卵巢（51.4%对30.6%）中检出的频率显著高于较低饲养密度的母鸡（P<0.05）。然而，在相同密度下，较高饲养密度的配备栖木和巢区的群养笼中母鸡的脾脏对肠炎沙门氏菌呈阳性的频率显著低于传统笼中的母鸡（90.3%对68.1%）。这些结果表明，饲养密度会影响母鸡对肠炎沙门氏菌的易感性，但其他饲养系统参数也可能对感染结果产生影响。
