Drummond J G, Curtis S E, Simon J
Am J Vet Res. 1978 Feb;39(2):211-2.
Young pigs were exposed to an aerosol of a nonpathogenic strain of Escherichia coli and then were retained in air-pollutant exposure chambers for a 2-hour clearance period. In series 1 (n = 80 pigs), 40 exposed young pigs (principals; 15.5 days of age) were placed in an atmosphere of filtered room air + 50 ppm of atmospheric NH3 during the clearance period; control pigs were exposed to filtered room air without added NH3. In series 2 (n = 24 pigs), 12 exposed young pigs (principals; 6.2 days of age) were similarly maintained, but at a lower concentration of atmospheric NH3 (75 ppm). At the end of the clearance period pigs were killed and pulmonary bacterial clearance was determined. Pigs kept in the NH3-contaminated atmospheres (either concentration) harbored more bacteria, on the average, in their lungs than did the controls. If series 1 and 2 data were combined, pigs kept in the NH3-contaminated atmospheres had 51% more bacteria in their lungs than did the controls. Pulmonic weight and ratio of pulmonic weight to body weight of pigs kept in the NH3-contaminated atmosphere were greater than those of the controls in series 1, but not in series 2. Gross and histopathologic examinations of lung tissue generally revealed no differences between controls and principals in either series 1 or 2.
将幼猪暴露于一种非致病性大肠杆菌菌株的气溶胶中，然后将它们置于空气污染物暴露室中2小时以进行清除期观察。在第1组（n = 80头猪）中，40头暴露的幼猪（主要对象；15.5日龄）在清除期被置于过滤后的室内空气 + 50 ppm大气NH₃的环境中；对照猪暴露于未添加NH₃的过滤后的室内空气中。在第2组（n = 24头猪）中，12头暴露的幼猪（主要对象；6.2日龄）以类似方式饲养，但大气NH₃浓度较低（75 ppm）。在清除期结束时，处死猪并测定肺部细菌清除情况。平均而言，置于受NH₃污染环境（任一浓度）中的猪肺部携带的细菌比对照组更多。如果将第1组和第2组的数据合并，置于受NH₃污染环境中的猪肺部细菌比对照组多51%。在第1组中，置于受NH₃污染环境中的猪的肺重量以及肺重量与体重之比大于对照组，但在第2组中并非如此。在第1组和第2组中，对肺组织进行大体和组织病理学检查，结果显示对照组和主要对象之间通常没有差异。
