Zhao Y, Zhao D, Ma H, Liu K, Atilgan A, Xin H
Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, USA.
Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, USA; Department of Mechanical Engineering, Nanjing Institute of Industry Technology, Nanjing, China.
Poult Sci. 2016 Jul 1;95(7):1473-1481. doi: 10.3382/ps/pew053. Epub 2016 Mar 18.
Airborne microorganism level is an important indoor air quality indicator, yet it has not been well documented for laying-hen houses in the United States. As a part of the Coalition for Sustainable Egg Supply (CSES) environmental monitoring project, this study comparatively monitored the concentrations and emissions of airborne total and Gram-negative (Gram(-)) bacteria in three types of commercial laying-hen houses, i.e., conventional cage (CC), aviary (AV), and enriched colony (EC) houses, over a period of eight months covering the mid and late stages of the flock cycle. It also delineated the relationship between airborne total bacteria and particulate matter smaller than 10 μm in aerodynamic diameter (PM10). The results showed airborne total bacteria concentrations (log CFU/m(3)) of 4.7 ± 0.3 in CC, 6.0 ± 0.8 in AV, and 4.8 ± 0.3 in EC, all being higher than the level recommended for human environment (3.0 log CFU/m(3)). The much higher concentrations in AV arose from the presence of floor litter and hen activities on it, as evidenced by the higher concentrations in the afternoon (with litter access) than in the morning (without litter access). The overall means and standard deviation of airborne total bacteria emission rates, in log CFU/[h-hen] (or log CFU/[h-AU], AU = animal unit or 500 kg live weight) were 4.8 ± 0.4 (or 7.3 ± 0.4) for CC, 6.1 ± 0.7 (or 8.6 ± 0.7) for AV, and 4.8 ± 0.5 (or 7.3 ± 0.5) for EC. Both concentration and emission rate of airborne total bacteria were positively related to PM10 Gram(-) bacteria were present at low concentrations in all houses; and only 2 samples (6%) in CC, 7 (22%) samples in AV, and 2 (6%) samples in EC out of 32 air samples collected in each house were found positive with Gram(-) bacteria. The concentration of airborne Gram(-) bacteria was estimated to be <2% of the total bacteria. Total bacteria counts in manure on belt (in all houses) and floor litter (only in AV) were similar; however, the manure had much more Gram(-) bacteria than the litter. The results point out the need to mitigate airborne total bacteria in laying-hen houses, especially in AV houses.
空气传播微生物水平是室内空气质量的一项重要指标，但在美国蛋鸡舍中的相关记录并不完善。作为可持续鸡蛋供应联盟（CSES）环境监测项目的一部分，本研究在蛋鸡养殖周期的中后期，对三种类型的商业蛋鸡舍，即传统笼养（CC）、开放式鸡舍（AV）和富集式鸡群饲养舍（EC），进行了为期八个月的空气传播总细菌和革兰氏阴性（Gram(-)）细菌浓度及排放的对比监测。研究还描绘了空气传播总细菌与空气动力学直径小于10μm的颗粒物（PM10）之间的关系。结果显示，CC舍中空气传播总细菌浓度（log CFU/m³）为4.7±0.3，AV舍为6.0±0.8，EC舍为4.8±0.3，均高于人类环境推荐水平（3.0 log CFU/m³）。AV舍中浓度高得多是因为有垫料以及母鸡在上面活动，下午（有垫料接触）的浓度高于上午（无垫料接触）就证明了这一点。空气传播总细菌排放率的总体均值和标准差，以log CFU/[h·只鸡]（或log CFU/[h·动物单位]，动物单位或500 kg活重）计，CC舍为4.8±0.4（或7.3±0.4），AV舍为6.1±0.7（或8.6±0.7），EC舍为4.8±0.5（或7.3±0.5）。空气传播总细菌的浓度和排放率均与PM10呈正相关。所有鸡舍中Gram(-)细菌的浓度都很低；在每个鸡舍采集的32个空气样本中，CC舍只有2个样本（6%）、AV舍有7个样本（22%）、EC舍有2个样本（6%）检测出Gram(-)细菌呈阳性。空气传播Gram(-)细菌的浓度估计不到总细菌的2%。传送带粪便（所有鸡舍）和垫料（仅AV舍）中的总细菌计数相似；然而，粪便中的Gram(-)细菌比垫料中的多得多。研究结果指出，有必要降低蛋鸡舍中空气传播总细菌的含量，尤其是AV舍。
