Instituto de Medicina Preventiva Veterinaria, Universidad Austral de Chile, Valdivia, Chile.
Facultad de Ciencias Veterinarias, Escuela de Graduados, Universidad Austral de Chile, Valdivia, Chile.
J Appl Microbiol. 2019 Aug;127(2):370-378. doi: 10.1111/jam.14288. Epub 2019 Jun 17.
A major drawback of using dairy slurry as fertilizer is that it may contains pathogens such as Mycobacterium avium subsp. paratuberculosis (MAP), and it could represent a risk to animal and public health. Thus, the aim of this study was to evaluate the fate of MAP and bacterial communities in dairy slurry after chemical treatments.
Cattle slurry, naturally contaminated with MAP, was collected from a dairy herd and divided into 32 glass bottles which were assigned to eight different treatments (control, 3·0% CaO, 0·5% NaOH; 0·087%, 0·11% and 0·14% H SO ; and 1·0 and 2·5% KMnO ). Treated dairy slurry samples were evaluated at 0, 1, 3, 7, 15, 30 and 60-days following treatment application for viable MAP and dairy slurry pH, and in addition temperature in this material was monitored continuously. Bacterial counts were estimated at each sampling time. A Bayesian zero-inflated Poisson mixed model was fitted to assess the effect of each treatment on the count of MAP cells. Model results indicated that only the 3·0% CaO treatment had a statistically important negative effect on MAP counts during the study period. For most treatments, MAP was undetectable immediately after chemical treatment but re-appeared over time, in some replicates at low concentrations. However, in those cases MAP counts were not statistically different than the control treatment. Regarding the fate of the other bacterial populations, the Firmicutes phylum was the dominant population in the un-treated slurry while Clostridia class members were among the most prevalent bacteria after the application of most chemical treatments.
Only 3% CaO treatment had a statistically important negative effect on MAP viability in cattle slurry.
This study provides evidence of MAP partial control in dairy slurry. This information should be considered as a best management practice to reduce MAP and other pathogens for slurry management on dairy farms.
使用乳清作为肥料的一个主要缺点是它可能含有分枝杆菌副结核亚种（MAP）等病原体，这可能对动物和公共卫生构成风险。因此，本研究的目的是评估 MAP 和细菌群落在经过化学处理后的乳清中的命运。
从一个奶牛场采集了天然污染有 MAP 的牛乳清，并将其分为 32 个玻璃瓶，分配到 8 种不同的处理（对照、3.0%CaO、0.5%NaOH；0.087%、0.11%和 0.14%H 2 SO 4 ；以及 1.0%和 2.5%KMnO 4 ）。在处理后 0、1、3、7、15、30 和 60 天，对处理后的乳清样品进行了活的 MAP 和乳清 pH 值评估，此外，还连续监测了该材料中的温度。在每个采样时间估计了细菌计数。采用贝叶斯零膨胀泊松混合模型来评估每种处理方法对 MAP 细胞计数的影响。模型结果表明，只有 3.0%CaO 处理在研究期间对 MAP 计数有统计学上的显著负面影响。对于大多数处理方法，化学处理后立即无法检测到 MAP，但随着时间的推移，在某些复制品中，MAP 会重新出现，浓度较低。然而，在这些情况下，MAP 计数与对照处理没有统计学差异。关于其他细菌种群的命运，厚壁菌门在未经处理的乳清中是主要种群，而梭菌纲成员是大多数化学处理后最常见的细菌之一。
只有 3%CaO 处理对牛乳清中的 MAP 活力有统计学上的显著负面影响。
本研究提供了在奶牛乳清中控制 MAP 的部分证据。这些信息应被视为减少乳清中 MAP 和其他病原体的最佳管理实践，以用于奶牛场的乳清管理。
