Agriculture and Agri-Food Canada, Morden Research and Development Centre, 101 Route 100, Morden, MB, R6M 1Y5, Canada.
Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, Canada.
Sci Rep. 2022 Dec 23;12(1):22233. doi: 10.1038/s41598-022-26201-2.
To reduce the transmission risk of bovine spongiform encephalopathy prions (PrP), specified risk materials (SRM) that can harbour PrP are prevented from entering the feed and food chains. As composting is one approach to disposing of SRM, we investigated the inactivation of PrP in lab-scale composters over 28 days and in bin composters over 106-120 days. Lab-scale composting was conducted using 45 kg of feedlot manure with and without chicken feathers. Based on protein misfolding cyclic amplification (PMCA), after 28 days of composting, PrP seeding activity was reduced by 3-4 log with feathers and 3 log without. Bin composters were constructed using ~ 2200 kg feedlot manure and repeated in 2017 and 2018. PMCA results showed that seeding activity of PrP was reduced by 1-2 log in the centre, but only by 1 log in the bottom of bin composters. Subsequent assessment by transgenic (Tgbov XV) mouse bioassay confirmed a similar reduction in PrP infectivity. Enrichment for proteolytic microorganisms through the addition of feathers to compost could enhance PrP degradation. In addition to temperature, other factors including varying concentrations of PrP and the nature of proteolytic microbial populations may be responsible for differential degradation of PrP during composting.
为了降低牛海绵状脑病朊病毒（PrP）的传播风险，规定的风险物质（SRM），这些物质可能携带 PrP，被防止进入饲料和食物链。由于堆肥是处理 SRM 的一种方法，我们研究了在实验室规模的堆肥器中经过 28 天和在桶式堆肥器中经过 106-120 天处理时 PrP 的失活情况。实验室规模的堆肥使用 45 公斤有和没有鸡毛的牧场粪肥进行。基于蛋白质错误折叠循环扩增（PMCA），在 28 天的堆肥后，添加羽毛的堆肥中 PrP 接种活性降低了 3-4 个对数级，而不添加羽毛的堆肥中降低了 3 个对数级。桶式堆肥器使用了大约 2200 公斤牧场粪肥，并在 2017 年和 2018 年重复进行。PMCA 结果表明，中心部位的 PrP 接种活性降低了 1-2 个对数级，但底部只降低了 1 个对数级。随后通过转（Tgbov XV）基因小鼠生物测定法评估证实了 PrP 感染性的类似降低。通过向堆肥中添加羽毛来富集蛋白酶微生物可能会增强 PrP 的降解。除了温度之外，其他因素，包括 PrP 的浓度变化和蛋白酶微生物群体的性质，可能是堆肥过程中 PrP 降解的差异原因。
