Strom Noah, Ma Yiwei, Bi Zheting, Andersen Daniel, Trabue Steve, Chen Chi, Hu Bo
Department of Bioproducts and Biosystems Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
Department of Food Science and Nutrition, University of Minnesota, Minneapolis, Minnesota, USA.
J Appl Microbiol. 2022 Apr;132(4):2906-2924. doi: 10.1111/jam.15384. Epub 2021 Dec 7.
Swine manure foaming is a major problem, causing damage to property, livestock, and people. Here, we identified the main chemicals and microbes that contribute to foaming.
Foaming and non-foaming swine manure were sampled from farms in Iowa and Illinois. Targeted and untargeted metabolomics analyses identified chemical markers that differed between foaming and non-foaming manure and between manure layers. Microbial community analysis and metagenomics were performed on a subset of samples. Foam contained significantly higher levels of total bile acids and long chain fatty acids like palmitic, stearic and oleic acid than the other manure layers. Foam layers also had significantly higher levels of ubiquinone 9 and ubiquinone 10. The slurry layer of foaming samples contained more alanine, isoleucine/leucine, diacylglycerols (DG), phosphtatidylethanolamines, and vitamin K2, while ceramide was significantly increased in the slurry layer of non-foaming samples. Eubacterium coprostanoligenes and Methanoculleus were more abundant in foaming samples, and E. coprostanoligenes was significantly correlated with levels of DG. Genes involved in diacylglycerol biosynthesis and in the biosynthesis of branched-chain hydrophobic amino acids were overrepresented in foaming samples.
A mechanism for manure foaming is hypothesized in which proliferation of Methanoculleus leads to excessive production of methane, while production of DG by E. coprostanoligenes and hydrophobic proteins by Methanosphaera stadtmanae facilitates bubble formation and stabilization.
While some chemical and biological treatments have been developed to treat swine manure foaming, its causes remain unknown. We identified key microbes and metabolites that correlate with foaming and point to possible roles of other factors like animal feed.
猪粪发泡是一个主要问题，会对财产、牲畜和人员造成损害。在此，我们确定了导致发泡的主要化学物质和微生物。
从爱荷华州和伊利诺伊州的农场采集发泡和未发泡的猪粪样本。靶向和非靶向代谢组学分析确定了发泡和未发泡粪便之间以及粪便各层之间不同的化学标志物。对一部分样本进行了微生物群落分析和宏基因组学研究。泡沫中总胆汁酸以及棕榈酸、硬脂酸和油酸等长链脂肪酸的含量明显高于其他粪便层。泡沫层中泛醌9和泛醌10的含量也明显更高。发泡样本的浆液层含有更多的丙氨酸、异亮氨酸/亮氨酸、二酰基甘油（DG）、磷脂酰乙醇胺和维生素K2，而非发泡样本的浆液层中神经酰胺明显增加。在发泡样本中，产粪甾醇真杆菌和甲烷袋状菌更为丰富，且产粪甾醇真杆菌与DG水平显著相关。参与二酰基甘油生物合成和支链疏水氨基酸生物合成的基因在发泡样本中过度表达。
推测了粪便发泡的一种机制，即甲烷袋状菌的增殖导致甲烷过度产生，而产粪甾醇真杆菌产生的DG和史氏甲烷短杆菌产生的疏水蛋白促进了气泡的形成和稳定。
虽然已经开发了一些化学和生物处理方法来处理猪粪发泡问题，但其原因仍然未知。我们确定了与发泡相关的关键微生物和代谢物，并指出了动物饲料等其他因素的可能作用。
