Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen, 40002, Thailand.
Department of Animal Science, Faculty of Natural Resources, Rajamangala University of Technology Isan, Sakon Nakhon, 47160, Thailand.
Sci Rep. 2023 Aug 14;13(1):13176. doi: 10.1038/s41598-023-40488-9.
Cyanogenic glycosides in forage species and the possibility of cyanide (CN) poisoning can have undesirable effects on ruminants. The literature estimates that unknown rumen bacteria with rhodanese activity are key factors in the animal detoxification of cyanogenic glycosides, as they are capable of transforming CN into the less toxic thiocyanate. Therefore, identifying these bacteria will enhance our understanding of how to improve animal health with this natural CN detoxification process. In this study, a rhodanese activity screening assay revealed 6 of 44 candidate rumen bacterial strains isolated from domestic buffalo, dairy cattle, and beef cattle, each with a different colony morphology. These strains were identified as belonging to the species Enterococcus faecium and E. gallinarum by 16S ribosomal DNA sequence analysis. A CN-thiocyanate transformation assay showed that the thiocyanate formation capacity of the strains after a 12 h incubation ranged from 4.42 to 25.49 mg hydrogen CN equivalent/L. In addition, thiocyanate degradation resulted in the production of ammonia nitrogen and acetic acid in different strains. This study showed that certain strains of enterococci substantially contribute to CN metabolism in ruminants. Our results may serve as a starting point for research aimed at improving ruminant production systems in relation to CN metabolism.
饲料作物中的氰苷和氰化物（CN）中毒的可能性会对反刍动物产生不良影响。文献估计，具有硫氰酸酶活性的未知瘤胃细菌是动物氰苷解毒的关键因素，因为它们能够将 CN 转化为毒性较小的硫氰酸盐。因此，鉴定这些细菌将有助于我们了解如何利用这种天然的 CN 解毒过程来改善动物健康。在这项研究中，一种硫氰酸酶活性筛选测定法揭示了从家养水牛、奶牛和肉牛中分离出的 44 株候选瘤胃细菌中有 6 株具有不同的菌落形态。通过 16S 核糖体 DNA 序列分析，这些菌株被鉴定为屎肠球菌和鸡肠球菌。CN-硫氰酸盐转化测定表明，在 12 小时孵育后，菌株的硫氰酸盐形成能力范围为 4.42 至 25.49mg 氢 CN 当量/L。此外，硫氰酸盐降解导致不同菌株产生氨氮和乙酸。这项研究表明，某些肠球菌菌株对反刍动物的 CN 代谢有很大贡献。我们的研究结果可能为研究如何改善与 CN 代谢有关的反刍动物生产系统提供起点。
