The growth and morphology of rumen methanogenic archaea (15 strains of 10 species in 5 genera, including 7 strains newly isolated in the present study) and bacteria (14 species in 12 genera) were investigated using unsupplemented in vitro pure cultures and cultures supplemented with cashew nut shell liquid (CNSL) and its phenolic compound components, anti-methanogenic agents for ruminant animals. Growth of most of the methanogens tested was inhibited by CNSL and alkylphenols at different concentrations ranging from 1.56 to 12.5 μg/ml. Of the alkylphenols tested, anacardic acid exhibited the most potent growth inhibition. Three gram-negative bacterial species involved in propionate production were resistant to CNSL and alkylphenols (>50 μg/ml). All the methanogens and bacteria that were sensitive to CNSL and alkylphenols exhibited altered morphology; disruption of the cell surface was notable, possibly due to surfactant activity of the tested materials. Cells division was inhibited in some organisms, with cell elongation and unclear septum formation observed. These results indicate that CNSL and alkylphenols, particularly anacardic acid, inhibit both rumen bacteria and methanogens in a selective manner, which could help mitigate rumen methane generation.

中文翻译：

---

瘤胃产甲烷古菌和细菌对腰果壳液及其烷基酚成分的生长和形态学反应

使用未补充的体外纯培养物和补充腰果的培养物研究瘤胃产甲烷古菌（5属10种15株，包括本研究新分离的7株）和细菌（12属14种）的生长和形态坚果壳液（CNSL）及其酚类化合物成分，反刍动物用抗产甲烷剂。大多数测试的产甲烷菌的生长在 1.56 至 12.5 μg/ml 的不同浓度范围内受到 CNSL 和烷基酚的抑制。在测试的烷基酚中，漆树酸表现出最有效的生长抑制作用。参与丙酸盐生产的三种革兰氏阴性细菌对 CNSL 和烷基酚类 (>50 μg/ml) 具有抗性。所有对 CNSL 和烷基酚敏感的产甲烷菌和细菌都表现出形态改变；细胞表面的破坏是显着的，可能是由于测试材料的表面活性剂活性。一些生物体的细胞分裂受到抑制，观察到细胞伸长和不清晰的隔膜形成。这些结果表明，CNSL 和烷基酚，尤其是漆树酸，以选择性方式抑制瘤胃细菌和产甲烷菌，这有助于减轻瘤胃甲烷的产生。