Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
Appl Microbiol Biotechnol. 2011 Jan;89(2):387-95. doi: 10.1007/s00253-010-2865-z. Epub 2010 Sep 24.
Linoleic acid was differentially catabolized by the various rumen microbial fractions, such as rumen bacteria (B), protozoa (P), and their mixture (BP). The predominant isomer of conjugated linoleic acids (CLA) synthesized by B, P, and BP from linoleic acid was 9c11t-CLA. The formation of 9c11t-CLA was higher (P < 0.05) in P suspension (53.6 μg/mg microbial nitrogen) compared with B (38.3 μg/mg microbial nitrogen) and BP (28.8 μg/mg microbial nitrogen) suspensions by 12 h of incubation. The second most abundant CLA isomer was 10t12c. The accumulation of 10t12c-CLA in BP suspension was 2.3 times lower (P < 0.05) than that in B suspension (84.8 μg/mg microbial nitrogen) by 12 h of incubation. The accumulation of 10t-18:1 in BP suspension during 6- and 12-h incubation periods were not different (P > 0.05) than that in B suspension (6.8 and 14.0 μg/mg microbial nitrogen, respectively). However, the accumulation of 11t-18:1 in BP suspension at 6- and 12-h incubations were 2.7 and 3.3 times higher (P < 0.05), respectively, than that in B suspension. There were no significant accumulations of 11t-18:1, 10t-18:1, and 18:0 in P suspension throughout the incubation period. It was concluded that B, P, and BP metabolized linoleic acid to different isomers of CLA, whereas B, including BP, was only capable of biohydrogenating the CLA isomers to 18:0 by the reduction of 18:1 isomers. P was incapable of biohydrogenating LA, but its association with B in the BP suspension altered the biohydrogenation of LA significantly compared with B alone.
亚油酸被不同的瘤胃微生物区系（如瘤胃细菌（B）、原生动物（P）及其混合物（BP））进行差异代谢。由 B、P 和 BP 从亚油酸合成的共轭亚油酸（CLA）的主要异构体是 9c11t-CLA。在 12 小时的孵育中，P 悬浮液（53.6 μg/mg 微生物氮）中合成的 9c11t-CLA 的形成高于 B（38.3 μg/mg 微生物氮）和 BP（28.8 μg/mg 微生物氮）悬浮液（P < 0.05）。第二丰富的 CLA 异构体是 10t12c。在 12 小时的孵育中，BP 悬浮液中 10t12c-CLA 的积累比 B 悬浮液（84.8 μg/mg 微生物氮）低 2.3 倍（P < 0.05）。在 6-12 小时的孵育期间，BP 悬浮液中 10t-18:1 的积累与 B 悬浮液（分别为 6.8 和 14.0 μg/mg 微生物氮）没有差异（P > 0.05）。然而，在 6-12 小时的孵育中，BP 悬浮液中 11t-18:1 的积累分别比 B 悬浮液高 2.7 和 3.3 倍（P < 0.05）。在整个孵育期间，P 悬浮液中没有显著积累 11t-18:1、10t-18:1 和 18:0。综上所述，B、P 和 BP 将亚油酸代谢为不同的 CLA 异构体，而 B，包括 BP，仅能通过将 18:1 异构体还原为 18:0 来生物氢化 CLA 异构体。P 不能生物氢化 LA，但与 B 一起存在于 BP 悬浮液中，与单独的 B 相比，显著改变了 LA 的生物氢化。
