Instituto de Ganadería de Montaña (CSIC-Universidad de León), Finca Marzanas s/n, 24346 Grulleros, León, Spain.
J Dairy Sci. 2010 Jul;93(7):3275-86. doi: 10.3168/jds.2010-3101.
Rumen microbial biohydrogenation of dietary unsaturated fatty acids has a major effect on the process of developing healthier dairy products. This study aimed to investigate in vivo the effect of diet supplementation with sunflower (SO) and fish (FO) oils on the rumen bacterial community in dairy sheep. First, 32 lactating ewes, divided in 8 lots of 4 animals each (2 lots per treatment), were fed a high-concentrate total mixed ration supplemented with 0, 2% SO, 1% FO, or 2% SO plus 1% FO. After 21 d, rumen fluid samples were taken from each lot for DNA extraction and fluorescence in situ hybridization (FISH) analysis. In a second experiment, 5 cannulated ewes were first fed the same TMR, with the exception of a higher forage level, and then changed to the same diet supplemented with 2% SO plus 1% FO. After 0, 3, and 10 d, rumen content samples were taken for DNA extraction and FISH analysis (fluid). Total bacteria and the Butyrivibrio group were studied in microbial DNA by terminal RFLP analysis (T-RFLP), and real-time PCR was used to quantify Butyrivibrio bacteria that produce vaccenic acid or stearic acid. In rumen fluid samples, total bacteria and clostridial clusters IX and XIV were analyzed by FISH. Dietary supplementation with SO plus FO seemed to induce important changes in the total bacteria and Butyrivibrio populations, and a high interindividual variation was observed, and the speed of the effect of the lipid supplementation depended on the individual microbial composition. Analysis by T-RFLP and FISH showed increases in cluster IX bacteria with SO plus FO supplementation, presumably Quinella-like microorganisms. The abundances of vaccenic acid- and stearic acid-producing Butyrivibrio relative to total bacteria, estimated by real time PCR, were low (0.28 and 0.18%, respectively, in rumen fluid, and 0.86 and 0.81% in rumen contents) and only that of SA-producing bacteria seemed to be reduced by diets containing FO, although differences were only significant in lactating ewes. The T-RFLP analysis showed a variable effect of lipid supplementation on different bacteria of the family Lachnospiraceae, which includes the cultured bacteria known to be actively involved in rumen biohydrogenation. These results suggest that the latter bacteria do not play a dominant role in this process, and therefore other as-yet-uncultivated microorganisms might be more relevant.
日粮不饱和脂肪酸的瘤胃生物氢化作用对开发更健康乳制品的过程有重大影响。本研究旨在体内研究日粮添加葵花籽油（SO）和鱼油（FO）对绵羊瘤胃细菌群落的影响。首先，将 32 只泌乳母羊分为 8 组，每组 4 只（每组 2 个处理），饲喂高浓缩全混合日粮，并添加 0、2%SO、1%FO 或 2%SO+1%FO。21 天后，从每组采集瘤胃液样品进行 DNA 提取和荧光原位杂交（FISH）分析。在第二项实验中，首先用相同的 TMR 饲喂 5 只套管绵羊，但饲料中的纤维含量更高，然后改用添加 2%SO+1%FO 的相同日粮。在 0、3 和 10 d 时，采集瘤胃内容物样品进行 DNA 提取和 FISH 分析（液体）。用末端限制性片段长度多态性分析（T-RFLP）研究微生物 DNA 中的总细菌和丁酸弧菌组，并用实时 PCR 定量产生瘤胃酸和硬脂酸的丁酸弧菌。在瘤胃液样品中，用 FISH 分析总细菌和梭菌簇 IX 和 XIV。SO+FO 日粮添加似乎诱导总细菌和丁酸弧菌种群发生重大变化，个体间存在很大差异，脂质添加的效果速度取决于个体微生物组成。T-RFLP 和 FISH 分析表明，添加 SO+FO 后簇 IX 细菌增加，可能是类似于 Quinella 的微生物。用实时 PCR 估计，瘤胃液中瘤胃酸和硬脂酸产生菌相对于总细菌的丰度较低（分别为 0.28%和 0.18%），只有 FO 日粮中 SA 产生菌的丰度似乎降低，尽管差异仅在泌乳母羊中显著。T-RFLP 分析显示，脂质添加对lachnospiraceae 科的不同细菌有不同的影响，该科包括已知在瘤胃生物氢化中积极参与的培养细菌。这些结果表明，后者细菌在这个过程中没有起主导作用，因此可能有其他尚未培养的微生物更为相关。
