摘要
In our previous studies, we revealed the effect of lactose inclusion in calf starters on the growth performance and gut development of calves. We conducted the present study as a follow-up study to identify the shift in rumen microbiota and its relation to rumen fermentation when calves are fed a lactose-containing starter. Thirty Holstein bull calves were divided into 2 calf starter treatment groups: texturized calf starter (i.e., control; n = 15) or calf starter in which starch was replaced with lactose at 10% (i.e., LAC10; n = 15) on a dry matter basis. All calves were fed their respective treatment calf starter ad libitum from d 7, and kleingrass hay from d 35. Rumen digesta were collected on d 80 (i.e., 3 wk after weaning) and used to analyze rumen microbiota and fermentation products. There was no apparent effect of lactose feeding on the α-diversity and overall composition of rumen microbiota. Amplicon sequencing and real-time PCR quantification of the 16S rRNA gene confirmed that the abundance of butyrate-producing bacteria (i.e., Butyrivibrio group and Megasphaera elsdenii) did not differ between the control and LAC10 groups. Conversely, the relative abundance of Mitsuokella spp., which produce lactate, succinate, and acetate, was significantly higher in the rumen of calves that were fed lactose, whereas the lactate concentration did not differ between the control and LAC10 groups. These findings suggest that the lactate production can be elevated by an increase of Mitsuokella spp. and then converted into butyrate, not propionate, since the proportion of propionate was lower in lactose-fed calves. In addition, we observed a higher abundance of Coriobacteriaceae and Pseudoramibacter-Eubacterium in the LAC10 group. Both these bacterial taxa include acetate-producing bacteria, and a positive correlation between the acetate-to-propionate ratio and the abundance of Pseudoramibacter-Eubacterium was observed. Therefore, the higher abundance of Coriobacteriaceae, Mitsuokella spp., and Pseudoramibacter-Eubacterium in the rumen of lactose-fed calves partially explains the increase in the proportion of rumen acetate that was observed in our previous study.
摘要译文
在我们以前的研究中，我们揭示了小牛初学者乳糖包容对小牛的生长性能和肠道发育的影响。我们将本研究作为随访研究，以确定瘤胃微生物的转变及其与瘤胃发酵时的关系，当牛犊喂养含乳糖的起动器时。将三十罗斯坦公牛小牛分为2只小牛起动器治疗组：纹理小牛起动器（即控制; n = 15）或小牛起动器，其中淀粉以10％（即lac10; n = 15）在干燥上替换乳糖基础。将所有小牛喂养它们各自的治疗小牛起动器AD Libitum，来自D 35的克莱林斯干草。在D 80（即断奶后3周）上收集瘤胃凹口，并用于分析瘤胃微生物和发酵产物。乳糖喂养对瘤胃微生物的α-多样性和整体组成的明显效果。 16S rRNA基因的扩增子测序和实时PCR定量证实，对照和LAC10组之间没有差异的丁酸盐产生的细菌（即抑制基团和Megasphaera Elsdenii）的丰富。相反，在乳糖的乳汁中瘤胃瘤胃中产生乳酸，琥珀酸和醋酸乳酸的相对丰度，其产生乳酸盐，琥珀酸盐和醋酸盐，而乳酸浓度在对照和LAC10基团之间没有区别。这些研究结果表明，乳酸盐产生可以通过增加Mitsuokella SPP来提高。然后转化为丁酸盐，而不是丙酸盐，因为丙酸盐的比例在乳糖喂食中较低。此外，我们观察到LAC10组中较高丰富的岩杆菌和伪敏杆菌。这两种细菌分类群都包括产生醋酸醋酸盐的细菌，并且观察到乙酸乙酯与丙酸盐比之间的正相关性和伪敏衡术的阳性相关性。因此，乳糖乳酸瘤胃中的粘菌菌较高丰度，乳糖乳汁瘤胃中的伪敏杆菌部分地解释了我们以前的研究中观察到的瘤胃醋酸盐比例的增加。
S. Koike[1];M. Ueno[1];H. Miura[1];A. Saegusa[2];K. Inouchi[2];Y. Inabu[3]†T. Sugino[3];L.L. Guan[4];M. Oba[4];Y. Kobayashi[1]. Rumen microbiota and its relation to fermentation in lactose-fed calves[J]. Journal of Dairy Science, 2021,104(10): 10744-10752