Choi Youyoung, Lee Shin Ja, Kim Hyun Sang, Eom Jun Sik, Jo Seong Uk, Guan Le Luo, Seo Jakyeom, Park Tansol, Lee Yookyung, Lee Sang Suk, Lee Sung Sill
Division of Applied Life Science (BK21), Gyeongsang National University, Jinju, Republic of Korea.
Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, Republic of Korea.
Front Vet Sci. 2023 May 18;10:1168237. doi: 10.3389/fvets.2023.1168237. eCollection 2023.
This study aimed to investigate cone essential oil (PEO) as a methane (CH) inhibitor and determine its impact on the taxonomic and functional characteristics of the rumen microbiota in goats. A total of 10 growing Korean native goats (, 29.9 ± 1.58 kg, male) were assigned to different dietary treatments: control (CON; basal diet without additive) and PEO (basal diet +1 g/d of PEO) by a 2 × 2 crossover design. Methane measurements were conducted every 4 consecutive days for 17-20 days using a laser CH detector. Samples of rumen fluid and feces were collected during each experimental period to evaluate the biological effects and dry matter (DM) digestibility after PEO oral administration. The rumen microbiota was analyzed via 16S rRNA gene amplicon sequencing. The PEO oral administration resulted in reduced CH emission (eructation CH/body weight, = 0.079) without affecting DM intake; however, it lowered the total volatile fatty acids ( = 0.041), molar proportion of propionate ( = 0.075), and ammonia nitrogen ( = 0.087) in the rumen. Blood metabolites (i.e., albumin, alanine transaminase/serum glutamic pyruvate transaminase, creatinine, and triglyceride) were significantly affected ( < 0.05) by PEO oral administration. The absolute fungal abundance ( = 0.009) was reduced by PEO oral administration, whereas ciliate protozoa, total bacteria, and methanogen abundance were not affected. The composition of rumen prokaryotic microbiota was altered by PEO oral administration with lower evenness ( = 0.054) observed for the PEO group than the CON group. Moreover, PICRUSt2 analysis revealed that the metabolic pathways of prokaryotic bacteria, such as pyruvate metabolism, were enriched in the PEO group. We also identified the Rikenellaceae RC9 gut group as the taxa potentially contributing to the enriched KEGG modules for histidine biosynthesis and pyruvate oxidation in the rumen of the PEO group using the FishTaco analysis. The entire co-occurrence networks showed that more nodes and edges were detected in the PEO group. Overall, these findings provide an understanding of how PEO oral administration affects CH emission and rumen prokaryotic microbiota composition and function. This study may help develop potential manipulation strategies to find new essential oils to mitigate enteric CH emissions from ruminants.
本研究旨在探究松果精油（PEO）作为一种甲烷（CH）抑制剂，并确定其对山羊瘤胃微生物群的分类和功能特征的影响。总共10只生长中的韩国本土山羊（体重29.9±1.58千克，雄性）被分配到不同的饮食处理组：对照组（CON；无添加剂的基础日粮）和PEO组（基础日粮+1克/天的PEO），采用2×2交叉设计。使用激光CH检测仪，每连续4天进行17至20天的甲烷测量。在每个实验期间收集瘤胃液和粪便样本，以评估PEO口服给药后的生物学效应和干物质（DM）消化率。通过16S rRNA基因扩增子测序分析瘤胃微生物群。PEO口服给药导致CH排放减少（嗳气CH/体重，P = 0.079），且不影响DM摄入量；然而，它降低了瘤胃中总挥发性脂肪酸（P = 0.041）、丙酸摩尔比例（P = 0.075）和氨氮（P = 0.087）。PEO口服给药显著影响血液代谢物（即白蛋白、丙氨酸转氨酶/血清谷丙转氨酶、肌酐和甘油三酯）（P < 0.05）。PEO口服给药降低了绝对真菌丰度（P = 0.009），而纤毛虫原生动物、总细菌和产甲烷菌丰度未受影响。PEO口服给药改变了瘤胃原核微生物群的组成，PEO组的均匀度低于CON组（P = 0.054）。此外，PICRUSt2分析表明，PEO组中丙酮酸代谢等原核细菌的代谢途径得到了富集。我们还使用FishTaco分析确定了Rikenellaceae RC9肠道菌群是可能导致PEO组瘤胃中组氨酸生物合成和丙酮酸氧化的KEGG模块富集的分类群。整个共现网络显示，PEO组中检测到更多的节点和边。总体而言，这些发现有助于理解PEO口服给药如何影响CH排放以及瘤胃原核微生物群的组成和功能。本研究可能有助于制定潜在的调控策略，以寻找新的精油来减少反刍动物的肠道CH排放。
