Li Xuan, Mu Chunlong, Wu Haiqin, Zoetendal Erwin G, Huang Ruihua, Yu Kaifan, Zhu Weiyun
Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science & Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
ISME Commun. 2025 Mar 9;5(1):ycaf043. doi: 10.1093/ismeco/ycaf043. eCollection 2025 Jan.
Dietary fiber is widely recognized for its benefits to human health. Individual variations in the ability to degrade dietary fiber are influenced by the gut microbiome that may be associated with the host's metabolic phenotype and genetic diversity. This is exemplified by the distinct fiber digestibility observed in obese (e.g. Meishan) and lean-breed (e.g. Yorkshire) pigs. However, the underlying mechanisms remain unclear. The present study found that with the same diet under the same environment, the obese-type Meishan pigs showed greater dietary fiber digestibility and harbored higher abundances of polysaccharide-degrading bacteria (, , and ) compared to lean-type Yorkshire pigs. Metatranscriptomic profiling revealed that the elevated presence of contributed to the enrichment of carbohydrate-active enzymes, particularly those degrading arabinoxylan, indicating a preference for arabinoxylan as a substrate in Meishan pigs. Further enzymatic-product measurements, combined with microbial enzyme profiles, validated greater microbial conversion of xylose into short-chain fatty acids (SCFAs) in Meishan pigs. Additionally, higher abundances of hydrogenotrophic microbes ( and ) were detected in the Meishan gut, along with the enrichment of methanogenesis and acetogenesis pathways. To determine whether methanogenesis drives inter-breed variation in arabinoxylan degradation, an experiment using the methanogen inhibitor, 2-bromoethanesulfonate (BES) was performed. The results confirmed that Meishan gut microbiome effectively reduced hydrogen accumulation through methanogenesis, promoting arabinoxylan degradation. Conversely, inhibiting methanogenesis by BES led to hydrogen accumulation, reduced SCFAs, β-xylosidase activity, and abundances. These findings demonstrate that the Meishan pigs have a superior ability of dietary fiber utilization with greater microbial conversion to more SCFAs, which is linked to stronger hydrogenotrophic methanogenesis. This study reinforces the role of gut microbial hydrogenotrophy in dietary fiber utilization in pigs.
膳食纤维因其对人体健康有益而被广泛认可。膳食纤维降解能力的个体差异受肠道微生物群影响，而肠道微生物群可能与宿主的代谢表型和遗传多样性有关。肥胖型（如梅山猪）和瘦肉型（如约克夏猪）猪之间明显的纤维消化率差异就例证了这一点。然而，其潜在机制仍不清楚。本研究发现，在相同环境下采用相同饮食时，与瘦肉型约克夏猪相比，肥胖型梅山猪表现出更高的膳食纤维消化率，且多糖降解菌（[具体菌种1]、[具体菌种2]和[具体菌种3]）的丰度更高。宏转录组分析表明，[具体菌种]的增加导致碳水化合物活性酶的富集，尤其是那些降解阿拉伯木聚糖的酶，这表明梅山猪偏好以阿拉伯木聚糖为底物。进一步的酶产物测量结合微生物酶谱，证实了梅山猪中微生物将木糖转化为短链脂肪酸（SCFA）的能力更强。此外，在梅山猪肠道中检测到更高丰度的氢营养微生物（[具体菌种1]和[具体菌种2]），同时甲烷生成和乙酸生成途径也得到了富集。为了确定甲烷生成是否驱动品种间阿拉伯木聚糖降解的差异，进行了一项使用产甲烷抑制剂2-溴乙烷磺酸盐（BES）的实验。结果证实，梅山猪的肠道微生物群通过甲烷生成有效地减少了氢气积累，促进了阿拉伯木聚糖的降解。相反，用BES抑制甲烷生成会导致氢气积累、SCFA减少、β-木糖苷酶活性降低以及[具体菌种]丰度降低。这些发现表明，梅山猪具有卓越的膳食纤维利用能力，能通过微生物将更多的膳食纤维转化为更多的SCFA，这与更强的氢营养型甲烷生成有关。本研究强化了肠道微生物氢营养在猪膳食纤维利用中的作用。
