Dietary fiber (DF) is often eschewed in swine diet due to its anti-nutritional effects, but DF is attracting growing attention for its reproductive benefits. The objective of this study was to investigate the effects of DF intake level on oocyte maturation and uterine development, to determine the optimal DF intake for gilts, and gain microbial and metabolomic insight into the underlying mechanisms involved. Seventy-six Landrace × Yorkshire (LY) crossbred replacement gilts of similar age (92.6 ± 0.6 d; mean ± standard deviation [SD]) and body weight (BW, 33.8 ± 3.9 kg; mean ± SD) were randomly allocated to 4 dietary treatment groups (n = 19); a basal diet without extra DF intake (DF 1.0), and 3 dietary groups ingesting an extra 50% (DF 1.5), 75% (DF 1.75), and 100% (DF 2.0) dietary fiber mixture consisting of inulin and cellulose (1:4). Oocyte maturation and uterine development were assessed on 19 d of the 2nd oestrous cycle. Microbial diversity of faecal samples was analysed by high-throughput pyrosequencing (16S rRNA) and blood samples were subjected to untargeted metabolomics. The rates of oocytes showing first polar bodies after in vitro maturation for 44 h and uterine development increased linearly with increasing DF intake; DF 1.75 gilts had a 19.8% faster oocyte maturation rate and a 48.9 cm longer uterus than DF 1.0 gilts (P < 0.05). Among the top 10 microbiota components at the phylum level, 8 increased linearly with increasing DF level, and the relative abundance of 30 of 53 microbiota components at the genus level (> 0.1%) increased linearly or quadratically with increasing DF intake. Untargeted metabolic analysis revealed significant changes in serum metabolites that were closely associated with microbiota, including serotonin, a gut-derived signal that stimulates oocyte maturation. The findings provide evidence of the benefits of increased DF intake by supplementing inulin and cellulose on oocyte maturation and uterine development in gilts, and new microbial and metabolomic insight into the mechanisms mediating the effects of DF on reproductive performance of replacement gilts.

中文翻译：

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介导日粮菊粉和纤维素补充剂对猪卵母细胞和子宫发育影响的微生物和代谢组学机制

膳食纤维 (DF) 由于其抗营养作用而在猪日粮中经常被避开，但 DF 因其生殖益处而受到越来越多的关注。本研究的目的是研究 DF 摄入水平对卵母细胞成熟和子宫发育的影响，以确定后备母猪的最佳 DF 摄入量，并获得微生物和代谢组学对所涉及的潜在机制的了解。76 只长白 × 约克郡 (LY) 杂交后备母猪的年龄相似（92.6 ± 0.6 日龄；平均值 ± 标准差 [SD]）和体重（体重，33.8 ± 3.9 公斤；平均值 ± SD）被随机分配到 4 个日粮治疗组（n = 19）；没有额外摄入 DF 的基础饮食 (DF 1.0)，以及 3 个饮食组摄入额外的 50% (DF 1.5)、75% (DF 1.75) 和 100% (DF 2.0) 由菊粉和纤维素组成的膳食纤维混合物 (1 :4)。在第 2 个发情周期的第 19 天评估卵母细胞成熟和子宫发育。通过高通量焦磷酸测序 (16S rRNA) 分析粪便样本的微生物多样性，并对血液样本进行非靶向代谢组学。体外成熟 44 h 和子宫发育后，卵母细胞出现第一极体的比率随着 DF 摄入量的增加呈线性增加；DF 1.75 后备母猪的卵母细胞成熟率快 19.8%，子宫比 DF 1.0 后备母猪长 48.9 cm（P < 0.05）。在门水平的前 10 个微生物群组分中，8 个随着 DF 水平的增加而线性增加，并且在属水平的 53 个微生物群组分中的 30 个（> 0.1%）的相对丰度随着 DF 摄入量的增加而线性或二次增加。非靶向代谢分析揭示了与微生物群密切相关的血清代谢物的显着变化，包括血清素，一种刺激卵母细胞成熟的肠道衍生信号。这些发现提供了证据，证明通过补充菊粉和纤维素增加 DF 摄入量对母猪卵母细胞成熟和子宫发育的益处，以及对介导 DF 对后备后备母猪繁殖性能影响的机制的微生物和代谢组学新见解。