Abstract：
Bovine reproduction, including male fertility traits like semen quality, are influenced by a variety of different factors like breed, nutrition, environment, and feeding management. Diet in a crucial determinant, and in this regard although corn silage is generally considered to be a favorable roughage for fattening meat type breeds, it tends to have a negative impact on semen quality. In the current study, alfalfa hay was substituted by corn silage as a roughage source in the diet of bulls to investigate its effects on the fertility of breeding bulls. A feeding trail spanning 140 days was conducted, with semen collection occurring twice a week commencing 60 days after the start of trial. Semen quality parameters, serum antioxidant indexes, sex hormone content in semen, rumen microflora, and sperm transcriptome were characterized. Feeding corn silage enhanced host antioxidant capacity, significantly decreased spermatozoal motility and increased sperm deformity rate in bulls. Furthermore, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) content in semen were significantly decreased (P < 0.05), and the inhibin B (INHB) content was significantly increased (P < 0.01). Feeding corn silage led to significant changes in the diversity of rumen microbiota of cattle at the phylum and genus levels, some of which were significantly correlated with semen quality. Subsequent RNA sequencing indicated that DHH and PITHD1, two genes related to sperm and reproductive development, were differentially expressed, and enrichment analysis also identified several pathways and biological functions relevant to sperm development and reproduction. These results indicate that feeding corn silage modulates semen quality via different pathways. Firstly, corn silage metabolites likely affect the secretion of INHB through the testicular capillaries, which affects semen quality by regulating genes involved in spermatogenesis. Secondly, low lignin content in silage corn appears to reduce abundance of rumen flora that are positively correlated with semen quality. Overall, results indicate that feeding bulls corn silage as the primary source of forage could negatively impact semen quality and may not be appropriate as the primary roughage of forage for breeding bulls.
摘要：
牛繁殖,包括男性生育能力特征，如精液质量，受到各种不同因素的影响，比如品种，营养,环境,和喂养管理。饮食是一个至关重要的决定因素，在这方面，尽管玉米青贮饲料通常被认为是育肥肉类品种的有利粗饲料，它往往会对精液质量产生负面影响。在目前的研究中,苜蓿干草被玉米青贮代替，作为公牛日粮中的粗饲料来源，以研究其对种牛繁殖力的影响。进行了为期140天的喂食路线，从试验开始后60天开始，每周收集两次精液。精液质量参数,血清抗氧化指标，精液中的性激素含量,瘤胃微生物,和精子转录组进行了表征。饲喂玉米青贮增强了寄主的抗氧化能力,公牛精子活力显着降低，精子畸形率增加。此外，精液中卵泡刺激素(FSH)和黄体生成素(LH)含量显著降低(P<0.05),抑制素B(INHB)含量显著升高(P<0.01)。饲喂玉米青贮导致牛瘤胃微生物多样性在门和属水平上发生显著变化，其中一些与精液质量显著相关。随后的RNA测序表明DHH和PITHD1这两个与精子和生殖发育有关的基因,差异表达，和富集分析还确定了与精子发育和繁殖相关的几种途径和生物学功能。这些结果表明，饲喂玉米青贮通过不同的途径调节精液品质。首先,玉米青贮代谢物可能通过睾丸毛细血管影响INHB的分泌，通过调节参与精子发生的基因影响精液质量。其次,青贮玉米中木质素含量低似乎会降低瘤胃植物区系的丰度，这与精液品质呈正相关。总的来说,结果表明，饲喂公牛玉米青贮作为饲料的主要来源可能会对精液质量产生负面影响，并且可能不适合作为公牛育种的饲料的主要粗饲料。
