在这项研究中,我们评估了饲喂普通饮食以达到中等(1.13kg/天)或较高(1.80kg/天)体重增加率的一岁牛肉公牛的精液和粪便微生物群.在饮食干预的第0天和第112天(n=19/组)以及使用电射精的繁殖后(n=6/组)收集精液样本,使用16SrRNA基因测序评估微生物群,定量PCR(qPCR),和培养。还评估了粪便微生物群,并评估其与精液微生物群的相似性。筛选了一个精矿细菌分离株(n=33)对28种抗生素的耐药性。在牛精液中检测到复杂而动态的微生物群,群落结构受采样时间的影响(R2=0.16,P<0.001)。选育后第0天至第112天微生物丰富度显著增加,多样性增加(P>0.05)。精液微生物群不受不同增重率的影响,它的整体组成与粪便微生物群不同,它们之间只有6%的类群共享。在需氧和厌氧培养下,共回收了来自49个不同属的364个分离株。在这些精液分离株中,有致病性物种和对几种抗生素具有抗性的物种。总的来说,我们的研究结果表明,牛精液含有丰富而复杂的微生物群,该微生物群随着时间和繁殖季节而变化,但似乎对通过普通饮食获得的不同收获具有抵抗力。精液微生物群与粪便微生物群不同,并具有潜在的致病性和抗生素抗性细菌。重要性来自人类和其他动物物种的越来越多的证据支持精液中共生微生物群的存在,并且这种精液微生物群可能不仅影响精子质量和生育能力,而且影响女性生殖。公牛的精液微生物群及其进化和塑造这个群落的因素,然而,在很大程度上仍未开发。在这项研究中,我们描述了一岁牛肉公牛的开创性微生物群及其对公牛年龄的反应,不同的体重增加,和交配活动。我们比较了精液和粪便微生物群之间的细菌组成,并评估了可培养的精液细菌的多样性及其耐药性。我们从测序中获得的结果,培养,和抗生素敏感性测试提供了有关分类组成的新信息,进化,以及影响一岁牛肉公牛开创性微生物群的因素。这些信息将作为进一步了解精液微生物组及其在牛的生殖健康和生育能力中的作用的重要依据。
In this study, we evaluated the seminal and fecal microbiota in yearling beef bulls fed a common diet to achieve moderate (1.13 kg/day) or high (1.80 kg/day) rates of weight gain. Semen samples were collected on days 0 and 112 of dietary intervention (n = 19/group) as well as postbreeding (n = 6/group) using electroejaculation, and the microbiota was assessed using 16S rRNA gene sequencing, quantitative PCR (qPCR), and
culturing. The fecal microbiota was also evaluated, and its similarity with seminal microbiota was assessed. A subset of seminal bacterial isolates (n = 33) was screened for resistance against 28 antibiotics. A complex and dynamic microbiota was detected in bovine semen, and the community structure was affected by sampling time (R2 = 0.16, P < 0.001). Microbial richness increased significantly from day 0 to day 112, and diversity increased after breeding (P > 0.05). Seminal microbiota remained unaffected by the differential rates of gain, and its overall composition was distinct from fecal microbiota, with only 6% of the taxa shared between them. A total of 364 isolates from 49 different genera were recovered under aerobic and anaerobic
culturing. Among these seminal isolates were pathogenic species and those resistant to several antibiotics. Overall, our results suggest that bovine semen harbors a rich and complex microbiota which changes over time and during the breeding season but appears to be resilient to differential gains achieved via a common diet. Seminal microbiota is distinct from the fecal microbiota and harbors potentially pathogenic and antibiotic-resistant bacterial species. IMPORTANCE Increasing evidence from human and other animal species supports the existence of a commensal microbiota in semen and that this seminal microbiota may influence not only sperm quality and fertility but also female reproduction. Seminal microbiota in bulls and its evolution and factors shaping this community, however, remain largely underexplored. In this study, we characterized the seminal microbiota of yearling beef bulls and its response to the bull age, different weight gains, and mating activity. We compared bacterial composition between seminal and fecal microbiota and evaluated the diversity of culturable seminal bacteria and their antimicrobial resistance. Our results obtained from sequencing,
culturing, and antibiotic susceptibility testing provide novel information on the taxonomic composition, evolution, and factors shaping the seminal microbiota of yearling beef bulls. This information will serve as an important basis for further understanding of the seminal microbiome and its involvement in reproductive health and fertility in cattle.