Core Microbiome of Slovak Holstein Friesian Breeding Bulls’ Semen

Abstract

Bacterial contamination of semen is an important factor connected to the health status of bulls that may significantly affect semen quality for artificial insemination. Moreover, some important bovine diseases may be transmitted through semen. Up to now, only a very limited number of complex studies describing the semen microbiome of bulls have been published, as many bacteria are hard to cultivate using traditional techniques. The 16S rRNA high-throughput sequencing strategy allows for the reliable identification of bacterial profiles of bovine semen together with the detection of noncultivable bacterial species. Fresh samples from Holstein Friesian breeding bulls (n = 55) were examined for the natural variability in the present bacteria. Semen doses were selected randomly from Slovak Biological Services in Nitra, Slovak Republic. The most predominant phyla within the whole dataset were Firmicutes (31%), Proteobacteria (22%), Fusobacteria (18%), Actinobacteria (13%) and Bacteroidetes (12%). Samples of semen were divided into two separate clusters according to their microbiome compositions using a cording partition around a medoids analysis. Microbiomes of the first cluster (CL1) of samples (n = 20) were based on Actinobacteria (CL1 average = 25%; CL = 28%) and Firmicutes (CL1 = 38%; CL2 = 27%), while the second cluster (CL2; n = 35) contained samples characterized by a high prevalence of Fusobacteria (CL1 = 4%; CL2 = 26%). Some important indicator microbial groups were differentially distributed between the clusters.

Identification of bull semen microbiota and possible alternatives for antibiotics in semen extenders

“…The five phyla present in each season in the present study (Actinobacteria, Bacteriodetes, Firmicutes, Fusobacteria, and Proteobacteria) were also identified in the prepuce (Wickware et al 2020) and semen samples (Medo et al 2021) of healthy bulls in various countries, as well as in human seminal plasma (Yang et al 2020). These findings led us to conclude that the seminal microbiota is not specific to geographic areas in bulls and, at the same time, raises the question of interspecies similarity in semen microbiota.…”

Mammals’ sperm microbiome: current knowledge, challenges, and perspectives on metagenomics of seminal samples

“…In addition, two significant groups of individuals were observed; the first group’s microbiome was based on Actinobacteria and Firmicutes , while the second group had a high prevalence of Fusobacteria . Therefore, there is individual variability between different bulls, so the influence of those microbial patterns on sperm quality must be studied ( Medo et al, 2021 ). The bacterial composition of semen from bulls with satisfactory (S) or unsatisfactory (U) semen quality, represented by poor sperm motility and/or morphology, was recently evaluated to determine whether the diversity and composition of the microbiota may be associated with decreased semen quality.…”

Seminal and vagino-uterine microbiome and their individual and interactive effects on cattle fertility

“…These authors also identified two distinct microbial clusters which were enriched either by phyla Actinobacteria and Firmicutes or by Fusobacteria. The most relatively abundant bacterial genera present in the dairy bull semen were Fusobacterium, Actinobacillus, Bacteroides, Cutibacerium, Staphylococcus, and Prevotella (Medo et al, 2021).…”

“…In addition to beef bulls, microbial composition and community structure of dairy bull semen has recently been characterized. Medo and colleagues characterized the seminal microbiota of 55 Holstein-Friesian bulls using 16S rRNA gene sequencing ( Medo et al, 2021 ; Table 1 ). These authors also identified two distinct microbial clusters which were enriched either by phyla Actinobacteria and Firmicutes or by Fusobacteria.…”

“…These authors also identified two distinct microbial clusters which were enriched either by phyla Actinobacteria and Firmicutes or by Fusobacteria. The most relatively abundant bacterial genera present in the dairy bull semen were Fusobacterium , Actinobacillus , Bacteroides , Cutibacerium , Staphylococcus , and Prevotella ( Medo et al, 2021 ). Likewise, a research team in Sweden reported that Holstein bulls (3–10 years old) harbored greater abundance of seminal bacterial genera Porphyromonas , Fusobacterium , and Ruminococcaceae ( Cojkic et al, 2021 ).…”