STUDY OF THE SPERM MICROBIOME OF BULLS USING METAGENOMIC ANALYSIS

Abstract

The study aimed to obtain information about the microbial communities in bull sperm, which is used for artificial insemination. The research included ten samples of cryopreserved bull sperm obtained from domestic breeding farms and 24 imported sperm samples. Next-generation sequencing technology on the Illumina Miseq platform was used for the analysis. Bioinformatics analysis was performed using the QIIME2 software package. The obtained whole-genome sequencing data showed a low level of biodiversity in the analysed samples. Diversity index values were determined for two groups of samples: sperm from domestic and foreign bulls. The Shannon index values were 1.40±0.12 and 1.30±0.08 for each group, respectively. Student's t-test calculations indicated no statistically significant differences in the α-biodiversity parameters between these groups. Up to 19 known bacterial types were detected in the samples, with only Proteobacteria, Firmicutes, Fusobacteria, Bacteroidetes, Actinobacteria, and Tenericutes present at frequencies exceeding 5%. Fusobacteria and Firmicutes dominated Russian bull sperm samples, while the predominant type in foreign bull sperm was Proteobacteria. Of the 18 detected bacterial classes, genetic material from 11 classes was found in at least one of the samples at a frequency exceeding 5%. Russian bull samples contained up to 13 genera of bacteria with genetic material above 1%, while foreign bull samples contained up to 15 genera. The predominant genus for domestic bull sperm samples was Fusobacterium, while for alien bull sperm, it was an unidentified genus of the Clostridiales order. The presence of representatives from the Campylobacter and Pseudomonas genera was also noted in the samples. Possible associations between the presence of specific bacterial taxa and morphofunctional indicators of bull sperm quality are discussed.