Higher abundance of DLD protein in buffalo bull spermatozoa causes elevated ROS production leading to early sperm capacitation and reduction in fertilizing ability

Lectin based differential profiling of sperm membrane glycans for assessment of buffalo (Bubalus bubalis) bull fertility

Spermatozoa membrane glycocalyx plays a crucial role in sperm functions, including maturation, female reproductive tract protection, oviductal epithelium adhesion, and oocyte fusion. This study investigated differences in glycan abundance and mapping in buffalo spermatozoa from high-fertile (HF) and low-fertile (LF) bulls. Semen samples were analyzed for motility, vitality, morphology, and functional characteristics before glycan profiling. Utilizing group of nine different lectins through cytochemistry and flow cytometry analyses we identified differentially abundant glycans (DAGs) on sperm membrane. HF bulls exhibited superior sperm quality and significantly higher glycan abundance than LF bulls. MAL-II (Maackia amurensis lectin II) depicted stronger binding affinity with HF sperm indicating a higher presence of α-2,3-linked sialic acid residues crucial for sperm function. JAC (Artocarpus integrifolia) binding revealed an abundance of N-acetylgalactosamine, while ABL (Agaricus bisporus lectin) indicated greater mannose-containing glycoconjugates in HF sperm. The glycan map of buffalo spermatozoa underscores a higher abundance of α-2,3-linked sialic acids and acetylgalactosamine in HF sperm, highlighting the potential role of glycan profiling as a screening tool for selecting highly fertile bulls. The findings of this study can pave the way to develop a fertility prediction tool as a rapid lab-on-strip device for enhancing the reproductive and breeding performance of buffalo bulls.

Insights into Adaption and Growth Evolution: Genome-Wide Copy Number Variation Analysis in Chinese Hainan Yellow Cattle Using Whole-Genome Re-Sequencing Data

Copy number variation (CNV) serves as a crucial source of genomic variation and significantly aids in the mining of genomic information in cattle. This study aims to analyze re-sequencing data from Chinese Hainan yellow cattle, to uncover breed CNV information, and to elucidate the resources of population genetic variation. We conducted whole-genome sequencing on 30 Chinese Hainan yellow cattle, thus generating 814.50 Gb of raw data. CNVs were called using CNVnator software, and subsequent filtering with Plink and HandyCNV yielded 197,434 high-quality CNVs and 5852 CNV regions (CNVRs). Notably, the proportion of deleted sequences (81.98%) exceeded that of duplicated sequences (18.02%), with the lengths of CNVs predominantly ranging between 20 and 500 Kb This distribution demonstrated a decrease in CNVR count with increasing fragment length. Furthermore, an analysis of the population genetic structure using CNVR databases from Chinese, Indian, and European commercial cattle breeds revealed differences between Chinese Bos indicus and Indian Bos indicus. Significant differences were also observed between Hainan yellow cattle and European commercial breeds. We conducted gene annotation for both Hainan yellow cattle and European commercial cattle, as well as for Chinese Bos indicus and Indian Bos indicus, identifying 206 genes that are expressed in both Chinese and Indian Bos indicus. These findings may provide valuable references for future research on Bos indicus. Additionally, selection signatures analysis based on Hainan yellow cattle and three European commercial cattle breeds identified putative pathways related to heat tolerance, disease resistance, fat metabolism, environmental adaptation, candidate genes associated with reproduction and the development of sperm and oocytes (CABS1, DLD, FSHR, HSD17B2, KDM2A), environmental adaptation (CNGB3, FAM161A, DIAPH3, EYA4, AAK1, ERBB4, ERC2), oxidative stress anti-inflammatory response (COMMD1, OXR1), disease resistance (CNTN5, HRH4, NAALADL2), and meat quality (EHHADH, RHOD, GFPT1, SULT1B1). This study provides a comprehensive exploration of CNVs at the molecular level in Chinese Hainan yellow cattle, offering theoretical support for future breeding and selection programs aimed at enhancing qualities of this breed.