Identification of HSP70-2 and PRM-1 mRNA, proteins, and analyses of their association with fertility using frozen-thawed sperm in Madura bulls

This study aims to identify HSP70-2 and PRM1 mRNA and protein in Madura bull sperm and demonstrate their relation as bull fertility biomarkers.The Madura bull fertility rates were grouped based on the percentage of first service conception rate (%FSCR) as high fertility (HF) (79.04%; n = 4), and low fertility (LF) (65.84%; n = 4). mRNA of HSP70-2 and PRM1 with Peptidylprolyl Isomerase A (PPIA) as a housekeeping gene were determined by RT-qPCR, while ELISA was used to measure protein abundance. In the post-thawed semen samples, sperm motility, viability, acrosome integrity, and sperm DNA fragmentation index were analyzed. Data analysis was performed on the measured parameters of semen quality, relative mRNA expression, and protein abundance of HSP70-2 and PRM1, among the bulls with various fertility levels (HF and LF) in a one-way ANOVA analysis. The Pearson correlation was used to analyze the relationship between semen quality, mRNA, proteins, and fertility rate.Relative mRNA expression and protein abundance of HSP70-2 and PRM1 were detected, and were found to be highly expressed in bulls with high fertility (p < 0.05) and were associated with several parameters of semen quality.HSP70-2 and PRM1 mRNA and protein molecules have great potential to serve as molecular markers for determining bull fertility.