Salivary Cell-Free HSD17B1 and HSPA1A Transcripts as Potential Biomarkers for Estrus Identification in Buffaloes (Bubalus Bubalis)

Abstract

Background: Estrus detection is a major problem in buffaloes because of the poor expression of estrus signs leading to low reproductive efficiency. Salivary transcripts analysis is a promising tool to identify biomarker; therefore, the present study was carried out to evaluate their potential as estrus biomarker. Methods: The levels of HSD17B1, INHBA, HSPA1A, Testin transcripts were compared in saliva during estrous cycle stages [early proestrus (day -2, EP), late proestrus (day-1, LP), estrus (E), metestrus (ME) and diestrus (DE)] of cyclic heifers (n=8) and pluriparoous (n=8) buffaloes by employing quantitative real-time polymerase chain reaction (qRT-PCR). Results: The levels of HSD17B1 (EP/DE 1.46-2.43 fold, LP/DE 2.49-3.06 fold; E/DE 7.21-11.9-fold P<0.01; ME/D 1.0-1.16 fold) and HSPA1A (EP/DE 0.93-2.39 fold, LP/DE 2.68-3.23 fold; E/DE 8.52-15.18 fold P<0.01; ME/D 0.86-1.01 fold) were significantly altered during the estrus than other estrous cycle stages in both cyclic heifers and pluriparous buffaloes. Receiver operating characteristic curve analysis revealed ability of salivary HSD17B1 (AUC 0.96; P<0.001) and HSPA1A (AUC 0.99; P<0.01) to differentiate E from other stages of estrous cycle. Conclusion: Significantly higher levels of HSD17B1 and HSPA1A transcripts in saliva during estrus phase suggest their biomarkers potential for estrus detection in buffaloes.