205 SITE OF OVULATION ALTERS GENE PROFILE IN THE OVIDUCT FROM NELORE (BOS TAURUS INDICUS) AND ANGUS HEIFERS (BOS TAURUS TAURUS)

Abstract

The oviduct plays a key role promoting a favourable microenvironment to gametes transport, fertilization and early embryo development. Numerous differences in reproductive physiology are known among animals of Zebu and European breeds. Reports indicate that female Zebu cattle have a higher number of follicles per wave than female European cattle and individual distinctions in the number of follicles recruited are present in both breeds, namely animals with high follicular count (HFC) and low follicular count (LFC). Furthermore, the follicular count is related to animal fertility and is greatly influenced by the activity of FSH, oestradiol, and androgens. However, little is known about the effects of follicular count differences between Zebu and European cattle, and between breeds in the oviduct molecular profile. Based in these information, we hypothesised that differences in bovine breed (Nelore and Aberdeen Angus), differences in the follicular count (FC), and differences in the antimere related to ovulation (ipsilateral and contralateral) alter the molecular profile of genes involved in oviducal functions during the initial period after ovulation. To do so, oviducts from Nelore heifers (HFC, n = 4; LFC, n = 4) and oviducts from Aberdeen Angus heifers (HFC, n = 4; LFC, n = 4) were isolated and oviducal segments were divided (infundibulum, ampulla, isthmus) from ipsilateral and contralateral antimere. Total RNA was extracted using Illustra TriplePrep Kit (GE Healthcare, Waukesha, WI, USA) and then reverse transcription was performed using a high-capacity cDNA kit (Life Technologies, Carlsbad, CA, USA), according to the manufacturer's protocols. Relative RT-qPCR analysis was performed with TaqMan^® Low Density Array (TLDA, Life Technologies). The mRNA abundance of the target was tested by ANOVA analysis, using PROC GLM procedure of SAS (SAS, 9.2, SAS Institute Inc., Cary, NC, USA). Individual differences were analysed through pair-wise comparisons (SAS). All the comparisons were performed in each segment (ampulla, infundibulum, and isthmus); no comparisons were performed between segments. The differences were considered significant when P < 0.05. In the ampulla, the mRNA abundance of COX2, OVGP1, GPR78, FUCA1, and ANXA4 showed higher levels in ipsilateral antimere compared to contralateral. Similarly, in the infundibulum the mRNA abundance of GRP78, PGTER4, FUCA2, and FUCA1 was higher in ipsilateral antimere. No difference was found in the isthmus. In conclusion, the breed and the follicular count have no effect on the molecular profile of bovine oviduct, suggesting the site of ovulation has the main effect in gene expression related to gametes transport, fertilization, and early embryo development.

Research supported by FAPESP 2012/09498-9 and 2012/50514-8.