Exosome miRNA expression in umbilical cord blood of high-parity piglets reveals the reproductive potential of sows

The objective of modern pig breeding is to exhaust the genetic potential in reproduction performance of sows regarding to litter size and litter weight of piglets. During gestation period, umbilical cord contributes to placenta-fetal communication and plays an indispensable role in the intrauterine embryonic development. In this study, we attempted to analyze the molecular mechanism of reproductive declined in high-parity sows from the perspective of umbilical cord blood. Firstly, we analyzed the reproductive character data of sows, and then the histological analysis of umbilical cord phenotype was performed. Next, we evaluated the effect of umbilical cord blood exosomes (UCB-EXO) on angiogenesis. Moreover, the expression characteristics of miRNA in UCB-EXO of high-parity sows with poor reproductive performance (OS) and multiparous sows with excellent reproductive performance (MS) were analyzed. Results showed that the reproductive performance performed best at 3rd-7th and gradually decreased after 8th parities. Angiogenesis was repressed in OS piglets. Moreover, the Exo-MS exhibited pro-angiogenesis properties, with those of Exo-OS were diminished. With the increase of parities, the angiogenesis and immune function of sows decreased significantly, greatly limited the reproductive potential of sows. The data demonstrated that miRNAs of UCB-EXO played a central role in intrauterine development and suggested a novel possible explanation for reproductive potential, provides reference for increasing female reproductive efficiency. Overall design: Investigation of miRNA transcriptome of UCB between OS and MS