Opioids are involved in reproduction and because they are widely used clinically, it seems important to study their effects on fertility. The opioid receptor that binds morphine is expressed in spermatozoa and when the spermatozoa are incubated with morphine during capacitation, the rate of blastocysts reached in vitro decreases. Therefore, it is important to take into account the effect of opioids on human fertility.

Using a deep sequencing experiment we identified a testis-enriched circular RNA, circ-Bbs9. The aim of this study was to elucidate the localisation, function of circ-Bbs9 in an in vitro model. The results show that circ-Bbs9 plays a critical role in Leydig cell proliferation through regulating the levels of cell cycle-related cyclin D2. Thus, our results emphasise the important role of circRNA in the male reproductive system.

The spiny mouse is the only rodent in the world with a menstrual cycle. This study aimed to determine whether its reproductive cycle can be easily synchronised; results show that, like humans, it cannot. As reproduction in the spiny mouse is remarkably similar to women, it may be a useful model to study female fertility.

FGF9 is involved in mammalian testis steroidogenesis. In the present study, our results demonstrate that long non-coding RNA LOC105611671 modulates FGF9 expression by targeting oar-miR-26a to promote testis steroidogenesis in Hu sheep. Our research provides a new theoretical basis for genetic and molecular research on testosterone biosynthesis in sheep.

Variation in the number of oocytes and embryos collected from ewe lamb donors limits the success of juvenile in vitro embryo transfer (JIVET). In this study, we demonstrated that circulating concentrations of anti-Müllerian hormone (AMH) before ovarian stimulation were positively correlated with the number of oocytes and embryos collected. These data demonstrate that AMH can be used to select suitable donors for ovine JIVET.

Numerous cell signalling pathways, and specifically the Hippo signalling pathway, play a significant role in early embryo development in mammals. Thus, this study investigated the presence of Hippo signalling pathway components during early bovine embryogenesis, and is the first to confirm the presence of upstream core cascade and downstream components of the Hippo signalling pathway during all stages of bovine preimplantation embryo development. Further understanding of the Hippo signalling pathway will help develop interventions to improve cell lineage and segregation during development, leading to healthier bovine embryos.

Calf birthweight is a vital breeding standard in dairy farms. Our study analysed the relationship between placental adipokines and calf birthweight. Placental adiponectin and leptin levels showed a significant positive correlation with calf birthweight. This study may provide a predictive measure for dairy cow breeding.

The fertilisation of oocytes by several spermatozoa (polyspermy) is a major shortfall in the success of IVF in the pig. This study shows that adding extracellular vesicles purified from oviduct fluid into the IVF medium reduces the level of polyspermy, in the same way as the fluid itself does. These results highlight the role of EVs in early reproductive events.

This study evaluated the developmental competency of ovaries stored at low temperature versus warm ovaries. In addition, the developmental competency of vitrified goat somatic cell nuclear transfer (SCNT)-derived blastocysts was evaluated. The number of oocytes recovered and their developmental competency did not different between ovaries stored at low temperature and warm ovaries. In addition, vitrification is a suitable procedure for the preservation of goat SCNT-derived blastocysts.

Comprehensive sperm functionality and morphometry characteristics were assessed by computer-aided sperm analysis hardware and software for the first time in free-ranging African elephants over two seasons. Sperm quality remains high throughout the year; however, during the rainy season most cows come into oestrus and sperm functionality parameters seem to peak over this period. Our data provide important baseline information for future studies.