β-defensins are a suite of natural antibiotics that are expanded to at least 57 genes in cattle. Our research has uncovered a new panel of these genes that are highly expressed in reproductive tissues. Results emerging in other species show that β-defensins can affect fertility via several mechanisms, including the regulation of sperm motility. The discovery and characterisation of new members of this multifunctional gene family hold significant promise as alternatives to antibiotics as well as targets for improved animal breeding.

Whether assisted reproductive technology (ART) increases the risk of Y chromosome microdeletion (YCM) de novo in ART-derived offspring remains elusive. Nineteen candidate genes related with YCM have been analysed in 199 fathers and their 228 sons (Chinese, Han ethnicity) by multiplex ligation-dependent probe amplification. The results suggest that ART does not increase the risk of YCM in male offspring.

This study investigated the pre- and postnatal effects of protein restriction on spermatogenesis in adult male rat offspring. We observed that the negative effects of protein undernutrition on the testicles are more severe when it occurs from conception to adulthood, resulting either in under-fertility or infertility. Nevertheless, if normal protein diet is offered after weaning, their reproductive capacity is recovered in adulthood.

In vitro-produced (IVP) embryos are susceptible to oxidative damage as a consequence of the increased oxidative stress in culture systems. This study examined the effects of antioxidant supplementation during IVP of bovine embryos and was found that antioxidant supplementation reduced oxidative stress and the rate of cellular death, but did not increase embryonic development and cryotolerance. These findings encourages the use of antioxidants in IVP systems to modulate oxidative stress and promote embryo viability.

Porcine oocyte aging resulting from asynchronised IVM impairs embryo developmental competence. The aim of the present study was to investigate whether trichostatin A (TSA) prolongs the maturation time and prevents the aging of oocytes. The results show that TSA prolongs IVM and prevents aging in porcine oocytes, which provides a feasible option by which to adjust the initiation time of downstream experiments based on porcine matured oocytes.

The rescue of germ cells from dead animals may be a key tool to preserve valuable genetic resources from endangered species. Xenografting of testis tissue from young males was carried out in critically endangered gazelle and Iberian lynx, with elongated spermatids developing in gazelle testis xenografts. Thus, differentiated germ cells could be obtained from individuals that die before sexual maturity; these results represent an important advance in biodiversity conservation.

In horses, early pregnancy loss is a major reason for low fertility but has so far mainly been explained by conceptus-related factors. Regulatory T lymphocytes, which contribute to the maintenance of gestation in several species, were studied for the first time in horse mares and levels were low in animals that subsequently suffered pregnancy loss. Treatments that stimulate regulatory T lymphocytes might be a therapy to avoid pregnancy loss in mares.

Previous studies proposed that the reproductive cycle of Myotis nigricans is geographically variable. Thus, the aim of this study was to evaluate how the reproduction of this species is regulated in a tropical environment. The data demonstrated that it presents an annual reproductive cycle with two peaks of spermatogenic activity followed by two periods of deactivated spermatogenesis, a pattern never before observed in any other species.

The efficiency of intracytoplasmic sperm injection (ICSI) is lower in bovines than in other species due, in part, to a lack of optimal conditions for its implementation. Therefore, the aim of the present study was to evaluate the effects of pretreatment of bovine spermatozoa with NaOH and dithiothreitol on the efficiency of ICSI. The results allowed to define a simpler treatment in sperm–Tyrode’s albumin lactate pyruvate (Sp-TALP) for 2 h, which worked better than any of the treatments assessed.

The final days before ovulation impact significantly on ovarian follicular functions and oocyte quality. Here, an hormonal withdrawal was applied on cows to study acquisition then loss of the oocyte developmental competence in oocyte companion cumulus cells. These cells showed few gene expression changes during the acquisition period, however during the loss period more relevant gene expression changes appeared. This highlights a role for cumulus cells principally in sustaining the oocyte viability in the latest stages before ovulation.

Biochemical changes that occur during lactation might compromise the reproductive performance of dairy cows. This study was designed to monitor the biochemical profiles of serum and follicular fluid (FF) of postpartum dairy cows during the summer and winter. The biochemical profile of serum and FF of dairy cows under heat-stress conditions demonstrates marked changes that may impair fertility during lactation.

Exposing embryos to stress factors such as in vitro culture or cryopreservation reduces embryo quality by increasing oxidative stress levels. The aim of the present study was to determine the effect of supplementing culture or vitrification–warming media with two different antioxidants (β-mercaptoethanol and l-ascorbic acid) on the quality of in vitro-produced porcine embryos. The results suggest that the addition of antioxidants to culture or vitrification–warming media is beneficial for embryo quality, because lower reactive oxygen species levels and better rates of survival were found for l-ascorbic acid-treated embryos.

The role of mitochondria in regulating sperm function is not fully elucidated. To obtain more information, we induced boar sperm in vitro capacitation (IVC) and in vitro acrosome exocytosis (IVAE) in the presence of oligomycin A, an inhibitor of mitochondrial ATP synthase. This inhibition immobilised spermatozoa and prevented the achievement of IVC and IVAE without significant changes in the overall energy status, excepting in the IVAE-linked mitochondrial energy peak. Results indicate that in conditions other than IVAE mitochondria control boar spermatozoa functions in ways not affecting the overall energy output.

An impaired uterine environment triggered by subclinical endometritis often compromises fertility in the bovine. We aimed to elucidate the pathways underlying the occurrence of subclinical endometritis and found a microRNA-mediated molecular mechanism that operates in the uterus of cows without clinical signs of endometritis. The result suggests a regulatory role for uterine miRNAs in the development and progression of endometrial inflammation that may lead to reduced fertility.