The negative consequences of obesity on reproduction are increasingly apparent and are of great concern given the incidence of obesity among people of reproductive age. It is not understood how obesity impacts fertility; consequently we investigated the effect of obesity on early embryo quality prior to implantation in the present study. Both male and female obesity compromised embryo development and quality, which may account for the decrease in reproductive fitness.

Chromatin structure is globally remodelled during embryo development and perturbations in chromatin structure are associated with aberrant embryo development. We found that inhibition of euchromatic histone-lysine N-methyltransferase 2 (EHMT2), a histone methyltransferase, leads to changes in global patterns of histone methylation and compromises embryo development. Our results suggest that even transient alterations in histone methylation patterns can have lasting effects on embryo development, highlighting the importance of understanding how chromatin structure is controlled during embryo development.

Several studies demonstrated a negative effect of subclinical endometritis on bovine reproductive performance, the mechanisms, however, remained unclear so far. Therefore our study tested the hypothesis that subclinical endometritis alters the endometrial or embryonic gene expression profile. As a result, the present data demonstrate that bovine subclinical endometritis alters the endometrial transcriptome dynamic within the oestrous cycle and results in distinct changes of the endometrial and embryonic gene expression profile.

Fibroblast growth factor (FGF) 8 functions as a mitogen and morphogen in a variety of cell types in vertebrate developmental processes. In the present study, we found that Xenopus SRY (sex-determining region Y)-box 2 acts as a transcription factor via direct interaction with the upstream region of the Xenopus FGF8 (XFGF8) gene in developing Xenopus embryos. Thus, our results provide an additional mechanism of XFGF8 gene regulation in early Xenopus development.

This study assessed the effects of follicle fluid on fertilisation ability of bovine oocytes. Supplementation of culture medium with follicle fluid during in vitro maturation of oocytes promoted sperm penetration during in vitro fertilisation both by improving cumulus expansion and by enhancing ATP levels in oocytes, which maintained their ability to be fertilised even after mitochondrial stress. This finding may be useful for further development of maturation media especially when oocytes are marked out for mitochondria-damaging treatments.

Antenatal glucocorticoids are administered to pregnant women in preterm labour and enhance survival of preterm infants by maturing the lungs prior to birth. However, these synthetic glucocorticoids may reduce normal patterns of fetal growth, with this study showing that this is significantly pronounced in female fetuses. These data suggest that the fetus and/or placenta of male and female fetuses may differentially regulate the response to maternal glucocorticoids.

Previous studies indicate that the genes that control circadian rhythmicity also have a role in parturition. A transgenic mouse was generated in which the rhythmicity-associated gene Bmal1 is deleted in the myometrium; females of this transgenic line were less likely to labour at the expected time of day than control mice. This report introduces a new transgenic mouse model and suggests an important role for myometrium-specific expression of Bmal1 in parturition timing.

Undernutrition as a result of dietary restriction can contribute to female infertility. In this study, we examine the effects of undernutrition on oocyte development and demonstrate that this process is dependent on GLUT1 expression and glucose uptake in cumulus-oocyte complexes. These results demonstrate the importance of proper nutrition and glucose metabolism in female fertility and implicate GLUT1 in this process.

This study brings new information on bone morphogenetic proteins (BMPs) that can contribute to the understanding of ovarian folliculogenesis. The levels of mRNA for BMP system in goat preantral follicles before and after culture for 18 days were evaluated. Increased levels of mRNA for BMP-2 and reduced mRNA for BMP-4, BMP-7, BMPR-IA and SMAD-5 were observed in cultured follicles. These data are essential for improvement of in vitro development of good-quality oocytes.

A basic understanding of the molecular pathways that regulate developmental events during early feline embryogenesis is still lacking. The aim of the study was to quantify mRNA profiles of pluripotency and differentiation-related markers during preimplantation development and results showed that these genes are expressed and undergo species-specific changes during early embryonic development. These findings add evidence to the hypothesis that behavior of these markers may differ among species.

Embryo survival is a major factor affecting reproductive success with both systemic progesterone and retinol demonstrating significant effects on embryo development. Our aim was to determine the effects of systemic progesterone on the uterine expression of retinol’s transportation protein, RBP4, in cyclic dairy cattle. RBP4 expression in the bovine uterus was altered by progesterone in a time- and concentration-dependant manner and therefore may play a role in regulating embryo development in cattle.

Mammary gland development during pregnancy is a tightly regulated process necessary for lactation, and strongly dependent on hormonal control. This report aimed to investigate whether the same hormonal changes that lead to parturition in rats were responsible for triggering mammary gland maturation required for the initiation of milk production. Our study provides clear in vivo evidence of the role of progesterone as a key hormonal player for both mammary development and milk production, and demonstrates that lactogenesis may be advanced as long as the action of progesterone is abolished.

Oocyte maturation is critical to its developmental potential and is characterized by changes in the distribution and activity of mitochondria in the oocyte. We investigated the effect of two fat energy sources, linoleic acid (LA; omega-6) and alpha-linolenic acid (ALA; omega-3), on bovine oocyte maturation and showed negative effects of LA and positive effects of ALA on the mitochondria profile. High LA levels in diets may be detrimental for oocyte development and result in reduced fertility.

Until now the only possible treatment for varicocele, the most common cause of primary male infertility, has been surgery. In the present study, anthocyanin improved sperm motility, spermatogenic cell density and testis weight. These actions are likely due to anthocyanin-induced reductions in oxidative damage resulting from varicocele-induced venous stasis. The results of the present study may be the initial step in developing a medical approach for the treatment of varicocele.

This is the first report showing the existence and interaction of kisspeptin and its receptors in porcine cumulus–oocyte complexes and its enhancing role in oocyte maturation and subsequent embryo developmental competence in an autocrine–paracrine manner. However, Kp supplementation may have a paradoxical impact on hatched blastocyst development reflecting systemic or local regulation during this early critical period.

The fatty acid composition of supplemented fat in the diet has a role in improving reproductive efficiency. The study was carried out to elucidate the effect of different sources of dietary energy (maize vs polyunsaturated fatty acid (PUFA)-rich sunflower oil) on sperm quality in rams and the result suggested that dietary PUFA protected sperm membrane integrity. Developing a dietary regimen that includes PUFA might improve the fertility potential of bulls.

Oxytocin and vasopressin are present in the yolk sac of the equine pre-attachment embryo. They are supposable candidates for the regulation of equine embryo expansion mediated by aquaporins and ATPases abundant in the trophoblast. Expression of oxytocin, vasopressin 1A and 2 receptors could be proven by means of RT-PCR and immunohistochemistry in equine embryos between Days 10 and 16, making involvement of these two hormones very probable for embryo expansion.

Oxidative stress is, in general, pernicious for cells, but specific stressors, such as hydrogen peroxide, may have a beneficial effect on cell function, depending on the concentration used. In this study we exposed bovine sperm cells to different levels of hydrogen peroxide before fertilisation and found that spermatozoa exposed to sublethal levels of hydrogen peroxide can produce more blastocysts of better quality, depending on the diameter of the fertilised oocyte. This implies that stressed spermatozoa may improve subsequent embryo development in combination with careful selection of oocytes.

Safe, steroid-free methods to control ovarian function in food-producing animals are needed. Aromatase inhibitors prevent the body from producing its own oestrogen and they have marked effects on the reproductive physiology of heifers. Results from the present study provide impetus for the development of an aromatase inhibitor-based protocol to control ovarian function in cattle.

A boar epididymal sperm glycocalyx approach was used to correlate the degree of maturation of ejaculated spermatozoa with plasma membrane glycocalyx component changes. Complementary qualitative and quantitative procedures were performed in boar epididymal spermatozoa throughout the epididymis to identify specific molecular modifications of carbohydrate residues (intensity, location and proteomic changes). The present study provides new insights correlating the glycocalyx changes with the degree of sperm maturation.

Hormonal induction is used to sample sperm from amphibians and fish in conservation breeding programs and aquaculture to be used fresh, or through cryopreservation to perpetuate genetic variation. We achieved improved sperm yield through comparing several hormones for induction, and provided new physiological insights to amphibian reproduction. These results will lower the costs and improve the efficiency of reproduction technologies for amphibians and fish.

Developmental competence of in vitro-produced bovine embryos is still compromised perhaps due to imperfect oocyte maturation. Therefore we analysed the structural changes during in vitro maturation of the bovine zona pellucida by polarisation light microscopy and identified a typical decrease in zona birefringence during maturation, which correlates with developmental competence. Thus, zona pellucida birefringence measurement is a new tool to assess correctness of in vitro maturation and developmental competence.

Spermadhesins are thought to play a prominent role in different aspects of animal fertilisation. The low purification efficiency and the incomplete characterisation of buck spermadhesins, as well as the multiplicity of their biotechnological applications, prompted us to establish an effective expression system to specifically produce the recombinant bodhesin Bdh-2 and to provide a technique for subsequent structural and physiological studies.

Little is known about the molecular mechanisms that regulate bovine trophoblast development. In current study, we demonstrated that impaired expression of two key regulatory proteins, E-cadherin and β-catenin along with defective β-catenin signaling activation occurs in trophoblast derived from bovine somatic nuclear transfer (SCNT). These deficiencies during embryo attachment could explain the insufficient placentation in the SCNT-derived fetus.

Nutritional state of the dam critically affects embryonic development and has lasting consequences for growth and lifetime health outcomes. Mechanisms controlling growth and differentiation of embryonic tissues in utero may be directly affected , or placental development may be primarily affected and indirectly limit nutrient availability to the embryo. Results of the present study are consistent with proposed benefits of feeding a specific nutrient supplement (l-arginine) during early pregnancy in the sow on placental vascularization and embryonic development.

A large group of men worldwide smoke cigarettes, which may adversely affect the health of their spermatozoa. This study was conducted in order to evaluate if zinc prevents damage of spermatozoa of rats exposed to cigarette smoke. The results showed that testosterone concentration, percentage of normal morphology, motility and DNA oxidative damage of spermatozoa were restored by zinc treatment.

The use of oocytes grown from preantral follicles could offer a significant alternative for the propagation of livestock as well as for the infertility treatment in human. In this study, the addition of fluid originated from bovine dominant follicles in goat preantral follicles culture medium promoted high rates of in vitro growth. Furthermore, the presence of follicular fluid in the culture of caprine preantral follicles allowed the recover of matured oocytes with ultrastructurally normal organelles.

Males reveal themselves as the weaker sex very early; preterm baby boys are more likely to die of respiratory failure than girls for reasons unknown. Changes in blood flow to the brain and lungs immediately after birth were compared between male and female preterm lambs but were not different. Failure of the circulatory transition at birth, during establishment of independent respiration, is not the cause of preterm males’ vulnerability, and points to a source other than the cardiopulmonary circulation.

It has long been thought that ewes need to be preconditioned by a period of complete separation from all rams before ram pheromones can induce ovulation. We showed that it is not separation but ram ‘novelty’ that is important. Separation for only a month enables ewes to respond to once-familiar rams, but induction of the full cascade of events leading to ovulation appears to be less successful.

The dynamics of protein tyrosine phosphorylation (PTP) in live spermatozoa during cryopreservation are not known. Using flow cytometry, we assessed the PTP in boar spermatozoa and the results provide the first quantitative evidence of dynamic changes in the subpopulation of boar spermatozoa undergoing PTP during cryopreservation. These findings may help in developing cryopreservation protocols for boar spermatozoa with better post-thaw function.

Females of many species store fertile spermatozoa in their oviducts for a long-time. We have identified a component of the oviduct: HSPA8 that when added to ram spermatozoa prolongs its shelf-life at ambient temperatures, meaning no ram need travel to meet his ewe to produce lambs in the future. This finding is likely to be of interest to agricultural ministries globally who seek to reduce the transport of farm animals to control disease outbreaks.

Decidualisation of endometrial stromal cells is essential for successful implantation and pregnancy and enhancing decidualization may overcome reduced endometrial receptivity, a major limiting factor in natural and assisted reproduction. The aim of this study was to determine whether dialysed seminal plasma with or without progesterone influenced decidualization of primary human endometrial stromal cells. Seminal plasma potentiated progesterone-induced decidualization, indicating that seminal plasma may enhance endometrial receptivity.

The mitochondria play crucial roles throughout embryonic development. To investigate whether mitochondrial heteroplasmy affects embryo development, cloned embryos with different levels of mitochondrial heteroplasmy were constructed. Blastocyst formation rates, the expression of pluripotency and mitochondrial regulator genes, and the methylation levels of these genes differed significantly with mitochondrial heteroplasmy. Therefore, mitochondrial heteroplasmy may affect embryonic development.

A ghrelin analogue Hexarelin (HEXr) has been proposed as a regulator of reproductive physiology. We investigated the effects of chronic HEXr administration on reproductive parameters of adult mice. A decreased number of fetuses/corpora lutea in treated females and a downward trend in the pregnancy index and percentage of females impregnated by males treated with HEXr were detected. We propose certain effects of HEXr on the implantation process and/or early development of embryos and over the in vivo reproductive capability of males.

Cryopreservation is relevant to preserve endangered wildlife species or genetic resources in domestic animals. The aim of the present study was to assess the integrity and of frozen–thawed ovarian tissue from bitch after xenografting. Despite a massive follicular loss, a follicle growth was observed at 8 weeks post-transplantation and several well-developed intact secondary follicles were present at the end of the experiment. This confirms canine ovarian tissue is well preserved by our slow freezing process.

Endometrial epidermal growth factor (EGF) regulates cysteine-rich protein 61 (CYR61) and both are implicated in key processes such as implantation and endometriosis. Specific inhibitor studies identified the contribution of Janus kinase 2 (JAK2) and the signal transducer and activator of transcription protein STAT3 to the regulation of CYR61 expression. The data provide new information on signaling EGF-JAK2/STAT3-CYR61 potentially relevant for endometrial physiology.

Circulating progesterone concentrations during the first week after conception have been associated with increased pregnancy rates in cattle. In the present study, administration of human chorionic gonadotrophin on Day 5 after oestrus resulted in the formation of an accessory corpus luteum (CL) and hypertrophy of the original CL, the result of which was an increase in P4 concentrations from Day 7 onwards. These elevated P4 concentrations were associated with increased conceptus size. Furthermore, conceptus size was highly correlated with interferon-τ secretion in vitro.

The existence of additive genetic variation in secondary sex ratio is questionable in dairy cattle and there were no reports on the study of the genetic trend of sex ratio in dairy cattle. The aims of this study were to estimate variance components and genetic trends for secondary sex ratio in Iranian Holsteins. Exploitable genetic variation in secondary sex ratio can take advantage of sexual dimorphism for economically important traits, which may facilitate greater selection intensity and thus greater response to selection, as well as reducing the replacement costs.

Blastocyst hatching is an important developmental process for successful implantation. The present study reveals that supplementation of a chemically defined protein-free medium with glucose and glycine synergistically improves the viability and hatching of in vitro-produced porcine blastocysts. The increase in quality of later-stage preimplantation embryos may enhance development to full term after embryo transfer.

Early pregnancy and embryonic loss have been studied in mares treated with a prostaglandin to stop progesterone production. Treatment on or before Day 16 had minimal effects on the conceptus (the embryo and its membranes) whereas treatment on Day 18 usually led to abortion and/or conceptus degeneration within 3 days, thereby providing a predictable system in which to investigate molecular changes underlying pregnancy failure.

Cytochrome P450 (CYP) enzymes are important for drug metabolism, but there is limited information on their development in the fetus and newborn. Their levels in sheep liver were low in the fetus, increased after birth and fetal administration of cortisol increased their levels, particularly of CYP2D6. We conclude that drug metabolism in the fetus is limited by the low CYP expression and that the prepartum fetal cortisol rise may stimulate their expression.