Ovulation is essential for reproduction. It is induced by a sequence of events that allows pregnancy to occur. The objective of this study was to understand where the hormone angiotensin II fits into this cascade of events. We conclude that angiotensin II is a key hormone for ovulation, acting as one of the earliest players of this process and eliciting increases in progesterone and prostaglandin secretion that are important for ovulation.

In recent years the use of artificial insemination in white-tailed deer hunting ranches has markedly increased, because producers obtain higher prices with high-scoring bucks. The main objective of this study was to compare the efficacy of two insemination techniques in these animals. Results indicate that insemination of frozen–thawed semen via the cervix would be advantageous for use in white-tailed deer because it is easier, faster, more cost effective and less invasive than uterine insemination using surgery.

Exposure of oocytes to the hyperglycaemia mimetic, glucosamine, during in vitro maturation impairs embryo development. This study demonstrates that in vivo glucosamine administration during the periconception period also has adverse effects on embryonic and fetal development in mice, with the nature of the effects dependent on maternal age. These results suggest that further studies should consider a potential role for altered activity of the hexosamine biosynthesis pathway in contributing to the effects of periconceptional maternal hyperglycaemia.

Activin is an important regulator of growth and immune responses. In the adult mouse, an inverse relationship was found between the production of activin and its binding protein follistatin in different regions of the male reproductive tract. This suggests that a reciprocal regulatory relationship involving activin and follistatin controls reproductive development, fertility and resistance to infectious disease in the male reproductive tract.

Adequate uterine capacity and placental function are crucial for normal fetal growth and development in all species. This study investigated the occurrence of intra-uterine growth retardation in pigs of different birthweight ranges and its impact on their subsequent development. A lower percentage of muscle fibres and a higher percentage of connective tissue in the semitendinosus muscle, greater fibre density and a lower height of the duodenal mucosa was found in low-birthweight pigs. Hence, low-birthweight animals will lead to greater economic losses to swine producers, which raise questions about the economic reality of rearing low-birthweight pigs.

In vitro maturation continues to produce oocytes of poorer competence than those mature in vivo, despite potential benefits for clinical infertility treatment and animal breeding. Cumulus cells are important to oocyte health, so we examined differences in the global gene expression of cumulus cells from in vivo- and in vitro-matured cumulus–oocyte complexes. Important gene expression differences were revealed that reflected differences in cumulus cell function. This included haemoglobin, which is found only within cumulus cells of in vivo-matured oocytes.

Sex determination and selection in the pig has a real impact in livestock breeding programmes. In the present study, we developed a new procedure based on the amplification of porcine-specific repetitive sequences for the rapid, reliable and efficient sex determination of porcine embryos and single cells. This is one of the few successful sexing methods in the pig and it might be used to deal with sex-dependent differences in porcine embryo physiology and manipulating sex ratios of offspring.

How can we improve oocyte competence after superstimulation? To answer this question, we tested two durations (4 and 7 days) of follicular growth with or without FSH support at end of the treatment (i.e. FSH starvation). The duration of follicular growth did not affect oocyte competence; however, FSH starvation compromised ovulation capability. Therefore, follicular age does not alter oocyte competence but follicles are dependent of gonadotropins to ovulate.

High feed levels are generally reported to reduce systemic progesterone in gilts, but conclusions about the effects on embryo survival are inconsistent. This paper shows that progesterone in utero–ovarian venous blood (local circulation), is pulsatile and much higher than systemic progesterone, and is increased on a higher feed level. This differential effect of feed level on local versus systemic circulation may explain the inconsistent findings between studies in regards to embryo survival.

There is much interest in recent years in the use of stem cells to study male and female germ cell development and eventually provide novel diagnostic and/or therapeutic applications. Here, the current state of the field of differentiation of germ cells is reviewed with a focus on the use of both human embryonic stem cells and induced pluripotent stem cells. Results to date suggest major hurdles that will need to be overcome if clinical applications are to be realised.

Poor survival of spermatozoa following freezing has been a major impediment towards establishing sperm banks (sperm repositories) for the endangered Asian elephant. The present study demonstrates that modification of Asian elephant sperm membranes using cholesterol-loaded cyclodextrins prior to freezing results in improved post-thaw sperm survival. This has major implications for species conservation by facilitating the establishment of a sperm bank and enhanced genetic management of the Asian elephant.

It is very difficult to maintain dissociated buffalo embryonic stem (ES) cells in culture. Supplementation of ES cell culture medium with Y-27632, a specific inhibitor of Rho kinase activity, was found to improve survival of buffalo ES cells under unfavourable conditions such as enzymatic dissociation to single cells or antibiotic-assisted selection after transfection, without compromising their pluripotency. It may help in developing better protocols for production of transgenic buffalo embryos.

Artificial insemination has considerable potential for the genetic management of captive Asian elephants. We demonstrate that a semen extender designed to prevent oxidative damage (Bullmax) preserves sperm DNA integrity better than a conventional extender (TEST), at 4°C or 15°C. Moreover, sperm DNA stability during incubation at 37°C proved to be a promising parameter for determining whether bulls or storage conditions were suitable for semen preservation.

Individual bovine in vitro embryo production can serve many purposes but is not a routine procedure due to low embryo numbers and quality, compared to group production. Individual embryo culture was optimised by the establishment of an oil-free, cell-free, semi-defined protocol leading to high embryo rates. The elucidation of specific needs of an individually growing embryo further unravelled the interactions between an individually developing embryo and changing culture conditions.

Ovulation in camelids is induced by a previously unidentified seminal plasma protein. The aim of the present study was to identify the protein that induces ovulation and to investigate its potential to induce ovulation in camelids. β-Nerve growth factor (β-NGF) was abundant in alpaca seminal plasma and induced ovulation in four of five female alpacas. This is the first study to identify β-NGF as the ovulation-inducing factor in camelids and this finding may lead to new methods for the induction of ovulation in camelids.

In the present study, we analysed for the first time the impact of pregnancy on thymocyte subpopulations in a mouse model. The findings show that the maternal thymus is aware of the pregnancy status and responds to it by modifying the proportion of lymphocyte subsets according to the male component of the cross-breeding and the pregnancy outcome. These effects may participate in the maintenance of maternal–fetal tolerance.

The spiny mouse is a unique rodent, giving birth to 1–4 pups of precocial nature after a relatively long gestation (39 days). We have developed for the first time, a superovulation protocol for the spiny mouse which elicits a 5-fold increase in the natural ovulation rate of this species. This technique will allow us to compare spiny mouse embryo development to other species and assess its usefulness as a model of early human pregnancy.

Embryonic stem (ES) cells require many growth factors for their survival and maintenance, many of which come from feeder layers on which the ES cells are cultured. We showed that genes expressing ACTIVIN-A, TGF-β1, BMP-4, gremlin and FGF-2 are expressed and that ACTIVIN-A and TGF-β1 are secreted by a buffalo fetal fibroblast feeder layer. This suggests that feeder cells produce signalling molecules that may help in the self-renewal of buffalo ES cells.

In pigs, oxidative stress effects the success rate of IVF and embryo development in vitro, but the methods used to reduce stress are not completely understood yet. The current study indicated that supplementing oocytes prior to fertilisation with the antioxidant n-acetyl-l-cysteine improves IVF and embryo development success. These findings emphasise the importance of reducing oxidative stress using antioxidant supplementation during the in vitro production of pig oocytes.

C-Type natriuretic peptide (CNP), a growth factor involved in fetal–placental growth and development, appears to be tightly regulated during ruminant pregnancy. In the present study of pregnant ewes, it was found that a period of fasting in late gestation increased CNP concentrations in maternal blood, likely reflecting increased production by the placenta. These results indicate that CNP production is acutely sensitive to dietary restriction during pregnancy and could thus be used to monitor nutrient supply to the fetus.

Cryopreservation of germplasm is widely used in breeding programs for many valuable agricultural species, although the honey bee remains a notable exception. In this study, honey bee semen was cryopreserved and used to inseminate sequential generations of queens. This work demonstrates the potential utility of cryopreservation in honey bee breeding programs, and in the conservation of unique genetic lines and threatened subspecies.

Oestrogen production by the trophoblast of the early equine conceptus is important for the establishment of pregnancy but its specific role(s) has not been defined. Having shown that the embryo proper can metabolise oestrogens, the present study sought to determine whether it could also biosynthesise them. Positive findings in this investigation are of interest in relation to the well recognised role of oestrogens in blood cell and blood vessel development.

The mechanisms causing the positive influence of very short-term nutritional supplementation on ovulation rate and prolificacy still need to be fully elucidated. The present study shows that glucogenic treatment in sheep modifies follicle and corpus luteum functionality, and improves oocyte quality. This finding is important for determining the intrinsic effect of high-energy diets on prolificacy and sets the basis for adapting nutritional supplementation in protocols for assisted reproduction.

The number of lambs born is limited by ovulation rate and embryo mortality, both of which are limited by the level of nutrition. However, supplements that increase ovulation rate might also increase embryo mortality. We tested this hypothesis and found that feeding lupin grain for 2 weeks after mating increased embryo survival, but sudden withdrawal of the supplement increased embryo mortality.

African elephants in zoos are not reproducing well, and many exhibit abnormal reproductive cycles, due in part to a condition known to cause infertility in women: hyperprolactinaemia. This study compared rates of hyperprolactinaemia with data collected 7 years prior, and found that the incidence has increased from one-third to two-thirds of acyclic females. We conclude that creating a self-sustaining population of African elephants will not be possible until we identify causes of hyperprolactinaemia and develop therapies to treat this serious fertility problem.

The relationship between the immune response and normal physiological processes such as involution in cattle is poorly understood. In this study we characterise the postpartum immune response at both a cellular and a molecular level in healthy cows. Our results show that postpartum inflammation and immune activation is not necessarily pathological and we speculate that dysregulation of this response determines susceptibility to uterine disease and sub-fertility in cattle.

High between-animal variability in ovarian responses to gonadotrophin treatment remains a major limit to the development of embryo biotechnologies in cattle. We show that anti-Müllerian hormone (AMH) endocrine concentrations are highly repeatable and tightly correlated with ovarian responses and embryo production in cows. We propose a prognostic method to discard low-responding individuals by the determination of AMH concentration in a single blood or plasma sample, taken from animals several months before their entry into embryo production protocols.

The aim of this study was to determine whether controlled ovarian hyperstimulation (COH) and in vitro maturation (IVM), the two common clinical procedures in human IVF treatment, have an impact on mitochondrial status in oocytes. The results indicate that COH and IVM inhibit mitochondrial DNA replication and alter mitochondrial function. The mitochondrial damage may partly explain the low efficiency of IVF and high rate of embryonic loss associated with these clinical procedures.

The reproductive seasonality of sheep suggests that melatonin receptors may be present in ram spermatozoa. The aim of the present study was to confirm the presence of these receptors in ram spermatozoa. Four sperm subpopulations were identified on the basis of immunocytochemical labelling patterns for MT₁ receptors, but there was only one pattern of labelling for MT₂ receptors. The biochemical pathway triggered by these receptors and their function in terms of fertility are currently under investigation.

Establishment of pregnancy in cattle is most vulnerable during the first few weeks, when the embryo is reliant on the uterine protein environment for development. We demonstrate that the growth of conceptuses from asynchronous (Day 9) transfers is superior to that of AI controls. Proteomic profiling of uterine luminal flushings identified 10 proteins that increased in abundance at this time point. Defining and characterising the uterine proteins affecting embryo growth could lead to intervention strategies to improve pregnancy rate.

No defined in vitro model currently exists to allow detailed and systematic investigation of maternal communications with gametes and embryo. Here we report establishment and characterisation of an in vitro model based on the interaction of boar spermatozoa with a porcine oviductal cell line. The simple in vitro assay system described here has the potential to be used in high-throughput genomic and proteomic approaches as well as being itself further developed towards an automated assay system for understanding maternal interactions with gametes and embryos.

Mediterranean buffaloes reproduce principally in autumn, when nocturnal melatonin levels are high, although variability in the melatonin receptor 1A (MTNR1A) gene also allows for reproductive activity in spring. Thus, the aim of the present study was to investigate the relationship between reproductive performance and variability in the MTNR1A gene. Buffaloes with the T/T and C/T genotypes exhibited a shorter interval between the first and second calving, because reproductive activity occurred during days with a long photoperiod. The findings of the present study could allow the selection at birth of buffaloes that would also be able to reproduce in spring, with a consequent deseasonalisation of production.

Immunocastration suppresses reproductive function, making it an attractive tool to improve the management of gonad-intact animals and an alternative to surgical castration. In the present study, neonatal immunocastration in bulls with a novel vaccine caused temporary endocrine but long-term disruption of testicular development, delaying puberty by 8 weeks. This supports the hypothesis of a developmental window during testicular development, such that disturbance of the endocrine drive to the gonads results in long-term impairment of gonadal function.

At-risk pregnancies are commonly treated with progesterone; however, the potential effects of supraphysiological concentrations of progesterone on the developing male are not known. Although sexual interest was not influenced in male rats treated neonatally with progesterone in the present study, these rats exhibited a reduction in copulatory behaviour and ejaculation. This suggests that the development of male sexual behaviour can be influenced by the prenatal environment, including by hormones that are prescribed for at-risk pregnancies.

Thyroid hormones are essential for fetal development because they act directly on the placenta. However, the role of the placenta in the complexity of maintaining a pregnancy and in impaired fetal development arising out of hypothyroidism is unknown. The objective of this study was to evaluate fetal development, placental morphology, vascularisation and the rate of proliferation and cell death of the placenta in rats with hypothyroidism. We observed that hypothyroidism impairs fetal development by affecting all layers of the placenta. It interferes with placental vascularisation, reduces the proliferation and cellularity and increases cell death of the placenta. These results allow us a better understanding of the pathogenesis of placental alterations and fetal growth restriction that occurs in hypothyroidism, which may contribute to more appropriate therapeutic interventions.

To better explore the pathogenesis of polycystic ovary syndrome (PCOS) disease so as to find a better treatment, we performed an initial proteomic study. Thirty-two protein spots were shown to be significantly differentially expressed between PCOS and normal follicular fluids, of which 20 unique proteins were identified to be associated with cellular metabolism and physiological processes. These results increase our understanding of PCOS and the identified genes may serve as candidate biomarkers to develop diagnostic and therapeutic tools.

Paracrine cell signalling is believed to be important for ovarian follicle development, and a role for some members of the ?broblast growth factor (FGF) family has been suggested. This work reviews the main controlling mechanisms of preantral and antral follicle development, with the main focus on the regulation of FGF family members, in particular FGF-2. These data confirm the importance of the FGF family in mammalian reproduction control.

In female pigs, nutrition during both early and late antral follicle development affects ovulation rate and the number of embryos, but the interaction has not been properly studied. The current study indicated that undernutrition during early antral follicle development has irreversible effects on subsequent reproduction. The finding emphasises the importance of adequate nutrition during late lactation in sows and one to three weeks before mating in gilts.

Large amounts of alcohol consumption during pregnancy can affect the health of the fetus and subsequent offspring. But do small amounts of fetal alcohol exposure have similar effects? We have developed a model of chronic low-dose maternal alcohol consumption in the rat and found that this restricts fetal growth and slows growth in adult male offspring. We will now use this model to determine whether low amounts of fetal alcohol exposure result in adult disease states, such as hypertension or diabetes.

This is the first study to address the male reproductive biology of Spix’s Yellow-toothed Cavy (Galea spixii). The aim of this study was to evaluate the phases of sexual development and spermatogenesis in this specie. It may be classified into the following phases: from birth to the age of 15 days (immature); 30 days of age (pre-pubertal); 45 to 105 days of age (pubertal); and 120 and 150 days of age (post-pubertal).

The oviduct protected the sperm DNA integrity for adequate embryo development. This study showed an increase in spermatozoa with DNA damage in co-incubation with tubal explants from the ampullar region but not from the isthmal region. The isthmal region is protected against sperm DNA damage induced by oxidant molecules, as it constitutes a sperm reservoir necessary for normal fecundation.

Stress is a consequence of modern life and can also be correlated with many perinatal and postnatal diseases. Herein, we analyse the influence of stress in maternal, placental and fetal weight of pregnant rats, placental morphology and expression of vascular-associated factors. Our results show relevant differences in the mother’s blood pressure, placental structure and offspring weight highlighting the complex and multifactorial biological processes, which can be associated with stress and contribute to understanding the importance of stress in pregnancy disorders.

Most organisms have developed a biological clock, synchronised with the surrounding environment, located in the pineal gland that acts as a photo-transducer conveying the environmental photic information to the brain via the release of melatonin, a powerful multifunctional hormone. This study demonstrates the ability of melatonin improving killifish' breeding efficiency playing an important role in the complex network of signals that centrally/locally control reproduction overall. The results obtained may be used in the reproductive biotechnologies of farmed species.

The seasonal infertility period in sows is the most economically important reproductive problem for pig producers. Significantly, there is an increase in pregnancy loss during this time. This review summarises recent advancements made in our understanding of the mechanisms that contribute to this reduced fertility. With emphasis on seasonal variation in ovarian function and its influence on subsequent fertility, there is clear evidence that reduced oocyte developmental competence contributes to seasonal infertility. With this new information in mind, researchers and producers can now devise strategies to overcome the seasonal infertility phenomenon.

Although the uterine circulation must enlarge considerably during pregnancy to ensure normal fetal development, the mechanisms responsible are unknown. We developed a new surgical procedure to determine whether uterine stretch alone can stimulate vascular growth, and found that it did indeed induce both lengthening and widening of uterine vessels. This discovery opens a new avenue of investigation into the underlying molecular signals and pathways that regulate uterine vascular enlargement in normal versus diseased (e.g. intrauterine growth restriction, preeclampsia) pregnancy.

Evaluation of egg quality is one of the main bottlenecks in aquaculture where high-quality eggs are required for effective commercial production and scientific research aimed at improvement of breeding procedures. We investigated the course of the cortical reaction in pikeperch eggs where noticeable and violent deformation of chorion could be observed shortly (3–5 min) after their activation. On the basis of the results obtained we have established a protocol for egg quality evaluation in this species according to the deformation rate of eggs following activation with water.

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.