Oviductal extracellular matrix hydrogels enhance in vitro culture of rabbit embryos and reduce deficiencies during assisted reproductive technologies.

In vitro embryo culture often falls short of mimicking the physiological dynamism occurring in the reproductive tract, prompting developmental plasticity in mammalian embryos with consequential genotypic and phenotypic deviations. Recent research highlights the potential of biological derivatives in in vitro culture to mitigate these effects, being the extracellular matrix (ECM) one of the most important components in retaining structural and biological signals derived from the native source tissue. Current bioengineering techniques could provide ECM-based biomaterials mimicking the native environment and offering optimal embryonic development.

Why choose the rabbit to work in reproductive technology?

Rabbits have played a significant role in both livestock production and the advancement of reproductive scientific research. Their unique biological traits, including induced ovulation and a reproductive process that closely mirrors that of humans, have been pivotal in their use as a model. Moreover, their body size is perfectly aligned with the 3Rs principles: Replacement, Reduction, and Refinement.

Transcriptomic Signatures of the Foetal Liver and Late Prenatal Development in Vitrified Rabbit Embryos.

Assisted reproduction technologies (ARTs) are generally considered safe; however, emerging evidence highlights the need to evaluate potential risks in adulthood to improve safety further. ART procedures like rederivation of embryos by vitrification differ from natural conditions, causing significant disparities between in vitro and in vivo embryos, affecting foetal physiology and postnatal life. This study aims to investigate whether hepatic transcriptome and metabolome changes observed postnatally are already present in foetal livers at the end of gestation.

Reproductive Performance of Female Rabbits Inseminated with Extenders Supplemented with GnRH Analogue Entrapped in Chitosan-Based Nanoparticles.

Rabbit is a reflexively ovulating species. Accordingly, in the practice of artificial insemination (AI) ovulation must be induced via exogenous GnRH (Gonadotropin-Releasing Hormone) administration, which may be performed intramuscularly, subcutaneously, or intravaginally. Unfortunately, the bioavailability of the GnRH analogue when added to the extender is lower due to the proteolytic activity in the seminal plasma and the poor permeability of the vaginal mucosa.

Roles of host genetics and sperm microbiota in reproductive success in healthy rabbit.

Although the effects of sperm microbiota and sperm quality have been described previously, recent studies provide evidence that female genital modifications triggered by seminal components could be of significant importance to identify some disturbances associated with fertility. So, sperm microbiota could play a key role in sperm quality, contributing to fertilisation. To understand how sperm microbiota diversity is influenced by the host genetics, the symbiotic bacteria in four inbred lines raised in the same animal facility and their effects on sperm quality and fertility were analysed.

Metabolomic Analysis Reveals Changes in Preimplantation Embryos Following Fresh or Vitrified Transfer.

Although assisted reproduction technologies (ARTs) are recognised as safe, and most of the offspring seem apparently healthy, there is clear evidence that ARTs are associated with changes in the embryo's developmental trajectory, which incur physiological consequences during the prenatal and postnatal stages of life. The present study aimed to address the influence of early (day-3 embryos) embryo transfer and cryopreservation on embryo survival, size, and metabolome at the preimplantation stage (day-6 embryos). To this end, fresh-transferred (FT) and vitrified-transferred (VT) embryos were compared using naturally-conceived (NC) embryos as a control reference.

Rederivation by Cryopreservation of a Paternal Line of Rabbits Suggests Exhaustion of Selection for Post-Weaning Daily Weight Gain after 37 Generations.

Rabbit selection programmes have mainly been evaluated using unselected or divergently selected populations, or populations rederived from cryopreserved embryos after a reduced number of generations. Nevertheless, unselected and divergent populations do not avoid genetic drift, while rederived animals seem to influence phenotypic traits such as birth and adult weights or prolificacy. The study aimed to evaluate the effect of a long-term selection for post-weaning average daily weight gain (ADG) over 37 generations with two rederived populations.

Long-Term Effects Following Fresh/Vitrified Embryo Transfer Are Transmitted by Paternal Germline in a Large Size Rabbit Cohort.

The concept of developmental programming suggests that the early life environment influences offspring phenotype in later life, whose effects may also be manifested in further generations. Valuable pieces of evidence come from the fields applying assisted reproductive technologies (ARTs), which deprive embryos of their optimal maternal environment and were thus associated with subsequent developmental deviations. Recently, we demonstrated that the in vitro manipulations during a vitrified embryo transfer procedure incurs a cumulative and transgenerational decline in the growth performance of the resulting offspring.

Long-Term Phenotypic and Proteomic Changes Following Vitrified Embryo Transfer in the Rabbit Model.

Nowadays, assisted reproductive technologies (ARTs) are considered valuable contributors to our past, but a future without their use is inconceivable. However, in recent years, several studies have evidenced a potential impact of ART on long-term development in mammal species. To date, the long-term follow-up data are still limited.

Developmental Plasticity in Response to Embryo Cryopreservation: The Importance of the Vitrification Device in Rabbits.

In this study, we evaluated the effect of embryo vitrification using two different devices on adulthood phenotype in rabbits. In vitro development, prenatal embryo survival, body weight, growth performance, haematological and biochemical peripheral blood analysis, reproductive performance, and lactation performance traits were compared between the experimental groups. They derived from naturally-conceived embryos (NC), fresh-transferred embryos (FT), vitrified-transferred embryos using mini-straw (VTs), or vitrified-transferred embryos using Cryotop (VTc).

The harmful effect of removing the extracellular vitrification medium during embryo cryopreservation using a nylon mesh device in rabbit.

During the last decades, many techniques have been developed to reduce sample volume and improve cooling and warming rates during embryo vitrification. The vast majority are based on the "minimum drop size" concept, in which the vitrification solution around embryos is reduced by aspiration, leaving a tiny part of volume surrounding embryos. However, novel cryodevices were aimed to remove the entire vitrification solution.

Minimally Invasive Embryo Transfer and Embryo Vitrification at the Optimal Embryo Stage in Rabbit Model.

Assisted reproductive techniques (ARTs), such as in vitro embryo culture or embryo cryopreservation, affect natural development patterns with perinatal and postnatal consequences. To ensure the innocuousness of ART applications, studies in animal models are necessary. In addition, as a last step, embryo development studies require evaluation of their capacity to develop full-term healthy offspring.

A single injection of corifollitropin alfa supplemented with human chorionic gonadotropin increases follicular recruitment and transferable embryos in the rabbit.

Superovulation protocols are designed to achieve maximum embryo yields. Nevertheless, ovarian response control and the quality of obtained embryos are still a challenge. On the other hand, to save the superovulated embryos until their subsequent use, it is usual to cryopreserve them, so it is also crucial to assess their cryotolerance.

Correction: Overweight in young males reduce fertility in rabbit model.

[This corrects the article DOI: 10.1371/journal.pone.

Correction: Successful re-establishment of a rabbit population from embryos vitrified 15 years ago: The importance of biobanks in livestock conservation.

[This corrects the article DOI: 10.1371/journal.pone.

Successful re-establishment of a rabbit population from embryos vitrified 15 years ago: The importance of biobanks in livestock conservation.

Genetic resource banks (GRB) are a valuable tool for maintaining genetic variability and preserving breeds from pathogens or catastrophe, enabling us to assess and correct breeding schemes, minimizing the impact of genetic drift and facilitating diffusion. This study tests their efficiency in re-establishing two extinct populations of a synthetic rabbit line selected for daily weight gain, using vitrified embryos from two generations (18th and 36th) separated by 15 years of genetic selection. The effect of long-term storage of vitrified embryos in liquid nitrogen was also evaluated.

Cryosurvival of rabbit embryos obtained after superovulation with corifollitropin alfa with or without LH.

The efficiency of an embryo bank depends on provision of optimal conditions for recovery, cryopreservation and transfer to a breed or strain. In this sense, increasing the number of embryos available using superovulation should improve the cryobank efficiency. However, vagueness of response to conventional protocols to control or increase ovarian response and the quality of oocytes and embryos and their cryotolerance remain a challenge.

Extra-uterine (abdominal) full term foetus in a 15-day pregnant rabbit.

Background: While ectopic pregnancies account for 1-2% of all pregnancies, abdominal pregnancy is extremely rare, accounting for approximately 1% of ectopic pregnancies. Extrauterine abdominal pregnancy is defined as the implantation and development of an embryo in the peritoneal cavity. The present report is the first of an incidental case of abdominal pregnancy within four full-term foetus simultaneously with 2 weeks of physiological gestation in a healthy doe rabbit.

Overweight in young males reduce fertility in rabbit model.

Semen quality has certainly declined over the past few decades, possibly owing to modern lifestyle factors. In this sense, the role of overweight and obesity in the development of subfertility in males has generated a considerable amount of interest in recent years. However, there is no consensus on whether overweight or obesity impaired sperm quality.

Effect of corifollitropin alfa supplemented with or without LH on ovarian stimulation and embryo viability in rabbit.

There is increasing interest in using rabbits for research as a laboratory model as well as for industrial production of meat, wool and fur. Superovulation in animals is used to produce a maximum number of transferable embryos per donor, in order to either support genetic improvement programs, ex situ conservation or to optimize other biotechnologies. Over time, the use of this biotechnology has shown variable outcomes as a consequence of several factors, such as the origin of exogenous hormone, posology and the effect of gonadotropins used simultaneously, the donor and the environment.

Embryo transfer manipulation cause gene expression variation in blastocysts that disrupt implantation and offspring rates at birth in rabbit.

Objective: In the current study we aimed to evaluate the effect of embryo transfer on gene expression during pre-implantation development and its consequences on implantation rate, offspring rate at birth and embryonic and fetal losses in the rabbit model.

Study Design: The mRNA expressions of 8 candidate genes were compared between 6-day-old in vivo-produced embryos (non-manipulated embryos) to those of 6-day-old embryos previously recovery at the third day of development and transferred into recipient rabbit females (manipulated embryos). Furthermore, we compared between both experimental groups the implantation rate and offspring rate at birth and embryonic and fetal losses.

Development of Cheaper Embryo Vitrification Device Using the Minimum Volume Method.

This study was designed to compare the efficiency of the Cryotop and Calibrated plastic inoculation loop (CPIL) devices for vitrification of rabbit embryos on in vitro development and implantation rate, offspring rate at birth and embryonic and fetal losses. CPIL is a simple tool used mainly by microbiologists to retrieve an inoculum from a culture of microorganisms. In experiment 1, embryos were vitrified using a Cryotop device and a CPIL device.

Oviductal and endometrial mRNA expression of implantation candidate biomarkers during early pregnancy in rabbit.

Prenatal losses are a complex problem. Pregnancy requires orchestrated communication between the embryo and the uterus that includes secretions from the embryo to signal pregnancy recognition and secretion and remodelling from the uterine epithelium. Most of these losses are characterized by asynchronization between embryo and uterus.

Effects of lanosterol on in vitro maturation of porcine oocytes.

FF-MAS and T-MAS sterols, intermediaries in the cholesterol biosynthetic pathway present in all cells, may represent the physiological signal that instructs the oocyte to reinitiate meiosis. The purpose of this study was to examine the hypothesis that exogenous lanosterol could be included in the sterol biosynthetic pathway from acetate to cholesterol and induce resumption of meiosis in oocytes cultured in vitro. Porcine oocytes were in vitro matured in medium supplemented with different concentrations of lanosterol.