In vitro survival of follicles in prepubertal ewe ovarian cortex cryopreserved by slow freezing or non-equilibrium vitrification.

Purpose: Vitrification is a well-accepted fertility preservation procedure for cryopreservation of oocytes and embryos but little is known regarding ovarian tissue, for which slow freezing is the current convention. The aim of the present study was to assess the efficiency of non-equilibrium vitrification compared to conventional slow freezing for ovarian cortex cryopreservation.

Methods: Using prepubertal sheep ovaries, the capacity of the tissue to sustain folliculogenesis following cryopreservation and in vitro culture was evaluated.

Intrinsic quality of goat oocytes already found denuded at collection for in vitro embryo production.

Although cumulus cells are essential for efficient oocyte maturation, the establishment of protocols that support IVD of embryos obtained from denuded oocytes (DOCs) is important for optimizing the use of reproductive biotechnologies. Thus, this study aimed to establish a protocol for IVD of goat DOC using different strategies of IVM and methods of oocyte activation. Four experiments were performed.

ANTIBODY RESPONSE TO EPSILON TOXIN OF CLOSTRIDIUM PERFRINGENS IN CAPTIVE RED DEER (CERVUS ELAPHUS) OVER A 13-MONTH PERIOD.

Deer are sensitive to clostridial diseases, and vaccination with clostridial toxoids is the method of choice to prevent these infections in ruminants. The purpose of this study was to evaluate the serologic responses in red deer (Cervus elaphus) over a 13-mo period after vaccination with a multivalent clostridial vaccine, containing an aluminium hydroxide adjuvant. Antibody production to the Clostridium perfringens type D epsilon toxin component of the vaccine was measured using an indirect enzyme-linked immunosorbent assay.

Inhibitors of c-Jun phosphorylation impede ovine primordial follicle activation.

Study Hypothesis: Is the c-Jun-N-terminal kinase (JNK) pathway implicated in primordial follicle activation?

Study Finding: Culture of ovine ovarian cortex in the presence of two different c-Jun phosphorylation inhibitors impeded pre-antral follicle activation.

What Is Known Already: Despite its importance for fertility preservation therapies, the mechanisms of primordial follicle activation are poorly understood. Amongst different signalling pathways potentially involved, the JNK pathway has been previously shown to be essential for cell cycle progression and pre-antral follicle development in mice.

Effects of bone morphogenetic protein 4 (BMP4) supplementation during culture of the sheep ovarian cortex.

The aim of the present study was to establish the presence of BMP type I and II receptor presence in preantral follicles and to investigate the effect of BMP4 supplementation on preantral follicle activation and development during organotypic culture of prepubertal ovine ovarian cortex pieces. Ovine ovarian fragments were cultured with varying concentrations (0, 25, 50 or 100 ng/ml) of BMP4 in the presence or absence of FSH in the culture media to determine the optimal minimum dose for preantral follicle activation and development. Follicular morphometry, immunohistochemistry for BMPR-IA, BMPR-IB, BMPR-II, proliferating cell nuclear antigen and TUNEL progesterone and 17β-oestradiol production were assessed.

Relative mRNA expression and immunolocalization for transforming growth factor-beta (TGF-β) and their effect on in vitro development of caprine preantral follicles.

This study aimed to evaluate the immunolocalization and messenger RNA (mRNA) expression for transforming growth factor-beta (TGF-β) and its receptors (TGF-βRI and RII), as well as mRNA expression for P450 aromatase and FSH receptor in caprine preantral follicles. The effects of TGF-β, FSH alone, or in association on the in vitro follicular development were also assessed. Immunohistochemical analyses showed the expression of TGF-β and its receptors in oocytes of all follicle stages and granulosa cells of primary and secondary follicles.

In vitro production of small ruminant embryos: late improvements and further research.

Beyond the potential use of in vitro production of embryos (IVP) in breeding schemes, embryos are also required for the establishment of new biotechnologies such as cloning and transgenesis. Additionally, the knowledge of oocyte and embryo physiology acquired through IVP techniques may stimulate the further development of other techniques such as marker assisted and genomic selection of preimplantation embryos, and also benefit assisted procreation in human beings. Efficient in vitro embryo production is currently a major objective for livestock industries, including small ruminants.

In vitro embryo production in goats: Slaughterhouse and laparoscopic ovum pick up-derived oocytes have different kinetics and requirements regarding maturation media.

A total of 3427 goat oocytes were used in this study to identify possible differences during in vitro embryo production from slaughterhouse or laparoscopic ovum pick up (LOPU) oocytes. In experiment 1, one complex, one semi-defined, and one simplified IVM media were compared using slaughterhouse oocytes. In experiment 2, we checked the effect of oocyte origin (slaughterhouse or LOPU) on the kinetics of maturation (18 vs.

[Regulating pre-antral follicle development: a brake on depletion of the ovarian reserve].

The process of folliculogenesis is a complex and dynamic process that is regulated by positive and negative factors. During folliculogenesis in the mammalian ovary, the primordial follicle pool is gradually reduced through successive waves of follicle growth. It is important that this pool is carefully regulated, otherwise premature ovarian failure will occur.

Influence of heparin or the presence of cumulus cells during fertilization on the in vitro production of goat embryos.

Considerable research has been focused on in vitro production (IVP) of goat embryos to improve its efficiency. In Experiment 1, the effect of the cumulus cells by comparing slaughterhouse-oocytes denuded on purpose (DOP) prior to IVF to intact COC, and the effect of heparin during IVF were assessed. In Experiment 2, oocytes that were already denuded at collection (DOC), DOP and intact COC were studied.

Assessment LOPU-IVF in Japanese sika deer (Cervus nippon nippon) and application to Vietnamese sika deer (Cervus nippon pseudaxis) a related subspecies threatened with extinction.

In mammals, recovery of oocytes by laparoscopic ovum pick-up (LOPU) coupled with in vitro production (IVP) of embryos represents a promising strategy for both amplification and genetic management of sparse animals from captive endangered wild species. As integrated technique developed mainly for domestic livestock, LOPU-IVP requires several studies to set up protocols for follicular stimulation or optimization of IVP before envisaging successful transposition to wild species. In deer, many endangered subspecies would be potentially concerned by applying such an approach using common subspecies for protocols optimization.