Impact of lipid content on oxygen reactive species and viability predictors in vitrified bovine embryos.

Given the significant variation in lipid levels among bovine embryos, our study was designed to associate lipid content to oxidative stress in individual embryos undergoing vitrification, and to assess how this and other morphological parameters impacts cryosurvival. Linear and logistic regression were performed to understand the influence of the variables in the cryosurvival. T-test or Kruskal Wallis were employed to compare means.

Morphology of 16-cell embryo in bovine: Inside cells, compaction, fragmentation and effects of X-sorted semen.

In mouse embryos, inside cells are allocated in 16-cell embryos through a well-orchestrated sequence of events involving compaction and polarization. The emergence of inside cells is of great importance as itl later gives rise to the inner cell mass and epiblast. In this study, we report the sequence of critical events in embryology (compaction, inside cells allocation and fragmentation) in bovine 72 h.

Outstanding Gir oocyte donors: How does individual factor affect in vitro embryo production efficiency?

The oocyte donor plays a pivotal role in bovine in vitro embryo production (IVP) success. The individual factor affects blastocyst/oocyte ratio and determine the existence of outstanding performing animals. The aim of this study was to assess the extent of individual factor effect to IVP efficiency, in a population of Gir oocyte donors.

Sperm head morphometry and chromatin alterations in bulls with different conception rates.

The objective of this investigation was to analyze timed-AI conception rates (CRs) of different sires in light of their conventional semen quality parameters, sperm head morphometry, and chromatin alterations. Semen was collected in the field from six Angus bulls and used for the timed-AI of 890 suckled multiparous Nellore cows at a single farm. Semen batches were evaluated on the following in vitro parameters: sperm motility, concentration, and morphology, sperm head morphometry, and chromatin alteration types.

Relationship between sperm ubiquitination and equine semen freezability.

This study aimed to assess the semen ubiquitin levels of stallions with good (GF) and poor semen freezability (PF) and to evaluate the relationship between sperm ubiquitination and sperm morphological defects. Five ejaculates from eight adult stallions (n = 40) were collected and cryopreserved. Then, the ubiquitin level in equine sperm cells was assessed by immunohistochemistry with epifluorescence microscopy, and sperm morphology was assessed by differential interference contrast microscopy.

Administration of PGF2α at the moment of timed-AI using sex-sorted or conventional semen in suckled nelore cows with different intensity of estrus behavior.

The aim of this work was to evaluate pregnancy rates (PR) and ovulatory characteristics of Nelore cows receiving PGF2α at the time of AI (artificial insemination) in a progesterone(P4)/estradiol-based timed-AI protocol. We also compared the effects of PGF2α treatment at AI in cows inseminated with conventional or sex-sorted semen, with the absence or expression of estrus. In experiment 1, a total of 701 suckled, multiparous Nelore cows from two commercial beef farms were submitted to the same protocol.

Coenzyme Q-10 improves preservation of mitochondrial functionality and actin structure of cryopreserved stallion sperm.

Coenzyme Q-10 (CoQ-10) is a cofactor for mitochondrial electron transport chain and may be an alternative to improve sperm quality of cryopreserved equine semen. This work aimed to improve stallion semen quality after freezing by adding CoQ-10 to the cryopreservation protocol. Seven saddle stallions were utilized.

Influence of seminal plasma during different stages of bovine sperm cryopreservation.

This study aimed to evaluate the effect of seminal plasma on bovine sperm cryopreservation and to assess the integrity of plasma and acrosomal membranes, mitochondrial potential, remodelling of F-actin cytoskeleton and sperm chromatin fragmentation during the cooling, equilibrium and freezing/thawing stages. Six ejaculates collected from seven Nelore bulls (n = 42) were used in this study. Each ejaculate was divided into two aliquots (with seminal plasma = SP group; without seminal plasma = NSP group) and packed to a final concentration of 50 × 10 sperm per straw.

Effects of Equine Chorionic Gonadotropin on Ovulatory and Luteal Characteristics of Mares Submitted to an P4-Based Protocol of Ovulation Induction With hCG.

The aim of this study was to evaluate the effect of equine chorionic gonadotropin (eCG) at the end of progesterone (P4) treatment on follicular and luteal characteristics during transition period (TP) and reproductive breeding season (RP). A total of 13 crossbred mares were distributed in two experimental groups in the spring and summer (n = 26). The animals received intravaginal P4 (1.

Oocyte origin affects the in vitro embryo production and development of Holstein (Bos taurus taurus) - Gyr (Bos taurus indicus) reciprocal cross embryos.

A reciprocal crossbred embryo production approach was used to assess effects of maternal breed on embryo development in tropical conditions (average temperature 22.0 °C and 77.9% relative humidity).

Evaluation of cooling and freezing systems of bovine semen.

Semen cryopreservation comprises different steps, among them are the cooling and freezing rates which significantly influence the quality of thawed sperm. Different systems with variable freezing rates are used for freezing bull semen in the field, with a consequence of variable success rates. The objective of this study was to compare different systems for freezing bull semen in the field.

Assessment of in vitro sperm characteristics and their importance in the prediction of conception rate in a bovine timed-AI program.

The aims of this study were to assess in vivo fertility and in vitro sperm characteristics of different sires and to identify sperm variables important for the prediction of conception rate. Multiparous Nelore cows (n = 191) from a commercial farm underwent the same timed artificial insemination (timed-AI) protocol. Three batches of frozen semen from three Angus bulls were used (n = 9).

HDAC inhibition decreases XIST expression on female IVP bovine blastocysts.

During initial development, both X chromosomes are active in females, and one of them must be silenced at the appropriate time in order to dosage compensate their gene expression levels to male counterparts. Silencing involves epigenetic mechanisms, including histone deacetylation. Major X chromosome inactivation (XCI) in bovine occurs between hatching and implantation, although in vitro culture conditions might disrupt the silencing process, increasing or decreasing X-linked gene expression.

Chromatin modifying agents in the in vitro production of bovine embryos.

The low efficiency observed in cloning by nuclear transfer is related to an aberrant gene expression following errors in epigenetic reprogramming. Recent studies have focused on further understanding of the modifications that take place in the chromatin of embryos during the preimplantation period, through the use of chromatin modifying agents. The goal of these studies is to identify the factors involved in nuclear reprogramming and to adjust in vitro manipulations in order to better mimic in vivo conditions.