Ovarian response to P4-PGF-FSH treatment in Suffolk sheep and P4-PGF-PMSG synchronization in cross-bred ewes, for IVD and ET protocol

Metabolomics analysis of the effect of GnRH on the pregnancy rate of ewes with estrus synchronization scheme based on progesterone

Introduction

Gonadotropin-releasing hormone (GnRH) is widely used in the timed artificial insemination protocol for sheep. However, there remains a debate regarding its impact on pregnancy rates during artificial insemination. This study aims to evaluate the effect of GnRH on the pregnancy rates in Huyang ewes, analyze the pre-implantation metabolite changes caused by GnRH using metabolomics, and elucidate the mechanism effect on pregnancy rates.

Methods

All ewes were administered a vaginal progesterone sponge containing 45 mg of flurogestone acetate for 12 days and received 330 units of equine chorionic gonadotropin (eCG) intramuscularly after sponge removal. The experimental group (n = 69) received an intramuscular treatment of 17 μg GnRH agonist triptorelin 48 h after sponge removal on Day 0, while the control group (n = 41) received 1 mL of sterile saline solution. All ewes underwent a single vaginal insemination 58 h after the withdrawal of the progesterone sponge. The difference in pregnancy rates between the two groups was calculated. Metabolomic analysis was performed on plasma samples collected on Day 7 after the treatment of GnRH agonist.

Results

Gonadotropin-releasing hormone (GnRH) treatment significantly reduced the pregnancy rate in the experimental group compared with the control group (72.2 vs. 82.9%, p < 0.05). Metabolomic analysis indicated that GnRH treatment affected metabolites involved in collagen synthesis and prostaglandin synthesis in the endometrial tissue, which includes a marked decrease in hydroxyproline amino acid content and a significant increase in corticosterone and prostaglandin D2 lipids and unsaturated fatty acids.

Conclusion

In summary, the injection of GnRH agonist Triptorelin 48 h after progesterone sponges removal reduces the pregnancy rate of Huyang ewe following artificial insemination. It also affects the metabolite levels related to endometrial collagen and prostaglandin synthesis, harming embryo implantation.

Field outcomes of laparoscopic ovum pick-up combined with in vitro embryo production in sheep: Effects of long-acting recombinant ovine FSH pre-stimulation, collection frequency, and donor breed

Laparoscopic ovum pick-up (LOPU) combined with in vitro embryo production (IVEP) is a technology platform that improves the utilization rate of the elite ewe's ovarian oocytes and increases the number of obtained offspring. This study aimed to evaluate the effects of FSH pre-stimulation, serial oocyte collection, and breed on LOPU-IVEP under field conditions. Donors were randomly assigned to five groups (group A: decreasing doses of pituitary FSH (p-FSH); group B: constant doses of p-FSH; group C: two doses of long-acting recombinant ovine FSH (ro-FSH); group D: single administration of a long-acting ro-FSH in; group E: no FSH stimulation). Oocyte yield following LOPU (average recovered oocytes: 20.9 ± 0.5; average viable oocytes: 17.2 ± 0.4) and oocyte developmental competence (average blastocysts: 7.0 ± 0.2) in group C were significantly better than these of group D and group E, and similar to these of groups A and B. Meanwhile, there were no differences in oocyte yield and developmental capacity using repeated LOPU session at 1-, 2-, and 3-month intervals (p > 0.05). Finally, we compared LOPU-IVEP outcomes among five sheep breeds. The results indicated that East Friesian × Chinese Mongolian crossbred sheep and purebred East Friesian sheep had the more recovered oocytes and viable oocytes compared with the Suffolk, Dorper, and Texel breeds, and average number of blastocysts in East Friesian × Chinese Mongolian sheep group was also highest among the groups (8.1 ±0.3, p < 0.05). In summary, the results of this study indicate long-acting ro-FSH pre-stimulation combined with 12 times LOPU sessions over one year maximizes embryo production of elite donor ewes under field conditions.

DIA-Based Proteomic Analysis Reveals MYOZ2 as a Key Protein Affecting Muscle Growth and Development in Hybrid Sheep

Hybridization of livestock can be used to improve varieties, and different hybrid combinations produce unique breeding effects. In this study, male Southdown and Suffolk sheep were selected to hybridize with female Hu sheep to explore the effects of male parentage on muscle growth and the development of offspring. Using data-independent acquisition technology, we identified 119, 187, and 26 differentially abundant proteins (DAPs) between Hu × Hu (HH) versus Southdown × Hu (NH), HH versus Suffolk × Hu (SH), and NH versus SH crosses. Two DAPs, MYOZ2 and MYOM3, were common to the three hybrid groups and were mainly enriched in muscle growth and development-related pathways. At the myoblast proliferation stage, MYOZ2 expression decreased cell viability and inhibited proliferation. At the myoblast differentiation stage, MYOZ2 expression promoted myoblast fusion and enhanced the level of cell fusion. These findings provide new insights into the key proteins and metabolic pathways involved in the effect of male parentage on muscle growth and the development of hybrid offspring in sheep.

Upgrading the fixed-time artificial insemination (FTAI) protocol in Romanian buffaloes

The present study describes the challenges of assisted reproduction in Romanian buffaloes while increasing the efficacy of artificial insemination by choosing the most suitable method. The modified fixed-time artificial insemination (FTAI) protocol with sexed semen was used to increase the conception rate. This study included a total of 80 buffalo heifers that received ovarian stimulation using the OvSynch protocol. Two groups (n = 40), namely, a control group, in which the classic FTAI method was performed, and an experimental group, in which deep intrauterine AI was performed in cows that had developed a dominant follicle (US+UcFTAI), were randomly selected. The conception rate (CR) was 63.6% in the experimental group, which was statistically higher (P < 0.05) than the control group (30%). The ultrasound examination indicated that, using the OvSynch protocol, 82.5% (33 out of 40) of buffaloes developed a dominant follicle (DF) while the distribution between the warm and cold seasons was 75 and 90%, respectively. The CR was 60% during the hot season and 66.6% during the cold season. At calving, 92.5% female fetuses were born. The improved FTAI method in this study enhanced the results by reducing the waste of sexed semen and maximizing the response to OvSynch, making it a recommendation for practitioners. This study presents preliminary results and highlights that genetic progress is difficult to achieve. A systematic approach is needed in order to choose the most suitable biotechnological method for each farm.

Cryopreservation and Transfer of Sheep Embryos Recovered at Different Stages of Development and Cryopreserved Using Different Techniques

This article presents data from experiments to determine the cryoresistance of Charollais sheep embryos, depending on the stage of embryo development and the method of freezing, as well as the results of embryo transfer. The study design consisted of a study on the cryopreservation of ewe embryos at different developmental stages (early, 2-8 blastomeric and late, at the morula/blastocyst stage), two cryopreservation protocols (slow freezing and ultra-fast vitrification), and embryo transfer of cryo- and fresh embryos. Embryos from Charollais sheep donors (n = 12) were recovered after induction of superovulation. The embryos were recovered surgically (laparotomy) on days 2 and 6 after insemination. Before there was transfer to recipients, part of embryos was cryopreserved using standard slow freezing and ultra-fast vitrification methods. The average ovarian response was 7.54 ovulations per donor, and 5.83 embryos per donor were collected. No effect of the cryopreservation method and embryo development stage on the preservation of the morphological structure of embryos was found. There were no significant differences in the survival rate of cryoembryos at different development stages, frozen using different techniques, and after transfer to recipients. Differences in cryoresistance between embryonic developmental stages in favor of the morula/blastocyst stage were found (survival after thawing 86.4% vs. 75.0% in early embryos). At different stages of development, the survival rate of fresh embryos (45.8%) compared to cryopreserved ones (30.2%) was significantly higher (p < 0.05), while among fresh ones, the best survival rate (50.0%) was observed after the transfer of morules and blastocysts.

Embryo production and transplantation in non-breeding season of meat sheep breeds by stimulating superovulation with different follicle-stimulating hormone preparations

The objective of this study was to investigate the response of Charolais and Ile-de-France meat sheep breeds to stimulate superovulation with various follicle-stimulating hormone (FSH) preparations. A total of 14 adult ewes of meat sheep breeds were used in our study as donors, including Charolais breed (n = 8) and Ile-de-France breed (n = 6). Donors ewes were randomly divided into two groups in equal numbers (first group, n = 7; second group, n = 7), every group included Charolais breed (n = 4) and Ile-de-France breed (n = 3). Ewes in the first group were treated with Folltropin-V (total dose of 200 mg per ewe, seven injections), and ewes in the second group were treated with FSH-P (total of 280 IU per ewe, six injections). Thirty-seven ewes of Edilbay breed used as recipients were divided into two groups (first group, n = 20; second group, n = 17). Our results showed that the number of corpora lutea in donor groups treated with Folltropin-V was significantly higher than in donor groups treated with FSH-P (p < .01). A greater number of embryos recovery and embryos suitable for transplantation were found in the first group compared with the second group of donors. After 30 days from transplantation, transabdominal ultrasonography showed that the presence of pregnancy in recipients groups was found in 16 recipient ewes (43.2%), in the first group of recipients were registered nine pregnant ewes of 20 recipient ewes (45.0%), and in the second group of recipients were registered seven pregnant ewes of 17 recipient ewes (41.2%). In conclusion, using Folltropin-V in Charolais and Ile-de-France meat sheep breeds is a more effective scheme for stimulating superovulation than using FSH-P.