Quality Improvement of Post-Thawed Stallion Epididymal Spermatozoa with Single Layer Centrifugation.

BACKGROUND: Epididymal sperm cryopreservation represents the ultimate option to preserve spermatozoa of valuable stallions. OBJECTIVE: The study aims to evalute whether single layer centrifugation (SLC) prior to cryopreservation or after post-thawing improves the quality of stallion epididymal sperm. MATERIALS AND METHODS: Epididymal sperms of stallions were harvested (N=20). Sperm samples were subjected to treatments: conventional centrifugation, SLC prior to cryopreservation (SLC-PC) or SLC post-thaw (SLC+). All samples were cryopreserved, thawed and evaluated. SLC+ were thawed, single layer cenrifuged and resuspended in freezing extender (SLC+F) or cooling extender (SLC+C). Total motility, progressive motility, morphology, mitochondrial functionality, membrane integrity and DNA integrity were evaluated. RESULTS: SLC-PC and SLC+F yielded higher total motility, while SLC+F yielded the highest progressive motility. Mitochondrial functionality was significantly higher in all SLC groups. Membrane integrity was higher in SLC-PC. The percentage of morphologically normal spermatozoa was higher in SLC-PC and SLC+F. CONCLUSION: SLC prior to cryopreservation or post-thaw improves the quality of stallion epididymal spermatozoa. When SLC is performed post-thaw, freezing extender is the best medium to resuspend the pelleted semen.

Management Strategies Aiming to Improve Horse Welfare Reduce Embryonic Death Rates in Mares.

The objective of this retrospective study was to evaluate the effect of management strategies aiming to improve animal well-being on pregnancy and embryonic death (ED) rates. Breeding records of a cohort of 1206 Thoroughbred mares brought to a stallion station facility, to be bred with the stallions housed there, were evaluated during ten breeding seasons. Mares were blocked according to management strategies in two groups: Stress and Relax. Strategies used to improve animal well-being (Relax group) were as follows: stopping the teasing routine, reducing or eliminating stall confinement, reducing the number of mares per group and maintaining herd stability during the breeding season. In barren mares, the pregnancy rate was higher in the Relax group (91.8%) when compared to the observed in Stress group (84.7%). However, no difference in pregnancy rates were observed (Stress = 85.2% vs. Relax = 86.2) in foaling mares. ED rate was higher in barren and foaling mares of the Stress group mares (25.5% and 26.8%, respectively) compared with the Relax group (16.1% and 14.7%, respectively). No significant differences were observed on foal heat pregnancy rate between groups; yet, the embryo loss on foal heat was significant reduced in Relax mares (Relax = 8.7% vs Stress = 24.5%). In conclusion, management strategies aimed to reduce social stress can reduce early pregnancy losses and the average cycles per pregnancy, improving reproductive performance in mares.

A novel strategy of mesenchymal stem cells delivery in the uterus of mares with endometrosis.

Mesenchymal stem cells (MSCs), because of their immunomodulation and trophic activities, in addition to their capacity to regenerate damaged tissues, have potential for treatment of many diseases. The success of stem cell therapies depends, in part, on the method of cell delivery, which should provide wide cell distribution and homing in to injured sites. The objective of the present study was to developing a novel strategy for delivery of MSCs into the uterus of mares with endometrosis (degenerative alteration of uterine glands and surrounding stroma). Endometrosis was confirmed in all mares (N = 6) used in this study. To trace multipotent equine adipose tissue-derived MSCs (eAT-MSCs) in endometrial tissue, before transplantation, cells were stained with a fluorescent dye. During a synchronized estrus, the eAT-MSCs (2 × 10(7) diluted in 20 mL of sodium chloride 0.9%) were inoculated into uterus using a simple technique, similar to artificial insemination (AI) in mares. At 7 and 21 days after transplantation, homing of fluorescently labeled eAT-MSCs was observed by confocal microscopy of uterine biopsies collected from the uterine body and in both uterine horns, including glandular and periglandular spaces, in three of four treated mares. Herein, we propose a new method of MSCs delivery in uterus of mares with endometrosis, which was minimally invasive and technically simple.