In vitro embryo production in horses

The aim of this work is to write a literature review covering the latest findings in the field of in vitro embryo production in horses. In order to perform in vitro embryo production, you first need to know the anatomy of a mare and management of sexual activity. Reproductive systém of mares consists of two ovaries, two oviducts, uterus, vagina and vulva. Unlike other livestock, the development of oocytes is in the cortex of the ovary. Sexual activity is driven neurohumoral and production of hormone is ensured by the central nervous system and endocrine glands. For in vitro embryo production must be obtained first oocytes. These are collected from either the living or the dead mares. For live mares are used ovum pick up (OPU, transvaginal ultrasound guided aspiration), standing flank laparotomy or transcutaneous flank puncture. OPU is a noninvasive method, where each follicle is flushed several times, and in the obtained solution is looked for oocytes. Invasive, but a very successful method for obtaining oocytes is transcutaneous flank puncture. There are three ways for collecting oocytes from abbatoir ovaries - either by slicing ovaries or curettage or aspiration. Very good results in amounts of obtained oocytes was proved by slicing ovaries. First, after collecting oocytes must be sorted according to cumulus-oocyte complex (COC) on compact, expanded or degenerating oocytes. Compact and expanded oocytes are distinguished under a microscope based on the morphology of the edges of this COC. Compact oocytes have a clear line margins, while margins of expanded oocytes are deformed and have heterogeneous cytoplasm. Best results for the production of embryos exhibit expanded oocytes. First, it has to be matured in the medium to the stage of MII. The culture system for oocyte maturation consists of the M199 with Earl's salts, 10% fetal bovine serum and 5 mU - ml of bovine follicle stimulating hormone in a humidified atmosphere of 5% CO2 in air at 38.2 ° C. It was found out that regardless of the duration of cultivation, results of development of blastocysts after 24 or 48 hours were the same. Standard IVF in horses can not be performed due to the zona pellucida and sperm capacitation. Therefore it is used intracytoplasmic sperm injection (ICSI), when one immobilized sperm is injected directly into the oocyte. Before ICSI sperm capacitation must be done by using the calcium ionophore. Oocytes were further cultured in vitro to the blastocyst stage. Another possibility is to transfer the fertilized oocyte directly to the uterine horn of the mare, or it is used cryopreservation for future