Technical difficulties in gonadal tissue removal of newly hatched chicken in gene preservation practice

SUMMARY Background: Nowadays in avian species the only practically used preservation method is semen freezing. However, female oocytes and embryos cannot be frozen because of their biophysical properties. Therefore, an alternative method is needed, to preserve female genetic material. Orthotopic transplantation of the ovary in dayold chicks can be a suitable technique for this purpose. In earlier studies turned out, that not every genotype is suitable as a recipient. White Leghorn and Novogen White proved to be appropriate recipient with Black Transylvanian Naked Neck, Hungarian Partridge colour and Hungarian Speckled chicken breeds as donors. Gonadal tissue transplantation resulted 80% and 72% rates of adhesion applied native and cryopreserved organs, respectively. Objectives: Providing the adhesion it is necessary to make precise ovariectomy in the recipient chicken. In case of the donor organ it is also important to remove the ovary as completely as possible. The aim of this study is to demonstrate the technique of ovariectomy, the difficulties of it and the related basic anatomical knowledges. Materials and Methods: The authors examined unhatched and dead chickens - both females and males - under stereomicroscope. After cleansing the abdominal area and making an incision on the skin, the yolk and the intestinal organs were removed. Thus, the authors could get a better lookout to the genital organs, kidneys, adrenal gland and the vascular system of them. For the ovariectomy, thumb forceps, microsurgery scissors and iris forceps are needed. Results and Discussion: The ovary is located in a serous cavity formed by air sacs. In day-old chicks, it is 3–4 mm long and triangular shaped. The cranial part of the ovary is in proximity of the adrenal gland and the caudal part is near by the kidney. Regarding the vascular system, the organ is lying just under the caudal vena cava and common iliac vein, furthermore, is also close to abdominal aorta. This anatomical position causes the difficulties of ovariectomy, because it is extremely hard to do completely without damaging the vessels or the ovary itself. As result of the detailed anatomical studies, removal of donor ovary of the exterminated chick could be done more precisely right now, but further examinations are needed to create a perfect technique for the removal or hinder the function of the recipient’s own gonad in a live bird