Avaliação do sêmen ovino texel criopreservado em tris gema de ovo sobre diferentes concentrações de melatonina manipulada - resultados preliminares

Abstract

Artificial insemination with cryopreserved semen is a valuable tool to genetic improvement programs and ovine breed conservation. The aim of this work was to evaluate the effect of adding pharmacy melatonin in diferente concentrations, to sêmen of Texel rams, previously diluted in TRIS-Egg yolk, analysing semen parameters after cryopreservation. Two ejaculates of four rams, aged from 8 months-2 year, with aid of na artificial vagina. These ejaculates were split into three aliquots, and so diluted: one in Tris-egg yolk, and the others in TRIS-egg yolk with melatonin at 2mMol and 4 mMol, to a final concentration of 100x106 sptz/mL. Samples were kept on a waterbath at 34°C. Then they were cooled at 5°C for one hour, filled into 0,25 mL straws. After closing with polyvinylic alcohol, straws were kept for 10 minutes over liquid nitrogen at 8cm from the liquid, and then frozen with liquid nitrogen at -196°C. Samples were thawed at least one week after freezing, and analysed with computerized microscopy through the CASA® system, for: sperm motility, velocity; with HOST test membrane integrity was verified. There was no difference between control and treatments 1 and 2. Demonstrating that the preliminary results obtained with this experiment are satisfactory