Viabilidade da dose fracionada de sêmen bovino criopreservado descongelada por diferentes métodos

Abstract

Given the low sperm concentration necessary to promote the fertilization of oocytes in FIV, this paper aims at evaluating the quality of dose of bovine semen cryopreserved after its splitting into two parts to make better use of it on the PIV program. The experiment used 110 doses of frozen semen in pallets of 0.25 mL from 10 bulls, which were divided into stages: A dose represented the control group, five were assigned to the group of direct thawing (DT) and 5 for the group of indirect thawing (IT). Doses were fractionated into two parts, forming two subgroups for each group, the unit sphere (UE) and polyvinyl alcohol unit (PAU). The first subgroup analysis was immediate, and the second was analyzed after 24h storage in N2. Results were obtained through descriptive statistics, Kruskal-Wallis and SNK (P <0.05), motility and force: immediate Indirect thawing: 48.8% / 2.4, IT-24: 54.2% / 2.5, immediate direct thawing: 67.8% / 3.0, direct thawing-24: 69.6% / 3.0, Control: 70% / 3.0. For acrosome injury and membrane integrity: immediate Indirect thawing: 24.3% / 40.5%, indirect thawing- 24: 36.2% / 44.3%, immediate direct thawing: 12.8% / 63.6%, DT -24h: 12.6% / 59.0%, control: 11.9% / 57.5%. Average sperm concentration: DI-immediate: 6.1 × 106 DI-24: 7.2 × 106, DD-immediate: 8.2 × 106, DD-24: 7.8 × 106 sperm / dose fraction. Thus for the fractionation of the dose of bovine semen cryopreserved best thawing method was straightforward, since it showed the best results in all parameters.