Efeito da adição de serina no diluente de resfriamento nos parâmetros de cinética espermática de caninos

Abstract

Growing zootechnical and conservation demands of endangered species of canids generate the desire to improve reproductive biotechnology in canines. The conservation of semen through refrigeration promotes cellular alterations capable of interfering in the viability of spermatozoa. Thus, the addition of a suitable extender which is capable of protecting and preserving spermatozoa is essential. The objective of this study was to evaluate the effect of the addition of serine in the extender medium on the sperm kinetics of cold canine semen. Twelve collections were performed, using 4 Australian Cattle Dog dogs being ejaculated with motility higher than 60% and vigor ≥3. 20% Tris yolk diluents (TG) were added with addition of nine different concentrations of serine (S) from 2.5mM to 200mM S. A group without amino acid was used as control. They were analyzed in the computerizedassisted sperm motility analysis the kinetic parameters at zero hours, 24, 48 and 72 cooling at 4° C. At time zero, the following results for total (MT) and progressive motility (MP) were: in the control (63.3 and 57.6%) and in the treatment 2.5mM S (59.2 and 52.3%), 5mM S (61.1 and 55.1%), 10mM S (57, 7 and 50.1%) and 20mM S (57.9 and 50.5%). After 24 hours the parameters DAP, DCL, DSL, VAP, VCL and VSL in the control treatments (30.6, 50.7 and 25.7 μm, 67.1, 111.11 and 56.4 μm / s) and 2.5mM S (28.9, 49.2 and 24.2μm, 64.4, 109.1 and 53.7μm / s) were higher and in the 48 hours the MT, MP and DAP of 5mM S (47.8 e 39.7%, 22.1 μm), showed superior results to the other treatments. In the final evaluation, 72 hours, the MT in the treatment 2.5mM S (27.7%) was superior, whereas the MP did not differ in treatments 2.5mM S (18.3%) and control (17.2%) those superior to the others. All treatments above 20 mM S presented lower results than those described. The addition of serine at concentrations up to 5 mM is promising for use in canine semen extender in order to maintain sperm motility parameters, the protective potential of the addition of serine in canine semen diluents being dose and time dependent.