The coconut water powdered use in the swine semen freezing process: I. Controls during the temperature fall

Abstract

Semen from eight bulls was collected using the gloved hand technique, using the total ejaculate. From each ejaculate, 10.2 x 10.9 sptL were collected for each treatment. Semen quality was evaluated by concentration (x10.6 sptz mL), volume (mL), total sperm (x 10.9 sptz), sperm vigor (0 to 5), percentage of motile cells (%), sperm morphology (%) and membrane integrity (%). Semen was diluted in Beltsville Thawing Solution (BTS) and coconut water powder (ACP). The ejaculate was diluted in equal parts (l:l) and incubated between 30 ºC and 15 ºC. Acrosome integrity and vitality tests were performed on pure and diluted semen by the bromophenol blue technique at a magnification of 1,000x. Plasma membrane integrity was assessed by fluorescent staining under dark-field optical microscopy. The experimental design was randomized blocks, using the Mann Whitney, Tukey and Student tests, with analysis of the differences between means performed by multifactorial variance with the General Linear Models of the Statistical Analysis System (SAS 6.03) program, at a confidence interval of p<0.05. The evaluations of in natura semen showed mean values ​​of sperm vigor (4.2) and percentage of motile spermatozoa (92%) above the minimum parameters required (3.0 and 70%) for its use in artificial insemination programs. In the characteristic percentage of motile cells, ACP (74%) was significantly better than BTS (67%) at 15 ºC. The best results were obtained with the use of the ACP diluent: intact acrosome (49.2%); live cells (62.5%) and intact membrane (65.6%). The ACP diluent provided a preservation medium that maintained a greater number of live sperm with intact membranes, and can be recommended for routine use in reproduction laboratories. The ACP diluent proved to be a good means of preserving swine sperm at temperatures between 17 and 15 ºC, and can be indicated for use in artificial insemination programs.