Influência da concentração inicial de frutose sobre a qualidade do sêmen fresco e conservado a 4ºC até 48h de caprinos criados em clima tropical.

Abstract

The aim of this study was to evaluate the influence of the initial concentration of fructose in goat seminal plasma on sperm quality. Six goats were used and divided into two experimental groups according to the initial concentration of fructose in seminal plasma: group I (> 710mg/dL) and group II (< 480mg/dL). The experiment was carried out in two stages: in the first, the effect of previous semen washing on sperm quality was tested. In the second stage, the exchange of seminal plasma between the animals of the two groups was carried out. Soon after dilution, the experimental samples from both stages were submitted to the Thermoresistance Test (TTR) and evaluated for vigor and motility (fresh). The remaining samples were stored at 4 ºC for 2, 12, 24 and 48 hours and submitted to TTR. At the end of each TTR, semen smears were made to assess possible morphological changes caused to sperm. Vigor, motility, Motility Degradation Rate (MDT) and morphological changes were submitted to ANOVA (SAS 7.0) and in case of significant difference, means were compared by Tukey test (p < 0.05). Sperm quality decreased with prolonged semen conservation time (p < 0.05). In the first stage, the unwashed semen in group I obtained better results than the semen submitted to washing, while in group II, this procedure improved the quality of the semen. The effect of the exchange of seminal plasma between the experimental groups is only beneficial in animals that have a low initial concentration of fructose. It is concluded that the initial concentration of fructose in seminal plasma is indicative of obtaining good sperm quality after cooling to 4 °C. It is recommended to wash the semen of goats with a low concentration of fructose in the seminal plasma before cooling.