Morfometría de la gónada masculina y espermatozoides de cuyes (Cavia porcellus) nativos y mejorados del sur de Ecuador

The aim of this research was to describe the morphometry of the testicles and sperm of guinea pigs (Cavia porcellus) of two genetic groups, native and improved, from southern Ecuador. Twenty-two native and 20 improved guinea pigs of the Peru line were used. The animals were reared in elevated cages and fed with forage and concentrate, until reaching the slaughter age of 97 to 112 days. After slaughtering, the testicles and epididymis were removed, and the epididymis was separated of the testis. Measurements of the testicles were done, and sperm was collected from the epididymis by the retrograde flow washing technique. Semen smears were prepared for sperm measurements. The data were processed by GLM analysis of variance and the LSMeans procedure was used to compare the means (SAS v. 9.0). The morphometric parameters of the testes were different (p<0.05) between subpopulations. Opposite testes from the same genetic group were similar, while the ipsilateral ones between subpopulations showed statistical differences (p<0.05). Testicular size was directly related to body weight, and the gonadosomatic index of native guinea pigs was higher than that of improved ones (p<0.05). Spermatozoa were different (p<0.05) between genetic groups in acrosome and head length and in head length / width ratio. In conclusion, this study showed morphological differences in the testes and sperm between the two genetic groups of guinea pigs.