Morphological and morphometric characterization of the guinea pig sperm (Cavia porcellus)

The aim of this study was to determine the morphological and morphometric characteristics of guinea pig sperm (Cavia porcellus), using an image analysis system. Semen from collected from five type 1 guinea pigs, four months old (1.19 ± 0.15 kg) by electroejaculation method, between 3 and 5 times for each animal, making a total of 22 adequate collections. The volume, pH, sperm concentration, total motility and percentage of live sperm were determined. The samples for the analysis of sperm morphology and morphometry were stained with Spermac® and analyzed using the Motic Image Plus® software. The morphology was analyzed according to the dynamics of its acrosomal reaction, distinguishing 4 classes. The length, width, area, perimeter, ellipticity, elongation, regularity and rugosity of the head of the guinea pig sperm were determined, as well as the midpiece length and the tail of the spermatozoa. Guinea pig sperm morphology was analyzed with a complete random design, and the morphometric parameters by random blocks, using Duncan's test to compare means in both cases. In relation to morphology, significant differences (P <0.05) were found in the percentage distribution of classes, the most recurrent being class 2 (41.67%), higher than the other 3 groups. An animal effect (P <0.05) was found in the morphometric variables of head and midpiece of guinea pig spermatozoa. The morphometric measurements of guinea pig spermatozoa were: length (7.45 ± 0.29 µm), width (6.55 ± 0.25 µm), area (43.02 ± 3.03 µm2), perimeter (26.56 ± 1.07 µm), midpiece length (12.02 ± 0.70 µm) and spermatozoa tail length (92.96 ± 3.96 µm).