Sperm quality and subpopulations of squirrel monkeys (Saimiri collinsi Osgood, 1916) and their correlations with fattening phenomenon
Fattening phenomenon, semen, neotropical primates, reproductive seasonality, mating season.
Among the neotropical primates, squirrel monkeys (Saimiri sp.) have reproductive seasonality, which is characterized by male weight gain during the reproductive season (mating period), knew as fattening phenomenon. Since the reproductive seasonality may influence spermatogenesis, there are few and divergent studies on this theme for the Saimiri genus. The relationship between fattening and sperm quality remains unknown. Therefore, the aim is to study the male Saimiri collinsifattening phenomenon, and propose fatted and gonadosomatic indexes, as well as investigate the effect of this phenomenon on sperm viability and subpopulations. This study was conducted at Centro Nacional de Primatas (CENP), Ananindeua, Brazil (1°22’58”S and 48°22’51”W). Twelve adult Saimiri collinsi males (n = 12) were used, distributed in four social groups. Three mixed groups was composed of adult males (n = 3) and females (n = 6) and one group with only adult males (n = 3). During 18 months, animals were weighed, arm and thorax skin folds and testicular volume were measured once each month. Semen was collected by electroejaculation and macroscopically evaluated (volume, color, degree of coagulation, opacity and pH). Microscopic sperm evaluation were either performed for all samples (motility and vigor, concentration, plasma membrane integrity and functionality, normal morphology and biometry). The Fatted Index (FI) makes possible to discriminate the fatted and non-fatted conditions. Fatted was identified in all individuals, almost synchronously, and fattening period was defined (March to May). All body biometrics parameters were higher in the fatted condition. There was no effect on ejaculates obtaining between conditions, but azoospermic samples differed significantly between fatted and non-fatted conditions, which 50% ejaculated obtained in fatted period were azoospermic and only 9% of semen from non-fatted were azoospermic. Plasma membrane integrity was lower in fatted period, however sperm functionality was maintained between fatted and no-fatted seasons. It was possible to determine the Fatted Index and the fattening phenomenon affected the ejaculates and sperm qualities.