Reproductive analysis of male and female captive jaguars (Panthera onca) in a Colombian zoological park

Abstract

A reproductive analysis of a captive group of jaguars (Panthera onca; n = 6) at the Santacruz Zoological Foundation in Cundinamarca, Colombia, was conducted by performing a longitudinal, noninvasive, hormonal analysis of estradiol and progestogens in females and of androgens in males. During four seasons, female jaguars confined in solitary were evaluated for ovarian activity and spontaneous ovulation, male jaguars for testicular activity. A second hormonal follow-up was conducted in the females after administration of gonadotropins. Hormones were extracted from fecal samples of three females (n = 3) and two males (n = 2). Estradiol measurements were obtained by RIA and progestogens by enzyme immunoassay. The linear mixed-effect regression showed that there was a significant effect of seasons in the concentrations of estradiol (chi square = 15.97, degrees of freedom = 3, P < 0.01). Posthoc comparisons of all pairs of seasonal means were conducted according to Tukey's honest significant difference, revealing significant differences between seasons: Dry 1 versus Rains 2 (P < 0.01), Rains 1 versus Rains 2 (P < 0.05), and Dry 2 versus Rains 2 (P < 0.05). Elevations of progestogens compatible with spontaneous ovulation occurred in three jaguars, and the linear mixed-effect regression showed that there was also a significant effect of seasons (chi square = 28.56, degrees of freedom = 3, P < 0.01). Posthoc comparisons showed significant differences only between seasons: Dry 2 versus Rains 2 (P < 0.01). The season with the lowest average concentration was Rains 2 (October, November, and December). During this season, periods of anestrous were registered that lasted between 31 and 83 days. The three females presented estradiol peaks after the administration of eCG. A noninvasive longitudinal analysis for androgens was also made (males 1 and 2) over the course of 1 year, and no significant differences were found between the different seasons. A seminal analysis of three adult male jaguars (Panthera onca; n = 3) was also performed after electroejaculation under general anesthesia (male 1 and 2) and by a postmortem epididymal wash (male 3). The mean concentration of spermatozoids was 5.7 × 10⁶ ± 1.1 × 10⁶ spermatozoa/mL. The progressive motility + standard deviation averaged 80%. The percentage of normal spermatozoids obtained by electroejaculation was 80 ± 2.8%, and the abnormalities found more frequently were head defects (7 ± 1.4%). The seminal fluid obtained by epididymal flush contained 35 ± 1.4% normal spermatozoids, and the most frequent abnormalities found corresponded to distal cytoplasmic droplets (39 ± 11.3%).

Keywords: Endocrinology; Estradiol; Jaguar; Progesterone; Spermatozoa; Testosterone.