Parámetros sanguíneos y perfil de hormonas reproductivas de hembras de Choloepus hoffmanni en cautiverio

Abstract

In wild animal species, the use of non-invasive and non-stressful procedures to determine hormone profiles, such as fecal steroid measurements, has considerably increased the comprehension of their reproductive physiology. Since there is limited information related to the reproductive hormone profiles of the two-toed sloth, Choloepus hoffmani, a study was conducted in captive specimens at the “Sloth Sanctuary” (Cahuita, Limón, Costa Rica), in order to determine: (i) the reliability of the fecal progesterone and estrogen extraction and its quantification with an AIA-360® analyzer, (ii) assess blood parameters in this species and (iii) evaluate if there is a correlation between fecal and plasmatic steroids. The study was performed over a three-month period, from November, 2013 to January, 2014, with a total amount of 208 fecal samples collected from five sexually mature females weighing 6.32 Kg in average. The average of the median concentrations of progesterone in feces of the five females was 124.21 ng/g, and 1 708.95 pg/g for estrogen. The average minimal and maximal values were 50.96 ng/g and 1 057.46 ng/g for progesterone and, 1 191.77 pg/g and 2 159.24 pg/g for estradiol. In plasma, progesterone median values were 1.26 ng/mL, showing a minimum of 0.32 ng/mL and 12.84 ng/mL as maximum values. The plasmatic estrogen levels were below the detection limit of the equipment (25 pg/mL). Although there was no strong statistical correlation between the fecal and plasmatic progesterone fluctuations, our data suggests that the plasmatic events are mostly reflected in feces two days afterwards. Also, the levels of progesterone were elevated during the first half of November and, subsequently, showed a successive and important reduction in all the females tested. Finally, our results demonstrated that fecal steroid extractions and their measurement in a AIA-360®, allowed the successful detection and represents an alternative non-invasive determination of hormone profiles in C. hoffmani.

Reproductive Cycle Stage Assessment in the Two-Toed Sloth (Choloepus Hoffmanni), Preliminary Results

“…Additionally, neither vulvar swelling nor marked physical changes during this phase were described by others. 8,14…”

“…In this study, the combined average duration of the estrous cycle, estimated by vaginal smears, was 15.1 ± 4.53 d. In another species of the same genus, C. didactylus , a longer duration of approximately 31 d was established by hormonal analysis in feces. 14 Herra-Vargas et al 8 evaluated the ovarian activity in C. hoffmanni with a fortnightly hormone assay, finding only two of five females showed regular cycles of progesterone.…”

“…11 Preliminary endocrine studies in two-toed sloths have so far failed to provide conclusive details about their reproductive cycle because of the small sample sizes. 8,10 Furthermore, when vaginal smears were performed in the Jiménez 2012 study, 10 samples were taken sporadically and did not follow the complete cycle. Moreover, the Papanicolaou staining technique was described as an inadequate method for staining the vaginal cells.…”