Seasonal variations in serum concentrations of testosterone, testicular volume and neck circumference of fallow deer (Dama dama) kept ex situ in a tropical region.

The fallow deer (Dama dama) is a species of Cervidae commonly kept in captivity, either in commercial farms or in zoos. The reproductive seasonality of this species is well known in the northern hemisphere, where photoperiod is a decisive factor in androgenic activity and, consequently, in the development of secondary sexual characteristics among male adults. The maintenance of this species in tropical regions has been successful, but there are no studies that demonstrate the maintenance of reproductive seasonality under these climatic conditions, which was the objective of the present study. To do so, the present investigation involved 27 fallow deer (D. dama) specimens, of which 14 were adults and 13 prepubescent (<8 months) individuals, all assessed during and outside (December-February) the reproductive season (June-August). The serum concentrations of testosterone, testicular volume, and neck circumference were analyzed among all animals during both seasons. The reproductive season was marked by expressive hormonal concentrations, increasing neck circumference and testicular volume, differing significantly between adults and prepubescent individuals outside the season. Positive correlations were observed among all analyzed variables: mean testicular volume and neck circumference (r = 0.92, p < 0.0001), testicular volume and testosterone concentrations (r = 0.79, p < 0.0001) and between neck circumference and testosterone concentrations (r = 0.67, p < 0.0001). Given the results found, the conclusion is that even under tropical climate conditions the reproductive seasonality of the fallow deer is well defined and may be related to photoperiod.

Estudo da correlação das características citológicas vaginais e os níveis séricos de estradiol e progesterona em leão africano (Panthera leo) mantidos em cativeiro / Vaginal citology, serum estradiol and progesterone: a correlation study on captive African lions (Panthera leo)

Foram estudados 11 exemplares de fêmeas adultas de leões africanos (Panthera leo) mantidas na Fundação Parque Zoológico de São Paulo (FPZSP) quanto às características da citologia vaginal, níveis hormonais (estradiol e progesterona) e suas correlações. As características celulares vaginais encontradas nas leoas foram semelhantes às descritas para os felinos domésticos. Adotando-se os padrões hormonais de estradiol (E2) e progesterona (P4) que definem as fases do ciclo estral de felinos domésticos, foi possível caracterizar três fases do ciclo ovariano nas leoas: Diestro, Estro e Interestro. O nível médio de E2 sérico encontrado na fase caracterizada como Estro (23,33 + / - 2,92 pg/ ml;, apresentou-se mais alto do que nas outras fases estudadas e o nível médio de P4 sérico encontrado na fase de Diestro (20,12 + / - 17,55 ng/ ml; apresentou diferença estatística significativa em comparação às outras fases estudadas. Demonstrou-se também, a existência de correlação de intensidade média entre os níveis séricos de P4 e o número de células superficiais corneificadas (r= - 0,603 e p = 0,0496) e entre P4 e células intermediárias (r = 0,637 e p = 0,0350). Também foi demonstrada a existência de correlação negativa de forte intensidade entre os números de células superficiais corneificadas e o de células intermediárias. (r = -0,979 e p < 0,0001). Concluímos que a correlação entre as características celulares vaginais e os níveis séricos de progesterona e estradiol permitiram-nos determinar três diferentes fases do ciclo ovariano da fêmea de leão africano.

Eleven captive adult female African lions (Panthera feo) at the Fundação Parque Zoológico de São Paulo were blood sampled in order to assess the serum hormone levels (estradiol and progesterone) and their correlation with the vaginal citology. The morphological and stainning characteristics of vaginal cells were similar to those described for domestic cats. Based on hormonal proflles of estradiol and progesterone described for domestic cats, three different phases for the ovarian cycle of the lionesses were clearly described: diestrus, estrus and interestrus. The mean serum estradiol concentrations in the estrus (23,33 + / - 2,92 pg/ ml) were significantly higher than in diestrus and interestrus. The mean serum progesterone values in diestrus (20,12 + / - 17,55 ng/ml) were significantly higher than in estrus and interestrus. There were correlations between progesterone values and the number of superficial cornifled vaginal cells (r = - 0,603 and p = 0,0496) and between progesterone and intermediate cells (r = 0,637 and p = 0,0350). There were also a strong negative correlation between the number of superficial cornified vaginal cells and intermediate cells (r= -0,979 e p < 0,0001). It concluded that the correlations between vaginal cells and the serum estradiol and progesterone levels allowed us to identify three different phases of the ovarian cycle in female African lion.