Can jaguar (Panthera onca) ovulate without copulation?

Threatened of extinction in Brazil, the jaguar is the largest predator in Latin America, playing an important role in the ecosystem where it is inserted. Despite of some important studies in this species, its reproductive physiology needs to be better understood for the development of more effective reproductive biotechnologies. One well studied biological aspect is the occurrence of ovulation following stimulation of the vaginal floor during copulation. This mechanical stimulation is responsible for the induction of ovulation in domestic and wild cats. Thus, the objective of the present study was to evaluate whether ovulation in captive jaguars can be induced by the above-mentioned mechanical stimulation but also by other forms of sensory stimulation. Nine jaguar (Panthera onca) females and six males were divided into three groups: Group 1 (four females), in which the females were close to the males, but with no possibility of copulation; Group 2 (three females), in which the females were in the same enclosure as the males, thereby being able to copulate; and Group 3 (two females), in which the females were completely isolated from any male of the species. Follicular growth was stimulated by administration of 800 IU of eCG, conducted three or five days before LOPU. In order to have certainty about the occurrence of ovulation, the ovaries were assessed by laparoscopy allowing the visualization of ovarian structures including follicles, recent ovulations, corpora hemorrhagica (CH) and corpora lutea (CL). Multiple CH were observed in the 2 females housed with males, as well as the two females kept in proximity of males, i.e. only visual contact (Group 1). None of the females in complete isolation from males showed CH or ovulation spots (Group 3). In summary, the seven females in contact or near proximity with males had multiple ovulations, regardless of copulation or not. Based on this evidence, we have established that jaguars are capable of two forms of induced ovulation: 1) the "mechanical" coitus-induced form that is traditional and thoroughly described for felines; 2) a "sensorial" form in which the nearby presence of a male can induce ovulation through the visual, olfactory and/or auditive senses. Further research is required for establishing the mechanisms and chemical mediators of sensorial stimulation. In addition, and consistent with expected results, we confirmed that females that received the same stimulation are incapable of ovulating when not exposed to any form of stimulation by males.

Comparison of semen samples collected from wild and captive jaguars (Panthera onca) by urethral catheterization after pharmacological induction.

This study was designed to evaluate the efficiency of medetomidine anesthesia for semen collection through urethral catheter in wild and captive jaguars. Six captive and five wild jaguars were chemically restrained with a combination of medetomidine (0.08-0.1 mg/kg) and ketamine (5 mg/kg). After medetomidine administration the urethra was catheterized using a urinary tomcat catheter (1 mm diameter × 130 mm length) to collect semen from all animals. By using this technique, we could collect an average of 347.2 µl of semen containing 2,635.2 sperm/ml. Forward progressive motility, sperm progressive motility, and sperm morphology analysis demonstrated that the methodology did not affect sperm quality. Thus, urethral catheterization after medetomidine administration is a practical and efficient method to collect high-quality semen from wild and captive jaguars; this will enable the development of reproductive assisted technologies for jaguars.

Ocelot and oncilla spermatozoa can bind hen egg perivitelline membranes.

We evaluated the capacity of ocelot and oncilla spermatozoa to bind to the perivitelline membranes (PVMs) of hen eggs in a sperm binding assay (S-PVM). In addition, a device that improves the standardization of the assay was developed. The number of sperm bound to the PVM in fresh (T1) and frozen-thawed (T2) semen from both species was compared to the sperm quality observed in routine tests. The PVM was stretched on a circular silicone device to create a standardized area for analysis. In both treatments and for both species, the spermatozoa were able to bind to the PVM, indicating that PVM may be used for a sperm binding assay in ocelot and oncilla. The S-PVM assay did not differ in fresh and frozen-thawed ocelot sperm (p>0.05). However, fewer oncilla sperm (p<0.05) were bound to the PVM in T2, indicating that the proposed test may be able to detect injuries that compromise sperm binding abilities. The device maintained the PVM stretched during the processing and defined the evaluation area.

Comparação entre duas concentrações de glicerol para a criopreservação de sêmen de suçuarana (Puma concolor) / Comparison between two glycerol concentrations to cryopreservation of semen of mountain lions (Puma concolor)

O desenvolvimento de biotécnicas de reprodução é uma importante ferramenta para a conservação de animais silvestres ameaçados de extinção. Procedimentos de reprodução assistida em suçuarana, no entanto, são escassos na literatura, em especial aqueles relacionados à criopreservação de sêmen. Neste sentido, o presente trabalho objetivou avaliar a congelabilidade do sêmen de suçuaranas adultas mantidas em cativeiro, por meio da comparação entre duas concentrações de glicerol no meio de congelamento. Foram usados cinco machos adultos de suçuarana, mantidos no Centro de Reabilitação de Animais Silvestres do Mato Grosso do Sul (CRAS/MS). As amostras foram coletadas por eletroejaculação e avaliadas quanto ao seu aspecto físico, volume, vigor, motilidade, concentração e índice espermático. De cada ejaculado duas alíquotas foram diluídas em meio Tris-citrato-gema de ovo, em concentrações finais de 5 e 7,5% de glicerol, resfriadas a uma taxa de -0,55ºC/min e congeladas a uma taxa de -5,8ºC/min. Depois de descongeladas, as amostras foram reavaliadas e submetidas aos testes de termorresistência e hiposmótico. O protocolo de criopreservação e descongelamento de sêmen proposto se mostrou eficiente em ambas as concentrações de glicerol testadas, não havendo diferença (p>0,05) entre estas.

The development of biotechnologies of reproduction is an important tool for the conservation of wild animals threatened with extinction. Assisted reproduction procedures in mountain lions, however, are scarce, especially those related to sperm cryopreservation. In this context, this study aimed to evaluate the freezing capacity of semen from adult mountain lions in captivity through the comparison of two concentrations of glycerol in the freezing media. Five adult male mountain lions were used, held at the Rehabilitation Center for Wild Animals of Mato Grosso do Sul (CRAS/MS). Samples were collected by electroejaculation and evaluated for physical appearance, volume, sperm progressive status, sperm motility, sperm concentration and sperm motility index. Each ejaculate was spliced into two aliquots and diluted in Tris-citrate-half egg yolk, at final concentrations of 5 and 7.5% glycerol, cooled at a rate of -0.55ºC/min and frozen at a rate of -5.8ºC/min. Once thawed, the samples were re-evaluated and tested for thermoresistance and hypoosmotic swelling. The suggested protocol for cryopreservation and thawing of semen is efficient in both glycerol concentrations tested, with no difference (p>0.05) between them.