Ovarian folliculogenesis in collared peccary, <i>Pecari tajacu</i> (Artiodactyla: Tayassuidae).

Abstract

Abstract:The sustainability and production of collared peccary (Pecari tajacu) has been studied in the last few years; however, further information on its reproduction is necessary for breeding systems success. Understanding folliculogenesis aspects will contribute to effective reproductive biotechniques, which are useful in the preservation and production of wildlife. The aim of this study was to evaluate the ovarian folliculogenesis in collared peccary. Ovaries from six adult females of collared peccary were obtained through ovariectomy and analyzed. These were fixed in aqueous Bouin's solution and sectioned into 7µm slices, stained with hematoxilin-eosin and analyzed by light microscopy. The number of pre-antral and antral follicles per ovary was estimated using the Fractionator Method. The follicles, oocytes and oocyte nuclei were measured using an ocular micrometer. Results showed that the length, width, thickness, weight, and the gross anatomy of the right and left ovaries were not significantly different. However, the mean number of corpora lutea was different between the phases of the estrous cycle (p<0.05), with the highest mean in the luteal phase. Primordial follicles were found in the cortex; the oocytes were enveloped by a single layer of flattened follicular cells. In the primary follicles, proliferation of the follicular cells gave rise to cuboidal cells (granulosa cells). The secondary follicle was characterized by two or more concentric layers of cuboidal cells (granulosa), beginning of antrum formation, and the presence of pellucid zone and theca cells. Antral follicles were characterized by a central cavity (antrum), the presence of cumulus oophorus and theca layers (interna and externa). In the right ovary, the values of the primordial and primary follicles were similar, but significantly different from the secondary ones (p<0.05). In the left ovary, significant differences were observed between all follicles in the follicular phase (p<0.05); the mean number of primordial and primary follicles was similar in the luteal phase. The mean number of pre-antral follicles and antral follicles in the follicular phase was higher in the left ovary (p<0.05). The mean number of antral follicles in the luteal phase was similar in both ovaries. We also found significant differences in mean diameter of preantral follicles, oocyte, granulosa layer and oocyte nucleus during the estrous cycle. In the antral follicles a significant difference was observed only in follicular diameter (p<0.05). The predominance of active primordial and primary follicles was found in both phases; otherwise the secondary follicles and antral follicles showed a high degree of degeneration. The results obtained in the present work will strengthen the development of biotechnology programs to improve the productive potential and conservation of the collared peccary. Rev. Biol. Trop. 60 (1): 437-445. Epub 2012 March 01.

In vitro maturation of collared peccary (Pecari tajacu) oocytes after different incubation times

“…On the other hand, the follicular development in collared peccaries was also similar to that found for other artiodactyl species regarding the stages of folliculogenesis, i.e. recruitment, selection and dominance (Guimarães et al 2012) when compared to buffalos (Manik et al 2002) and camelids (Basiouni 2007). Nevertheless, despite this similarity, the 24 h IVM time that is frequently used for buffaloes (Kadoom et al 2014) was not suitable for oocyte maturation in the collared peccaries.…”

“…Based on these studies, it was possible to know that specifically for females, they have symmetrical and oval ovaries with a relatively smooth surface, which can present irregular appearance due to corpus luteum or follicles (Garcia et al 2009). Moreover, the ovaries are enveloped by an ovarian bursa (Guimarães et al 2012), as also observed in swine (Męczyński 1974). Additionally, collared peccaries' estrous cycle lasts 21 days, with a follicular phase of 6 days and 15 days for the luteal phase (Maia et al 2014).…”

“…Therefore, in view of the need for studies related to the reproductive biotechniques in collared peccaries, the initial point has been to observe reproductive relationship with close domestic phylogenetic species, as swine and others artiodactyls. Thus, similarities were observed for folliculogenesis (Guimarães et al 2012), hormonal profiles (Ahuja-Aguirre et al 2017) and follicular histological characteristics (Lima et al 2013) between collared peccaries and swine and/or artiodactyla species, as buffalos.…”

Ovarian gene expression in collared peccary (Pecari tajacuLinnaeus, 1758) subjected to gonadotropin stimulation protocols

“…No statistical differences were observed for ovulation rate, calculated from CH number, between SWD and ALD groups. Comparable ovulation rate was reported in hunted wild (Mayor et al., 2006) and in captive (Guimarães et al., 2012) collared peccaries. Thus, as collared peccary is a polyovulatory species, an increase in the ovulation rate is undesirable after an ovarian stimulation hormone treatment.…”