Ovarian gene expression in collared peccary (Pecari tajacu Linnaeus, 1758) subjected to gonadotropin stimulation...

Ovarian response of collared peccaries (Pecari tajacu), after hormonal stimulation with gonadotropin association (eCG/hCG), was accessed by both gene expression and follicular development. Thus, collared peccaries (n = 8) were treated with the dose used for sows (swine dose, SWD) or with dose adjusted for peccary's weight (allometric dose, ALD). The gene expression of receptors was evaluated for both gonadotropins (FSHR and LHCGR) and growth factors (proteins codified by TGFβR-1, BMPR1-A and BMPR2 genes) in antral follicles, cortex and corpora haemorrhagica (CH). Five days after gonadotropin injection, all females presented CH. The ovulation rate was similar (p > .05) between SWD (4.00 ± 1.17) and ALD (2.50 ± 0.43) group. The total number of follicles per animal and amounts of small (<3 mm), medium (3-5 mm) and large (>5 mm) follicles was similar among groups. However, SWD produced large follicles heavier than ALD group, as accessed by weight of follicular wall biopsies. Ovarian follicles expressed both gonadotropin and growth factor receptors at levels which are independent from gonadotropin dose. In conclusion, the two gonadotropin doses (SWD and ALD) can be used for ovarian stimulation of collared peccary. Additionally, FSH and growth factors (TGFβR-1, BMPR1-A and BMPR2) receptors are more expressed in the early follicle development, while LH receptor seems to be more important in the final of follicular growth.