Comparison of three protocols for superovulation of brown brocket deer (Mazama gouazoubira)

Abstract

This study aims to evaluate the ovulation rate and the presence of functional corpora lutea after treatment by three different protocols designed to cause superovulation in brown brocket deer. Six female received an intravaginal device containing 0.33 g of progesterone (CIDR®) for 8 days, followed by 0.5 mg injection of estradiol benzoate at the time of insertion and 265 µg of cloprostenol at the time of removal. Afterwards, the hinds were divided into three groups (n = 2): Treatment A received injection of 600 IU eCG on Day 4 after CIDR® insertion; Treatment B received injection of 300 IU eCG at the same time; and Treatment C received injection of 250 IU FSH dissolved in PVP, also on Day 4 post-insertion. The treatments were crossed over with 44-48 day intervals after CIDR® removal, such that all the deer were submitted to all three treatments. The mean ovulation rate (Treatment A = 3.40 ± 0.68, Treatment B = 1.40 ± 0.24, Treatment C = 0.80 ± 0.49), total ovarian stimulation (Treatment A = 4.80 ± 1.02, Treatment B = 1.80 ± 0.37, Treatment C = 1.40 ± 0.60), and mean CL diameter (Treatment A = 7.33 ± 0.76 mm, Treatment B = 3.94 ± 0.19 mm, Treatment C = 2.18 ± 0.49 mm) in Treatment A were significantly higher than the mean ovulation rates, total ovarian stimulation, and mean CL diameter in Treatments B and C. The mean fecal progesterone metabolites at the luteal phase in Treatment A (6,277.94±2,232.47 ng/g feces) was significantly different from Treatment C (1,374.82±401.77 ng/g feces). Thus, although fertility was not evaluated directly, Treatment A proved capable of induce superovulation in the species Mazama gouazoubira, presenting the greatest mean ovulation rates, with the formation of functional corpora lutea.

Comparing two different superovulation protocols on ovarian activity and fecal glucocorticoid levels in the brown brocket deer (Mazama gouazoubira)

“…Moreover, this mean was higher than the ovulation means obtained for other species, such as E. davidianus (CL 3.83 [15]), O. virginianus (3.10 CL [19]) and C. elaphus , which were not selected for a MOET program (2.15 CL [14]). Higher mean ovulation (3.40 ± 0.68 CL) has already been obtained for the species M. gouazoubira , in a previous experiment which used similar SOV protocols with modifications in the EB dosage (0.5 mg) used to induce ovulatory follicular atresia and synchronize the follicle wave in conjunction with the CIDR® and eCG (600UI) used to induce SOV [7]. …”

“…The use of a lower dose of EB and a higher dose of eCG seem to have been a positive factor. It has already been shown that high levels of estradiol at the moment of insertion of the progesterone implant and early administration of gonadotropins have a negative impact on superovulatory response and on follicular wave synchronization [23,42] and that the ovulation rate increases in a dose-dependent manner [43] in relation to an increase in the eCG dosage [7]. However, even using a lower dose of EB, it is probable the protocol is not yet well adjusted to the needs of this species, since the hinds presented behavioral estrus following the administration of EB.…”

“…Data from endocrinology studies, based on progestogen data, indicate a mean luteal phase duration of 24.6 ± 1.4 day and a mean interluteal phase duration of 1.7 ± 0.1 day [3]. It is also one of the most studied species regarding the endocrinology of the estrous cycle and pregnancy [3] and the development of reproductive biotechnologies, such as estrus synchronization [5,6] and superovulation [5,7]. …”

“…The abundance of this species and the preceding studies, which increased knowledge concerning the species, favor its use as an experimental model to evaluate reproductive techniques that could be used as a starting point for other neotropical deer species [7], since 59% of these species are classified as vulnerable or threatened with extinction [2]. …”

“…Although multiple ovulation has been performed successfully in brown brocket [7], red ( Cervus elaphus [8-17], fallow ( Dama dama [11,13,18]), Pere David’s ( Elaphurus davidianus [15]), white-tailed deer ( Odocoileus virginianus , [19]), and some other domestic species [20,21], the procedure often results in highly variable superovulatory responses [10,20,21] and thus it is the weakest link in the chain of events required for successful multiple ovulation/embryo transfer technology (MOET) [22]. …”