Genetic influences on reproduction of female red deer (Cervus elaphus) (2) seasonal and genetic effects on the superovulatory response to exogenous FSH

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

BACKGROUND

Stress is a limiting factor in assisted reproduction in wild animals maintained in captivity. However, the knowledge of assisted reproduction techniques for wild animals is useful for future in situ and ex situ conservation programs. Thus, this study evaluated the ovulation rate, presence of functional corpora lutea and fecal glucocorticoid levels following treatments promoting superovulation in captive brown brocket deer.

METHODS

The crossover design used six hinds, allocated to two groups (n=6): eCG Treatment, CIDR for 8 days, followed by 0.25 mg of EB on day 0, 700 IU of eCG on day 4 following device insertion and 265 mug of PGF2alfa on day 8; and FSH Treatment, CIDR for 7.5 days, followed by 0.25 mg of EB on day 0, 130 mg of FSH in 8 equal doses and 265 mug of PGF2alfa on day 7.5. Induced adrenal activity and treatment efficacy were evaluated by corpora lutea (CL) counts and fecal glucocorticoid and progestin concentration (ng/g feces) analyses for five different phases: Pre, two days before treatment; Early, first four days of treatment; Late, last four days of treatment; Total, entire treatment period; and Post, five days posttreatment.

RESULTS

eCG Treatment resulted in the highest number of CL (P lower than 0.05). There was no significant difference for fecal glucocorticoid concentrations in five different time periods between the treatments; however Pre fecal glucocorticoid concentrations (90.06+/-19.64) were significantly different from Late (200.76+/-26.39) within FSH Treatment. The mean fecal progestin concentration and mean ovulation rate were higher in eCG Treatment (4293.69+/-769.47, 7.0+/-1.8) than in FSH Treatment (1571.26+/-240.28, 2.6+/-0.8) (P lower than or equal to 0.05).

CONCLUSIONS

Although the eCG Treatment induced a good superovulatory response, with the formation of functional corpora lutea, we cannot yet affirm that we have established a suitable protocol for induction of SOV in the species M. gouazoubira because approximately 65% of the deer showed premature regression of the corpora lutea. Moreover, multiple FSH applications in FSH Treatment resulted in a low ovulation rate and induced an increase in fecal glucocorticoid levels.

The role of chromosome variation in the speciation of the red brocket deer complex: the study of reproductive isolation in females

BACKGROUND

The red brocket deer, Mazama americana, has at least six distinct karyotypes in different regions of South America that suggest the existence of various species that are today all referred to as M. americana. From an evolutionary perspective, the red brockets are a relatively recent clade that has gone through intense diversification. This study sought to prove the existence of post-zygotic reproductive isolation in deer offspring between distinct chromosome lineages. To achieve this, inter-cytotype and intra-cytotype crosses were performed, which resulted in both F1 hybrid (n = 5) and pure offspring (n = 3) in captivity.

RESULTS

F1 females were analyzed in terms of their karyotypes, ovarian histology, estrous cycles and in vitro embryo production. Pure females presented parameters that were similar to those previously reported for M. Americana; however, the parameters for hybrid females were different. Two hybrids were determined to be sterile, while the remaining hybrids presented characteristics of subfertility.

CONCLUSIONS

The results support the existence of well-established reproductive isolation among the most distant karyotype lineages and elucidates the need to define all karyotype variants and their geographical ranges in order to define the number of species of red brocket.

The impact of past introductions on an iconic and economically important species, the red deer of Scotland

The red deer (Cervus elaphus) is an iconic species in Scotland and, due to its value as a game species, an important element of the Scottish rural economy. The native status of this species is sometimes questioned because of many recorded introductions of nonnative deer in the past that were an attempt to improve trophy size. In this study, we assessed the impact of past introductions on the genetic makeup of Scottish red deer by genotyping at 15 microsatellite loci a large number of samples (n = 1152), including mainland and island Scottish red deer and individuals from several putative external source populations used in introductions to improve trophy size. Population structure and introgression assessment analyses revealed that the impact of introductions was weak in Highland red deer populations but more prominent on the islands, especially on those where current red deer populations are mostly or entirely derived from introductions (Harris & Lewis, Arran, and Rum). Frequent imports of Central-Eastern European red deer into English deer parks were reflected in the higher genetic introgression values found in some of the individuals collected in parks.

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

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.

Multiple ovulation and embryo transfer with fresh, frozen and vitrified red deer (Cervus elaphus) embryos in Argentina

Two multiple ovulation and embryo transfer (MOET) programs with fresh, frozen and vitrified red deer embryos were carried out during the reproductive season of 2005 and 2006 in a local breeding farm in Argentina. Multiparous (n=10 and 9, respectively) weaned hinds were used as donors for each year. The estrous synchronization treatment of donors and recipients consisted of inserting an ovine intravaginal sponge containing medroxiprogesterone acetate (MAP) for 12 days. Superovulation was conducted with a total dose of 180 mg of NIH-FSH-P1 (Folltropin-V, Bioniche, Belleville, Ontario, Canada), given i.m. in eight decreasing doses every 12h (40, 40; 27, 27; 15, 15; 8, 8 mg), from days 10 to 13. Donor females were mated with one stag of proven fertility. The recovery rate was 84.1% (122/145), obtaining 45.1% (55/122) of transferable embryos, 24.6% (30/122) of degenerated embryos and 30.3% (37/122) of unfertilized oocytes. Pregnancy rates after transfer of fresh, OPS vitrified/warmed and ethylene glycol (EG) frozen/thawed embryos were 64.3% (18/28), 53.3% (8/15) and 70.0% (7/10), respectively. Vitrification and freezing with ethylene glycol procedures constitute an interesting alternative for red deer embryo cryopreservation.

Effect of exogenous gonadotrophins on ovarian morphology and oocyte maturation in the southern hairy nosed wombat Lasiohinus latifrons during the breeding season

The effect of the exogenous administration of porcine follicle-stimulating hormone (pFSH) and pregnant mare serum gonadotrophin (PMSG) on ovarian follicular development and oocyte maturation in the southern hairy nosed wombat Lasiorhinus latifrons was investigated. Three experimental groups were administered pFSH at various doses and for different treatment lengths, followed by 25 mg porcine luteinising hormone (pLH) 12 h after the last dose of pFSH. Another group was given PMSG followed 72 h later by 25 mg pLH. Animals were killed 24 h after pLH. The left ovary was fixed for histology and the morphology of the antral follicles was determined, whereas follicular oocytes in the right ovary were aspirated, fixed, stained with 4′,6′-diamidino-2-phenylindole, and viewed for nuclear maturation. There was no significant difference in the mean number of ovarian follicles >1 mm, or in the size class of follicles assessed between control and experimental groups. However, a trend was observed suggesting a possible increase in follicles >3.0 mm in experimental groups compared with control animals. In all females administered exogenous porcine gonadotrophins, but not controls, some of the mural granulosa cells of large tertiary antral follicles had markedly enlarged nuclei (approximately 14 µm in diameter). All oocytes from the control group remained at the germinal vesicle stage, whereas approximately 40% of oocytes retrieved from the pFSH groups and 82.4% retrieved from the PMSG-primed animals had undergone germinal vesicle break down, with a small number reaching meiosis II. The present study shows that exogenous administration of either pFSH or PMSG to hairy nosed wombats can induce follicular growth and oocyte maturation. Such findings could be useful in the development of reproductive technology in this species.

New developments reproductive technologies in deer

In vitro embryo production is the platform for advanced reproductive technologies, such as cloning. The in vitro embryo production system developed for farmed red deer (Cervus elaphus) evolved along similar lines to that pioneered by other domestic species researchers. However, applying existing in vitro embryo production methods from these other species resulted in limited success and has necessitated developing a species-specific methodology for red deer based on the their physiology. Analysis of oviduct fluid led to the development of a semi-defined fertilization and culture media system, Deer Synthetic Oviduct Fluid (DSOF), which resulted in successful culture of red deer embryos to the blastocyst stage. Transvaginal ultrasound-guided ovarian examination and ovum pickup has enabled the study of seasonality constraint and propagation from selected female genetics, respectively. During the 4-month breeding season (April-July), 15% of cleaved oocytes developed to blastocysts, whereas no blastocysts developed from oocytes collected after July. The process of developing an in vitro embryo production system for farmed red deer may serve as a beneficial model for the propagation of endangered cervine species.