Spermatic profile of captive giant anteaters (Myrmecophaga tridactyla): Knowing more to preserve better.

The giant anteater (Myrmecophaga tridactyla) is being threatened by natural habitat destruction and fragmentation, illegal hunting and road kills. In this context, the generation of basic information on the reproductive parameters of this species is vital, aiming to improve reproductive management via, amongst others, assisted reproductive technologies. This study aimed to describe the morphological and functional features of semen collected from captive giant anteaters. Electroejaculation was performed in 13 animals housed in zoos located in São Paulo state, Brazil. Semen samples were collected from 13 animals in 16 procedures. Samples were evaluated for volume, motility, vigor, pH, concentration, sperm morphology, and functional tests. The following mean values were obtained: volume 1.28 ± 0.27 mL; motility 28.3 ± 6.2%; vigor 2.4 ± 0.25; concentration 129.4 ± 36.1 × 106 sperm/mL; pH 7.4 ± 0.2. Total acrosome, head, midpiece, and tail sperm abnormalities were 3.2 ± 0.8%, 25.4 ± 3.6%, 20.7 ± 3.2%, and 14.7 ± 2.6%, respectively. Intact acrosome was found in 83.7 ± 3.1% and intact membrane in 81.1 ± 4.0% of all samples collected. Mitochondrial activity was 66.4 ± 6.0% (Class I), 18.7 ± 2.9% (Class II), 8.0 ± 2.0% (Class III), 3.9 ± 1.0% (Class IV), and 3.0 ± 0.9% (Class V). Sperm DNA fragmentation rate was 13.2 ± 3.7%. These results indicated that electroejaculation is a feasible method for semen collection in giant anteaters, allowing a more detailed description of the semen in this species.

State of the art of assisted human reproduction

Background: Infertility is a disease observed in approximately 10% of the reproductive age population (20-44 years old), and is defined as the failure to conceive after twelve months of regular sexual intercourse, without contraception; in women older than 35 years old, this period is reduced to 6 months. The main causes of infertility are tubal, ovarian and uterine and sperm abnormalities, endometriosis, and those with undetermined causes. Over the past 30 years, several techniques were developed to overcome these factors including gamete cryopreservation, controlled ovarian stimulation, intra-uterine insemination, in vitro fertilization, intracytoplasmatic sperm injection). Review: Despite advances in assisted reproductive technologies (ART), treatment success is still strongly dependent on oocyte and sperm quality, and resulting embryo viability. The most promising advance on oocyte quality assessment is the evaluation of the ovarian reserve by the quantification of the anti-müllerian hormone (AMH). Since ovarian reserve is closely related to oocyte quality, AMH levels could be an indicator of both oocyte production capacity and the potential of these oocytes to generate a viable embryo. On the other hand, despite the development of techniques to overcome male factor infertility, attention has been paid on the semen evaluation, since routine sperm evaluation techniques are known to be ineffective, especially in those cases of unexplained infertility. Therefore, techniques were developed to assess acrosome and membrane integrity, mitochondrial potential, DNA integrity, and fertilizing capacity of sperm. However, further studies are necessary to evaluate sperm DNA integrity without damaging the cell, allowing the injection of a spermatozoon with an intact DNA when using ICSI. Regarding embryo quality, even with a good quality oocyte (as assessed by the current techniques) and an apparently normal sperm, there are still chances of generating an embryo with genetic abnormalities. In such cases, and in cases of recurrent failures, women over 35 years of age, and couples with a pre-existing genetic risk, the preimplantation genetic diagnosis (PGD) appears to be an important tool to improve the odds of pregnancy and avoid abortions or the conception of fetuses with genetic abnormalities. The technique of PGD, usually performed with PCR or FISH, has gained a powerful tool with the development of the Comparative Genomic Hybridization (CGH). However, recent studies aiming to identify markers of oocyte and sperm quality and embryo viability are in course using mass spectroscopy. With this sensitive technique applied to body fluids (i.e., blood, follicular fluid, seminal plasma), granulosa cells, sperm, and culture media, researches are being conducted to non-invasively identify biomarkers that will help understand reproductive mechanisms and to efficiently predict the outcome of ARTs. Conclusion: Significant advances in ART have been observed in the last few years, yet, failures still occur with high frequency. This review will focus on techniques to assess oocyte quality, sperm function and embryo viability, aiming to provide tools for a precise prognosis when treating infertile couples.