Ultrasound-assisted liquefaction of dromedary camel semen

Cooled storage of semen from livestock animals (Part II): Camelids, goats, and sheep

This review is part of the Festschrift in honor of Dr. Duane Garner and provides an overview of current techniques in cooled storage of semen from livestock animals such as camelids, goats, and sheep. Facing worldwide environmental changes and a trend towards more conscious and healthy eating behaviors, the development of a stable animal breeding industry is a significant challenge for the near future. In the present review, factors influencing semen handling in camelids, goats and sheep are described and relevant methods as well as current trends to improve liquid-storage of cooled semen are discussed, including extenders, additives, cooling rates, and storage temperatures. The species-specific physiology and resulting challenges are taken into consideration. While the main problem for camelid semen processing is the relatively greater viscosity as compared with that of some other animals, the deciding factor for successful artificial insemination (AI) in goats and sheep is the site (i.e., cervical or vaginal) of semen placement in the reproductive tract. Due to the type of cervical anatomy, the penetration of the cervix when using AI instruments is rather difficult. Furthermore, the seminal plasma of small ruminants affects the interaction with milk-based extenders and egg yolk which results in species-specific regimens for cooled liquid-preservation. Comparing all three species, the greatest pregnancy rates were obtained by AI with goat semen after cooled liquid-storage for several days.

In vitro embryo production (IVEP) in camelids: Present status and future perspectives

Camels are a fundamental livestock resource with a significant role in the agricultural economy of dry regions of Asia and Africa. Similarly, llamas and alpacas are an indigenous resource considered as beasts of burden in South America because of their surefootedness and ability to adapt. Camel racing, a highly lucrative and well-organized sport, camel beauty contests, and high demand for camel milk lead to a steady interest in the multiplication of elite animals by in vitro embryo production (IVEP) in this species during the last few decades. Although offspring have been produced from in vitro produced embryos, the technique is still not that well developed compared with other domestic animal species such as cattle. IVEP involves many steps, including the collection of oocytes from either slaughterhouse ovaries or live animals through ultrasound-guided transvaginal aspiration; in vitro maturation of these collected oocytes; collection and preparation of semen for fertilization; culture and passaging of cells for nuclear transfer, chemical activation of the reconstructed embryos, and in vitro culture of embryos up to the blastocyst stage for transfer into synchronized recipients to carry them to term. This review discusses the present status of all these steps involved in the IVEP of camelids and their future perspectives.

An automated instrument for intrauterine insemination sperm preparation

Sperm preparation is critical to achieving a successful intrauterine insemination and requires the processing of a semen sample to remove white blood cells, wash away seminal plasma, and reduce sample volume. We present an automated instrument capable of performing a sperm preparation starting with a diluted semen sample. We compare our device against a density gradient centrifugation by processing 0.5 mL portions of patient samples through each treatment. In 5 min of operating time, the instrument recovers an average of 86% of all sperm and 82% of progressively motile sperm from the original sample while removing white blood cells, replacing the seminal plasma, and reducing the volume of the sample to the clinically required level. In 25 min of operating time, density gradient centrifugation recovers an average of 33% of all sperm and 41% of progressively motile sperm. The automated instrument could improve access to IUI as a treatment option by allowing satellite doctor’s offices to offer intrauterine insemination as an option for patients without the clinical support required by existing methods.

Ramifications of protease-based liquefaction of camel semen on physical, kinematic and surface glyco-pattern of cryopreserved spermatozoa

The efficiency of incorporating different proteases in the diluent for reducing camel semen viscosity, and subsequent ramifications on morpho-functional and glycan surface properties of cryopreserved spermatozoa were investigated. Ejaculates (n = 48) were collected from three adult camels, Camelus dromedarius, during the breeding season (January - March). A portion of each raw ejaculate was evaluated for sperm physical and morphological traits, whereas the other portion was divided into three aliquots assigned for the following liquefaction treatments: control (untreated), 0.1 mg/mL papain or 5 U/mL bromelain. All samples were diluted with Tris-lactose diluent containing the anti-enzyme E-64 to neutralize both proteases before being processed for cryopreservation. Post-thaw physical and kinematic properties of spermatozoa were analyzed using a computer-assisted sperm analysis (CASA) system. The sperm surface glycocalyx pattern was evaluated with a panel of 14 fluorescent lectins. Although bromelain was more effective in elimination of semen viscosity, there was a negative correlation between bromelain supplementation and values for the variables: normal sperm, intact acrosome and intact sperm cell membrane. Bromelain supplementation, compared to papain-treated and control samples, was positively correlated with secondary sperm abnormalities, increased straight-line velocity (VSL, μm/s) and straightness (%) of spermatozoa. Results from the glycan analysis indicated that both proteases did not affect the N-linked glycan content of the entire sperm surface, whereas the treatment with proteases induced little change in N-acetylgalactosamine and fucose terminating glycans in the tail region of the sperm. Functional studies are needed to evaluate the sperm fertility rates of bromelain- and papain-treated semen for application in camel assisted reproductive technologies.

Liquid storage of dromedary camel semen in different extenders

This study was conducted to assess the effects of commercial extenders and storage temperature on dromedary camel sperm quality during liquid preservation. In Experiment 1, ejaculates (n = five males; replicated seven times) were split and diluted with synthetic (OPTIXcell, EquiPlus, INRA96, Bioxcell or AndroMed; Experiment 1a) or egg-yolk based (Biladyl, Green buffer or Triladyl; Experiment 1b) extenders and stored for 48 h at 4 °C. In Experiment 2, split ejaculates (n = five males; replicated six times) were used to directly compare Green buffer, OPTIXcell and Triladyl extenders over 48 h of storage at 4 °C. Ejaculates collected in Experiment 3 (n = five males; replicated five times) were diluted with Green buffer or Triladyl before chilled storage for 48 h at 4 or 15 °C. Sperm kinematics, viability and acrosome integrity were assessed during liquid storage. In Experiment 1a, there was the greatest total sperm motility (TM) in the OPTIXcell group following 24 and 48 h of storage, while in Experiment 1b, there was the greatest TM after 48 h of storage with Triladyl and Green buffer. In Experiment 2, there were greater TM and viable acrosome intact spermatozoa in the Triladyl and Green buffer than with OPTIXcell group. In Experiment 3, there was a greater TM in the Triladyl than Green buffer group at 24 and 48 h of storage regardless of storage temperature (which had no effect on sperm quality). In conclusion, camel sperm have greater viability when preserved in liquid form for 48 h following dilution with Triladyl and storage at either 4 or 15 °C.

The use of some assisted reproductive technologies in old world camelids

The use of camels for racing, milking and as show animals is growing in popularity, thus there is increased enthusiasm to breed more of the genetically superior animals. This review highlights recent developments in assisted reproductive techniques in camels, such as embryo transfer and artificial insemination, to ensure more rapid genetic progress. This paper discusses the difficulties involved in handling the semen due to its high viscosity and ways to reduce it. It also examines methods for short term liquid storage of fresh semen with and without the use of antioxidants to reduce oxidative stress. The widespread use of AI in camels is hindered by the lack of a reliable method for deep freezing and long term storage but various freezing protocols, cryoprotectants and freezing and thawing methods are discussed as well as different insemination techniques. Embryo transfer requires the donor to be superovulated and the recipients synchronized. This review discusses different protocols used for superovulation of donor animals and the problems involved. It also examines various methods to synchronize recipients, or how to make best use of non-synchronized or non ovulated recipients. Cryopreservation of embryos would greatly improve the wider use of ET and spread of genetics worldwide so methods for slow cooling and new methods of vitrification with promising results are discussed.

Physical and kinematic properties of cryopreserved camel sperm after elimination of semen viscosity by different techniques

This investigation aimed to determine the influence of using different techniques for liquefaction of semen on post-thaw physical and dynamic characteristics of camel spermatozoa. A total of 144 ejaculates were collected from 3 adult camels, Camelus dromedarius, twice-weekly over 3 consecutive breeding seasons. A raw aliquot of each ejaculate was evaluated for physical and morphological properties, whereas the remaining portion was diluted (1:3) with glycerolated Tris lactose egg yolk extender, and was further subjected to one of the following liquefaction treatments: control (untreated), 5μl/ml α-amylase, 0.1mg/ml papain, 5u/ml bromelain, or 40-kHz nominal ultrasound frequency. The post-thaw objective assessment of cryopreserved spermatozoa, in all groups, was performed by a computer-assisted sperm analysis (CASA) system. The results revealed that all liquefaction treatments improved (P<0.05) post-thaw motility, viability and sperm motion criteria. However, an adverse effect (P<0.05) was observed in acrosome integrity, sperm cell membrane integrity and percent of normal sperm in all enzymatically-treated specimens compared to both control and ultrasound-treated semen. These results elucidate the efficiency of utilizing ultrasound technology for viscosity elimination of camel semen. In addition, developing enzymatic semen liquefaction techniques is imperious to benefit from when applying assisted reproductive technologies, particularly AI and IVF, in camels.

Supplementation of tris-based extender with plasma egg yolk of six avian species and camel skim milk for chilled preservation of dromedary camel semen

The present study was conducted to investigate a suitable source (Expt. 1) and concentration (Expt. 2) of plasma egg yolk (PEY) and concentration of camel skim milk (CSM; Expt. 3) to supplement tris based extender for chilled storage of dromedary camel semen. In Expt. 1, PEY (20%) of six avian species (domestic chicken, domestic duck, Japanese quail, partridge, pigeon and guinea fowl) was added to semen extender. In Expt. 2, different concentrations (0, 10, 20, 30 and 40%) of selected PEY from Expt.1 were added to semen extender. In both Expt. 1 and 2, CSM remained constant (20%). In Expt. 3, semen extender was supplemented with different concentrations of CSM (0, 20, 40, 60 and 80%) while the concentration of PEY remained constant. The sperm viability parameters were assessed at 6, 12 and 24h following chilled storage. In Expt. 1, progressive forward motility (PFM) of diluted semen supplemented with pigeon PEY was similar to domestic duck and Japanese quail PEYs (P>0.05) and superior to other PEYs (P<0.05). In Expt. 2, PFM following the addition of 20% pigeon PEY was similar to 10 and 30% (P>0.05) and greater than 0 and 40% (P<0.05). In Expt. 3, total motility, PFM and live percentage of sperm were better in 20% compared to 40, 60 and 80% CSM (P<0.05). In the last experiment, PFM in 20% was better than 0% CSM (P<0.05). In conclusion, pigeon PEY at the concentration of 20% and CSM at the concentration of 20% could provide beneficial effect on some of the sperm viability parameters during chilled storage of dromedary camel semen.