Use of commercial extenders, with and without the addition of egg yolk, for cooling llama semen

Male reproductive biotechnologies in South American Camelids Part I: Semen collection, evaluation and handling

This review describes the first steps necessary to apply any reproductive biotechnology in South American camelids (SAC) semen or sperm: sample collection, evaluation and handling. In camelids, the length and position adopted for mating and the site of semen deposition have conditioned semen collection methods. The advantages and disadvantages of available collection methods are summarized. The two main drawbacks for applying assisted reproductive techniques in SAC: sperm concentration and rheological characteristics are discussed. Techniques currently available to reliably evaluate diverse sperm characteristics are described, as are different methods to improve semen handling. Finally, advances made regarding the role of seminal plasma in SAC spermatozoon physiology are addressed. Part II of the review will cover the subsequent steps of dilution and cryopreservation of samples. Current results obtained using artificial insemination (AI) in SAC will also be covered in Part II.

Male reproductive biotechnologies in South American Camelids Part II: Semen dilution, cryopreservation and artificial insemination

Even though South American Camelids (SAC) are a rustic species, adapted to harsh environments, their ability to reproduce is low in their natural habitat. Conception and birth rates in camelids vary from 50 % to 90 %. This depends on the mating system used, sire and dam fertility, postpartum interval, environmental conditions, and nutrition. Reproductive biotechnology can reduce generation intervals and quickly spread high-quality genetics, addressing the growing need for genetically superior animals. The advantages of using artificial insemination (AI) and semen preservation are widely known. However, no cryopreservation protocol providing an acceptable sperm survival and pregnancy rate after thawing is currently available for SAC. Not having an effective semen cryopreservation protocol has hindered rapid genetic improvement and efficient use of males. For all these reasons, this biotechnology is currently only used for research purposes but not commercially in SAC. In Part I of this review on reproductive biotechnology, the initial steps of semen and/or sperm collection, evaluation and handling were discussed. The objective of Part II of the review is to describe the progress achieved in semen or sperm dilution, cooling and freezing. Current results obtained using AI in SAC will also be covered.

Effect of Three Semen Extenders on Sperm Quality and In Vitro Fertilization Rates of Fresh and Cryopreserved Sperm Collected from Llama (Lama glama) Vas Deferens

The advances in Assisted Reproductive Technologies (ARTs) applied in South American camelid species are still scarce. The aim of this study was to compare the effects of three semen extenders, before and after the cryopreservation of spermatozoa obtained from the vas deferens, on sperm quality parameters and in vitro fertilization rates of llama (Lama glama) oocytes. Mature fertile llama males (Lama glama; n = 6; age: 48-60 mo.; BCS: ~2.7) were included in the study. Sperm samples were collected from each male using the surgical technique of the vas deferens deviation. Then, the sperm samples were pooled and diluted with the Tris-EY, Andromed®, or BioxCell® extender in order to subsequently carry out the sperm cryopreservation process. The sperm quality assessment related to each extender was performed before and after cryopreservation with regard to sperm morphological abnormalities, acrosome integrity, sperm viability, membrane permeability, and sperm motility traits. Moreover, in vitro fertilization (IVF) procedures were carried out to evaluate the in vitro fertility of the cryopreserved sperm samples using each extender. Overall, significant differences were observed before and after cryopreservation regarding acrosome integrity, sperm viability, membrane permeability, and sperm motility traits among the extenders used, where Tris-EY and Andromed® were better than BioxCell® (p < 0.05); however, no differences were observed regarding the sperm morphological abnormalities among extenders (p > 0.05). Moreover, multiple differences were observed with regard to the velocity and linearity kinematic parameters obtained by computerized analysis before and after the cryopreservation process, irrespective of the extender used (p < 0.05). Finally, differences were observed regarding the in vitro fertilization rates among the different extender-derived samples (p < 0.05). In conclusion, the sperm quality using Tris-EY and Andromed® was better before and after cryopreservation compared to that using BioxCell®. Although the number of fertilized oocytes obtained after the IVF process between Tris-EY and Andromed® was similar, Andromed®-derived samples showed the best sperm quality results before and after cryopreservation. This indicates that the cryopreservation extender is a determining factor in significantly improving in vitro fertilization rates when using sperm samples obtained from vas deferens in llama (Lama glama) males.

Cooling of alpaca spermatozoa using an extender with the addition of different percentages of seminal plasma

The objective of this study was to evaluate the effect of the addition of different percentages of seminal plasma (SP) during the cooling at 5 °C of alpaca spermatozoa from vas deferens. Fifteen pools of sperm from vas deferens were evaluated and then divided into four aliquots that were diluted to a final concentration of 30 × 106 sperm/ml with either: (1) Tris with 20% egg yolk (T-EY) (control, 0% SP), (2) T-EY with 10% SP, (3) T-EY with 25% SP, and (4) T-EY with 50% SP. Samples were cooled at 5 °C and the following sperm parameters were evaluated after 24 and 48 h of storage: motility, viability, membrane function, acrosome integrity, morphology, and chromatin condensation. Motility was also evaluated after 72 h of storage. A significant decrease in progressive and total sperm motility was observed in samples cooled with 50% SP with respect to all diluted samples, while these parameters were preserved in samples cooled with 0%, 10%, and 25% SP. The percentages of sperm viability, normal morphology, and highly condensed chromatin did not change after the cooling process and were similar between cooled samples. Although a significant decrease was observed in the percentage of spermatozoa with functional membranes and with an intact acrosome in all refrigerated samples compared to raw sperm, the greatest decrease was observed in samples cooled with 50% SP. No advantage was observed from the addition of SP to alpaca spermatozoa obtained from vas deferens and being cooled. In addition, to preserve the sperm motility of cooled samples for up to 72 h, it should be recommended to include a 10% SP in the extender.

Pregnancy and birth rate outcomes in alpacas (Vicugna pacos) inseminated with frozen semen using two commercial extenders

The aim of this study was to evaluate alpaca pregnancy outcomes and birth rates of females inseminated with frozen semen using two commercial extenders. A total of 18 ejaculates from 8 adult alpaca males were obtained with artificial vagina, and macroscopic and microscopic semen characteristics were assessed. Afterwards, samples were divided into two aliquots, diluted with Biladyl® B or AndroMed®, and cooled for 2 h at 5°C. At that moment, sperm motility was evaluated, and samples were frozen through a gradual descent of temperature using a liquid nitrogen tank. To analyse frozen sperm quality, samples were thawed at 38°C for 30 s. Even though a significant decrease in sperm motility and viability was detected when thawed (p < .05), no superiority was found between the two commercial extenders (Biladyl® B vs. AndroMed®). A total of 36 alpaca females were artificially inseminated (AI) between 30 and 34 h post-injection of a GnRH analogue, administered when a growing dominant follicle was detected through transrectal palpation and ultrasonography. Obtained pregnancy rates were similar between Biladyl® B (33.3%, 6/18) and AndroMed® (22.2%, 4/18). No significant differences were detected in birth rates between the two tested extenders, obtaining 4 and 3 births for Biladyl® and AndroMed®, respectively. In conclusion, alpaca pregnancies and alive offspring can be obtained through AI with frozen semen at similar efficiency rates using commercial diluents, Biladyl® B or AndroMed®.