First llama (Lama glama) pregnancy obtained after in vitro fertilization and in vitro culture of gametes from live animals

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.

Use of dimethylformamide to cryopreserve alpaca semen previously incubated with collagenase

The objective of this study was to evaluate the effect of collagenase and two final dimethylformamide (DMF) concentrations (4% and 7%) on alpaca frozen-thawed sperm quality. A total of 25 ejaculates from 5 alpaca were obtained using electroejaculation. Each individual ejaculate was evaluated and then diluted 4:1 in a solution of 1 mg/ml collagenase in HEPES-TALP medium and incubated for 4 min at 37°C. Subsequently, samples were diluted in TRIS-fructose-citric acid-egg yolk and cooled to 5°C. Then, each sample was divided in two aliquots and DMF at final concentration of 4% or 7% was added, equilibrated for 1 hr at 5°C and frozen over liquid nitrogen vapours. A Kruskal-Wallis test was used to evaluate the sperm morphometry, and Completely Random Block designs were used to analyse sperm motility, viability, membrane function and acrosome status. After collagenase incubation, none of the samples showed thread formation, and sperm parameters were preserved. Non-progressive motile sperm were higher (p < .05) in equilibrated samples (4% DMF: 31.8 ± 8.3% and 7% DMF: 36.3 ± 11.8%) compared to raw (10.1 ± 4.3%) and frozen-thawed semen (4% DMF: 9.7 ± 1.8% and 7% DMF: 7.5 ± 3.2%). Sperm membrane function, membrane integrity and intact acrosomes were higher (p < .05) in raw semen (40.1 ± 12.2%, 94.6 ± 3.2% and 91.3 ± 8.1%) compared to frozen-thawed samples (4% DMF: 19.8 ± 4.7%, 53.2 ± 2.7%, 65.7 ± 8.7% and 7% DMF: 20.4 ± 4.5%, 54.1 ± 1.4%, 64.6 ± 9.1%). Length of the sperm head was lower in frozen-thawed samples, being statistically different with 4% DMF compared to pre-freezing samples. The ratio between acrosome and head areas was greater (p < .05) in frozen-thawed samples. Incubation of raw alpaca semen with collagenase decreased the thread formation without affecting sperm quality. Frozen of collagenase treated alpaca semen with 4% or 7% DMF did not preserve the sperm parameters in thawed samples.

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.

Effect of macromolecule supplement on nuclear and cytoplasmic maturation, cryosurvival and in vitro embryo development of dromedary camel oocytes

The current evaluation of oocyte vitro maturation (IVM) media has progressed toward more defined conditions in human and livestock. In this study, the replacement of fetal calf serum (FCS) with bovine serum albumin (BSA) and polyvinyl alcohol (PVA) was evaluated during IVM in dromedary camel. Nuclear maturation rates in presence of FCS and PVA were comparable (81.6 ± 1 and 75.5 ± 5%, respectively). BSA, whether used alone or in combination with FCS, significantly reduced nuclear maturation (51.6 ± 3.9 and 54.6 ± 1.1%, respectively), compared to FCS and PVA. BSA also increased the rates of chromosome aberrations compared to FCS and PVA (25.7 ± 7.4, 8.8 ± 2.3 and 6.0 ± 2.0%, respectively). IVM macromolecule differentially affected morphological aspects of cumulus expansion and FCS promoted the highest dissociation of cumulus cells, compared to all the other groups. FCS significantly increased mean lipid intensity of oocytes compared to BSA, FCS-BSA and PVA which could explain the lower cryo-survival of oocytes matured in presence of FCS compared to BSA and PVA (56.1 ± 5.2, 91.0 ± 19.5, and 87.8 ± 6.7%, respectively). Mitochondrial activity was not affected by macromolecules, but oocytes cultured with PVA had the best redox status, compared to other IVM groups. Cleavage was not affected by IVM macromolecule, but FCS promoted significantly higher rate of morula development (51.6 ± 5.2 vs. 33.6 ± 2.9% for PVA) and blastocyst development (36.8 ± 1.4 vs. 20.5 ± 2.0% for BSA). Although adding FCS during IVM supported highest hatching rate of the resulting blastocysts, differential cell number showed no long lasting effect of IVM macromolecules on blastocyst quality. Obtained results suggest the possibility to switch from undefined to more defined IVM systems for efficient in vitro maturation and subsequent vitrification of dromedary camel oocytes. Keywords: camel, oocyte maturation, protein supplement, cryosurvival.

Production, Preservation, and Transfer of South American Camelid Embryos

The current review summarizes progress in the field of in vitro and in vivo production of South American Camelid embryos. Both methods require ovarian superstimulation (with FSH and eCG) to obtain multiple ovulations (in vivo embryo production) or to induce follicle growth for oocyte collection (in vitro embryo production). Moreover, superstimulation entails prior administration of hormones that inhibit follicular growth (progesterone, progestagens, and estrogens). Cumulus-oocyte complexes obtained must mature in vivo (buserelin administration) or in vitro to then be subjected to in vitro fertilization or intracytoplasmic sperm injection. All these techniques also require morphologically normal, motile spermatozoa to achieve fertilization. Methods used to decrease semen viscosity and to select the best spermatozoa (Percoll®; Androcoll-ETM) are described. Additionally, nuclear transfer or cloning has been applied in llamas. Up to now, embryo deep-freezing and vitrification have progressed slowly but are at the height of development. Embryos that are obtained by any of these techniques, either in vivo or in vitro, need to be transferred to synchronized recipient females. The best results are achieved after transfer to the left uterine horn with an ipsilateral ovulation. No live offspring have been obtained after the transfer of cryopreserved embryos. Applying reproductive biotechnologies, such as those described, will permit the expansion of genetically selected animals in the population and also that of wild camelid species, vicunas, and guanacos, whose embryos could then be transferred to the uterus of domestic species.

Effect of oocyte maturation time, sperm selection method and oxygen tension on in vitro embryo development in alpacas

We evaluated the effect of in vitro maturation time, sperm selection and oxygen tension on alpaca embryo development. In Experiment I, Cumulus Oocyte- Complexes (COCs) were obtained from abattoir ovaries and in vitro matured in TCM-199 for 24 (n = 217), 28 (215), or 32 h (223) at 38.5 °C, high humidity and 5% CO₂ in air. Oocytes from 24 (n = 392), 28 (n = 456) or 32 (n = 368) h groups were in vitro fertilized with epididymal sperm and cultured in SOFaa at 38.5 °C, high humidity and 5% CO₂, 5% O₂ and 90% N₂ for 7 days. Embryo development was evaluated on Day 2, 5 and Day 7 of in vitro culture (Day 0 = in vitro fertilization). In Experiment II, a 2 by 2-factorial design was used to determine the effect of sperm selection (Swim-up vs Percoll) and oxygen tension (20% vs 5%) during embryo culture and their interaction on embryo development. COCs were in vitro matured for 32 h at 38.5 °C and 5% CO₂ in air and then in vitro inseminated with epididymal sperm processed by swim-up or Percoll. Zygotes were cultured in SOFaa + cumulus cells at 38.5 °C under 20 or 5% of O₂ tension and high humidity for 7 days. A total of 235, 235, 253 and 240 oocytes were assigned to: swim-up+20 O₂, swim-up+5 O₂ or Percoll+20 O₂, Percoll+5 O₂, groups respectively. The proportion of oocytes reaching MII stage was highest after 32 h of in vitro maturation (P < 0.05). Blastocyst rate (29.1 ± 2.7%) was also highest for COCs matured for 32 h (Exp I). In Experiment II, Blastocysts rate (26.03 ± 4.7; 27.7 ± 4.3; 29.7 ± 3.8 and 27.6 ± 4.2% for swim-up+20 O₂, swim-up+5 O₂ or Percoll+20 O₂, Percoll+5 O₂, respectively) was not affected by sperm selection method (P = 0.8), oxygen tension (P = 0.9) or their interaction (P = 0.5).

In vitro-production of embryos using immature oocytes collected transvaginally from superstimulated wood bison (Bison bison athabascae)

Two experiments were done to test the hypothesis that morphologic characteristics of wood bison cumulus-oocyte complexes (COC) are reflective of the ability of the oocyte to develop to an advanced embryonic stage after in vitro maturation, fertilization and culture, and to determine the effect of prolonging the interval from the end of superstimulation treatment to oocyte collection (FSH starvation period). Experiments were done during the anovulatory season. In Experiment 1, ovarian superstimulation was induced in 10 bison with two doses of FSH given at 48 h intervals beginning at the time of follicular wave emergence. COC were collected 3 days (72 h) after the last dose of FSH by follicular aspiration and classified as compact, expanded or denuded. The COC were matured in vitro for 24 h before fertilization in vitro (Day 0). Embryo development was assessed on Days 3, 7 and 8. The blastocyst rate was 7/34, 2/10 and 0/3 in COC classified as compact, expanded and denuded, respectively; however, only compact COC resulted in embryos that reached the expanded blastocyst stage. In Experiment 2, COC were collected at either 3 or 4 days (72 or 96 h) after the last dose of FSH (n = 16 bison/group) to determine the effect of the duration of FSH starvation on oocyte competence. The COC were classified as compact good (>3 layers of cumulus cells), compact regular (1-3 layers of cumulus cells), expanded or denuded, and then matured, fertilized and cultured in vitro. Although follicles were larger (P < 0.05) in the 4-day FSH starvation group, there was no effect of starvation period on the distribution of COC morphology; overall, 112/194 (57.7%) were compact, 29/194 (26.3%) were expanded, 39/194 (20.1%) were denuded, and 14/194 (7.2%) were degenerated (P < 0.05). Similarly, there was no effect of starvation period on embryo development. Compact good COC had the highest cleavage (88%) and blastocyst rates (54%; P < 0.05), followed by compact regular COC at 73% and 25%, respectively. Expanded and denuded COC had low cleavage (40% vs. 59%, respectively) and blastocyst rates (5% vs. 8%, respectively). We conclude that morphologic characteristics of wood bison COC are reflective of the ability of the oocyte to develop into an embryo in vitro. Importantly, oocytes collected from superstimulated bison during the anovulatory season were competent to develop to the blastocyst stage following in vitro maturation, fertilization and culture.