Evaluation of equine semen frozen in extenders free of egg yolk using two different freezing curves.

A chemically defined cryopreservation extender that maintains seminal parameters is relevant. Fifteen ejaculates from 5 stallions (n= 5; r=3) were diluted in 5 extenders: 1) EDTA-glucose based extender with egg-yolk and dimethylformamide (EY); 2) commercial equine extender (CE); 3) CE with dimethylformamide (CE-3); 4) bovine commercial extender with liposomes (OP); 5) bovine commercial extender with soybean lecithin (BIO), and frozen using a slow and a rapid temperature descent curve. Post-thaw evaluations were: sperm kinematic parameters, viability and acrosome status, membrane lipoperoxidation and DNA fragmentation. Sperm data were analysed using an ANOVA or Friedman test (results mean ± SD). Paired comparison between the two freezing curves was analysed using the Wilcoxon test. Total and progressive motility were significantly higher (P<0.05) in the EY and CE-3 samples using the slow curve, whereas for the fast curve, total and progressive motility were significantly higher (P<0.05) in the EY samples compared to all the extenders and the samples frozen in CE-3 were significantly higher than the remaining extenders (P<0.05). The percentages of live acrosome intact sperm and of live non-peroxidized sperm were significantly higher (P<0.05) in the EY extender when using either of the freezing curves and in turn, were significantly higher (P<0.05) in samples frozen in CE-3 compared to the remaining extenders. Intact DNA was significantly lower (P<0.05) in the BIO extender, using the rapid curve. To conclude, the commercial equine extender with 3% dimethylformamide, without egg-yolk, could be a suitable alternative for extenders with egg-yolk.

Comparison of different cryoprotectants for freezing donkey (Equus asinus) semen.

The aim of this study was to evaluate two cryoprotectants, dimethylformamide (DMF) and methylformamide (MF) in two concentrations (5 and 7 %) in vitro in donkey semen using a rapid freezing technique and the effect on pregnancy rates in mares. Twenty-four ejaculates from 8 jacks (n = 8; r = 3) were divided into 4 extenders: BotuSemen Gold with 5 % or 7 % MF and 5 % or 7 % DMF, all containing 11 % lactose, 20 % egg-yolk and 0.5 % Equex. Post-thaw evaluations included: sperm motility, membrane function and acrosome status. A linear mixed effect model was used to test the effect of different freezing media on semen parameters. No differences were observed between the 4 freezing media used, for any of the seminal parameters (P > 0.05). However, samples with 5 % DMF showed the highest percentages of sperm with acrosomes and functional membranes (DMF: 5 %: 53.67 ± 22.01; 7 %: 33.92 ± 23.4; MF: 5 %: 44.5 ± 20.46; 7 %: 38.75 ± 27.4) (Data: mean ± SD; P > 0.05). Hence, thirty mares were inseminated: 15 with 5 % DMF and 15 with 7 % DMF. The pregnancy rate was 46 % (7/15) and 0 % (0/15) using the extender with 5 % or 7 % DMF, respectively (P = 0.003). To conclude, the use of 5 % or 7 % of MF or DMF did not affect the in vitro parameters. Despite the lack of differences in vitro with the two DMF concentrations, in vivo results only showed pregnancies when using 5 % DMF. Thus, the results of this study demonstrate the importance of accompanying in vitro semen evaluations with studies that evaluate post-insemination pregnancy rates.

Effect of storage and single layer centrifugation before cryopreservation on stallion sperm cryosurvival.

The objectives of this study were to evaluate the effect of a short, cooled storage before cryopreservation on sperm progressive motility (PM) and compare the effect of different centrifugation methods on post-thaw PM of stored samples. Semen was diluted in chilling extender and aliquoted in 6 protocols: i) Standard centrifugation (SC) followed by freezing; ii) Single Layer Centrifugation (SLC) followed by freezing; iii) Storage for 8 h/5 °C before SC; iv) Storage for 8 h/5 °C before SLC; v) Storage for 8 h/15 °C before SC; and vi) Storage for 8 h/15 °C before SLC. PM was assessed before centrifugation, after centrifugation, and post-thawing. Stallions were classified as "good freezers" (GF) or "bad freezers" (BF). The PM in samples immediately frozen was greater than in the stored ones (71.98 ± 14.2, 52.91 ± 17.8, 53.93 ± 18.9 for no storage, 5 ºC storage and 15 ºC storage, respectively) (P˂ 0.0001). There was an effect of storage condition (p ˂ 0.0001), centrifugation method (p ˂ 0.0001), and freezability (P=0.0016), with an interaction between them (P= 0.0004), on PM after centrifugation. Post-thaw PM was greater in samples treated by SLC than in samples processed by SC, for all storage conditions (p ˂ 0.05). All BF stallions 'showed post-thaw PM ˂ 30 % when samples were previously stored. Storage at 5 ºC or 15º C for 8 h maintains an appropriate quality in GF stallions. Applying a sperm selection technique as SLC is suggested to improve post-thaw motility, allowing GF straws to be frozen after storage, although BF semen should be prepared by SLC immediately after collection.

Synchronization of time of development of ovarian follicular waves in South American Camelids.

South American camelids (SAC) are induced ovulating animals. In unmated females, ovarian follicle development occurs in waves of growth and regression, while mating when there is the presence of a mature follicle leads to ovulation. The capacity to respond to an ovulatory stimulus depends on the stage of the follicular wave development. Treatments to control ovarian follicular development have been performed to synchronize timing of wave emergence and development of the dominant follicle at a predictable time. Thus, synchronization of the time of follicular wave development allows for performing fixed time mating or artificial insemination, and superestimulatory treatments for multiple follicule development. Protocols are based on removal of the suppressive effect of the dominant follicle, that can be achieved by physical ablation or by inducing ovulation (with LH or GnRH) or atresia (with progesterone or progestagens alone or combined with estradiol) of this follicle. Differences between treatments should be taken into consideration when choosing a protocol for fixed time mating or artificial insemination, especially when applying the use these technologies for SAC production by commercial enterprises. Furthermore, the objective of applying synchronization protocols should be considered, because not all of these are effective in inhibiting follicular growth before initiation of a superestimulatory treatment for multiple follicle development.

Leptin and IGF1 receptors in alpaca (Vicugna pacos) ovaries.

Folliculogenesis and ovulation are regulated by gonadotrophins and other factors such as Insulin like growth factor 1 (IGF1) and leptin. In various species the presence of IGF1 receptor (IGF1R) and leptin receptor (ObR) has been detected in the ovary, but not in the alpaca. Thus, the aim of the present study was to evaluate the presence of these receptors in this tissue and analyze if the presence of these receptors in the ovary is related to the presence of a corpus luteum (CL) and if abundances, as determined by immunostaining intensity vary with follicle size. The IGF1R and ObR were identified in primary and secondary follicles, granulosa and theca interna cells of tertiary follicles and in CL. There were greater abundances of IGF1R in granulosa cells of tertiary follicles of ovaries without compared with those with CL. In both groups, the immunostaining of granulosa cells was greater than in theca interna cells. The abundance of ObR was greater in primary and secondary follicles, and theca interna cells of tertiary follicles in ovaries with than those without CL. Immunostaining of granulosa cells was greater than theca interna cells only in ovaries without CL. There were no differences in the abundance of ObR and IGF1R between primary and secondary follicles and granulosa cells of tertiary follicles, neither in ovaries with or without CL. The abundance of IGF1R was not correlated with abundance of ObR neither in ovaries with or without CL. These results indicate a possible role for IGF and leptin in ovarian function. Furthermore, these receptors could be regulated by ovarian steroid hormones because abundance of these receptors in ovaries varies depending on whether there is a CL present in the ovary.

Seminal plasma affects the survival rate and motility pattern of raw llama spermatozoa.

The objectives of this study were to evaluate the effect over time of different percentages of seminal plasma (SP) on llama sperm characteristics in raw semen and correlate the techniques routinely used to evaluate sperm viability and acrosome status with the Fluorescein Isothiocyanate -Arachis hypogea agglutinin/Propidium Iodide (FITC-PNA/PI). Eighteen ejaculates, obtained from 6 male llamas using electroejaculation, were incubated in 0.1% collagenase in HEPES-TALP (HT), centrifuged and resuspended with SP and HT: 0, 10, 50 and 100% SP. Samples were incubated (37 °C) until evaluation at 0; 1.5 and 3 h. Split plot and factorial designs were used to analyze sperm motility, viability, membrane function and acrosome status and Spearman's test was used for correlation. At 0 h, samples with 100% SP showed oscillatory motility; whereas in samples with 0 and 10% SP, progressive motility was predominant. Viability, membrane function and total motility decreased significantly at 3 h of incubation in samples with 100% SP. Sperm with intact acrosomes were fewer in 0% SP media at all times. FITC-PNA/PI correlated with 6-Carboxyfluorescein Diacetate and Propidium Iodide (CFDA/PI) and with Coomassie Blue (CB) stains (r = 0.8; p = 0.0 and r = 0.5; p = 0.0 respectively). CONCLUSIONS: the motility pattern of llama sperm is influenced by the concentration of SP. The use of SP as the only medium is not able to maintain sperm motility, viability and membrane function for 3 h. A certain percentage of SP is necessary in the medium to avoid spontaneous acrosome reactions. The correlations observed could help to shorten evaluation times and reduce costs in sperm laboratories.

Porcine sperm vitrification I: cryoloops method.

The aims of this study were to evaluate porcine sperm vitrification in cryoloops, with and without two different cryoprotectants and assess two warming procedures. Extended (n = 3; r = 4) and raw (n = 5; r = 2) semen was diluted in media without and with cryoprotectants (4% dimethylformamide and 4% glycerol) to a final concentration of 20 × 106 spermatozoa ml-1 and vitrified using the cryoloops method. Two warming procedures were evaluated: rapid method (30 s at 37°C) and an ultra-rapid method (7 s at 75°C, followed by 30 s at 37°C). Total motility (phase contrast), sperm viability (6-carboxifluorescein diacetate and propidium iodide stain), membrane function (hypo-osmotic swelling test), acrosome integrity (phase contrast), chromatin condensation (toluidine blue stain) and chromatin susceptibility to acid denaturation (acridine orange stain) were evaluated before and after vitrification and analysed using Friedman's test. In all media, the only seminal parameters that were maintained after vitrification were chromatin condensation and integrity. Vitrification of porcine spermatozoon using cryoloops, both in the presence or absence of cryoprotectants and independent of the warming procedure used, permits conservation of sperm chromatin condensation and integrity. It would be interesting to further verify this by producing porcine embryos using vitrified spermatozoon with intracytoplasmic sperm injection.

Porcine sperm vitrification II: Spheres method.

Owing to current problems in boar sperm cryopreservation, this study proposes to evaluate vitrification in spheres as an alternative cryopreservation procedure, comparing the use or not of permeable cryoprotectants and two warming methods. Extended (n = 3; r = 4) and raw (n = 5; r = 2) porcine spermatozoa were diluted in media, in the absence or presence of either 4% dimethylformamide or 4% glycerol, to a final concentration of 5 × 106  spermatozoa/ml and vitrified using the spheres method. Two warming procedures were evaluated: a rapid method (30 s at 37°C) and an ultrarapid method (7 s at 75°C, followed by 30 s at 37°C). Percentages of total motility (phase contrast), membrane function (hypo-osmotic swelling test), acrosome integrity (phase contrast), sperm viability (6-carboxyfluorescein diacetate and propidium iodide stain), chromatin condensation (toluidine blue stain) and chromatin susceptibility to acid denaturation (acridine orange stain) were evaluated in the samples before and after vitrification. Results, analysed using Friedman's test, suggest that rapid warming of raw porcine spermatozoa vitrified without permeable cryoprotectants may preserve DNA condensation and integrity better than the other processing methods studied in this work. Hence, porcine sperm vitrification using spheres could be used to produce embryos with ICSI to further validate this method.

Comparison of differents methods of sperm selection of llama raw semen.

The objective of this study was to compare the efficiency of different sperm selection methods applied to the same llama ejaculate. Four treatments were compared: two variants of the swim up technique (with and without seminal plasma), and two different colloids, Androcoll-E-Large and Percoll(®). Using electroejaculation, 21 semen samples were obtained from 7 llama males (n=7, r=3). The ejaculates were incubated in a solution of 0.1% collagenase, to decrease thread formation, and then split into 4 aliquots: one aliquot was layered over a column of Androcoll-E-Large (SLC) and the second over a column of Percoll (45%). The third aliquot was deposited in a tube with culture medium and was incubated at a 45° angle for 30min at 37°C (SU1). The last aliquot was centrifuged to separate the spermatozoa and seminal plasma. The sperm pellet obtained was resuspended, and transferred to a tube with culture medium which was incubated at an angle of 45° for 30min at 37°C (SU2). Both aliquots SLC and P showed higher proportions of progressive motility and plasma membrane functionality (p≤0.05) than raw semen. There were no significant differences (p>0.05) in sperm viability and in normal spermatozoa between raw semen and treatments. Nevertheless, only SLC did not have a significant increase of bent tails. In conclusion SLC centrifugation would be the method of choice for selecting llama spermatozoa.

Oestrogen and Progesterone Receptors and COX-2 Expression in Endometrial Biopsy Samples During Maternal Recognition of Pregnancy in Llamas (Lama glama).

Endometrial expression of oestrogen receptor-α (ERα), progesterone receptor (PR) and cyclooxigenase-2 (COX-2) was evaluated in non-pregnant and pregnant llamas during the period when luteolysis/maternal recognition of pregnancy is expected to occur. Females (n = 28) were divided into two groups: non-pregnant llamas were induced to ovulate with a Buserelin injection, and endometrial biopsies were obtained on day 8 (n = 5) or 12 (n = 5) post-induction of ovulation. Animals of the pregnant group (n = 18) were mated with a fertile male. Pregnancy was confirmed by the visualization of the embryo collected by transcervical flushing in 5 of 9 animals on day 8 post-mating and by progesterone profile on day 12 post-mating in 4 of 9 animals, when endometrial biopsies were obtained. An immunohistochemical technique was used to evaluate receptors population and COX-2 expression. Pregnant llamas showed a higher percentage of positive cells and stronger intensity for ERα than for non-pregnant llamas in stroma on day 8 and in the luminal epithelium on day 12 post-induction of ovulation, while a deep decrease in endometrial PR population was reported in pregnant llamas on that day in luminal and glandular epithelia and stroma. In the luminal epithelium, COX-2 expression was lower in pregnant than in non-pregnant animals. Briefly, the increase of ERα in pregnant llamas gives further support to the hypothesis that oestrogens are involved in the mechanism of maternal recognition of pregnancy. Endometrial PR decrease in pregnant llamas might be a necessary event to allow the expression of proteins involved in conceptus attachment, a mechanism widely accepted in other species. Moreover, embryo seems to attenuate maternal PGF(2α) secretion during early pregnancy by decreasing the endometrial expression of COX-2 in the luminal epithelium of pregnant llamas.

Evaluation of the acrosomal status in Lama glama sperm incubated with acrosome reaction inducers.

UNLABELLED: The objectives of this study were to evaluate the effect of different acrosome reaction (AR) inducers on viability and acrosomal status in llama spermatozoa, by using the FITC-PNA/PI technique and evaluate if there is a positive correlation between the FITC-PNA/PI and the Coomassie blue (CB) staining techniques. After incubating twenty ejaculates in 0.1% collagenase the centrifuged pellets were resuspended in TALP-BSA medium. An aliquot was sonicated to remove the acrosomal content (positive control). The rest of the sample was incubated for 3h at 38 °C with 5% CO2 and 100% humidity. TREATMENTS: Three aliquots were further incubated 1h with one of the following AR inducers: calcium ionophore, ionomycin or progesterone. CONTROLS: One without inducers and the other, incubated with dimethyl sulfoxide (vehicle of the inducing agents). Acrosomes were evaluated at time 0 and after 4h incubation. Calcium ionophore was the most potent agent for inducing the AR (67.2 ± 14.4% live+dead AR sperm) (P < 0.05). These samples showed no motility and viability was very low (0-30%). Both ionomycin and progesterone presented significantly higher (P < 0.05) percentages of total AR sperm than the controls, but had similar percentages of dead reacted sperm to the controls. A positive correlation was observed between the intact acrosome FITC-PNA/PI pattern (live+dead sperm) and the acrosome-present CB pattern (r = 0.64; P = 0.000) in all the evaluated samples. CONCLUSIONS: the FITC-PNA/PI technique simultaneously evaluates viability and acrosomal status in llama spermatozoa and calcium ionophore could be used as a control of AR.

Blastocele fluid from in vitro- and in vivo-produced equine embryos contains nuclear DNA.

Normal mammalian early embryonic development involves apoptosis of blastomeres as a remodeling process during differentiation, starting at the blastocyst stage. Genomic DNA has been recently detected in the blastocele fluid of human embryos and has been amplified by real-time polymerase chain reaction (PCR) to diagnose the sex of in vitro-produced human embryos. This new approach varies from conventional preimplantation genetic diagnosis in that no cells are extracted from the embryo and only the blastocele fluid is aspirated and used as a DNA sample for diagnosis. In the present work, we investigated whether the blastocele fluid of equine preimplantation embryos contains nuclear DNA and whether this DNA could be used to diagnose the sex of the embryos by conventional PCR, using specific primers that target the TSPY and AMEL equine genes. The sex of 11 of 13 in vivo-produced embryos and of four of five in vitro-produced embryos was successfully diagnosed. The PCR amplification product was analyzed using genetic sequencing reporting that the DNA present in blastocele fluid was genomic. Additionally, after polyacrylamide gel electrophoresis and silver staining, the blastocele fluid from three different embryos produced a ladder pattern characteristic of DNA fragmented during apoptosis. Therefore, the results presented in this work report that blastocele fluid from in vivo- and in vitro-produced equine embryos contains nuclear DNA which is probably originated by apoptosis of embryonic cells, and this DNA could be used to diagnose the sex of preimlpantation embryos by conventional PCR.

In vitro equine embryo production using air-dried spermatozoa, with different activation protocols and culture systems.

The aim of this work was to evaluate the use of air-dried spermatozoa for in vitro production of equine embryos and verify if sperm extract activation and in vivo culture improve in vitro embryo production. Cooled spermatozoa (control) and air-dried spermatozoa stored for 2, 14 or 28 days were used for ICSI sperm extract, or ionomycin was used for oocyte activation, and embryos were in vitro or in vivo (in mare's oviduct) cultured for 7 days. With in vitro culture, cleavage rate was higher when activating with sperm extract (P < 0.05). No differences in embryo development were seen between the two activation treatments nor between storage periods (P > 0.05). Blastocysts were obtained with cooled spermatozoa, and morulae were achieved using in vivo culture with 28-day storage spermatozoa and ionomycin-activated oocytes. When in vivo culture was performed, sperm DNA fragmentation was assessed using the sperm chromatin dispersion test and did not show statistical correlation with cleavage nor embryo recovery rates. In conclusion, equine embryos can be produced using air-dried spermatozoa stored for several weeks. Sperm extract activation increased cleavage rates but did not improve embryo development. In vivo culture allowed intrauterine stage embryos to be achieved.

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

The aim of this study was to evaluate the developmental competence and pregnancy rate of llama hatched blastocysts produced in vitro using gametes from live animals and two different culture conditions. Fifteen adult females were superstimulated with 1500 IU of eCG, eleven (73%) responded to the treatment and were used as oocyte donors. Follicular aspiration was conducted by flank laparotomy. Semen collections were performed under general anesthesia by electroejaculation of the male. Sixty-six COCs were recovered from 77 aspirated follicles (86% recovery) and were randomly placed in Fertil-TALP microdroplets with the sperm suspension (20 × 10(6)live spermatozoa/ml). After 24 h, they were placed in SOFaa medium supplemented with FCS and randomly assigned to one of two culture conditions. Culture condition 1 (CC1) consisted of 6 days of culture (n=28) and culture condition 2 (CC2) consisted of renewing the culture medium every 48 h (n=35). In CC1, the blastocyst rate was 36% (10/28) and the hatched blastocyst rate was 28% (8/28) whereas in CC2, the blastocyst rate was 34% (12/35) and the hatched blastocyst rate was 20% (7/35) (p>0.05). No pregnancies were obtained after embryo transfer (ET) of CC1 blastocysts (0/8) while one pregnancy was obtained (1/7) after transferring a hatched blastocyst from CC2. Forty-two days after the ET, the pregnancy was lost. This study represents the first report of a pregnancy in the llama after intrauterine transfer of embryos produced by in vitro fertilization using gametes from live animals.

Llama oviductal sperm reservoirs: involvement of bulbourethral glands.

The aim of this study was to elucidate the role of llama seminal plasma in the formation of oviductal sperm reservoirs. Female llamas with follicles in the mature phase were mated with a bulbourethral glands-removed male. Females mated with nonbulbourethral glands-removed males were used as control. Oviducts were obtained by surgery 24 h after mating. The uterotubal junction and isthmus were examined by scanning electron microscopy, and mucopolysaccharides were identified by Alcian blue staining. To know the proteins probably involved in sperm reservoir formation, SDS-PAGE of seminal plasma (8% and 18% resolving gel) was made. Spermatozoa only adhered to the oviductal mucosa surface of uterotubal junction of females mated with nonbulbourethral glands-removed males confirming that seminal plasma and, in particular, bulbourethral secretions are related with the oviductal sperm reservoir formation. Histological sections showed sperm in the lumen, immersed in substance, positive for acid mucopolysaccharides. Alcian blue staining of seminal plasma proteins SDS-PAGE showed a band of high molecular weight containing mucopolysaccharides, only present in nonbulbourethral glands-removed males. Bulbourethral glands would secrete at least eight different proteins that most likely participate in the process of sperm storage in the oviduct.

Vitrification of in vitro mature alpaca oocyte: effect of ethylene glycol concentration and time of exposure in the equilibration and vitrification solutions.

The effect of different ethylene glycol concentrations, times of exposure and vitrification procedure on viability, cleavage and blastocyst rate of in vitro matured alpaca oocytes chemically activated after vitrification was analyzed. In Experiment 1, oocytes were incubated for 12-15 min with different concentrations of ethylene glycol (EG) in the equilibration solution (ES) followed by chemical activation and in vitro cultured for 8 days to determine oocyte viability, cleavage and blastocyst rates. In Experiment 2, oocytes were incubated in the equilibration solution containing 4% of EG for 12-15 min and then randomly assigned to vitrification solutions containing 25, 35 or 45% of EG for 30s, vitrified and stored at -196°C. In Experiment 3, oocytes were incubated in the equilibration solution containing 4% of EG for 12-15 min and then randomly assigned to the vitrification solution containing 35% of EG for 15, 30 or 45s, vitrified and stored at -196°C. For Experiments 2 and 3, non-vitrified and vitrified oocytes were activated and cultured in vitro. In Experiment 1, oocyte viability was lowest at concentrations of 6 or 8%, intermediate at 2 or 4% and highest at 0% of EG. Oocyte viability and cleavage rate were affected by EG concentration, time of exposure in the vitrification solution or vitrification procedure in Experiment 2 and 3. Alpaca oocytes were viable after vitrification, given that oocyte viability, cleavage and blastocyst rate were affected by the vitrification procedure, EG concentration and time of exposure in the equilibration and vitrification solutions.

In vitro production of embryos in South American camelids.

Studies in reproductive biotechnology techniques have been minimal in South American camelids (SAC). Complex reproductive characteristics of these species contribute to slow progress. Nevertheless, some techniques, such as in vitro fertilization, intracytoplasmic sperm injection and nuclear transfer have been applied and have produced advances in knowledge on embryo environment and in vitro conditions necessary for development. Embryo production may have a high impact in both domestic and wild camelids population. Studies addressed to improve in vitro embryo production and oocyte collection could be a potential key to develop IVF and embryo production as a routine procedure in camelids.

Development of an artificial insemination protocol in llamas using cooled semen.

The objective of this study was to design an AI protocol using cooled semen to obtain pregnancies in the llama. Each raw ejaculate was subdivided into four aliquots which were extended 1:1 with: (1) 11% lactose-egg yolk (L-EY), (2) Tris-citrate-fructose-egg yolk (T-F-EY), (3) PBS-llama serum (S-PBS) and (4) skim milk-glucose (K). Each sample reached 5°C in 2.5 h and remained at that temperature during 24 h. Percentages of the semen variables (motility, live spermatozoa) in ejaculates and samples cooled with L-EY were significantly greater than those obtained when cooling with the other extenders; therefore this extender was used (1:1) for all inseminations. Females were randomly divided into four groups (A-D) according to insemination protocol. Group A: females were inseminated with a fixed dose of 12 × 10(6) live spermatozoa kept at 37°C. Group B: females were inseminated with a fixed dose of 12 × 10(6) live spermatozoa, cooled to 5°C and kept for 24 h. Group C: females were inseminated with the whole ejaculate (variable doses), cooled to 5°C and kept for 24 h. These groups (A-C) were inseminated between 22 and 24 h after induction of ovulation. Group D: females were inseminated with the whole ejaculate (variable doses), cooled to 5°C, kept for 24 h and AI was carried out within 2 h after ovulation. Pregnancy rates were 75%, 0%, 0% and 23% for groups A, B, C and D respectively. These results indicate that it is possible to obtain llama pregnancies with AI using cooled semen and that the success of the technique would depend on the proximity to ovulation.

In vitro embryo production in llamas (Lama glama) from in vivo matured oocytes with raw semen processed with Androcoll-E using defined embryo culture media.

The aim of this study was to carry out in vitro fertilization using spermatozoa selected with Androcoll-E™ and to evaluate the efficiency of the culture medium DMEM-F12 for in vitro embryo development in the llama. Twelve adult females from 18 superstimulated (67%) were used as oocyte donors. They were superstimulated with 1500 IU of eCG and after 5 days, received a single dose of buserelin. Twenty hours post-injection, follicular aspiration was conducted by flank laparotomy. Semen collections were performed under general anesthesia by electroejaculation of the male. The ejaculates were processed with a solution of collagenase (0.1%) and an Androcoll-E™ column was used to improve the sample. Sixty nine COCs were recovered from 79 aspirated follicles (87% recovery). Only expanded COCs were used (n = 67); they were randomly placed in groups of 1-5 in Fertil-TALP and the sperm suspension (20 × 10(6) live spermatozoa/ml) was added to each fertilization microdroplet. After 24 h, they were randomly placed in one of two culture media: SOF (n = 34) or DMEM-F12 (n = 33) and incubated for 6 days in humidified atmosphere of 5% CO(2) , 5% O(2) and 90% N(2) at 38°C. The blastocyst rate was 20% (7/34) in SOF medium (3 hatched, 2 expanded and 2 early blastocysts) and 15% (5/33) in DMEM medium (all expanded blastocysts). In conclusion, using Androcoll-E™ it is possible to select good quality spermatozoa from llama ejaculates for in vitro fertilization and to produce blastocysts in DMEM-F12 medium. This is also the first time that hatched llama blastocysts have been produced after culture in a defined medium such as SOFaa.

Evaluation of Lama glama semen viscosity with a cone-plate rotational viscometer.

Llama semen is highly viscous. This characteristic is usually evaluated subjectively by measuring the thread formed when carefully pippeting a sample of semen. The aims of this study were (i) to objectively determine and analyse llama semen viscosity, (ii) to compare semen viscosity between ejaculates of the same male as well as between different males, (iii) to study the correlation between viscosity and other semen characteristics and (iv) to evaluate the effect of collagenase on semen viscosity. Semen viscosity was evaluated using a cone-plate Brookfield rotational viscometer. A non Newtonian, pseudoplastic behaviour was observed in the 45 semen samples evaluated. Rheological parameters were determined obtaining the following results (mean ± SD): apparent viscosity at 11.5 s(-1): 46.71 ± 26.8 cpoise and at 115 s(-1): 12.61 ± 4.1 cpoise; structural viscosity (K) (dyne s cm(-2)): 2.18 ± 1.4 and coefficient of consistency (n): 0.45 ± 0.1. Statistical differences were found between different ejaculates of the same male for structural viscosity and apparent viscosity at 11.5 s(-1) (P < 0.01). Correlation was found only between coefficient of consistency (n) and sperm concentration (P < 0.01). Significant differences for coefficient of consistency (n) and viscosity at 115 s(-1) were found between samples incubated with and without collagenase (P < 0.05).