Llama Sperm Research Articles

Effect of ovarian superstimulation on COC collection and maturation in alpacas

The objective of the present study was to compare the ovarian follicular response, cumulus-oocyte complex (COC) collection rate, and maturational status of COC collected from alpacas subsequent to treatment with two different superstimulatory protocols. Alpacas ( n = 7 per group) were treated with: (1) 200 mg of FSH im divided bid for 3 d, plus a single i.v. dose of 1000 IU hCG 24 h after the last FSH treatment, or (2) 1200 IU of eCG as a single i.m. dose, plus a single i.v. dose of 1000 IU of hCG on day 3 after eCG treatment (day 0 = start of superstimulatory treatment). At 20–24 h post-hCG treatment, the ovaries were surgically exposed and COC were collected by needle aspiration of all follicles ≥6 mm. The FSH and eCG treatment groups did not differ with respect to the number of follicles ≥6 mm at the time of COC collection (20.0 ± 7.5 versus 27.0 ± 3.3; P = 0.5), the number of COC collected (26.2 ± 8.4 versus 23.3 ± 3.7; P = 0.7), or the collection rate per follicle aspirated (89% versus 87%; P = 0.7). No differences were detected between FSH- and eCG-treated alpacas in the number of expanded COC collected per alpaca (11.5 ± 2.9 versus 8.8 ± 2.8; P = 0.54), the number of expanded COC in metaphase II (8.5 ± 1.9 versus 6.0 ± 2.1; P = 0.1), or the number of compact COC with ≥3 layers of cumulus cells (12.5 ± 4.3 versus 14.3 ± 2.6; P = 0.72). A greater proportion ( P < 0.05) of compact COC collected after FSH treatment matured in vitro to the metaphase II stage than after eCG treatment. Eight expanded alpaca COC were fertilized in vitro with llama sperm, three of which were fixed and stained 18 h after exposure to sperm and five were cultured in vitro. Two of the three stained oocytes were in the pronuclear stage, and all five of the cultured oocytes developed to the two-cell and morula stages at 2 and 7 days, respectively, after in vitro fertilization. In summary, FSH and eCG treatments were equally effective for ovarian superstimulation and oocyte collection. Cumulus-oocyte complexes were collected from more than 80% of follicles aspirated during laparotomy. Nearly one third of the COC collected after superstimulation were in metaphase II, and more than 70% of the remaining COC progressed to metaphase II after in vitro maturation for 26 h, bringing the mean number of oocytes available for in vitro fertilization to 16 per alpaca. Preliminary results support the hypothesis that alpaca oocytes obtained after superstimulation in the absence of progesterone are developmentally competent since morulae developed from all five COC fertilized and cultured in vitro .

The effect of enzymes on semen viscosity in Llamas and Alpacas

The effect of four enzymes: collagenase, fibrinolysin, hyalurodinase, and trypsin were recorded on the viscosity, motility, percent live spermatozoa and acrosome integrity of Llama and Alpaca semen. Semen samples were collected using a modified artificial vagina for each of the five llamas and five alpacas. A 25% solution of the of enzyme at a concentration of 1 mg/ml was added to the ejaculate. Analysis of variance was used to determine differences in eliminating viscosity and alterations in motility, percent live spermatozoa and the acrosomal integrity at 0 (time of semen collection), 2 and 5 min. In Llama and Alpaca semen, collagenase eliminated viscosity in 100 and 99% of the samples, respectively. Correspondingly, fibrinolysin in 89 and 59%; hyalurodinase in 88 and 36%; and trypsin in 55 and 68% of the samples ( p<0.05). In the Llama sperm, motility decreased ( p<0.05) with the addition of fibrinolysin (28%), trypsin (13%), hyalurodinase (12%), and collagenase (4%). In Alpaca semen, the enzymes used had no effect on sperm motility. Percent live spermatozoa variably decreased after the addition of fibrinolysin, hyalurodinase and trypsin. There was no significant difference in the acrosome integrity in Llama and Alpaca makes following the addition of the enzymes. Overall, collagenase had little or no influence in decreasing motility, percent live spermatozoa and acrosome integrity, whereas, it was effective in eliminating semen viscosity.