Elsevier

Livestock Science

Volume 251, September 2021, 104627
Livestock Science

Non-enzymatic extraction of spermatozoa from alpaca ejaculates by pipetting followed by colloid centrifugation

https://doi.org/10.1016/j.livsci.2021.104627Get rights and content
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Highlights

  • Alpaca ejaculates were liquified by gentle pipetting in Tris-citrate-fructose buffer.

  • Sperm were separated from seminal plasma with or without colloid centrifugation.

  • Motility and membrane integrity were greater after colloid centrifugation than in controls.

  • Sperm quality in colloid centrifuged samples was maintained during 24h cold storage.

  • Sperm quality in thawed samples was also greater after colloid centrifugation but the freezing protocol requires optimization.

Abstract

Viscous camelid ejaculates present problems for sperm handling and sperm preservation. In the present study, a technique that had been used for dromedary camel semen was tested with alpaca semen. Ejaculates (n=9) were collected by artificial vagina at San Marcos University, Lima, and were liquefied by gentle pipetting in tris-citrate-fructose. Half of the sample was prepared by Single Layer Centrifugation (SLC) through a colloid; the other half was centrifuged without colloid as a control. Each control and SLC sample was then split into two parts; one part was stored cooled for 24 h at 5 °C and the other part was frozen, resulting in 4 treatments for each ejaculate. All samples were evaluated for sperm motility, hypoosmotic swelling test (HOST), plasma membrane integrity, and morphology, immediately after centrifugation and again after storage Total motility and plasma membrane integrity were greater in samples prepared by SLC than controls (motility 72±13% vs. 57±7%; plasma membrane integrity 63±13% vs. 54±8%, for SLC and controls respectively). Normal morphology and HOST were not different between treatments (65±13 vs. 61±13% and 42±6 vs. 39±10%, for SLC and controls respectively). After 24 h cooled storage, motility and plasma membrane integrity were greater for SLC samples (motility: 51±16 vs. 34±15%; p<0.001; membrane integrity: 51±15 vs. 40±18%; P < 0.05 for SLC and controls, respectively); HOST (40±14 vs. 34±11%) and normal morphology (67±13 vs. 63±14%) were not different between treatments. Sperm quality decreased considerably after cryopreservation (P<0.001 for all parameters); however, motility (P<0.01), plasma membrane integrity (P<0.05) and morphology (P<0.05) were higher for SLC than for controls. These results indicate that alpaca spermatozoa can be extracted from semen using a combination of pipetting and SLC, potentially with a beneficial effect on sperm quality. Samples could be stored cooled for 24 h, retaining better motility than controls; motility and plasma membrane integrity were greater in SLC samples than controls after freezing and thawing but the freezing protocol requires improvement.

Keywords

Silane silica-coated nanoparticles
South American camelids
Artificial insemination
Sperm quality
Sperm freezing

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