Coconut Water as an Extender Component for Cooled Equine Sperm

Abstract

The aim of this study was to evaluate the effect of coconut water as a component of extender in different formulations for cooling equine sperm. One ejaculate of fourteen stallions was collected. Sperm was diluted to 50 × 10⁶ sperm/mL using five different extenders: ACP-105: powdered coconut water extender (ACP-105, ACP Biotecnologia, Brazil); ACP-Milk: ACP-105 + 20 g/L of skimmed milk; ACP-EY 2.5%: ACP-105 + 2.5% of egg yolk; ACP-EY 5%: ACP-105 + 5% of egg yolk; and BotuSêmen (Botupharma, Botucatu, Brazil) and cooled in passive cooling device (BotuFlex, Botupharma, Botucatu, Brazil) at 5 and 15°C for 24 hours. Sperm kinetics and plasma membrane integrity (PMI) were evaluated by computer-assisted sperm analysis and fluorescence staining, respectively, at T0 (before cooling) and T24 (24 hours after cooling). Sperm kinetics did not differ at T0 among groups (P > .05); however, at T24, these parameters were significantly lower in ACP-105 (5°C, total motility [TM]: 9.2 ± 3.6%; progressive motility [PM]: 2.7 ± 1.6%; percentage of fast-moving spermatozoa [RAP]: 4.8 ± 3.0%; 15°C, TM: 10.6 ± 3.0%; PM: 1.1 ± 0.5%; RAP: 4.8 ± 1.9%) and ACP-EY 5% (5°C, TM: 28.0 ± 6.3%; PM: 5.7 ± 1.8%; RAP: 15.9 ± 6.0%; 15°C, TM: 30.0 ± 6.0%; PM: 6.9 ± 2.1%; RAP: 17.6 ± 5.3%) compared with BotuSêmen (5°C, TM: 66.2 ± 5.6%; PM: 21.1 ± 2.8%; RAP: 53.9 ± 6.1%; 15°C, TM: 63.4 ± 5.4%; PM: 17.2 ± 2.8%; RAP: 51.4 ± 6.3%) (P < .05). All groups exhibited similar PMI at tested moments and cooling temperatures (5°C: 83%; 15°C: 84%) (P > .05). Further studies are necessary to evaluate powdered coconut water in different compositions of sperm extender; however, coconut-based extender as used in this study was not an alternative to preserve sperm parameters of cooled equine sperm.

Keywords: Semen; equine reproduction; fertility; stallion.