Determination of optimal glucose concentration for microcalorimetric metabolic evaluation of equine spermatozoa

Abstract

The heat conduction microcalorimeter can be used to evaluate the metabolic rates of the sperm cell. Two ejaculates of four stallions were cooled to +50C and checked for sperm motility (bright field microscopy), viability (eosin 3%), functional membrane integrity (hyposmotic swelling test), and heat production (microcalorimetry). Glucose and sperm cell concentrations were determined in order to measure the heat outputs resulting from sperm metabolism. Sperm viability, membrane integrity and sperm motility did not differ among the different glucose concentrations tested. Nevertheless, the highest heat output detected by the microcalorimeter was obtained with 6 mM glucose and 108 spermatozoa/mL. Since conduction microcalorimetry offered additional information on equine sperm metabolism, it could be used as a method to study equine semen preservation.