Effect of different storage temperatures on the metabolic activity of spermatozoa following liquid storage of boar semen

This study investigated the effects of different temperatures (5 and 16C) on the metabolic activity of boar spermatozoa preserved in a standard semen extender, Kortowo 3 (K3), supplemented with or without egg yolk lipoprotein fractions (LPF) isolated from hen or ostrich egg yolk. Besides motility and plasma membrane integrity (PMI) assessments of spermatozoa, analysis of the metabolic activity of spermatozoa included mitochondrial energy status, oxygen uptake, ATP content and L-lactate production. Total motility and PMI of spermatozoa decreased over time. The metabolic activity of spermatozoa was significantly higher in the extenders containing LPF than in the K3 extender. Marked changes in the sperm metabolic activity observed during storage of semen samples at 5C indicated that glycolysis (fructolysis) was the major metabolic pathway. It seemed likely that mitochondrial respiration was the predominant metabolic activity exhibited by spermatozoa during storage at 16C. The findings of this study indicate that different storage temperatures can modulate the metabolic pathways of boar spermatozoa during liquid semen storage.