Abstract

Sperm mitochondria are vital organelles for energy production and pre- and post-fertilization sperm functions. The potential influence of the age of the bull and season on the sperm-borne mitochondrial copy number and the transcription activity has not yet been investigated. Therefore, the expression patterns of all protein-coding mitochondrial genes were identified throughout the year along with mitochondrial copy numbers in young and old bulls' spermatozoa. For that, high-quality semen samples (