Mitochondria in teleost spermatozoa

There is an extraordinary diversity of reproductive modes in teleost and this variability is related to the phylogenetic relationships and adaption to very different biotopes. As in all vertebrates, sperm is produced as the end product of the process of spermatogenesis, and regarding teleost the spermatozoa lack an acrosome in almost all species and motility is activated as a response to osmolarity and ion content of the aquatic medium where the sperm is released. In this context, mitochondria possess a fundamental role for fish spermatozoa motility and integrity, hence, fertilizing potential; they are the energy supplier that allows flagellar movement and their dysfunction could play a main role in structural and functional damage to the spermatozoa. The ATP production through oxidative phosphorylation provides not only energy for cell activities, which includes Na+/K+ ATPase pump, endocytosis, protein synthesis and many other cell processes; but also produces reactive oxygen species, that under mitochondrial dysfunction causes oxidative stress.