Pikeperch (Sander lucioperca) is a highly profitable commercial species whose economic value has greatly increased in the last decade. As in other species, the quality of spermatozoa in this species is a principal feature inherent in fertilization success and efficient natural and artificial reproduction. The capacity of fish spermatozoa to be activated and tolerate environmental changes (in osmolality, ion composition, external pH, temperature, etc.) during the motility period contributes to fertilization success. In this study, we investigated the effects of environmental osmolality and ion composition on spermatozoa motility. To determine if the activation mechanism is affected by sperm quality parameters, we measured semen characteristics such as semen volume, spermatozoa concentration, seminal fluid osmolality and ion composition, and spermatozoa lipid composition. An additional parameter of sperm quality reflecting spermatozoa osmoresistance, the swelling rate, was measured by the nephelometry method. We detected that sperm samples with the highest content of palmitic (C16:0) and palmitoleic (C16:1) acids showed the lowest motility activation under the studied conditions, suggesting that these fatty acids are possible markers for the determination of spermatozoa quality in fish. Our results show that pikeperch spermatozoa can be activated under different osmotic conditions and that cell swelling always accompanies motility. However, spermatozoa sustain their volume under hypotonic conditions when motility is not initiated, suggesting that pikeperch spermatozoa activation is mainly controlled by ion composition rather than the osmolarity of the surrounding medium.

• Klíčová slova
• Fish spermatology, Pikeperch, Semen quality, Spermatozoa motility, Spermatozoa volume,
• MeSH
• analýza spermatu veterinární   MeSH
• motilita spermií fyziologie   MeSH
• okounovití * fyziologie   MeSH
• sperma * fyziologie   MeSH
• spermie fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

In most fish exhibiting external fertilization, spermatozoa become motile after release into water, triggered by differences between intracellular and extracellular conditions such as osmotic pressure, ion composition, and pH. The rapid change in osmolarity initiating spermatozoon motility induces osmotic pressure, resulting in active water movement across the cell membrane. Mechanisms of ion and water transport across the plasma membrane and cell volume regulation are important in maintaining structure and functional integrity of the cell. The capacity of the fish spermatozoon plasma membrane to adapt to dramatic environmental changes is an essential prerequisite for motility and successful fertilization. Adaptation to change in external osmolality may be the basis of spermatozoon function and an indicator of sperm quality. The involvement of specific water channels (aquaporins) in cell volume regulation and motility is highly likely. The goal of this review is to describe basic mechanisms of water transport and their role in fish spermatozoon physiology, focusing on osmoresistance, cell volume regulation, motility, and survival.

• Klíčová slova
• Aquaporins, Motility, Osmoresistance,·Water transport,
• MeSH
• akvaporiny fyziologie   MeSH
• kryoprezervace MeSH
• lidé MeSH
• lipidy fyziologie   MeSH
• osmoregulace * MeSH
• ryby fyziologie   MeSH
• spermie fyziologie   MeSH
• uchování spermatu MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• akvaporiny MeSH
• lipidy MeSH

The lipid composition of sperm membranes is crucial for fertilization and differs among species. As the evolution of internal fertilization modes in fishes is not understood, a comparative study of the sperm lipid composition in freshwater representatives of externally and internally fertilizing fishes is needed for a better understanding of taxa-specific relationships between the lipid composition of the sperm membrane and the sperm physiology. The lipidomes of spermatozoa from stingray, a representative of cartilaginous fishes possessing internal fertilization, and sterlet, a representative of chondrostean fishes with external fertilization, have been studied by means of nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), electrospray MS, gas chromatography-(GC) MS, and thin-layer chromatography (TLC). NMR experiments revealed higher cholesterol content and the presence of phosphatidylserine in stingray compared to sterlet sperm. Unknown MS signals could be assigned to different glycosphingolipids in sterlet (neutral glycosphingolipid Gal-Cer(d18:1/16:0)) and stingray (acidic glycosphingolipid sulpho-Gal-Cer(d18:1/16:0)). Free fatty acids in sterlet sperm indicate internal energy storage. GC-MS experiments indicated a significant amount of adrenic acid, but only a low amount of docosahexaenoic acid in stingray sperm. In a nutshell, this study provides novel data on sperm lipid composition for freshwater stingray and sterlet possessing different modes of fertilization.

• Klíčová slova
• fertilization mode, freshwater fish, lipidomics, mass spectrometry, sperm, thin-layer chromatography,
• MeSH
• chromatografie na tenké vrstvě MeSH
• druhová specificita MeSH
• fertilizace fyziologie   MeSH
• glykosfingolipidy chemie   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• kyseliny dokosahexaenové chemie   MeSH
• lipidomika MeSH
• lipidy chemie   MeSH
• magnetická rezonanční spektroskopie MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• ryby fyziologie   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• spermie chemie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glykosfingolipidy MeSH
• kyseliny dokosahexaenové MeSH
• lipidy MeSH