Physico-chemical properties and protein profiles of sperm from three freshwater chondrostean species: a comparative study among Siberian sturgeon (Acipenser baerii), sterlet (Acipenser ruthenus) and paddlefish (Polyodon spathula)

Abstract

Summary Physico-chemical properties (spermatozoa motility, spermatozoa concentration, seminal plasma protein concentration, osmolality, pH, ions) and sperm protein profiles were evaluated in three Acipenseriforme species [Siberian sturgeon (Acipenser baerii), sterlet (Acipenser ruthenus) and paddlefish (Polyodon spathula)]. The spermatozoa velocity was observed significantly highest in sterlet and lowest in Siberian sturgeon (P < 0.05). Spermatozoa velocity was positively correlated to pH and the concentration of Na+ in seminal plasma in all species examined. Other tested parameters, in particular the concentration of K+, expressed species specific patterns, which could be linked to taxonomical status of species. The protein profiles of seminal plasma indicated a protein band with a molecular weight of 32.6 kDa exclusively detected in paddlefish. In spermatozoa, 95 protein spots were detected in Siberian sturgeon and sterlet, respectively, whereas only 70 spots were observed in paddlefish. Each spermatozoa protein map expressed a strong species specific pattern, which offers a basic benchmark to trace molecular differences among Acipenseriformes. It can be concluded that results presented in this study could be applied for successful reproduction management and cryopreservation protocols of these endangered species.