Spermatozoa and seminal plasma enzyme activity in Persian sturgeon,Acipenser persicus, in relation to short-term storage

Abstract

An important component of semen examination is the comparison between the characteristics of fresh and stored semen (Lahnsteiner, Berger, Weismann & Patzner 1996). The relationships among the parameters of fresh and cryopreserved semen may be determined to identify markers for prediction of the effectiveness of the cryopreservation procedure for fish semen (Lahnsteiner et al. 1996). As the quality of cryopreserved semen is significantly lower than that of fresh semen, such markers are important for successful cryobanking of fish semen (Piros, Glogowski, Kolman, Rzemieniecki, Domagala, Horvath, Urbanyi & Ciereszko 2002). The handling and storage of gametes is central to many assisted reproductive procedures and may be broadly considered as either short-term storage, at temperatures above 0°C, or long-term storage at temperatures below 0°C. Short-term storage of fish gametes may be necessary when the availability of male and female gametes for in vitro fertilization is asynchronous (Lahnsteiner, Weismann & Patzner 1997) or if the sources of gametes are spatially separated. Preservation may also be necessary during transport to a facility with the capacity to cryopreserve gametes for long-term storage, in certain instances when spermatozoa and oocytes have been removed from moribund or recentlydead animals in the field. Several factors can, however, affect the quality and viability of the stored sperm. In this regard, the assessment of the biochemical characteristics of sperm, particularly in terms of enzyme characteristics, can provide new insights into spermatozoa motility and fertilization ability, thus creating opportunities for improving artificial reproduction and germplasm resource conservation procedures (Li, Hulak & Linhart 2008). The enzymology of fish gametes is not well known, when compared with that associated with mammalian semen. Detailed results of research on the enzymes of fish spermatozoa are available with respect to aspartate aminotransferase (AST), lactate dehydrogenase (LDH), acid phosphatase (AcP), b-N-acetylglucosaminidase (b-N AGase) and arylsulfatase (AS) (Schmehl, Graham & Erdhal 1987; McNiven, Gallant & Richardson 1992; Ciereszko & Dabrowski 1994; Piros et al. 2002;). AS and b-N AGase are among the key enzymes, localized within the mammalian acrosome, that play a pivotal role during penetration of the oocyte (Nikolajczyk & O’Rand 1992; Brandon, Srivastava, Heusner & Fayer-Hosken 1997). The activity of AS and b-N AGase during fertilization in sturgeon can provide useful information regarding speciesspecific fertilization and prevention of polyspermy (when a single egg is fertilized by more than one sperm) as postulated by Cherr and Clark (1985). AcP, one of the enzymes found in sperm, has been described in mammalian spermatozoa and seminal plasma (Yousef, Diamandis, Jung & Diamandis 2001) and has also been observed in spermatozoa