Fish sperm motility assessment as a tool for aquaculture research: a historical approach

Abstract

Fish sperm motility is nowadays considered the best biomarker for the quality of fish spermatozoa, and sperm motion parameters from more than 300 fish species have been reported in more than 1500 scientific articles covering a wide range of topics, from molecular biology to ecology. The most studied topics have been (i) the sperm storage (involving both the use of chilled-storage protocols for shortterm periods and sperm cryopreservation techniques for long-term storage), (ii) the sperm physiology (fathom in the spermatozoa activation process and the whole propulsion machinery of the sperm cells) and (iii) the broodstock management (covering aspects such as rearing conditions, dietary requirements or hormonal induction treatments). In addition, other aquaculture and ecological topics, such as (iv) the knowledge of the breeding cycle of the species, (v) the phenomenon of the sperm competition and (vi) ecotoxicological studies for the evaluation of aquatic environments, have also been approached from the evaluation of sperm motion performance. Therefore, fish sperm motility assessment can serve as a potential tool for aquaculture and ecological purposes, covering key topics of fundamental and applied research. This review gives an overview of the major research areas in which fish sperm motility has been applied successfully.

Effects of cooling rates on the quality of Prochilodus lineatus (Valenciennes, 1836) sperm

“…In the comet assay, sperm cells are placed on agarose gel using glass slides and, after cell discharge and DNA denaturation, alkaline electrophoresis is performed (Beirão, Cabrita, Soares, Herráez, & Dinis, 2008;Küçük, 2018;Lee & Steinert, 2003). The technique is based on different electrophoretic DNA patterns obtained from DNA fragments, where cells (DNA spermatozoa) with DNA archived in a comet-like tail structure are observed, larger when the DNA structure damage is greater (Gallego & Asturiano, 2018).…”

Improvement of techniques for sperm evaluation and cryobanking in European eel.

“…Although DMSO is the most used cryoprotectant for fish sperm (Gallego and Asturiano, 2018a;Martínez-Páramo et al, 2017), methanol has also been widely used in freshwater species such as sturgeons, salmonids, tench or Eurasian perch within others (reviewed by Asturiano et al, 2017). Furthermore, it has been recently used in cryopreservation protocols for Japanese eel sperm (Koh et al, 2017;Müller et al, 2017;.…”

“…The first eel sperm cryopreservation protocol was developed for Japanese eel by Tanaka et al (2002a). They used DMSO at 10% v/v as cryoprotectant, which is the most common cryoprotectant used in sperm of marine fish species (Gallego and Asturiano, 2018a), and it was used together with a designed extender solution that included NaCl, NaHCO3 and soya lecithin.…”

“…This is crucial, since when spermatozoa start their motility, the stored ATP required for the movement of the flagellum will last for only a few minutes (Ingermann, 2008). The cryoprotectant used was dimethyl sulphoxide (DMSO) at 10% v/v, which is the most common compound used as cryoprotectant in sperm of marine fish species (Gallego and Asturiano, 2018a), and the extender diluent included NaCl, NaHCO3 and soya lecithin ( Table 1). The use of DMSO caused a hypertonicity in the medium that activated sperm motility (Horváth et al, 2005), but due to the inclusion of NaHCO3 in the extender, the spermatozoa motility was prevented and the protective capacity of the freezing medium was improved (Tanaka et al, 2002b).…”

“…The success of artificial reproduction of fish species including the validation of cryopreservation protocols, depend greatly on the accurate evaluation of the sperm quality, which is the best way to define the fertility potential of males (Gallego and Asturiano, 2018a;Kime et al, 2001;Rurangwa et al, 2004). There are several characteristics of semen that contribute to define the sperm quality, however, sperm motility is considered the best biomarker and shows high correlation with fertilization and hatching ratios in some fish species (Gallego and Asturiano, 2018b).…”