Exploration of natural cryoprotectants for cryopreservation of African catfish, Clarias gariepinus, Burchell 1822 (Pisces: Clariidae) spermatozoa

Abstract

Toxicity is a major limitation to successful spermatozoa cryopreservation of fish. Due to this problem, it is critical to find potential cryoprotectants which are more environmental-friendly, non-toxic, easily prepared, and available at affordable prices. Hence, the objective of the present study was to investigate several natural cryoprotectants for optimal cryopreservation of the African catfish, Clarias gariepinus, Burchell 1822 (Pisces: Clariidae) spermatozoa. Three natural cryoprotectants were tested -egg yolk, glucose, and honey, while DMSO was used as a control at different concentrations (5, 10, and 15%). Sperms were diluted with coconut water at a dilution level of 1 : 20 sperm to extender (v/v). Diluted sperms were kept at 4°C for 5 min, then at 0, -4, and -79°C for 5 min respectively, and stored in liquid nitrogen (-196°C) for 45 days. The cryopreserved sperms were thawed in a water bath (37°C) for 5 min and evaluated for fertilization and hatching rates. The data were subjected to analysis of variance (ANOVA), followed by comparison of means using Duncan's Multiple Range Test. The fertilization and hatching rates of African catfish in all cryoprotectants improved with concentration increasing from 5 to 10% but then decreased when concentration was increased to 15%. The ANOVA test showed that the differences in cryoprotectants used significantly affected fertilization and hatching rates of African catfish. Overall, the fertilization and hatching rates were higher in DMSO for all concentrations compared to other cryoprotectants. However, 10% egg yolk resulted in higher fertilization and hatching rates compared to other natural cryoprotectants. It was concluded that 10% egg yolk was the most suitable concentration for African catfish spermatozoa cryopreservation compared to other natural cryoprotectants tested.

Equilibration and freezing interactions affecting bull sperm characteristics after thawing

“…Extenders used serve as protection during cooling and freezing (Linhartova et al 2014) and preserve spermatozoa motility after subsequent thawing (Muchlisin et al 2015). Nevertheless, the most suitable interactions of extender vs equilibration length still are not determined sufficiently (Shahverdi et al 2014).…”

Effect of two freezing extenders on characteristic of fresh and frozen-thawed semen in endangered Old Kladruber stallions - A pilot study

“…comm.). This might be a consequence of pedigree, as Squires (2013) reported the poorest quality in the Friesian, Andalusian, and Saddlebreds; moreover, quite high inbreeding depression in this breed (Vostra-Vydrova et al 2016) might negatively interfere with reproduction (Roldan et al 2006) Even though the cryopreservation process was introduced many years ago, the possibility of increasing effectiveness has been studied intensively across species since that time (Muchlisin et al 2015;Zhang et al 2015). Although our knowledge and techniques for freezing stallion ejaculate have improved within the last 20 years, a considerable proportion of stallions are still not suitable for semen freezing (Katila 2001).…”

Induced spawning of siban fish Cyclocheilichthys apogon using Ovaprim

“…Successful fertilization was observed 8 hours after incubation. Unfertilized eggs were identified by their opacity; the unfertilized eggs were removed from the jar, while hatching rate was monitored at two-hour intervals 13 . The larvae were fed on Tubifex sp.…”