OBJECTIVE: To determine the most suitable antioxidant for the cryopreservation of the depik fish spermatozoa.

MATERIALS AND METHODS: A completely randomized design with a non-factorial experiment was used and the tested antioxidants were glutathione, beta-carotene, ascorbic acid, and butylated hydroxytoluene (BHT) at 6 % concentrations. All treatments had three replications. The sperms were collected from 10 male fishes and diluted with Ringer solution in a ratio of 1: 20 (v/v, sperm: Ringer solution). Then 5% DMSO and 5 % egg yolk were added to the diluted sperms. Furthermore, 6 % of the tested antioxidants were added to the diluents, and then, cryopreservation was carried out in liquid nitrogen for 14 days.

RESULTS: The ANOVA test showed that the application of antioxidants significantly affected the sperm motility, fertility, and hatching rates of the eggs (P < 0.05). Furthermore, the antioxidants also protected the sperm cells during cryopreservation, with glutathione being the best antioxidant.

OBJECTIVE: To determine the most suitable antioxidant for the cryopreservation of the depik fish spermatozoa.

MATERIALS AND METHODS: A completely randomized design with a non-factorial experiment was used and the tested antioxidants were glutathione, beta-carotene, ascorbic acid, and butylated hydroxytoluene (BHT) at 6 % concentrations. All treatments had three replications. The sperms were collected from 10 male fishes and diluted with Ringer solution in a ratio of 1: 20 (v/v, sperm: Ringer solution). Then 5% DMSO and 5 % egg yolk were added to the diluted sperms. Furthermore, 6 % of the tested antioxidants were added to the diluents, and then, cryopreservation was carried out in liquid nitrogen for 14 days.

RESULTS: The ANOVA test showed that the application of antioxidants significantly affected the sperm motility, fertility, and hatching rates of the eggs (P < 0.05). Furthermore, the antioxidants also protected the sperm cells during cryopreservation, with glutathione being the best antioxidant.

OBJECTIVE: To determine the most suitable type of cryoprotectant and pre-freezing for the successful cryopreservation of goldfish sperm.

MATERIALS AND METHODS: A completely randomized design with two factors was utilized in this study. The first factor is the type of cryoprotectants, which included methanol, ethanol, ethylene glycol, glycerol, and DMSO. The second is pre-freezing times of 10, 20, 30, and 40 min at each of the pre-freezing temperatures of 4 degree C, -10 degree C, and -79 degree C, meaning that the total times for the ramping down of temperature were 30, 60, 90 and 120 min, respectively. The Ringer solution and 10% egg yolk were used as extender and extracellular cryoprotectant. The sperm was stored at -179 degree C for 7 days.

RESULTS: The ANOVA test showed that cryoprotectants and pre-freezing significantly affected the motility, viability, and fertility of goldfish sperm after freezing in liquid nitrogen for 7 days (P<0.05). Furthermore, 10% DMSO combined with 15% egg yolk with an pre-freezing time of 20 min can maintain sperm motility, viability, and fertility higher than other treatments, by 79%, 80%, and 33%, respectively. The agarose gel electrophoresis showed no DNA fragmentation in all samples, including fresh sperm.