Effect of type and concentration of antioxidant on sperm motility, viability, and DNA integrity of climbing perch Anabas testudineus Bloch, 1792 (Pisces: Anabantidae) post-cryopreservation

Sperm quality is preserved through the crucial involvement of antioxidants, which play a vital role in minimizing the occurrence of reactive oxygen species (ROS) during the cryopreservation process. The suitability of the type and concentration of antioxidants are species-dependent, and this study is crucial in order to improve the quality of the climbing perch sperm post-cryopreservation. Therefore, this study aimed to determine the best type and concentration of antioxidants for cryopreservation of climbing perch Anabas testudineus sperm. To achieve this, 6 types of antioxidants, namely, ascorbic acid, beta-carotene, glutathione, butylated hydroxytoluene (BHT), myo-inositol, and alpha-tocopherol, with inclusion of a control were tested in 3 replications at three concentration levels of 0 mg/L (control), 20 mg/L, 40 mg/L, and 60 mg/L. Sperm was diluted in a glucose-base extender at a ratio of 1:60 (sperm: glucose base), then 10 % DMSO and 5 % egg yolk was added before cryopreservation for two weeks. The results showed that the type and concentration of antioxidants had a significant effect on the motility and viability of cryopreserved climbing perch sperm (P < 0.05), where the best results for ascorbic acid, beta-carotene, glutathione, myo-inositol, and alpha-tocopherol were obtained at a concentration of 60 mg/L, while BHT was at a concentration of 20 mg/L. The best results for glutathione, myo-inositol, and alpha-tocopherol were significantly different from other treatments, while the best results for ascorbic acid and beta-carotene (60 mg/L) were not significantly different from the 40 mg/L concentration, while the best results for BHT were not significantly different from the control treatments. Therefore, the best concentration of glutathione, myo-inositol, and alpha-tocopherol was 60 mg/L, while for ascorbic acid and beta-carotene it was 40 mg/L, and BHT was not recommended. DNA integrity analysis indicated the absence of fragmentation in all samples, including fresh, control, and treated sperm. Based on practical and economic considerations, myo-inositol at 60 mg/L was recommended for cryopreservation of climbing perch A. testudineus sperm.

Effect of salinity on growth of Abant trout Salmo trutta abanticus

Abant trout Salmo trutta abanticus were grown for 154 days at three salinities of 0, 9 or 18 to assess mass gain, condition factor, food conversion ratio and food consumption. Appetite was significantly higher at 0 than at salinities of 9 or 18. Salinities >18 may have detrimental effects on biomass production. The mean ± S.E. of the condition factor at the three salinities were 1.29 ± 0.20 at 0, 1.22 ± 0.22 at 9 and 1.10 ± 0.20 at 18. Fish reared at a salinity of 0 showed higher mass gain, food conversion ratio and food consumption.