Evaluation of ionic and biochemical changes in ovarian fluid of Caspian brown trout (Salmo trutta caspius Kessler, 1877) broodstock fed with vitamin C, astaxanthin and soybean lecithin supplements and its effect on sperm motility

In this study, the effects of different levels of dietary supplementation with vitamin C, astaxanthin and lecithin on ionic (K+, Na+, Ca2+ and Mg2+) and biochemical (Total protein, cholesterol and glucose) indices of ovarian fluid, also its effect on sperm motility duration in Caspian brown trout (Salmo trutta caspius) were investigated. For this purpose, nine experimental diets: C0A0L0 (0 mg kg-1 vitamin C, 0 mg kg-1 astaxanthin and 0% soybean lecithin), C300A50L0, C700A100L0, C0A50L6, C300A100L6, C700A0L6, C0A100L9, C300A0L9 and C700A50L9 were formulated and broodstocks (2.51±0.05 kg) were fed for four months. After maturation and stripping, ovarian fluid was separated for ionic and biochemical indices. To evaluate sperm motility, 1 μl of milt was placed under a microscope with fresh water (as a control treatment) or ovarian fluid of experimental fishes. Sperm motility was measured with a chronometer. Results showed that the highest amounts of Na+, K+, Ca2+ and Mg2+ ions were obtained in ovarian fluid of C300A100L6, C300A100L6, C0A100L9 and C300A100L6, respectively, which were significantly different from C700A50L9 (p<0.05). Also, the highest levels of protein, cholesterol and glucose were observed in C700A50L9, C0A50L6 and C0A100L9 treatments, which were significantly different from C0A0L0 treatment (p<0.05). Lowest duration of sperm motility was obtained in fresh water (43.96±2.25 seconds) which was significantly different from other treatments (p<0.05); however, the highest sperm motility was observed in C300A100L6 and C0A100L9 treatments (80.76±2.03 and 80.7±1.76 seconds, respectively).