Effects of dietary supplementation of vitamin C, astaxanthin and soybean lecithin on some biochemical indices of ovarian fluid and reproductive performance in Caspian brown trout broodstocks (Salmo trutta caspius)

In this study, the effects of different levels of dietary supplementation with vitamin C, astaxanthin and lecithin on some biochemical indices of ovarian fluid (Total protein, ACP, ALP, LDH and AST enzymes) and reproductive performance (fecundity and fertilization rate) of Caspian brown trout (Salmo trutta caspius) were investigated. For this purpose, nine experimental diets were formulated and supplemented with different combinations of vitamin C at levels of 0, 300 and 700 mg kg-1 diet, astaxanthin at levels of 0, 50 and 100 mg kg-1 diet and soybean lecithin at levels of 0, 6 and 9% (C0A0L0, C300A50L0, C700A100L0, C0A50L6, C300A100L6, C700A0L6, C0A100L9, C300A0L9, C700A50L9) and broodstocks (2.51±0.05 kg) were fed for four months. After maturation and stripping, ovarian fluid was separated for biochemical indices and oocytes used for reproductive performance. Based on the results, a significantly increase was observed in the total protein content of ovarian fluid of fish fed with the treatments C300A100L6, C700A50L9, C700A0L6, C0A100L9 and  C300A0L9 compared to the control (p<0.05). Also, the lowest LDH ​​were obtained in treatments C300A100L6, C0A100L9 and C0A50L6, which were significantly different from the control (p<0.05). Treatments C700A0L6 and C0A100L9 had the lowest AST ​​and the highest ALP values, both of which were significantly different from the control (p<0.05). The highest fecundity and fertilization rate were observed in C0A100L9 and C300A100L6 treatments which were significantly different from the control (p<0.05). In conclusion, dietary supplementation of 300 mg kg-1 vitamin C with 100 mg kg-1 astaxanthin and 6% lecithin led to a decrease in AST and LDH enzymes activity and improvement of fecundity and fertilization rates.