Total antioxidant capacity, catalase activity, and lipid peroxidation changes in seminal plasma of sex-reversed female and male rainbow trout (Oncorhynchus mykiss) during spawning season.

The advantages of gender-related characteristics are used in aquaculture practice to improve production. For instance, all-female stock is preferable than mixed or all-male stock in salmonid culture. The most effective way to obtain all-female populations is the using of sex-reversed (SR) female trouts, genotypically female but phenotypically male, by masculinizing androgen hormones as breeders in artificial insemination. This study was conducted to evaluate changes in the total antioxidant capacity (TAC), protein concentration, catalase (CAT) activity, lipid peroxidation level (LPO; malondialdehyde), and Fourier transform infrared spectra of seminal plasma of SR female and normal (N) male trouts during the spawning season. Seminal plasma TAC values of N male and SR female trouts were determined as 0.015 ± 0.004 and 0.116 ± 0.033 mM of Trolox equivalents, respectively, in the middle of the spawning season. Some regions related to aromatic rings in seminal plasma Fourier transform infrared spectra of SR female trouts differed from N male trouts were indicated to the higher TAC values. At the middle of the spawning season, protein concentrations were determined as 569.5 ± 139.4 mg/dL in SR female trouts and 66.3 ± 22.7 mg/dL in N male trouts. LPO levels in seminal plasma of N male trouts varied from 46.33 ± 12.05 × 10(-3) to 270.02 ± 70.64 × 10(-3) nmol/mg protein, whereas from 13.87 ± 4.98 × 10(-3) to 48.49 ± 17.31 × 10(-3) nmol/mg protein in SR female trouts throughout the spawning. CAT activities of seminal plasma in N male trouts ranged from 0.38 ± 0.26 to 0.47 ± 0.32 kU/mg protein, whereas those values in SR female trouts varied between 0.21 ± 0.10 and 0.43 ± 0.15 kU/mg protein. Moreover, there were the pairwise significant correlations among all variables except between CAT and TAC (P > 0.05). Remarkable correlations were found between LPO-protein (r = -0.922, P < 0.05, n = 190), LPO-TAC (r = -0.859, P < 0.05, n = 98), and TAC protein (r = +0.879, P < 0.05, n = 98). Similar to seminal plasma of N male trouts, TAC values, protein concentrations, and CAT activities in seminal plasma of SR female trouts have shown decline, whereas LPO levels increased toward the end of the spawning seasons. Seminal plasmas of SR female trouts were characterized by higher protein concentrations and TAC values and lower LPO levels than that from N male trouts.