An investigation on fatty acid, cholesterol and fat-soluble vitamin levels of sperm with XX and XY chromosomes from male rainbow trout (Oncorhynchus mykiss)

An Investigation on Fatty Acid, Cholesterol and Fat-Soluble Vitamin Levels of Sperm with XX and XY Chromosomes from Male Rainbow Trout (Oncorhynchus mykiss) In this study, the fatty acid, cholesterol and fat-soluble vitamin (A, D, E and K) levels of sperm with XX and XY chromosomes from male rainbow trout (Oncorhynchus mykiss) was determined. In addition, testis weight, testisomatic index value and sperm characteristics (semen volume, semen pH, sperm motility ratio, sperm motility duration and total sperm number) were investigated. For this purpose, it was used the 15 male fish with XX chromosomes (transformed) with mean weight of 1187±70 g at age 3 and 15 male fish with XY chromosomes (ordinary) weighting 1245±151 g and at age 3. The mean testis weight (87±21 g), testisomatic index value (6.99±1.23), semen volume (236±36 ml), sperm motility ratio (92±3%), sperm motility duration (221±98 second) and total sperm number (426.02±6 x109) of the fish with XX chromosomes were found significantly higher than the mean testis weight (22±5 g), testisomatic index value (6.99±1.23), semen volume (236±36 ml), sperm motility ratio (92±3%), sperm motility duration (221±98 second) and total sperm number (426.02±6 x109) of the fish with XY chromosomes (P<0.01). However, the difference between pH values (respectively; 7.7±0.3 and 7.9±0.4) of sperm with XX and XY chromosomes fish was not significant statistically (P>0.01). In addition, the differences in total levels of saturated (respectively; 28.13% and 26.96%), polyunsaturated (56.83% and 54.66%), n-3 (42.74% and 40.95%) and n-6 series (13.38% and 12.97%) fatty acid in sperm with XX and XY chromosomes fish were found to be significant (P<0.01), but the difference in total monounsaturated fatty acid levels (15.86 and 15.83%) was not significant (P>0.01). The differences in levels of docosahexaenoic (24.52% and 22.93%), linoleic (6.35% and 6.06%) and linolenic (1.18% and 1.05%) acid of sperm with XX and XY chromosomes fish were significant (P<0.01), but the differences in levels of eicosapentanoic (14.59% and 14.42%), arachidonic (5.53% and 5.46%) and docosapentaenoic (1.60% and 1.67%) acid were not significant (P>0.01). On the other hand, the cholesterol (1418 mg/100 g), betasterol (13.05 mg/100 g), alpha-tocopherol (23.42 mg/100 g), alpha-tocopherol acid (22.42 mg/100 g), vitamin D3 (0.9 mg/100 g) and vitamin K2 (2.06 mg/100 g) levels of the semen with XX chromosomes fish were determined significantly lower than the cholesterol (1663 mg/100 g), betasterol (28.42 mg/100 g), alpha-tocopherol (38.21 mg/100 g), alpha-tocopherol acid (38.71 mg/100 g), vitamin D3 (3.3 mg/100 g) and vitamin K2 (2.17 mg/100 g) levels of semen with XY chromosomes fish (P<0.01). However, the stigmasterol (27.54 mg/100 g), r-tocopherol (0.6 mg/100 g) and vitamin K1 (2.55 mg/100 g) levels of the semen with XX chromosomes fish were found significantly higher than the stigmasterol (24.78 mg/100 g), r-tocopherol (0.3 mg/100 g) and vitamin K1 (2.12 mg/100 g) levels of semen with XY chromosomes fish (P<0.01). In this study, a pozitif and strong (P<0.001) relation between the mean testis weight and testisomatic index value of both XX (r = 0.868) and XY (r = 0.944) chromosomes fish was determined. It was showed pozitif and strong (P<0.001) relation between the sperm vitamin D3 value with testisomatic index (r = 0.995), sperm pH (r = 0.862) and total sperm number (r = 0.989) values of XX chromosomes fish. Similar relations were also found between the sperm motility ratio with betasterol (r = 0.974), henicosanoic acid (r = 0.819) and alpha-tocopherol acid (r = 0.799) values of sperm in XX chromosomes fish. In addition, it was obtained a pozitif and strong (P<0.001) relation between the testisomatic index value with semen volume (r = 0.827) and vitamin D3 (r = 0.995) values of XY chromosomes fish. It was determined a pozitif and strong (P<0.001) relation between the sperm pH value with linoleadic acid (r = 0.910), linoleic acid (r = 0.836) and oleic acid (r = 0.788) values of sperm with XY chromosomes fish. it was found a pozitif and strong (P<0.001) relation between the motility ratio and henicosanoic acid value (r = 0.828) of sperm with XY chromosomes fish. Similar relations were also found between the total sperm number with linoleic (r = 0.950), oleic (r = 0.922), linoleaidic (r = 0.858) and linolenic (r = 0.840) acid values of sperm with XY chromosomes fish. Under the light of this study, it is concluded that the sperm quality of broodstock rainbow trout with XX chromosomes was higher than those of the fish with XY chromosomes. Keywords: Rainbow Trout, Chromosome, Sperm Quality, Fatty acids, Cholesterol, Fat-soluble vitamins (A, D, E and K)