Effects of Dietary Antarctic Krill on the Reproductive Performance and Antioxidant Function in Male Broodstock Tongue Sole (Cynoglossus semilaevis)

Abstract:

The tongue sole C. semilaevis is a flatfish with high economic value and is extensively exploited in northern China. However, broodstock nutrition of this species is still based on a diet of fresh feeds, which has an important sanitary risk, and contributes to the deterioration of water quality. Therefore, a 90 days feeding trial was conducted to investigate the effect of dietary Antarctic krill meal in broodstock diets on reproductive performance and antioxidant function of male tongue sole Cynoglossus semilaevis. Three diets were formulated to contain respectively 0, 10%, 20% Antarctic krill meals. Three-year-old tongue sole C. semilaevis were stocked in concrete tanks (25 m3) and acclimated to laboratory conditions for 7 days. Then they were randomly divided into three groups, each group had three polyethylene tanks (diameter: 230 cm, high: 100 cm), and they were fed to apparent satiation twice per day for 12 weeks. Results showed that, the hepatosomatic index, sex index, sperm concentration and testosterone contents had no significant differences on each experimental groups (P>0.05). The superoxide dismutase (SOD) activities in semen and eggs had no significant differences between K-10 and K-20 group (P>0.05), but were significantly higher than that of the control group (P<0.05); The malondialdehyde (MDA) content in semen, serum and liver had no significant differences between K-10 and K-20 group (P>0.05), but were significantly lower than that of the control group (P<0.05). In conclusion, the present study suggested that dietary Antarctic krill meal had no significant effect on reproductive performance (P>0.05), but can significant improve antioxidant function for male C. semilaevis (P<0.05).