HIGH DIETARY DOSES OF ORGANIC AND INORGANIC SELENIUM ON GROWTH PERFORMANCE, TISSUE SELENIUM ACCUMULATION AND BLOOD BIOCHEMICAL PARAMETERS OF GIBEL CARP (CARASSIUS AURATUS GIBELIO VAR. CAS V)

To investigate the effects of high doses of organic and inorganic selenium in feed on the growth performance, selenium accumulation and plasma biochemical parameters of gibel carp, organic selenium and inorganic selenium were used as different types of selenium sources, and gibel carp with an initial body weight of (62.95±0.23) g was used for a 90d feeding experiment. The results indicated that the addition of 0, 10 and 20 mg/kg organic and inorganic selenium to the feed did not have a significant effect on the survival rate and the digestibility of the dry matter. Moreover, the addition of organic selenium significantly increased the selenium digestibility of the organic selenium treatment group (P<0.05), while the addition of inorganic selenium to the feed had no significant effect on the selenium digestibility (P>0.05). The addition of organic selenium to the feed increased the growth of gibel carp (P<0.05), reaching the highest level in the 20 mg/kg treatment group (P<0.05). The addition of inorganic selenium to the feed significantly reduced the specific growth rate of the gibel carp (P<0.05), and there was no significant difference in the specific growth rate between the 10 mg/kg inorganic selenium treatment group and the control group (P>0.05). The addition of organic selenium to the feed had no any significant effect on the hepatosomatic index of gibel carp, while the addition of 10 mg/kg inorganic selenium significantly reduced the hepatosomatic index (P<0.05). The addition of organic and inorganic selenium to the feed had no any significant effect on the renosomatic index of gibel carp. The addition of both organic and inorganic selenium significantly increased the selenium content of whole fish, liver, kidney, muscle, bone and gonads, and the organic selenium addition group had significantly higher selenium content in bone, muscle, gonads and whole fish than the inorganic selenium addition group (P<0.05). The addition of organic selenium and inorganic selenium to the diet significantly increased the plasma glucose content, decreased the total plasma bilirubin content and reduced the activity of glutamate and ghrelin (P<0.05), and the addition of 20 mg/kg organic selenium and 10 mg/kg inorganic selenium to the diet significantly reduced the plasma iron ion content (P<0.05). The results showed that the high levels of organic and inorganic selenium in the feed were well tolerated by the gibel carp and the high levels of organic selenium in the feed had no toxic effect on the gibel carp after 90d of the feeding. High levels of dietary organic selenium boosted growth performance and selenium bioaccumulation of gibel carp.