Effects of dietary sodium selenite and selenoyeast on growth performance, antioxidant responses and low temperature stress resistance of juvenile yellow catfish (Pelteobagrus fulvidraco)

In order to investigate the effects of dietary sodium selenite and selenoyeast on growth performance, antioxidant responses and low temperature stress resistance of juvenile yellow catfish Pelteobagrus fulvidraco, four isonitrogenous and isolipid diets containing graded levels of Se, 0.028 (control, G0), 0.25 (sodium selenite, G1), 0.30 (selenoyeast, G2), 0.52 (selenoyeast, G3) mg/kg were randomly fed to P. fulvidraco initial weight (2.12±0.01) g for 56 days. At the end of breeding experiment, the low temperature stress test was conducted. The results showed that sodium selenite and selenoyeast had no significant effects on the final weight, weight gain rate, feed coefficient and survival rate. Sodium selenite and selenium yeast significantly increased the selenium content of whole body and muscle, and G3 group was significantly higher. The selenium content of whole body had no significant difference between G1 and G2 groups, but the selenium content of muscle in G2 group was significantly higher than that of G1 group. Sodium selenite and selenium yeast significantly increased GPx activity in liver. In G1 and G2 groups, SOD activity was significantly higher than that in G0 group. At 22 °C, the total protein, cholesterol, triglycerides, and urea nitrogen contents had no significant difference among all the groups, but G2 group had significantly higher glucose than G0 and G1 groups. The relative expression of HSP70 mRNA had no significant difference. At 13 °C, the total protein, cholesterol content had no significant difference. The triglyceride content in G1 group was significantly higher than those in G0 and G3 groups, but was not significantly different compared to G2 group. Glucose in G2 and G3 groups were significantly higher than those in G0 and G1 groups. The urea nitrogen content in G2 group was significantly lower than that in G1 group. The relative expression of HSP70 mRNA in G0 group was significantly higher than those in other groups. The results showed that 0.30 mg/kg selenoyeast in juvenile P. fulvidraco diet was better than 0.25 mg/kg sodium selenite, taken the growth performance, selenium deposition, antioxidant activity and low temperature stress resistance into consideration.