THE GROWTH CHARACTERISTICS AND HYPOXIA TOLERANT ABILITY OF YELLOW CATFISH AND HYBRID CATFISH

This study investigated growth performance and hypoxia tolerant ability of the yellow catfish and the hybrid catfish called “Huangyou No. 1” for an 8-week trial. The results showed that the average weight of the hybrid catfish was (19.60±0.88) g/tail at week 8, which was significantly higher than that of the yellow catfish was (15.74±0.42) g/tail (P<0.05) with a 24.52% increase. The feed coefficient of the hybrid catfish and the yellow catfish were 1.18±0.14 and 1.36±0.21, respectively. The survival rate of young hybrids catfish was 87.78±1.92, which was significantly higher than that of the yellow catfish at 67.78±1.92 (P<0.05). The survival rate of the hybrid catfish was 29.51% higher than that of the yellow catfish. The hybrid catfish and yellow catfish were placed in water with dissolved oxygen content of (1.48±0.27) mg/L and then hypoxia stress for 0, 6h, 12h and 24h before collecting serum and liver for measurements. Hypoxia stress significantly regulated the LDH activity, SOD activity, CAT activity at 6h and the T-AOC at 12h in the serum and liver of both hybrid catfish and yellow catfish (P<0.05). The brain and liver HIF-1α mRNA level of both hybrid catfish and yellow catfish increased significantly by hypoxic stress (P<0.05) with higher level in hybrid catfish at 6h, 12h and 24h. These results indicated that long-term hypoxic stress may cause oxidative damage to hybrid catfish and yellow catfish, but hypoxia tolerance of hybrid catfish is higher than that of yellow catfish.