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Li B.,Huazhong Agricultural University | Li B.,Institute of Fisheries Science of Wuhan | Fan Q.,Huazhong Agricultural University | Yang K.,Huazhong Agricultural University | And 7 more authors.
Chinese Journal of Applied and Environmental Biology | Year: 2011

Some health yellow catfish juveniles were chosen to raise in the water with different ammonia concentrations (A 1-3.36 mg L -1, A 2-6.72 mg L -1, A 3-13.44 mg L -1, A 4-26.88 mg L -1, and A 0-no exogenous ammonia), respectively. 450 catfish samples in good health and condition were distributed equally among fifteen 280-L circular fiberglass tanks, and the exposure time was 56 d. The results showed that un-ionized ammonia significantly influenced on growth, foraging and blood parameters of the yellow catfish juveniles, but had no significant effect on the body composition (P>0.05). With the increase of un-ionized ammonia, foraging rate decreased dramatically and foraging efficiency reduced. Compared to the control group, the special growth rate and survival rate in high concentration groups were lower. Plasma ammonia concentration increased significantly with the increase of unionized ammonia concentration (P<0.01), and the blood ammonia concentration of treatment group was less than the surrounding total ammonia (TAN). However, plasma urea nitrogen levels showed no significant difference among experimental groups. Alkaline phosphatase (AKP) activity and Cortisol levels increased quickly in two concentration groups (13.44 mg L -1, 26.88 mg L -1), and although those of Al and A2 increased, however, there were no significant differences among different groups (P>0.05). Glucose (GLU) concentrations showed a gradual decreasing trend, especially decreased rapidly in two high concentration groups (13.44 mg L -1, 26.88 mg L -1). Alamine aminotransferase (ALT) and aspartate aminotransferase (AST) were correlated to ammonia concentration. The more ammonia in the blood was, the more ALT and AST increased. Therefore, yellow catfish juveniles were unsuitable for raising in the water with high levels of ammonia, and the concentration of ammonia should be less than 6.72 mg L -1.

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