Effects of Salinity on Growth and Energy Budget of Juvenile Cobia, Rachycentron canadum

Authors

  • Gang Chen,

    1. Department of Aquaculture, College of Fisheries Guangdong Ocean University, Zhanjiang, Guangdong 524025 China
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  • Zhongliang Wang,

    1. Department of Aquaculture, College of Fisheries Guangdong Ocean University, Zhanjiang, Guangdong 524025 China
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  • Zaohe Wu,

    Corresponding author
    1. Department of Aquaculture, College of Fisheries Guangdong Ocean University, Zhanjiang, Guangdong 524025 China
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  • Binhe Gu,

    Corresponding author
    1. Department of Aquaculture, College of Fisheries Guangdong Ocean University, Zhanjiang, Guangdong 524025 China
      Corresponding authors.
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  • Zhongliang Wang,

    1. South China Sea Institute of Oceanography, Chinese Academy of Sciences, Guangzhou, Guangdong 510301 China, and Graduate School of the Chinese Academy of Sciences, Beijing 100049 China
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  • Zhongliang Wang,

    1. Guangdong Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang China, and Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524025 China
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  • Zaohe Wu

    Corresponding author
    1. Guangdong Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang China, and Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524025 China
      Corresponding authors.
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Corresponding authors.

Abstract

The effects of salinity on the growth and energy budget of juvenile cobia, Rachycentron canadum, were evaluated. Triplicate tanks with ten fish per tank (initial weight 17.58 ± 0.26 g/fish, mean ± SD) reared at salinities of 5, 10, 15, 20, 25, 30, and 35 ppt were fed with fresh squid to satiety for 15 d. Results indicated that there were no significant differences in daily ration level in wet weight (RLw), dry weight (RLd), and energy (RLe) of the fish. There were also no significant variations in daily fecal production (fe) and apparent digestibility coefficient of energy (ADCe) among salinity treatments. Specific growth rates (SGRs) in wet weight (SGRw), dry weight (SGRd), and energy (SGRe) showed domed curves relative to salinity. Quadratic regression analyses of SGRw, SGRd, and SGRe against salinity indicated that the optimal salinity for maximal growth of juvenile cobia was 29.9, 29.9, and 28.5 ppt, respectively. Similar to the trend of SGR, food conversion efficiency for juvenile cobia in wet weight (FCEw), dry weight (FCEd), and energy (FCEe) increased with the increases in salinity, maximized at 30 ppt, and then decreased when salinity reached 35 ppt.

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