Effects of dietary protein and lipid levels with different protein‐to‐energy ratios on growth performance,feed utilization and body composition of juvenile red‐spotted grouper,Epinephelus akaara |
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| Authors: | JT Wang T Han XY Li YX Yang M Yang SX Hu YD Jiang S Harpaz |
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| Institution: | 1. Department of Aquaculture, Zhejiang Ocean University, Zhoushan, China;2. Department of Poultry and Aquaculture, The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel |
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| Abstract: | An 8‐week feeding trial was conducted to assess dietary protein and lipid levels on growth performance, feed utilization and body composition of juvenile red‐spotted grouper (7.85 ± 0.03 g fish?1). Nine semi‐purified diets were formulated containing varying protein levels (440–520 g kg?1, dry matter) and lipid levels (60–120 g kg?1, dry matter). The weight gain of juvenile Epinephelus akaara was affected by dietary protein (p = .005) and its interaction with dietary lipid (p = .020). Viscerosomatic index, intraperitoneal fat ratio and whole‐body lipid level increased with increasing dietary lipid level (p < .001). Nitrogen retention was not affected by dietary protein and lipid, while lipid retention decreased with increasing dietary lipid level (p < .001). The plasma blood urea nitrogen increased with increasing dietary protein level (p = .003). This study showed that diet with 520 g kg?1 protein and 60 g kg?1 lipid with 30.58 mg kJ?1 P:E provided a maximal growth for this species. Moreover, an increase in dietary lipid levels (from 60 to 90 g kg?1) could reduce the protein requirement (from 520 to 480 g kg?1) without affecting the growth performance, while higher fat deposition was observed in fish fed high‐lipid diets. |
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| Keywords: | body composition dietary protein and lipid growth performance protein‐to‐energy ratio red‐spotted grouper Epinephelus akaara |
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