Dietary zinc requirement of juvenile grass carp (Ctenopharyngodon idella) based on growth and mineralization |
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| Authors: | J‐J LIANG H‐J YANG Y‐J LIU L‐X TIAN G‐Y LIANG |
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| Institution: | Nutrition Laboratory, Institute of Aquatic Economic Animals, School of Life Science, Sun Yat‐Sen University, , Guangzhou, China |
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| Abstract: | A growth trial was conducted to estimate the optimum requirement of dietary zinc (Zn) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.97 ± 0.05 g) were fed diets containing graded levels (13, 25, 34, 53, 89 and 135 mg kg?1) of Zn for 8 weeks. Grass carp fed with dietary Zn levels higher than 34 mg kg?1 significantly increased final body weight, weight gain and specific growth rate (P < 0.05). For body composition, fish fed with dietary Zn levels higher than 53 mg kg?1 significantly decreased the moisture contents but increased the lipid contents of whole body and liver. Whole body, scales, vertebrae and liver mineralization were all affected significantly (P < 0.05) by dietary Zn levels. Zn contents in whole body, scales, vertebrae and plasma were linearly increased up to the 53 mg kg?1 dietary Zn and then remained stable beyond this level. Grass carp fed with dietary Zn levels higher than 53 mg kg?1 significantly increased triacyglyceride and total cholesterol contents and plasma alkaline phosphatase activity in plasma (P < 0.05). Broken‐line analysis indicated that 55.1 mg kg?1 dietary Zn was required for maximal tissue storage and mineralization as well as optimal growth of grass carp. |
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| Keywords: | body composition diet grass carp (Ctenopharyngodon idella) growth performance mineralization zinc requirement |
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