Dietary magnesium requirement and effects on growth and tissue magnesium content of juvenile grass carp (Ctenopharyngodon idella) |
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| Authors: | JJ LIANG LX TIAN YJ LIU HJ YANG GY 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 concentration of dietary magnesium (Mg) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (5.56 ± 0.02 g) were fed diets containing graded levels (187, 331, 473, 637, 779 and 937 mg kg?1) of Mg for 8 weeks. Weight gain, specific growth rate and feed efficiency were linearly increased up to 637 mg kg?1 dietary Mg and then levelled off beyond this level. For body composition, dietary Mg levels higher than 473 mg kg?1 significantly decreased the moisture content but increased the lipid content of whole body, muscle and liver. Dietary Mg levels higher than 473 mg kg?1 significantly decreased the ash contents of vertebrae, scales and muscle. Mg contents in whole body, vertebrae, scales and plasma were increased up to 637 mg kg?1 dietary Mg and then levelled off beyond this level. However, Ca and P contents seem to be inversely related to dietary Mg. Dietary Mg levels higher than 473 mg kg?1 significantly decreased Zn and Fe contents in whole body and vertebrae. Broken‐line analysis indicated that 687 mg kg?1 dietary Mg was required for maximal tissue Mg storage, as well as satisfied for the optimal growth. |
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| Keywords: | body composition diet grass carp (Ctenopharyngodon idella) growth performance magnesium requirement mineralization |
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