饲料V_C对草鱼生长、肌肉品质及非特异性免疫的影响

Effects of dietary vitamin C on growth,meat quality and non-specific immunity indices of grass carp,Ctenopharyngodon idellus

采用维生素C（Vc，以Vc磷酸酯为Vc源）添加量分别为50mg／kg、100mM,g、150mg／kg、200mg＆g、300mg／kg饲料的配合饲料，喂养体质量（42．4±5．0）g的草鱼（Ctenopharyngodonidellus）60d，以不添加Vc的基础饲料饲喂组为对照，探讨Vc对草鱼生长性能、肌肉品质和非特异性免疫的影响。结果表明，饲料中添加Vc能显著提高草鱼增重率，降低饲料系数，当Vc添加量为150～200mg／kg时，草鱼生长性能最佳；随Vc添加量增加，肌肉失水率、肌纤维直径和肌原纤维耐折力呈增加趋势；肌肉胶原蛋白含量和肝脏Vc含量随Vc添加量的增加而增加；Vc添加量为150mg／kg及以上水平时，各实验组草鱼血清碱性磷酸酶（AKP）活性比对照组显著提高（P〈0．05）；Vc添加量达到300mg／kg后血清溶菌酶（LSZ）活性比对照组显著提高（P〈0．05）；各组间血清超氧化物歧化酶（SOD）活性差异不显著（P〉0．05）。上述研究表明，饲料中添加Vc能促进草鱼生长，改善肌肉品质，增强非特异性免疫力。适宜的Vc添加量为150mg,／kg饲料。

The study was conducted to investigate the effects of supplemental vitamin C （Vc） in diets on growth, meat quality and non-specific immunity indices of grass carp, Ctenopharyngodon idellus. Six practical diets were added with Vc of 0 （control group）, 50, 100, 150, 200 and 300 mg/kg diet, which was supplied as L-ascorbyl- 2-phosphate. Each diet was fed to triplicate groups of grass carp with initial body weight of （42.4±5.0） g for 60 days. The results showed that growth rate of grass carp significantly increased （P〈0.05）, whereas feed conversion rates decreased （P〈0.05） with the increase of supplemental Vc in diets. The optimal growth of grass carp was obtained when fishes were fed with diets supplemented with 150-200 mg/kg Vc. With supplemental Vc increased, water loss rate, myofibril length and muscle fiber diameter tended to increase. Muscle collagen content and Vc concentration in liver also increased with the increase of Vc supplement （P〈0.05）. The activity of alkaline phosphatase （AKP） were significantly higher than that of control group when supplemental Vc was 150-300 mg/kg diet and lysozyme （LSZ） activity significantly increased when supplemental Vc was 300 mg/kg diet. There was no effect of supplemental Vc in diets on the activity of superoxide dismutase （SOD） （P〉0.05）. Results above indicate that growth performance, meat quality and serum non-specific immunity indice of grass carp can be improved by supplemental Vc in diets. For grass carp fingerling, the optimal Vc supplement in diet is suggested to be 150 mg/kg.