饲料中不同种类的碳水化合物对大菱鲆生长性能和代谢反应的影响

为探讨在低蛋白水平(40%)下,饲料中不同种类的碳水化合物(葡萄糖、蔗糖和糊精)对大菱鲆幼鱼(8.12±0.04)g]生长、成活、饲料利用、体组成和血液生理生化指标等的影响,实验在对照组饲料中未添加可消化碳水化合物,含40%的蛋白质和18%的脂肪,然后在对照组饲料的基础上,调节脂肪水平为12%,分别添加15%的葡萄糖、蔗糖和糊精配制3组实验饲料。在流水式养殖系统中进行9周的大菱鲆生长实验。结果显示,各处理组大菱鲆成活率均高于95.24%,并且各组间无显著差异;对照组和糊精组大菱鲆的增重率(WGR)和特定生长率(SGR)均显著高于葡萄糖组和蔗糖组。各组间的日摄食率(DFI)没有显著差异。对照组和糊精组饲料效率(FE)显著高于蔗糖组,但葡萄糖组FE与其它各组无显著差异;各处理组间蛋白质和脂肪表观消化率(ADC)未受碳水化合物种类的显著影响,而可消化碳水化合物的ADC依次为:葡萄糖组>糊精组>蔗糖组(。葡萄糖组的能量ADC最高,蔗糖组的最低;除对照组肌肉脂肪含量显著高于其它各组外,碳水化合物的种类对大菱鲆肌肉常规组成及糖原含量无显著影响,但显著影响了肝脏的脂肪和糖原含量。大菱鲆肝脏脂肪含量依次为对照组>糊精组>蔗糖组>葡萄糖组,肝脏糖原含量依次为葡萄糖组>蔗糖组>糊精组>对照组;不同碳水化合物种类对大菱鲆幼鱼血浆葡萄糖含量没有显著影响,但显著影响血浆总氨基酸、胰岛素、总胆固醇(CHO)和甘油三酯(TAGs)的含量。结果表明,本实验条件下,大菱鲆对糊精的利用效率优于葡萄糖和蔗糖,并且不同种类的碳水化合物通过糖脂关联代谢等途径对大菱鲆幼鱼的体组成和血液生理生化指标造成一定的影响。

Effects of Different Dietary Carbohydrates on Growth Performance and Metabolism Response of Juvenile Turbot Scophthalmus maximus

A study was conducted to evaluate the ability of juvenile turbot Scophthalmus maximus to utilize different molecular complexity of carbohydrates in diets. The control diet without carbohydrates supplementation contained 40% protein and 18% lipid. Based on it, 15% of three kinds of carbohydrate (glucose, sucrose and dextrin) were respectively added into the diet. At the same time, dietary lipid content was adjusted to 12% to keep isoenergetic with the control diet. Triplicate groups of fish (initial body weight: 8.12 ± 0.04 g) were hand-fed one of the four diets to apparent satiation for 9 weeks. The results showed that survival rate, daily feed intake (DFI), the apparent digestibility coefficients (ADCs) of protein and lipid, contents of moisture, crude protein, ash and glycogen in muscle, contents of moisture, crude protein and ash in liver, condition factor (CF) and plasma glucose were not significantly affected by dietary treatments (P > 0.05). Weight gain rate (WGR) and specific growth rate (SGR) of fish fed dietary dextrin and the control diet were significantly higher than those of fish fed dietary glucose and sucrose (P < 0.05). Feed efficiency (FE) of fish fed the control diet and dietary dextrin was significantly higher than those fed dietary sucrose (P < 0.05). However, there was no significant difference in FE between fish fed dietary glucose and the other three groups (P > 0.05). The order of the ADC of carbohydrate was glucose > dextrin > sucrose. The ADC of energy was significantly highest in fish fed dietary glucose and lowest in fish fed dietary sucrose (P < 0.05). Fish fed the control diet had the significantly highest lipid contents in muscle (P < 0.05), and there was no significant difference in lipid content of muscle among the other three groups (P > 0.05). The order of the liver lipid content was control > dextrin > glucose > sucrose (P < 0.05). The order of the liver glycogen was glucose > sucrose > dextrin > control (P < 0.05). Total amino acid concentration in plasma of fish fed the control diet was significantly higher than those fed dietary glucose and sucrose (P < 0.05). Plasma insulin of fish fed dietary dextrin was significantly higher than those fed the control diet (P < 0.05). Total cholesterol (CHO) in plasma of fish fed the control diet was the highest one followed by dietary dextrin. The lowest was found in fish fed dietary glucose and sucrose (P < 0.05). Triacylglycerols (TAGs) in plasma of fish fed the control and dietary dextrin were significantly higher than those fed dietary glucose and sucrose (P < 0.05). In conclusion, the present study suggested that turbot can utilize dextrin more efficiently than glucose and sucrose.