饲料糖水平对大黄鱼生长和糖代谢的影响

EFFECTS OF DIETARY CARBOHYDRATE ON GROWTH PERFORMANCE AND GLYCOMETABOLISM OF LARGE YELLOW CROAKER LARIMICHTHYS CROCEA

  • 摘要: 以初始体重为(137.5±0.4)g的大黄鱼Larimichthys crocea为实验对象,在海水浮式网箱中进行为期8周的摄食生长实验,研究饲料中糖水平对其生长、饲料利用、血液生化指标和糖代谢酶活力等的影响,以确定大黄鱼的饲料糖需求量。实验饲料按等氮(粗蛋白质45%)等能(18 kJ/g)设计,糖含量分别为1.75%、6.67%、13.64%、21.15%、26.69%和32.25%。结果表明随着饲料糖水平的升高,大黄鱼特定生长率(SGR)先升高后降低,当糖含量为26.69%时,SGR达最大值,显著高于糖含量为1.75%、6.67%、13.64%和32.25%处理组(P < 0.05)。饲料效率(FER)和蛋白质效率(PER)均在糖含量为13.64%-21.15%时显著高于其他处理组(P < 0.05)。随饲料中糖水平的升高,全鱼粗脂肪含量显著降低,在糖含量为32.25%时降至最低(10.56%),显著低于其他处理组(P < 0.05)。肝体比和肝糖原含量均随饲料糖水平的升高而显著升高(P < 0.05),在糖含量为32.25%时达到最大值,显著高于糖含量为1.75%和6.67%处理组(P < 0.05)。随饲料糖水平的升高,血浆甘油三酯和胆固醇水平均显著降低(P < 0.05),而血糖水平不受饲料糖含量的影响(P>0.05)。大黄鱼血清溶菌酶、脂蛋白脂酶和肝脂酶活性均随饲料糖水平的升高显著降低(P < 0.05),而肠淀粉酶活性表现为先升高后降低,在糖含量为26.69%时,酶活力达到最大值。随饲料糖水平的升高,大黄鱼肝脏己糖激酶活性先上升后下降,在糖含量为21.15%时达到最大值,显著高于糖含量为32.25%处理组(P < 0.05),而丙酮酸激酶活力在糖水平为32.25%时达到最大值,显著高于糖含量为1.75%和6.67%处理组(P < 0.05)。用二次多项回归模型拟合特定生长率和饲料糖水平的关系,得到大黄鱼饲料中最适糖含量为22.7%。

     

    Abstract: To evaluate the effects of dietary carbohydrate on growth performance, feed utilization, plasma parameters, and glycometabolism enzyme activities of large yellow croaker Larimichthys crocea, triplicate groups of fishthe initial body weight:(137.5±0.35) g were randomly fed six isonitrogenous (45% crude protein) and isoenergetic (18 kJ/g gross energy) diets containing graded levels of carbohydrate (1.75%, 6.67%, 13.64%, 21.15%, 26.69% and 32.25%) in floating sea cages for an 8-week feeding trial. Results showed that the highest specific growth rate (SGR) was by 26.69% of dietary carbohydrate. The highest dietary carbohydrate content (32.25%) significantly decreased the SGR (P < 0.05). Both feed efficiency ratio (FER) and protein efficiency ratio (PER) of large yellow croaker fed diets with 13.64% and 21.15% of carbohydrate were significantly higher than those of other groups (P < 0.05). The whole-body lipid content significantly decreased the increased dietary carbohydrate contents with the lowest lipid content 32.25% of carbohydrate group (P < 0.05). Hepatosomatic index (HSI) and liver glycogen content significantly increased with the increased dietary carbohydrate contents (P < 0.05). Plasma total cholesterol and triglyceride levels significantly decreased with the increased dietary carbohydrate level (P < 0.05), but plasma glucose did not impact by dietary carbohydrate level (P>0.05). The increased dietary carbohydrate significantly depressed activities of serum lysozyme, lipoprotein lipase and hepatic lipase (P < 0.05). The activities of intestinal tract amylase and hepatic hexokinase (HK) increased signifi-cantly and then decreased with the highest value at 26.69% and 21.15% dietary carbohydrate contents, respectively (P < 0.05). Dietary carbohydrate significantly up-regulated activities of pyruvate kinase (PK) with the peak level by 32.25% carbohydrate group (P < 0.05). These results indicated the requirement of dietary carbohydrate for large yellow croaker was 22.7%.

     

/

返回文章
返回