摄食不同蛋白质水平饲料的珍珠龙胆石斑鱼幼鱼生长与血清激素和消化酶活性的相关性分析

Correlation analysis of fish growth performance and serum hormone and digestive enzyme activities of juvenile pearl gentian grouper (Epinephelus lanceolatus♂×E. fuscoguttatus♀) fed with different protein levels diets

  • 摘要: 为评估蛋白质水平与珍珠龙胆石斑鱼幼鱼生长、血清激素和消化酶活性的相关性,探究珍珠龙胆石斑鱼饲料中蛋白质水平对其健康生长的影响,实验选取珍珠龙胆石斑鱼初始体质量(6.50±0.00) g随机分为6组,每组4个重复,分别投喂35%、40%、45%、50%、55%和60%蛋白质水平的饲料,通过8周的摄食生长实验。结果显示,50%组的增重率(WGR)和特定生长率(SGR)显著高于其他组;55%和60%组血清总蛋白(TP)含量显著高于35%组;50%组血清生长激素(GH)和胰岛素(INS)含量显著低于其他组,45%组血清胰岛素样生长因子Ⅰ(IGF-Ⅰ)含量显著高于其他组;50%组胃蛋白酶活性和肠胰蛋白酶活性显著高于其他组,肠淀粉酶活性随饲料蛋白质水平的升高呈逐渐下降的趋势,并在55%和60%组达到最低值。WGR与血清GH之间呈极显著的负相关关系。研究表明,以WGR为评价指标,经折线模型拟合得出珍珠龙胆石斑鱼幼鱼对饲料中蛋白质的需求量为51.57%。

     

    Abstract: An 8-week feeding trial was conducted to assess the correlation of the dietary protein with growth of juvenile pearl gentian grouper (Epinephelus lanceolatus♂×E. fuscoguttatus♀), serum hormone and digestive enzyme activities, to explore the effects of dietary protein levels on healthy growth. Grouper average body weight (6.50±0.00) g were randomly divided into 6 groups with 4 replicates in each group. The fish were fed isoenergetic and isolipidic experimental diets with protein levels 35%, 40%, 45%, 50%, 55% and 60%, respectively. The results showed that weight gain rate and specific growth rate of the fish fed with 50% protein diet were significantly higher than those of fish fed other protein level diets. The concentrations of total protein (TP) in 50% group and 60% group were significantly higher than 35% group. The concentrations of growth hormone (GH) and insulin (INS) in 50% group were significantly lower than those in other groups. The highest insulin-like growth factors-Ⅰ (IGF-Ⅰ) concentration was found in 45% group and significantly higher than those in other groups. Pepsin and intestinal trypsin activities in 50% group were significantly higher than those in other groups. With increasing dietary protein levels, intestinal amylase activity was decreased, the lowest value was found in 55% group and 60% group and significantly lower than those in other groups. There was extremely significantly negative correlation between WGR and GH. According to these results, based on broken-line regression analysis of WGR, a diet containing 51.57% protein is recommended for efficient growth of juvenile pearl gentian grouper.

     

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