An 8‐week feeding trial was conducted to investigate the effects of dietary carbohydrate‐to‐lipid (CHO:L) ratios on growth, liver and muscle glycogen content, haematological indices, and liver and intestinal enzyme activity of juvenile grouper (Epinephelus coioides). Five isonitrogenous (496.0 g/kg protein) and isoenergetic (21.6 KJ/g gross energy) diets with varying CHO:L ratios of 0.65 (D1), 1.31 (D2), 2.33 (D3), 4.24 (D4) and 8.51 (D5), respectively, were fed to triplicate groups of 20 fish (average 10.02 ± 0.1 g) for 8 weeks. Results showed that the weight gain rate, specific growth rate and protein efficiency ratio (PER) of juvenile grouper increased first and then decreased with the increase in CHO:L ratio, reaching a maximum value in the D4 (CHO:L = 4.24) diet. The trend for the feed conversion ratio was opposite to the PER. Along with the diet CHO:L ratios, the apparent digestibility coefficients (ADC) of crude lipid and energy for the juvenile groupers decreased gradually, while the ADC of dry matter, liver and muscle glycogen level increased gradually. Total protein, triglycerides and cholesterol in serum were all maximized in the D4 diet and glucose in the D5 (CHO:L = 8.51) diet. Digestive enzyme activity in the intestine was significantly affected by dietary CHO:L ratio. Liver hexokinase, phosphofructokinase and glucose‐6‐phosphate dehydrogenase activity increased significantly as CHO:L ratio increased. Liver lysozyme and acid phosphatase activity in the groupers fed the D3 (CHO:L = 2.33) diet was significantly higher than that of other diets. Liver fructose‐1,6‐bisphosphatase and alkaline phosphatase activity reached a maximum value in the D4 diet and was significantly higher than that in the D1 diet. Taking the above results together, it can be concluded that an optimal dietary CHO:L ratio of 2.33 is suitable for grouper culture concerning growth performance and health.

中文翻译：

---

日粮糖脂比对橙斑石斑鱼石斑鱼幼鱼生长，血浆生化指标，消化和免疫酶活性的影响

进行了为期8周的喂养试验，以研究饮食中碳水化合物与脂质（CHO：L）的比例对少年石斑鱼（Epinephelus coioides）的生长，肝和肌肉糖原含量，血液学指标以及肝和肠道酶活性的影响）。五种同氮（496.0 g / kg蛋白质）和同能（21.6 KJ / g总能量）的饮食，CHO：L比率分别为0.65（D1），1.31（D2），2.33（D3），4.24（D4）和8.51（D5） ）分别喂食20条鱼（平均10.02±0.1 g）一式三份，持续8周。结果表明，少年石斑鱼的增重率，比生长率和蛋白质效率比（PER）随着CHO：L比的增加而先升高然后降低，在D4（CHO：L = 4.24）日粮中达到最大值。饲料转化率的趋势与PER相反。随着日粮CHO：L比例的增加，少年石斑鱼的粗脂肪和能量的表观消化系数（ADC）逐渐降低，而干物质，肝脏和肌肉糖原水平的ADC逐渐升高。总蛋白质 D4饮食中血清甘油三酯和胆固醇均最高，D5（CHO：L = 8.51）饮食中葡萄糖最高。饮食中的CHO：L比值显着影响肠道的消化酶活性。肝己糖激酶，磷酸果糖激酶和葡萄糖-6-磷酸脱氢酶活性随着CHO：L比的增加而显着增加。喂D3（CHO：L = 2.33）日粮的石斑鱼的肝溶菌酶和酸性磷酸酶活性显着高于其他日粮。D4日粮中肝果糖1,6-双磷酸酶和碱性磷酸酶的活性达到最大值，并且显着高于D1日粮。综合以上结果，可以得出结论，最佳的饮食CHO：L比值为2.33适用于与生长性能和健康有关的石斑鱼养殖。