Determination of nutrient requirements for a cultured fish species is necessary to develop a nutritionally-balanced and cost-effective diet because feed contributes greatly to aquaculture operation costs. Lipids are crucial nutrients that provide essential fatty acids, phospholipids, and energy. Thus, the current study was conducted to determine an optimum dietary lipid level for juvenile hybrid pufferfish (Takifugu obscurus ♀ × T. rubripes ♂). Five isonitrogenous diets were prepared to contain various lipid levels at 6%, 9%, 12%, 15% and 18%, resulting in the corresponding protein-to-energy ratios as 29.8, 28.5, 28.0, 26.9, and 25.8 g/MJ, respectively. Three hundred juveniles weighing 4.18 ± 0.08 g (mean±SD) were randomly distributed to 15 tanks, resulting in 20 fish per tank (three replicates per treatment). The feeding trial lasted for 8 weeks. At the end of the trial, final weight, feed intake, weight gain, and specific growth rate of the fish fed 9% and 12% lipid diets were significantly higher than those fed 15% and 18% lipid diets (P < 0.05). Whole-body lipid contents significantly increased with the increasing dietary lipid level, whereas no difference in whole-body moisture, protein, and ash contents in response to the various dietary lipid levels was detected. There was a pattern in the fatty acid profile showing that pooled saturated fatty acid and n-3 polyunsaturated fatty acid levels decreased as the dietary lipid level increased. The fish fed the 12% lipid diet showed a significantly lower aspartate aminotransferase activity in comparison to those fed the 6% and 18% diets. According to the broken-line regression analysis, the optimum dietary lipid level and protein-to-energy ratio were estimated to be 10% and 28.5 g/MJ, respectively.

确定养殖鱼类的营养需求对于开发营养均衡且具有成本效益的饮食是必要的，因为饲料对水产养殖运营成本的影响很大。脂质是提供必需脂肪酸、磷脂和能量的重要营养素。因此，本研究旨在确定杂交河豚幼鱼 ( Takifugu obscurus ♀ × T. rubripes ♂ ) 的最佳膳食脂质水平）。制备了五种等氮日粮，分别含有 6%、9%、12%、15% 和 18% 的不同脂质水平，相应的蛋白质与能量比分别为 29.8、28.5、28.0、26.9 和 25.8 g/MJ ， 分别。300 只体重为 4.18 ± 0.08 g（平均值±标准差）的幼鱼被随机分配到 15 个鱼缸中，每个鱼缸有 20 条鱼（每个处理三个重复）。喂养试验持续了8周。试验结束时，饲喂 9% 和 12% 脂质日粮的鱼的终重、采食量、增重和比生长率显着高于饲喂 15% 和 18% 脂质日粮的鱼（P < 0.05)。随着膳食脂质水平的增加，全身脂质含量显着增加，而未检测到响应各种膳食脂质水平的全身水分、蛋白质和灰分含量的差异。脂肪酸谱中存在一种模式，表明合并的饱和脂肪酸和 n-3 多不饱和脂肪酸水平随着膳食脂质水平的增加而降低。与饲喂 6% 和 18% 日粮的鱼相比，饲喂 12% 脂质日粮的鱼的天冬氨酸氨基转移酶活性显着降低。根据折线回归分析，最佳膳食脂质水平和蛋白质能量比估计分别为 10% 和 28.5 g/MJ。