Although sterlet sturgeon is a valuable candidate for aquaculture development, information regarding the nutrient requirements of this species is limited. Therefore, in this study, we aimed to determine the optimum protein level required by sterlet sturgeon fingerlings. Groups of fingerlings (mean initial body weight ± SD: 7.02 ± 0.02 g; N = 3) were assigned to one of the six dietary protein levels at 29.1%, 39.1%, 46.8%, 49.2%, 53.7%, and 57.6% on a dry matter basis. Isocaloric (18.3 ± 0.2 kJ GE/g diet) semi-purified diets were prepared using white fish meal and casein as the major sources of protein. After the 8-week feeding trial, the fingerlings fed the 49.2% protein diet exhibited the best results in terms of weight gain, feed efficiency, and whole-body nutrient composition (crude protein, crude lipid, gross energy, and amino acid contents), whereas those fed the 53.7% and 57.6% protein diets showed poor performance. Application of the two-slope straight broken-line and quadratic models on the dataset of weight gain revealed the optimum protein level to be 45.9% and 44.1%, respectively. Based on the model selection criteria, including the adjusted coefficient of correlation and corrected Akaike information criterion, the protein level (44.1%) estimated using the quadratic model was more accurate than that obtained using another model (45.9%). Taken together, 44.1% protein level (18.3 kJ GE/g diet on dry matter basis) resulted in the optimal growth of the sterlet sturgeon fingerlings (initial body weight: approximately 7 g).

中文翻译：

---

小鲟鱼种（Acipenser ruthenus）的膳食蛋白质需求

虽然小鲟是水产养殖发展的重要候选者，但有关该物种营养需求的信息有限。因此，在本研究中，我们旨在确定小鲟鱼苗所需的最佳蛋白质水平。鱼种组（平均初始体重 ±  SD : 7.02 ± 0.02 g；N = 3) 被分配到六种膳食蛋白质水平之一，以干物质为基础，分别为 29.1%、39.1%、46.8%、49.2%、53.7% 和 57.6%。使用白鱼粉和酪蛋白作为蛋白质的主要来源制备等热量（18.3 ± 0.2 kJ GE/g 饮食）半纯化饮食。经过 8 周的饲喂试验，饲喂 49.2% 蛋白质日粮的鱼种在增重、饲料效率和全身营养成分（粗蛋白、粗脂肪、总能量和氨基酸含量）方面表现出最好的结果。 ，而那些喂食 53.7% 和 57.6% 蛋白质饮食的人表现不佳。在增重数据集上应用双斜直线折线和二次模型显示最佳蛋白质水平分别为 45.9% 和 44.1%。根据模型选择标准，包括调整的相关系数和校正的 Akaike 信息标准，使用二次模型估计的蛋白质水平 (44.1%) 比使用另一个模型 (45.9%) 获得的更准确。总而言之，44.1% 的蛋白质水平（18.3 kJ GE/g 干物质饲料）导致了小鲟鱼鱼种的最佳生长（初始体重：约 7 g）。