We evaluated citric acid supplementation (0, 10, 20, and 30 g/kg) in plant protein‐based diets for juvenile tambaqui, Colossoma macropomum. In Experiment 1, fish (n = 160; 27.56 ± 2.73 g) were distributed in 310 L tanks (n = 16) for 80 days. Zootechnical performance, hematological parameters, and mineral composition (muscle and bones) did not differ significantly (p > .05). The inclusion of citric acid‐reduced pH of diets (p = .001) and stomach (p = .035). In Experiment 2, fish (n = 60; 48.00 ± 1.98 g) were distributed in fecal collection aquaria (200 L) for 21 days. The following were observed: a linear effect for the crude protein (p = .0004) and crude fat (p = .0037) digestibility coefficients; a quadratic effect for crude energy (p = .0037) and dry matter (p = .0004); an optimal supplementation level of 18.5 g/kg. Calcium (p = .0060) and magnesium (p = .0222) showed a linear effect, while phosphorus (p = .0001) had a quadratic effect with the 20 g/kg optimum supplementation level. To conclude, the supplementation of this organic acid in diets does not negatively affect fish nutritional status, health or welfare, and increases nutrient and mineral availability.

中文翻译：

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少年坦巴奎，大巨像的植物蛋白日粮中补充柠檬酸

我们评估了以植物蛋白为基础的日粮中补充柠檬酸（0、10、20和30 g / kg）的丹巴基幼鱼，巨像。在实验1中，将鱼（n = 160； 27.56±2.73 g）分配到310 L的水箱（n = 16）中80天。动物技术性能，血液学参数和矿物质组成（肌肉和骨骼）没有显着差异（p  > .05）。饮食中柠檬酸降低的pH值（p = .001）和胃的pH值（p = .035）。在实验2中，将鱼（n = 60； 48.00±1.98 g）分配到粪便收集水族箱（200 L）中21天。观察到以下结果：粗蛋白的线性效应（p= .0004）和粗脂肪（p = .0037）的消化率系数；对于粗能量（二次效果p = 0.0037）和干物质（p = 0.0004）; 最佳补充水平为18.5克/千克。钙（p = .0060）和镁（p = .0222）表现出线性效应，而磷（p = .0001）具有二次效应，最佳添加量为20 g / kg。总之，在饮食中添加这种有机酸不会对鱼类的营养状况，健康或福利产生负面影响，并且会增加营养和矿物质的利用率。