The dietary folic acid requirement of fingerling Catla catla (3.4 ± 0.17 g; 7.6 ± 0.41 cm) was evaluated by feeding casein–gelatin‐based isonitrogenous (350 g/kg crude protein) and isocaloric (16.72 kJ/g GE) diets containing different concentrations of folic acid (0, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0 mg/kg) to triplicate groups to apparent satiation at 08:00, 12:30 and 17:30 hr for 16 weeks. Absolute weight gain (AWG; 40.07 g/fish), specific growth rate (SGR; 2.25%), feed conversion ratio (FCR; 1.53), protein retention efficiency (PRE; 31.42%) and protein gain (PG; 6.74) improved significantly (p < .05) with increasing folic acid levels up to 0.4 mg/kg diet and then reached a plateau. However, maximum liver folic acid concentration increased up to 0.6 mg/kg diet. Dietary folic acid levels also significantly affected (p < .05) body composition of fish. No significant change (p > .05) in haematological parameters except in fish fed folic acid‐free diet was noted. Antioxidant and immune parameters increased with increasing concentration of dietary folic acid up to 0.4 mg/kg diet. Broken‐line regression analysis of AWG, FCR, PRE, PG, HCT and liver folic acid concentrations of fingerling C. catla against dietary folic acid levels indicated optimum growth, FCR, PRE, PG, HCT and liver folic acid saturation ranging between 0.22 and 0.56 mg/kg diet, respectively.

中文翻译：

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幼鱼Catla，Catla catla（汉密尔顿）的膳食中叶酸的需求量

通过饲喂酪蛋白-明胶为基础的异氮（350 g / kg粗蛋白）和等热量（16.72 kJ / g GE）的日粮，评估鱼种Catla catla（3.4±0.17 g; 7.6±0.41 cm）的日粮叶酸需求浓度的叶酸（0、0.2、0.4、0.6、0.8、1.0、2.0 mg / kg）一式三份，分别在08：00、12：30和17:30 hr服药16周。绝对增重（AWG; 40.07 g /鱼），比生长率（SGR; 2.25％），饲料转化率（FCR; 1.53），蛋白质保留效率（PRE; 31.42％）和蛋白质增高（PG; 6.74）显着提高（p <.05），叶酸水平提高到0.4 mg / kg日粮，然后达到平稳状态。但是，最大肝叶酸浓度增加到0.6 mg / kg饮食。饮食中叶酸水平也显着影响 鱼类的身体组成（p <.05）。 除饲喂无叶酸饮食的鱼外，血液学参数没有显着变化（p > .05）。饮食中叶酸的浓度增加到0.4 mg / kg时，抗氧化和免疫参数会增加。鱼种C.ACAT的AWG，FCR，PRE，PG，HCT和肝叶酸浓度的折线回归分析 饮食中叶酸水平的变化表明最佳生长，FCR，PRE，PG，HCT和肝叶酸饱和度分别在0.22和0.56 mg / kg饮食之间。