本试验旨在研究饲粮维生素B₂添加水平对育成期水貂生长性能、营养物质消化率及氮代谢的影响。选取（65±5）日龄、体重[（1 213.38±72.72）g]相近的健康雄性短毛黑水貂96只，随机分为6个组，每组16个重复，每个重复1只水貂。采用单因素试验设计，各组饲粮维生素B₂添加水平分别为0（Ⅰ组）、2.5（Ⅱ组）、5.0（Ⅲ组）、10.0（Ⅳ组）、20.0（Ⅴ组）、40.0 mg/kg（Ⅵ组）。预试期7 d，正试期58 d。结果表明：1）饲粮维生素B₂添加水平显著影响水貂末重和料重比（P<0.05），极显著影响水貂平均日增重（P<0.01），其中以Ⅴ组平均日增重、末重最大，料重比最小。Ⅴ组平均日增重显著或极显著高于Ⅰ、Ⅱ、Ⅲ和Ⅳ组（P<0.05或P<0.01），Ⅴ、Ⅵ组料重比显著或极显著低于Ⅰ组（P<0.05或P<0.01），Ⅴ、Ⅵ组末重显著高于Ⅰ组（P<0.05）。2）饲粮维生素B₂添加水平极显著影响水貂粗蛋白质消化率和粗脂肪消化率（P<0.01），对水貂干物质采食量、干物质排出量和干物质消化率影响不显著（P>0.05）。Ⅵ组粗脂肪消化率最高，Ⅰ组最低，Ⅰ组极显著低于Ⅱ、Ⅴ和Ⅵ组（P<0.01）。Ⅴ组粗蛋白质消化率最高，极显著高于Ⅰ组（P<0.01）。3）饲粮维生素B₂添加水平显著影响育成期水貂氮沉积、净蛋白质利用率和蛋白质生物学价值（P<0.05），对食入氮、粪氮和尿氮影响不显著（P>0.05）。Ⅴ组净蛋白质利用率最高，显著高于Ⅰ和Ⅱ组（P<0.05），与Ⅲ、Ⅳ和Ⅵ组差异不显著（P>0.05）。Ⅴ组蛋白质生物学价值最高，Ⅴ和Ⅵ显著高于Ⅰ组（P<0.05），与Ⅱ、Ⅲ和Ⅳ组差异不显著（P>0.05）。Ⅵ组氮沉积最高，Ⅰ组最低，Ⅰ组显著低于Ⅴ和Ⅵ组（P<0.05），与Ⅱ、Ⅲ和Ⅳ组差异不显著（P>0.05）。综合各项指标，在本试验条件下，饲粮中维生素B₂添加水平为20.0 mg/kg（饲粮中维生素B₂水平为23.35 mg/kg）时，育成期水貂可以获得较好的生长性能及较高的营养物质消化率、氮利用率。

This experiment was conducted to evaluate the effects of dietary vitamin B₂ level on growth performance, nutrient digestibilities and nitrogen metabolism of growing minks. Ninety-six healthy short black male minks at the age of (65±5) days with the similar weight[(1 213.38±72.72) g] were randomly divided into 6 groups with 16 replicates per group and 1 mink per replicate. The experiment used a single factorial experiment design, and the dietary vitamin B₂ supplemental levels of 6 groups were 0 (group Ⅰ), 2.5 (group Ⅱ), 5.0 (group Ⅲ), 10.0 (group Ⅳ), 20.0 (group Ⅴ) and 40.0 mg/kg (group Ⅵ), respectively. The adaptation period lasted for 7 days and the formal period lasted for 58 days. The results showed as follows:1) dietary vitamin B₂ level had significant effects on the final weight and feed to gain ratio of minks (P<0.05), and had extremely significant effect on the average daily gain of minks (P<0.01), the average daily gain and final weight of group Ⅴ were the highest, while the feed to gain ratio was the lowest. The average daily gain of group Ⅴ was significantly higher than that of groups Ⅰ, Ⅱ, Ⅲ and Ⅳ (P<0.05 or P<0.01), the feed to gain ratio of groups Ⅴ and Ⅵ was significantly lower than that of group Ⅰ (P<0.05 or P<0.01), the final weight of groups Ⅴ and Ⅵ was significantly higher than that of group Ⅰ (P<0.05). 2) Dietary vitamin B₂ level had extremely significant effects on the crude protein digestibility and ether extract digestibility of minks (P<0.01), while had no significant effects on the dry matter intake, dry matter output and dry matter digestibility of minks (P>0.05). The ether extract digestibility of group Ⅵ was the highest, which of group Ⅰ was the lowest, the ether extract digestibility of group Ⅰ was extremely significantly lower than that of groups Ⅱ, Ⅴ and Ⅵ (P<0.01). The crude protein digestibility of group Ⅴ was the highest, which was extremely significantly higher than that of group Ⅰ(P<0.01). 3) Dietary vitamin B₂ level had significant effects on the nitrogen deposition, net protein utilization and the biological value of protein of minks (P<0.05), while had no significant effects on the nitrogen intake, fecal nitrogen and urine nitrogen of minks (P>0.05). The net protein utilization rate of group Ⅴ was the highest, which was significantly higher than that of groups Ⅰ and Ⅱ (P<0.05), but had no significant difference with that of groups Ⅲ, Ⅳ and Ⅵ (P>0.05). The biological value of protein of group Ⅴ was the highest, which of groups Ⅴ and Ⅵ was significantly higher than that of group Ⅰ (P<0.05), but had no significant difference with that of groups Ⅱ, Ⅲ and Ⅳ (P>0.05). The nitrogen deposition of group Ⅵ was the highest, which of group Ⅰ was the lowest, the nitrogen deposition of group Ⅰ was significantly lower than that of groups Ⅴ and Ⅵ (P<0.05), but had no significant difference with that of groups Ⅱ, Ⅲ and Ⅳ (P>0.05). Considering all the factors, when dietary vitamin B₂ level is 20 mg/kg (dietary vitamin B₂ level is 23.35 mg/kg), growing minks can obtain the better growth performance and higher nutrient digestibilities and nitrogen utilization under the condition of this experiment.