本试验旨在研究饲粮中核黄素添加水平对生长獭兔肉品质、毛囊发育和免疫性能的影响。选择体重相近的3月龄獭兔160只，随机分为4组，每组40个重复，每个重复1只兔。各组分别饲喂在基础饲粮中添加0（对照）、3、6和12 mg/kg核黄素的饲粮。预试期7 d，正试期53 d。结果表明：与对照组相比，饲粮中添加6、12 mg/kg核黄素显著降低了獭兔肌肉的滴水损失（P<0.05），饲粮中添加3、6、12 mg/kg核黄素显著提高了獭兔皮肤中总毛囊密度（P<0.05），饲粮中添加3、6 mg/kg核黄素显著提高了獭兔皮肤中初级毛囊密度（P<0.05），饲粮中添加6、12 mg/kg核黄素显著提高了獭兔皮肤中次级毛囊密度（P<0.05），饲粮中添加3、6 mg/kg核黄素显著降低了獭兔皮肤中次级毛囊密度/初级毛囊密度（P<0.05）。饲粮中核黄素添加水平对獭兔的胸腺重、胸腺指数及血清免疫球蛋白G、免疫球蛋白A、白细胞介素-2含量影响显著（P<0.05），且均随着饲粮中核黄素添加水平的升高呈先增加后降低的趋势，并均在6 mg/kg添加组中达到最大值，显著高于对照组（P<0.05）。由此可见，3~5月龄生长獭兔饲粮中核黄素适宜添加水平为6 mg/kg（实际测定饲粮中核黄素水平为8.35 mg/kg）。

This experiment was conducted to investigate the effects of dietary nicotinic acid supplemental level on meat quality, hair follicle development and immune performance of growing Rex rabbits. A total of 160 three-month-old Rex rabbits with similar body weight were randomly divided into 4 groups with 40 replicates per group and 1 rabbit per replicate. Rabbits in the control group were fed a basal diet, and the others in the experimental groups were fed the experimental diets supplemented with 3, 6 and 12 mg/kg riboflavin, respectively. The pre-test period lasted for 7 days, and the experimental period lasted for 53 days. The results showed that compared with the control group, dietary supplemented with 6 and 12 mg/kg riboflavin significantly reduced the meat drip loss of Rex rabbits (P<0.05), dietary supplemented with 3, 6 and 12 mg/kg riboflavin significantly increased the skin total hair follicles density of Rex rabbits (P<0.05), dietary supplemented with 3 and 6 mg/kg riboflavin significantly increased the skin primary hair follicles density of Rex rabbits (P<0.05), and dietary supplemented with 6 and 12 mg/kg riboflavin significantly increased the skin secondary hair follicles density of Rex rabbits (P<0.05), dietary supplemented with 6 and 12 mg/kg riboflavin significantly decreased the ratio of secondary hair follicles density to primary hair follicles density of Rex rabbits (P<0.05). Dietary riboflavin supplemental level significantly affected the thymus weight, thymus index and the content of immunoglobulin G, immunoglobulin A and interleukin 2 in serum of Rex rabbits (P<0.05), and all the above indices were showed a firstly increase then decrease tendency with dietary riboflavin supplemental level increasing, and got the max value in the 6 mg/kg supplemental group, which significantly higher than those in the control group (P<0.05). In conclusion,the suitable dietary riboflavin supplement level of growing Rex rabbits aged from 3 to 5 months is 6 mg/kg (measured dietary riboflavin level is 8.35 mg/kg).