本试验旨在研究饲粮胆碱水平对3~5月龄獭兔生长性能、血清生化指标、盲肠发酵及毛皮质量的影响。选用200只体重相近、健康状况良好的3月龄獭兔，随机分成5组（每组40个重复，每个重复1只），分别饲喂胆碱实测水平为0.08%（A组）、0.09%（B组）、0.10%（C组）、0.11%（D组）和0.12%（E组）的试验饲粮。预试期7 d，正试期60 d。结果表明：饲粮胆碱水平对平均日采食量无显著影响（P>0.05），但极显著影响平均日增重（P<0.000 1）和料重比（P=0.000 2）。平均日增重和料重比在D组分别达到最高值和最低值，且均与A组差异极显著（P<0.01）。饲粮胆碱水平显著影响血清尿素氮（P=0.048 2）和总蛋白含量（P=0.011 7），而对谷丙转氨酶活性及甘油三酯、总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇含量均无显著影响（P>0.05）。与A组相比，B、C和D组尿素氮含量显著降低（P<0.05），C、D和E组总蛋白含量显著降低（P<0.05）。饲粮胆碱水平极显著影响盲肠内容物pH（P<0.000 1）、总挥发性脂肪酸浓度（P<0.000 1）、乙酸比例（P=0.003 2）、乙酸/（丙酸+丁酸）（P=0.004 5），显著影响丙酸比例（P=0.030 7），但对丁酸比例和氨态氮浓度无显著影响（P>0.05）。与A组相比，C、D和E组pH极显著降低（P<0.01），D组总挥发性脂肪酸浓度极显著升高（P<0.01），D和E组乙酸比例极显著降低（P<0.01），C、D和E组丙酸比例显著升高（P<0.05），C、D和E组乙酸/（丙酸+丁酸）极显著升高（P<0.01）。饲粮胆碱水平极显著影响毛皮面积（P<0.000 1），显著影响毛皮重量（P=0.015 6），但对毛皮厚度和被毛长度无显著影响（P>0.05）。D和E组毛皮面积极显著高于A、B和C组（P<0.01），D组毛皮重量显著高于其他各组（P<0.05）。综合本试验测定指标，3~5月龄獭兔饲粮适宜的胆碱水平为0.11%。

This experiment was conducted to investigate the effects of dietary choline level on growth performance, serum biochemical indices, caecum fermentation and fur quality of 3 to 5-month-old Rex rabbits. Two hundred 3-month-old healthy Rex rabbits with similar body weight were randomly divided into 5 groups with 40 replicates in each group and 1 rabbit in each replicate. Rabbits in 5 groups were fed experimental diets which containing 0.08% (group A), 0.09% (group B), 0.10% (group C), 0.11% (group D) and 0.12% choline (group E), respectively. The choline levels in experimental diets were measured values. The experiment lasted for 7 days for adaptation, and 60 days for test. The results showed as follows: dietary choline level had no significant effect on average daily feed intake (ADFI) (P>0.05), but had significant effects on average daily gain (ADG) (P<0.000 1) and feed/gain (F/G) (P=0.000 2). The highest ADG and the lowest F/G were all found in group D, and there were significant differences in them between groups D and A (P<0.01). Dietary choline level had significant effects on the contents of serum urea nitrogen (P=0.048 2)and total protein (P=0.011 7), but had no significant effects on the activity of alanine aminotransferase and the contents of triglycerides, total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol (P>0.05). Compared with the group A, the urea nitrogen content in groups B, C and D was significantly decreased (P<0.05), and the total protein content in groups C, D and E was significantly decreased (P<0.05). Dietary choline level had significant effects on cecal digesta pH (P<0.000 1), total volatile fatty acid concentration (P<0.000 1), acetic acid proportion (P=0.003 2), acetic acid/(propionic acid+butyric acid) (P=0.004 5) and propionic acid proportion (P=0.030 7), but had no significant effects on butyric acid proportion and ammonia nitrogen concentration (P>0.05). Compared with the group A, the pH in groups C, D and E was significantly decreased (P<0.01), the total volatile fatty acid concentration in group D was significantly increased (P<0.01), the acetic acid proportion in groups D and E was significantly decreased (P<0.01), the propionic acid proportion in groups C, D and E was significantly increased (P<0.05), and the acetic acid/(propionic acid+butyric acid) in groups C, D and E was significantly increased (P<0.01). Dietary choline level had significant effects on fur area (P<0.000 1) and fur weight (P=0.015 6), but had no significant effects on fur thickness and wool length (P>0.05). The fur area in groups D and E was significantly higher than that in groups A, B and C (P<0.01), and the fur weight in group D was significantly higher than that in other groups (P<0.05). Considering all indices of this experiment,the appropriate dietary choline level is 0.11% for 3 to 5-month-old Rex rabbits.