This experiment was conducted to investigate the effects of dietary choline level on growth perform-ance, 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 experi-ment 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 aver-age daily gain (ADG) (P<0. 000 1) and feed/gain (F/G) (P=0. 000 2). The highest ADG and the low-est 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 aminotrans-ferase 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 concen-tration 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 in-creased (P<0. 05), and the acetic acid/(propionic acid+butyric acid) in groups C, D and E was signifi-cantly 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.%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<0.0001)和料重比(P=0.0002)。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 =0.0482)和总蛋白含量(P =0.0117),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<0.0001)、总挥发性脂肪酸浓度(P<0.0001)、乙酸比例(P=0.0032)、乙酸/(丙酸+丁酸)(P=0.0045),显著影响丙酸比例(P=0.0307),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<0.0001),显著影响毛皮重量(P=0.0156),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%。
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