本试验旨在研究饲粮中胆碱添加水平对3~5月龄獭兔肝脏脂肪代谢的影响。选用200只体重相近的3月龄獭兔，随机分成5组（每组40个重复，每个重复1只），分别饲喂在基础饲粮基础上添加0（对照）、200、400、600和800 mg/kg的50%氯化胆碱（折算为胆碱的添加水平后分别为0、87、174、261和348 mg/kg）的试验饲粮，试验饲粮实测胆碱水平分别为812、902、993、1 086和1 170 mg/kg。预试期7 d，正试期53 d。结果表明：饲粮中胆碱添加水平显著影响肝脏中单不饱和脂肪酸和多不饱和脂肪酸的含量（P<0.05）。与对照组相比，饲粮中添加87、174、261和348 mg/kg的胆碱显著增加血清中类胰岛素样生长因子1（IGF-1）和瘦素（LEP）的含量（P<0.05），饲粮中添加174和261 mg/kg的胆碱显著增加血清中生长激素（GH）的含量（P<0.05），饲粮中添加261和348 mg/kg的胆碱显著增加血清中脂蛋白酯酶（LPL）的活性和极低密度脂蛋白（VLDL）的含量（P<0.05），饲粮中添加261 mg/kg的胆碱显著提高肝脏中肉碱棕榈酸转移酶1（CPT1）mRNA的表达水平（P<0.05）。综上所述，饲粮中添加261 mg/kg的胆碱（饲粮实测胆碱水平为1 086 mg/kg）改变了獭兔肝脏中脂肪酸组成，促进了肝脏中脂肪酸氧化关键基因CPT1的表达，同时加强了肝脏中甘油三酯（TG）的输出过程。

This experiment was conducted to investigate the effects of choline supplemental level on lipid metabolism in liver of 3-to 5-month-old Rex rabbits. Two hundred 3-month-old 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 the 5 groups were fed experimental diets which supplemented with 0 (control), 200, 400, 600 and 800 mg/kg 50% choline chloride (converted from 50% choline chloride to choline, the supplemental levels were 0, 87, 174, 261 and 348 mg/kg, respectively) based on a basal diet, and the measured levels of choline in experimental diets were 812, 902, 993, 1 086 and 1 170 mg/kg, respectively. The pre-test period lasted for 7 days, and the experimental period lasted for 53 days. The results showed that dietary choline supplemental level had significant effects on the contents of monounsaturated fatty acids and polyunsaturated fatty acids in liver (P<0.05). Compared with control group, dietary supplemented with 87, 174, 261 and 348 mg/kg choline significantly increased the contents of insulin-like growth factor 1 (IGF-1) and leptin (LEP) in serum (P<0.05), dietary supplemented with 174 and 261 mg/kg choline significantly increased the content of growth hormone (GH) in serum (P<0.05), dietary supplemented with 261 and 348 mg/kg choline significantly increased the lipoprotein lipase (LPL) activity and very low density lipoprotein (VLDL) content in serum (P<0.05), and dietary supplemented with 261 mg/kg choline significantly increased the carnitine palmitoyltransferase-1 (CPT1) mRNA expression level in liver (P<0.05). In conclusion, dietary supplemented with 261 mg/kg choline (the measured level of choline in the diet is 1 086 mg/kg) alters the fatty acid composition in liver, promotes the CPT1 gene expression, which is the key enzyme fatty acid oxidation, strengthens the output process of triglycerides (TG) from liver.