本试验旨在探究饲粮中添加不同水平叶酸和维生素B₁₂（VB₁₂）对五龙鹅生长性能、屠宰性能、脂肪沉积及极长链脂肪酸延长酶7（ELOVL7）基因表达量及其在不同组织器官中表达差异性的影响及相关性分析。试验选用5周龄五龙鹅420只，随机分为7组，每组6个重复，每个重复10只鹅，公母各占1/2，Ⅰ~Ⅵ组为试验组，Ⅶ组为对照组。试验采用2×3两因素交叉等重复的析因设计，饲粮中叶酸的添加水平分别为0.25、2.00 mg/kg，VB₁₂的添加水平分别为0.003、0.009、0.018 mg/kg，试验期为4周。采用实时荧光定量PCR技术测定五龙鹅肝脏中ELOVL7基因的表达量，并选取对照组的五龙鹅，检测ELOVL7基因在心脏、肝脏、肾脏、腹脂、肺、肌胃、腺胃、胸肌、腿肌、脾脏、胰腺11个部位的表达分布情况。结果表明：1）饲粮中添加不同水平叶酸和VB₁₂的交互作用对五龙鹅末重影响显著（P<0.05），Ⅴ组体重最大，对平均日增重、料重比影响不显著（P>0.05）。2）饲粮中添加不同水平叶酸和VB₁₂的交互作用对血清甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇（LDL-C）含量影响显著（P<0.05）。饲粮中添加不同水平叶酸对血清TG和LDL-C含量影响显著（P<0.05）；不同水平VB₁₂对血清葡萄糖（GLU）和LDL-C含量影响显著（P<0.05）。3）饲粮中添加不同水平叶酸和VB₁₂交互作用对胸肌率影响显著（P<0.05），对屠宰率、半净膛率、全净膛率和腿肌率影响均不显著（P>0.05）。Ⅰ、Ⅴ组胸肌率显著高于对照组（P<0.05）。4）饲粮中添加不同水平叶酸和VB₁₂交互作用对皮脂率、腹脂率、肌间脂带宽、胸肌肌内脂肪率和腿肌肌内脂肪率影响显著（P<0.05）；Ⅴ组腹脂率显著低于其他各组（P<0.05）。5）饲粮中添加不同水平叶酸和VB₁₂的交互作用对肝脏中ELOVL7基因的表达量影响显著（P<0.05）；饲粮中添加不同水平叶酸和VB₁₂均能使肝脏中ELOVL7基因的表达量高于对照组，Ⅴ组表达量最高，显著高于对照组（P<0.05）。6）肝脏中ELOVL7基因表达量与屠宰率呈显著负相关（P<0.05），与血清TG、LDL-C含量呈显著负相关（P<0.05），与血清总胆固醇（TC）含量呈极显著负相关（P<0.01），与肌间脂带宽呈显著正相关（P<0.05），与皮脂率、腹脂率、腿肌肌内脂肪率呈显著负相关（P<0.05）。7）ELOVL7基因在腹脂中的表达量最高，其次是肺和胰腺，在胸肌、腿肌中的表达量较低。在本试验条件下：1）饲粮中添加适宜水平的叶酸和VB₁₂对五龙鹅ELOVL7基因表达、脂类代谢生化指标和机体营养组成有显著干预作用；2）叶酸0.25 mg/kg和VB₁₂ 0.009 mg/kg组合（Ⅴ组）最佳。

The aim of this study was to investigate the effects of dietary different levels of folic acid and vitamin B₁₂ (VB₁₂) on growth performance, slaughter performance, fat deposition, very long chain fatty acid elongase 7 (ELOVL7) gene expression level and expression difference in different tissues of Wulong geese, and to analyze the correlation. A total of 420 Wulong geese at 5 weeks of age were randomly divided into 7 groups. Each group had 6 replicates and each replicate consisted of 5-male and 5-female geese. GroupsⅠto Ⅵ were experimental groups,and groupⅦ was a control group. The trial used a 2×3 factorial crossover design. The supplementation levels of folic acid were 0.25 and 2.00 mg/kg and the supplementation levels of VB₁₂ were 0.003 and 0.009,0.018 mg/kg. The experiment lasted for 4 weeks. The Real-time PCR was used to test the ELOVL7 gene expression level in the liver of Wulong geese in groups, and geese in the control group was selected to detect ELOVL7 gene expression in 11 tissues of heart, liver, kidney, abdominal fat, lung, gizzard, gland stomach, breast muscle, leg muscle, spleen and pancreas. The results showed as follows:1) the interaction of dietary different levels of folic acid and VB₁₆ had a significant effect on final weight of Wulong geese (P<0.05), the weight of group Ⅴ was the highest, and had no significant effect on average daily gain and feed to gain ratio (P>0.05). 2) The interaction of dietary different levels of folic acid and VB₁₆ had significant effects on the contents of triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) in serum (P<0.05). Dietary different levels of folic acid had significant effects on the contents of TG and LDL-C in serum (P<0.05), and dietary different levels of VB₁₂ had significant effects on the contents of glucose (GLU) and LDL-C in serum (P<0.05). 3) The interaction of dietary different levels of folic acid and VB₁₆ had a significant effect on the percentage of breast muscle (P<0.05), and had no significant effects on dressing percentage, percentage of half-eviscerated yield, percentage of eviscerated yield and percentage of leg muscle (P>0.05). The percentage of breast muscle in groups Ⅰ, Ⅴ was significantly higher than that in control group (P<0.05). 4) The interaction of dietary different levels of folic acid and VB₁₆ had significant effects on subcutaneous fat percentage, abdominal fat percentage, fat strip width, intramuscular fat (IMF) percentage in the breast muscle and IMF percentage in the leg muscle (P<0.05), and the subcutaneous fat percentage in group Ⅴ was significantly lower than that in other groups (P<0.05). 5) The interaction of dietary different levels of folic acid and VB₁₆ had a significant effect on ELOVL7 gene expression level in the liver (P<0.05); dietary different levels of folic acid or VB₁₆ could increase ELOVL7 gene expression level in the liver compared with the control group (P<0.05). 6) The ELOVL7 gene expression level in the liver had significantly negative correlation with dressing percentage (P<0.05), TG and LDL-C contents in serum (P<0.05), total cholesterol (TC) content in serum (P<0.01), subcutaneous fat percentage, abdominal fat percentage, IMF percentage in the leg muscle (P<0.05), and had significantly positive correlation with fat strip width (P<0.05). 7)The ELOVL7 gene expression level in the liver was the highest in abdominal fat percentage, and followed by the lung and pancreas, and that in the leg muscle and breast muscle was the lowest. In conclusion, 1) dietary different levels of folic acid and VB₁₂ significantly altered the expression of ELOVL7 gene, lipid metabolism biochemical indexes and organic nutrient composition of Wulong geese; 2) the 0.25 mg/kg folic acid and 0.009 mg/kg VB₁₂ (group Ⅴ) is the best combination.