本试验旨在研究饲粮粗蛋白质水平对49日龄幼兔生长性能、营养物质表观消化率、血清抗氧化及脂肪代谢相关指标的影响。试验选择160只体重[（1 528.80±9.77）g]相近的49日龄新西兰幼兔，随机分为4组，每组20个重复，每个重复2只。幼兔分别饲喂4种不同粗蛋白质水平（A组14.0%、B组15.5%、C组17.0%、D组18.5%）的饲粮，试验期28 d。结果表明：1）饲粮粗蛋白质水平对幼兔末重和平均日增重（ADG）无显著影响（P>0.05），其中A组、D组ADG稍高于B组、C组。饲粮粗蛋白质水平对肝脏发育有一定影响，其中D组肝脏重显著高于C组（P<0.05）。A组~C组胃pH随着饲粮粗蛋白质水平升高而升高（P<0.05），盲肠pH无显著变化（P>0.05）。2）C组、D组粗脂肪表观消化率显著高于B组（P<0.05），A组磷表观消化率显著高于B组（P<0.05），A组、D组氮表观消化率高于B组、C组，但无显著差异（P>0.05）。消化代谢试验结果显示，采食量随饲粮粗蛋白质水平升高而降低，C组最低，采食氮D组最高，粪氮排泄、粪水分含量均以A组最低，A组粪水分含量显著低于B组、C组（P<0.05），与粗蛋白质表观消化率结果一致。3）各组间血清总蛋白（TP）、白蛋白（Alb）、球蛋白（Glb）、尿素氮（UN）含量均无显著差异（P>0.05）；各组间血清胆碱酯酶（CHE）、碱式磷酸酶（AKP）、谷草转氨酶（ALT）、谷丙转氨酶（AST）活性无显著差异（P>0.05）。A组血清谷胱甘肽过氧化物酶（GSH-Px）、过氧化氢酶（CAT）活性高于B组、C组、D组，丙二醛（MDA）含量低于B组、C组、D组，但无显著差异（P>0.05）。4）饲粮粗蛋白质水平对血清葡萄糖（GLU）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDLC）、低密度脂蛋白胆固醇（LDLC）含量无显著影响（P>0.05），但A组肝脏乙酰辅酶A羧化酶（ACC）活性显著低于B组、D组（P<0.05），糖原含量、脂肪酸合成酶（FAS）活性低于其他3组，但无显著差异（P>0.05）。5）A组饲料成本与其他3组相比，分别降低了64.2、122.7、178.1元/t。由此可见，饲粮粗蛋白质水平为14%时对营养物质表观消化率、氮排泄、血清抗氧化指标有较好的效果。肉兔生产中适当降低饲粮粗蛋白质水平不会影响肉兔的生长性能，还能提高营养物质表观消化率，降低氮排泄，提高机体抗氧化能力，同时降低肝脏中脂肪的合成，促进机体健康。

The aim of this trial was to study the effects of the dietary protein level on growth performance, nutrient apparent digestibilities, serum antioxidant and lipid metabolism related indicators of 49-day-old young rabbits. One hundred and sixty 49-day-old New Zealand young rabbits with similar body weight[(1 528.80±9.77) g] were randomly divided into 4 groups, 20 replicates in each group and 2 rabbits in each replicate. The young rabbits were fed four diets with different crude protein levels:14.0% in group A, 15.5% in group B, 17.0% in group C and 18.5% in group D. The trial lasted for 28 days. The results showed as follows:1) the dietary crude protein level did not affect the final weight (FW) and average daily gain (ADG) of young rabbits (P>0.05). The ADG in group A and group D was higher than that in group B and group C. The dietary crude protein level significantly affected the liver weight (P<0.05). The liver weight in group D was significantly higher than that in group C (P<0.05). The pH in stomach significantly increased with the increase of dietary crude protein level (P<0.05), but the pH in cecum had no significant change (P>0.05). 2) The ether extract apparent digestibility in group C and group D was significantly higher than that in group B (P<0.05), the phosphorus apparent digestibility in group A was significantly higher than that in group B (P<0.05). While the nitrogen apparent digestibility in group A and group D was higher than that in group B and group C, but there was no significant difference (P>0.05). The results of digestion test showed that the intake decreased with the increase of dietary crude protein level, and group C had the lowest value; nitrogen intake in group D had the highest value, and the faece nitrogen and faece water content were the lowest in group A, the faece water content in group A was significantly lower than that in group B and group C (P<0.05), which was consistent with the results of crude protein apparent digestibility. 3) There were no significant difference in total protein (TP), albumin (Alb), globulin (Glb), urea nitrogen (UN) contents in serum (P>0.05). Also there were no significant difference in cholinesterase (CHE), alkaline phosphatase (AKP), alanine aminotransferase (ALT), aspartate aminotransferase activities in serum (P>0.05). Compared with group B, group C and group D, the activities of glutathion peroxidase (GSH-Px) and catalase (CAT) in serum in group A was higher, the content of malonaldehyde (MDA) in serum was lower in group A, but there was no significant difference (P>0.05). 4) The dietary crude protein level did not affect serum glucose (GLU), triglyceride (TG), high-density lipoprotein cholesterol (HDLC) and low-density lipoprotein cholesterol (LDLC) contents in serum (P>0.05). However, in liver, the activity of acetyl-CoA carboxylase (ACC) in group A was significantly lower than that in group B and group D (P<0.05). Compared group B, group C and group D, the content of glycogen and the activity fatty acid synthase (FAS) were lower, but there was no significant difference (P>0.05). 5) Compared with group B, group C and group D, the feed cost of group A was decreased by 64.2, 122.7 and 178.1 yuan/t, respectively. In this trial, it can be seen that the dietary crude protein at 14.0% has a good effect on the apparent digestibilities of nutrients, nitrogen excretion and serum antioxidant indicators. In industry of meat rabbits, reducing the dietary crude protein level will not affect the growth performance of meat rabbits. The dietary low crude protein level can improve the apparent digestibilities of nutrients and antioxidant capacity, and also reduce nitrogen excretion and decrease synthesis of fat in the liver. All those can show that dietary low crude protein level can promote the body health.