配制3个不同脂肪水平(4.5%、6.5%、8.5%)的实用饲料，在高脂肪水平（8.5%）饲料中添加0.1%复合降脂因子，组成4种等氮（粗蛋白质含量为30%）试验饲料，研究饲料脂肪水平和复合降脂因子对罗非鱼生长性能、体组成、肝胰脏代谢相关酶和抗氧化酶活性的影响。选取初体重为(4.21±0.09) g的奥尼罗非鱼360尾，随机分成4组（每组设3个重复，每个重复30尾），每组随机饲喂1种试验饲料，试验期为8周。结果表明：随着饲料脂肪水平的增加，罗非鱼的特定生长率（SGR）和蛋白质效率(PER)显著升高（P<0.05），饲料系数（FCR）显著降低（P<0.05）；在8.5%脂肪水平下添加0.1%复合降脂因子后，罗非鱼的PER显著升高（P<0.05），FCR显著降低（P<0.05）。饲喂脂肪水平为8.5%的饲料会显著升高罗非鱼的肝脂和体脂含量(P<0.05)，但在添加0.1%复合降脂因子后，罗非鱼的肝脂和体脂含量显著降低（P<0.05）。随着饲料脂肪水平的增加，罗非鱼的肝胰脏谷草转氨酶(GOT)和谷丙转氨酶(GPT)活性均显著降低(P<0.05)，过氧化氢酶（CAT）活性和丙二醛（MDA）含量显著升高(P<0.05)；在8.5%脂肪水平下添加0.1%复合降脂因子后，罗非鱼的肝胰脏GOT和GPT活性显著升高(P<0.05)，CAT活性和MDA含量显著降低(P<0.05)。由此得出，增加饲料脂肪水平会显著提高罗非鱼的生长性能，但较高的脂肪水平会降低罗非鱼肝脏的生理机能；添加复合降脂因子能够显著改善罗非鱼肝脏的生理机能，进而促进生长。因此，复合降脂因子可以作为一种安全高效的保肝剂应用于罗非鱼的养殖生产。

A feeding experiment was conducted to investigate the effects of dietary lipid level and compound lipotropic agent on growth performance, body composition and activities of metabolism related enzymes and antioxidant enzymes in hepatopancreas of tilapia. Four practical diets were formulated to contain 3 levels of lipid (4.5%, 6.5% and 8.5%) and a level of compound lipotropic agent (0.1% compound lipotropic agent and 8.5% lipid) on an equal nitrogen basis (CP=30%). Three hundred and sixty hybrid tilapia (Oreochromis niloticus×O. aureus) with an initial body weight of (4.21±0.09) g were randomly divided into 4 groups (with 3 replicates of 20 fish) and each group were fed 1 experimental diet. The experiment lasted for 8 weeks. The results showed as follows: with the dietary lipid level increasing, the specific growth rate (SGR) and protein efficiency ratio (PER) were significantly increased (P<0.05), and the feed conversion ratio (FCR) was significantly decreased (P<0.05); supplemented with 1% compound lipotropic agent in 8.5% lipid diet could significantly increase PER (P<0.05), and significantly decrease the FCR (P<0.05). Fish fed the diet containing 8.5% lipid could significantly increase the hepatopancreas lipid and body lipid contents (P<0.05), but the diet supplemented with 0.1% compound lipotropic agent could significantly decreased the hepatopancreas lipid and body lipid contents (P<0.05). With the dietary lipid level increasing, the activities of glutamyl oxaloacetic transaminase (GOT) and glutamyl pyruvic transaminase (GPT) in hepatopancreas were significantly decreased (P<0.05), and the catalyse (CAT) activity and MDA content were significantly increased (P<0.05); supplemented with compound lipotropic agent in 8.5% lipid diet could significantly increase the activities of GOT and GPT (P<0.05), and significantly decrease the catalyse (CAT) activity and MDA content (P<0.05). The results suggest that increasing dietary lipid level can significantly improve the growth performance of tilapia, but the higher lipid levels can damage the physiological function of liver. The results also suggest that 0.1% compound lipotropic agent supplementation in diet can improve the physiological function of liver and growth of tilapia. Therefore, compound lipotropic agent can be added into the diet of tilapia as a safe and efficacious liver protecting additive. ［Chinese Journal of Animal Nutrition, 2010，22（6）:1585-1591］