实用饲料添加肌醇对草鱼生长、脂质代谢及抗氧化机能的影响

为探讨肌醇对草鱼生长、脂质代谢及抗氧化机能的影响,以实用饲料配方为基础,分别添加0(对照)、50、100、150、200、300和400 mg/kg肌醇,配制成7组等氮等脂的饲料,每组饲料设4个重复,每个重复饲喂初始体质量为(15.00±0.15)g的草鱼25尾,养殖56 d。结果显示,饲料中添加100~150 mg/kg肌醇能显著提高草鱼终末均重(FBW)、增重率(WGR)、特定生长率(SGR)及饲料效率(FE);随饲料肌醇添加水平的上升,全鱼脂肪、肝脏脂肪和脂肪沉积率先升后降,在50~300 mg/kg均与对照组存在显著差异,且均在100 mg/kg达到最大值。肌肉脂肪则逐渐下降并趋于稳定,在100 mg/kg达到最小值,100~400 mg/kg差异不显著;肠脂肪酶、血浆总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)含量及高密度/低密度脂蛋白胆固醇(HDL-C/LDL-C)均呈先升后降的趋势,除LDL-C在各组间差异不显著外,其余指标均在100~150 mg/kg达到最大值;添加肌醇能显著增强肝脏和肌肉中肉碱脂酰转移酶(CPT-I)和乙酰辅酶A羧化酶(ACC)的活性。与对照组相比,100 mg/kg肝脏CPT-I的增幅比例低于ACC的增幅比例,肌肉则相反;当肌醇添加水平为100~150 mg/kg时,肝脏和肌肉中超氧化物歧化酶(SOD)的活性显著升高,丙二醛(MDA)含量及血浆中谷丙转氨酶(ALT)、谷草转氨酶(AST)均显著降低。研究表明,实用饲料添加适宜的肌醇能改善草鱼的生长、饲料转化和肝脏功能,促进脂肪消化,加快脂肪酸的合成与分解代谢,使全鱼和肝脏增脂、肌肉降脂,且能够提高肝脏和肌肉的抗氧化机能。以FE和SGR为效应指标,草鱼实用饲料肌醇适宜添加量为90.3~96.4 mg/kg。

Effects of inositol supplementation to practical dietary on growth performance, lipid metabolism and antioxidant activity of Ctenopharyngodon idella

A study was conducted to evaluate the effect of the dietary inositol levels on growth, lipid metabolism and antioxidant activity of grass carp. Seven isonitrogenous (30.78% protein) and isolipidic (6.04% lipid) practical diets with graded levels of inositol (0, 50, 100, 150, 200, 300, 400 mg/kg) were fed to 25 juvenile fish averaging (15.00±0.15) g (mean±SE) in quadruplicate aquaria for 56 d. The results showed that the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR) and feed efficiency (FE) at dietary inositol levels of 100–150 mg/kg were significantly higher than those of other groups. With the increasing of inositol dietary level, the crude lipid contents of whole-body and liver and lipid deposition rate significantly increased when dietary inositol was 50-300 mg/kg, but the muscle lipid content of fish fed the 100 mg/kg inositol diet or higher was significantly lower than the control group and the group fed diet containing 50 mg/kg inositol. Intestinal lipase, plasma total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterin (LDL-C), high-density lipoprotein cholesterin (HDL-C) contents and high density/low density lipoprotein cholesterin (HDL-C/LDL-C) rose in first and then declined, and all reached the maximum at dietary inositol levels of 100–150 mg/kg, except the LDL-C content. Dietary inositol supplementation resulted in marked increase of carnitine palmityl tratnsferase-I (CPT-I) and acetylCOAcarboxylase (ACC) activities in liver and muscle. Compared with the control group, the growth rate of CPT-I in liver was lower than that of ACC, while the growth rate of CPT-I in muscle was higher than that of ACC. Significantly higher superoxide dismutase (SOD) activities in liver and muscle were obtained in fish fed 100–150 mg/kg than those fed the control, and lowest malondildehyde (MDA) concentration, transaminase (AST) and alanine transaminase (ALT) activities were also found in that. In conclusion, the appropriate dietary inositol supplementation to grass carp has an improving effect on growth performance and feed conversion efficiency, promotes the capacity on lipid digestion and the synthesis and degradation of tissue fatty acid, increases the crude lipid contents of whole-body and liver and decreases that in muscle, but improves antioxidant activity of liver and muscle. FE and SGR analyzed by broken-line regression indicated that the suitable inositol supplementation to practical dietary of grass carp is 90.3–96.4 mg/kg.