Adjoumani Jean-Jacques Yao, Wang Kaizhou, Zhou Man, Liu Wenbin, Zhang Dingdong
Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing, 210095, People's Republic of China.
Fish Physiol Biochem. 2017 Dec;43(6):1733-1745. doi: 10.1007/s10695-017-0405-9. Epub 2017 Sep 30.
An 8-week feeding experiment was conducted to determine the effect of dietary betaine levels on the growth performance, antioxidant capacity, and lipid metabolism in high-fat diet-fed blunt snout bream (Megalobrama amblycephala) with initial body weight 4.3 ± 0.1 g [mean ± SEM]. Five practical diets were formulated to contain normal-fat diet (NFD), high-fat diet (HFD), and high-fat diet with betaine addition (HFB) at difference levels (0.6, 1.2, 1.8%), respectively. The results showed that the highest final body weight (FBW), weight gain ratio (WGR), specific growth rate (SGR), condition factor (CF), and feed intake (FI) (P < 0.05) were obtained in fish fed 1.2% betaine supplementation, whereas feed conversion ratio (FCR) was significantly lower in the same group compared to others. Hepatosomatic index (HSI) and abdominal fat rate (AFR) were significantly high in fat group compared to the lowest in NDF and 1.2% betaine supplementation, while VSI and survival rate (SR) were not affected by dietary betaine supplementation. Significantly higher (P < 0.05), plasma total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), aspartate transaminase (AST), alanine transaminase (ALT), cortisol, and lower high-density lipoprotein (HDL) content were observed in HFD but were improved when supplemented with 1.2% betaine. In addition, increase in superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) in 1.2% betaine inclusion could reverse the increasing malondialdehyde (MDA) level induced by HFD. Based on the second-order polynomial analysis, the optimum growth of blunt snout bream was observed in fish fed HFD supplemented with 1.2% betaine. HFD upregulated fatty acid synthase messenger RNA (mRNA) expression and downregulated carnitine palmitoyltransferase 1, peroxisome proliferator-activated receptor α, and microsomal triglyceride transfer protein mRNA expression; nevertheless, 1.2% betaine supplementation significantly reversed these HFD-induced effects, implying suppression of fatty acid synthesis, β-oxidation, and lipid transport. This present study indicated that inclusion of betaine (1.2%) can significantly improve growth performance and antioxidant defenses, as well as reduce fatty acid synthesis and enhance mitochondrial β-oxidation and lipid transportation in high-fat diet-fed blunt snout bream, thus effectively alleviating fat accumulation in the liver by changing lipid metabolism.
进行了一项为期8周的饲养实验，以确定日粮中甜菜碱水平对初始体重为4.3±0.1克（平均值±标准误）的高脂日粮喂养团头鲂生长性能、抗氧化能力和脂质代谢的影响。配制了5种实用日粮，分别包含正常脂肪日粮（NFD）、高脂日粮（HFD）以及添加不同水平（0.6%、1.2%、1.8%）甜菜碱的高脂日粮（HFB）。结果表明，补充1.2%甜菜碱的鱼体最终体重（FBW）、增重率（WGR）、特定生长率（SGR）、肥满度（CF）和采食量（FI）最高（P<0.05），而该组的饲料转化率（FCR）显著低于其他组。与NDF组和补充1.2%甜菜碱组最低值相比，脂肪组的肝体指数（HSI）和腹脂率（AFR）显著较高，而脏体比（VSI）和存活率（SR）不受日粮中甜菜碱补充的影响。在HFD组中观察到血浆总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL）、天冬氨酸转氨酶（AST）、丙氨酸转氨酶（ALT）、皮质醇显著升高（P<0.05），高密度脂蛋白（HDL）含量降低，但补充1.2%甜菜碱后有所改善。此外，添加1.2%甜菜碱可使超氧化物歧化酶（SOD）、过氧化氢酶（CAT）增加，还原型谷胱甘肽（GSH）升高，从而逆转HFD诱导的丙二醛（MDA）水平升高。基于二次多项式分析，在补充1.2%甜菜碱的HFD日粮喂养的团头鲂中观察到最佳生长。HFD上调脂肪酸合酶信使核糖核酸（mRNA）表达，下调肉碱棕榈酰转移酶1、过氧化物酶体增殖物激活受体α和微粒体甘油三酯转移蛋白mRNA表达；然而，补充1.2%甜菜碱可显著逆转这些HFD诱导的效应，这意味着脂肪酸合成、β-氧化和脂质转运受到抑制。本研究表明，添加1.2%甜菜碱可显著提高高脂日粮喂养团头鲂的生长性能和抗氧化防御能力，减少脂肪酸合成，增强线粒体β-氧化和脂质转运，从而通过改变脂质代谢有效减轻肝脏脂肪积累。
