草鱼PGC-1α基因的表达及饲喂n-3 HUFAs对其影响

获得了草鱼过氧化物酶体增殖物激活受体γ辅助活化因子1α(PGC-1α)部分cDNA序列(GenBank注册号为HM015283),并进行了序列同源性分析;采用实时定量反转录聚合酶链式反应(qRT-PCR)方法,检测了PGC-1α基因在草鱼不同组织的表达状况;研究了投喂高不饱和脂肪酸(HUFAs)对草鱼肝胰脏PGC-1α基因时序表达的影响。结果显示,所获得的草鱼PGC-1α基因部分cDNA序列长度为612bp,与人、牛、小鼠、斑马鱼和金鱼等动物的同源性为75%～97%;该基因在草鱼肝胰脏、肾脏、肌肉、心脏、鳃等10个组织中均有表达,其中在肾脏和心脏中表达丰度最高,在精巢和脾脏中表达丰度最低;草鱼摄食HUFAs饲料后第7天PGC-1α基因的表达水平极显著升高,随后又迅速下降。研究首次克隆得到草鱼PGC-1α基因部分cDNA序列,并发现该基因在草鱼能量代谢水平高的组织中表达较高,且其表达受到HUFAs的调控,其时序表达模式为先升高,然后恢复到正常水平。     

草鱼PPARα和PPARγ基因的克隆与组织表达差异

根据GenBank上登录的过氧化物酶体增殖物激活受体s(Peroxisome proliferator activated receptor,PPARs)基因序列设计2对引物,提取草鱼肝脏组织总RNA,经RT-PCR扩增获得了PPARα 624bp和PPARγ438 bp.并利用半定量RT-PCR分析T草鱼PPARα和...     

团头鲂PGC1α分子特征及其对营养限制、高糖饲料和葡萄糖负荷的响应

为探究过氧化物酶体增殖活化受体γ辅激活因子1α(peroxisome proliferator activated receptorγcoactivator 1α,PGC1α)基因在团头鲂糖代谢中的作用,实验从团头鲂肝脏中克隆获得了PGC1α基因的片段序列,并对其开展了生物信息学分析;同时研究了饥饿、高糖(糖水平:45%)饲料及葡萄糖负荷对团头鲂脑和肝脏PGC1α表达的影响。结果显示,获得的团头鲂PGC1α基因c DNA片段长为2 566 bp,其中包含1 404 bp的开放阅读框并编码467个氨基酸,与草鱼的同源性为96.79%;与正常投喂组相比,饥饿10 d组鱼脑和肝脏中PGC1α的mRNA水平显著升高,饥饿再投喂1 h后恢复至对照组的表达水平。饲喂高糖饲料(12周)后,与对照组相比,鱼脑和肝脏中PGC1α的mRNA水平显著降低。此外,葡萄糖负荷后,脑和肝脏中PGC1α的mRNA水平在2 h内显著降低至最小值,随后逐渐升高至基础水平。研究表明,PGC1α在团头鲂糖代谢过程中可能发挥重要作用。     

草鱼PGC-1β基因克隆及高糖高脂饲料对其表达的影响

为探讨过氧化物酶体增殖物激活受体γ辅激活因子-1β(peroxisome proliferator-activated receptor-γ coactivator-1 beta, PGC-1β)基因在草鱼能量代谢中的作用,本研究克隆了草鱼PGC-1β基因的核心序列,并对其进行了生物信息学分析;利用Real-time PCR技术检测了PGC-1β在不同组织的表达状况;同时研究了饥饿、饥饿再投喂及高糖(糖含量45%)高脂(脂含量8%)饲料对草鱼肝胰脏PGC-1β表达的影响。结果显示,所获得的草鱼PGC-1β基因部分cDNA片段长为885bp(GenBank登录号为：KM580493.1),共编码293个氨基酸,与斑马鱼的同源性为81%;该基因在脑中的表达量最高,肠和肝胰脏次之;与正常投喂组相比,饥饿(7d)导致PGC-1β在肝脏中的mRNA水平显著升高(P<0.05),再投喂后几乎恢复到对照组的表达水平。饲喂高脂以及高糖高脂饲料(65d)后,与对照组相比,草鱼肝胰脏中PGC-1β的mRNA水平显著升高(P<0.05)。研究结果表明,PGC-1β基因在草鱼能量代谢旺盛的组织中高表达,同时饥饿处理、饲料糖和脂肪水平等营养状况显著影响PGC-1β mRNA的表达。以上提示,PGC-1β在草鱼能量代谢过程中可能起到重要作用。     

草鱼肠道、肝胰脏对饲料蛋白质酶解速度的比较

草鱼样品体重(1543±213)g。采用离体消化培养和茚三酮比色方法,以草鱼前肠、中肠、后肠和肝胰脏的粗酶液作为酶源,对鱼粉、豆粕、菜粕和棉粕进行酶解,并测定酶解14h内,豆粕酶解液中氨基酸生成量随时间的变化,以及0至4h,内4种饲料蛋白质酶解液中氨基酸的生成量。结果表明,(1)在0至4h内,4种饲料酶解液OD570随时间变化的线性关系较好。(2)对于同种蛋白质饲料原料,以中肠组织粗酶液的酶解速度最大,其余依次为前肠、后肠及肝胰脏粗酶液。表明草鱼中肠对饲料蛋白质的酶解能力强于前肠和后肠,同时,肠道酶液的酶解速度均大于肝胰脏。(3)对于4种不同的蛋白质饲料原料,以鱼粉酶解氨基酸生成速度最大,其他依次为豆粕、菜粕、棉粕。(4)草鱼肝胰脏粗酶液对豆粕的酶解氨基酸生成速度最大,表明草鱼对豆粕进行酶解消化的能力较强。实验证实,饲料原料种类的差异和饲料蛋白质组成与性质的差异使其酶解氨基酸生成量和生成速度有差异。     

糖对草鱼肝脂代谢关键基因转录水平的调控研究

在目前集约化水产养殖模式下,草鱼肝脂质代谢紊乱问题比较严重,已引起人们的高度关注。为获知糖对草鱼肝脂代谢的影响及作用机理,本研究分别从活体和细胞水平上分析了糖对肝脂代谢5个关键基因转录水平变化的影响。采用实时荧光定量PCR(qRT-PCR)技术,检测了在低糖(糖含量24%)和高糖(糖含量42%)投喂条件下草鱼肝脏中固醇调节元件结合蛋白-1c、过氧化物酶体增殖物激活受体α和乙酰辅酶A羧化酶的转录水平变化,H·E染色观察肝脏组织形态学变化;并检测了在不同浓度葡萄糖作用下,草鱼肝细胞中固醇调节元件结合蛋白-1c、脂肪酸合酶和脂蛋白脂酶基因的表达变化。结果显示,肝组织中固醇调节元件结合蛋白-1c、乙酰辅酶A羧化酶在高糖组中的表达量显著高于对照组和低糖组(P0.05),过氧化物酶体增殖物激活受体α在高糖和低糖条件下变化不明显(P0.05);H·E染色观察发现在高糖条件下草鱼肝组织出现了大量的脂肪蓄积;在其肝细胞中固醇调节元件结合蛋白-1c、脂肪酸合酶、脂蛋白脂酶的mRNA表达量随葡萄糖浓度增加均呈先升后降趋势,分别在葡萄糖浓度为10mmol/L和20mmol/L时达到最高值(P0.05)。研究结果表明,葡萄糖可能通过调节固醇调节元件结合蛋白-1c、乙酰辅酶A羧化酶和脂蛋白脂酶等基因的表达进而调节体内糖向脂的转化过程。研究结果为丰富鱼类糖代谢调控机理提供研究资料,并有望为提高鱼类饲料糖的利用效率提供理论依据。     

肉碱对草鱼生长性能、体成分和脂肪代谢酶活性的影响

在基础饲料中分别添加100、200、300和400mg/kg DL-肉碱,饲喂平均体重134.3±12.1g的草鱼(Ctenopharyngodon idella)8W,以增重率、饲料系数(FCR),肌肉和肝胰脏中蛋白脂肪含量,肠道脂肪消化酶,肝胰脏脂蛋白脂酶(LPL)、肝脂酶(HL)和脂肪酸合成酶(FAS)等指标为判据,研究肉碱对草鱼生长性能、体成分和脂肪代谢酶活性的影响。结果表明,添加200mg/kg肉碱提高鱼体增重率5.70%(P < 0.05),降低FCR5.26%(P < 0.05);添加200～400mg/kg肉碱显著降低了肌肉和肝胰脏中的脂肪含量(P < 0.05);当肉碱添加量为300mg/kg时,肌肉蛋白含量最高;肉碱对肌肉水分和灰分、肝胰脏的蛋白含量无影响(P > 0.05);添加200、400mg/kg肉碱显著降低了血清胆固醇含量(P < 0.05);在脂肪代谢酶活性方面,200mg/kg肉碱组肠道脂肪消化酶和HL活性较对照组提高28.0%、38.6%(P < 0.05);添加400mg/kg肉碱提高肠道脂肪消化酶、HL及总脂酶活性41.41%、36.26%、10.66%(P < 0.05),降低FAS活性47.3%(P < 0.05)。综上所述,适量肉碱能改善草鱼生长性能、降低肌肉和肝胰脏脂肪含量及促进脂肪降解。建议草鱼饲料中肉碱添加量为200mg/kg。     

盐度胁迫对尼罗罗非鱼肝脂肪酸组成与脂代谢相关基因表达的影响

为探讨盐度胁迫对尼罗罗非鱼（）肝脂肪酸代谢的影响,本研究分别在盐度8和盐度16的水体中对尼罗罗非鱼进行两周的胁迫实验,比较盐度胁迫过程中肝脂肪酸组成变化,以及脂蛋白脂肪酶（lipoprotein lipase,LPL）、苹果酸酶（malic enzyme,ME）和过氧化物酶体增殖物激活受体α亚基（peroxisome proliferator-activated receptor,PPAR-α） mRNA表达量变化。结果表明,胁迫12 h,盐度组血浆渗透压升至最高,16盐度组血浆渗透压显著高于8盐度组（<0.05）,96 h后饱和脂肪酸含量逐渐恢复至初始水平;胁迫期间,盐度组单不饱和脂肪酸含量显著低于淡水组（<0.05）。盐度组脂蛋白脂肪酶（LPL）、苹果酸酶（ME）、过氧化物酶体增殖物激活受体α亚基（PPAR-α） mRNA表达量均显著高于淡水组（<0.05）。结果表明,盐度胁迫影响了肝脂肪酸组成和脂代谢过程。本研究旨在为鱼类渗透调节中脂类能量利用提供基础资料。     

四氯乙烯和镉联合胁迫对草鱼SOD和POD活性影响

为了考察超氧化物歧化酶(SOD)和过氧化物酶(POD)是否可以作为四氯乙烯(PCE)和镉(Cd2+)联合污染生物指标,采用静水生物测试法,研究了PCE和Cd2+联合胁迫对草鱼(Ctenopharyngodon idellus)肝胰脏、肾脏和鳃组织SOD以及肝胰脏、肾脏POD的影响。结果表明:(1)PCE和Cd2+复合污染胁迫时,草鱼肝胰脏SOD随着时间变化呈现"降低-升高-降低"的变化趋势,且最高浓度组始终低于对照;(2)肾脏SOD在所有暴露浓度组随着时间变化呈现"降低-升高-降低"的变化趋势,除最低浓度组在120 h显著高于对照外,其他均显著低于对照;(3)鳃组织SOD也呈现"降低-升高-降低"的变化趋势,但始终低于对照;(4)高浓度组(1/4TU和1/2TU)草鱼肝胰脏和肾脏POD活性随着暴露时间变化呈"降低-升高-降低"的变化趋势,但肝胰脏和肾脏的POD活性始终显著低于对照(P0.05);(5)草鱼鳃组织SOD活性明显低于肝胰脏和肾脏。PCE和Cd2+分别破坏了酶的蛋白结构和诱导了鱼体细胞膜的脂质过氧化,二者联合污染比单一污染加剧了草鱼的毒性效应。     

蚕豆、大巢菜籽及苦瓜籽饲料对草鱼生长、肌肉成分、组织生化指标和消化酶活性的影响

分别以常规配合饲料(配合饲料组)、浸泡蚕豆(浸泡蚕豆组)、含75%蚕豆(蚕豆饲料组)、60%大巢菜籽(巢菜籽饲料组)、60%苦瓜籽(苦瓜籽饲料组)的饲料饲喂体重为(59.0±0.6)g的草鱼(Ctenopharyngodon idella),养殖8周后,配合饲料的增重率显著高于其他各组(P0.05),饲料系数显著低于其他各组(P0.05);与浸泡蚕豆组相比,蚕豆饲料组的增重率提高56.9%,而巢菜籽饲料组、苦瓜籽饲料组的增重率则分别下降30.6%、21.2%(P0.05);浸泡蚕豆组、蚕豆饲料组、巢菜籽饲料组、苦瓜籽饲料组的肌肉胶原蛋白含量较配合饲料组显著提高,而肌肉脂肪含量显著下降(P0.05);苦瓜籽饲料组的肌肉总氨基酸(TAA)、鲜味氨基酸(DAA)含量显著高于配合饲料组和浸泡蚕豆组(P0.05)。在生化指标方面,与配合饲料组相比,投喂蚕豆、巢菜籽饲料及浸泡蚕豆显著降低了肝胰脏超氧化物歧化酶(SOD)活性(P0.05),提高了肝胰脏丙二醛(MDA)含量和肌肉肌酸激酶(CK)活性(P0.05),但蚕豆饲料组的肝胰脏丙二醛(MDA)含量低于浸泡蚕豆组(P0.05);在消化酶方面,投饲蚕豆、巢菜籽、苦瓜籽饲料和浸泡蚕豆显著降低了前肠脂肪酶活性(P0.05),提高了α-淀粉酶活性(P0.05),蚕豆饲料组、巢菜籽饲料组及浸泡蚕豆组的碱性蛋白酶活性较对照组显著降低(P0.05)。上述结果表明,饲喂以蚕豆、大巢菜籽、苦瓜籽为主要成分的配合饲料及浸泡蚕豆可改变草鱼肌肉组成,但也降低了草鱼生长性能;综合生长性能和肌肉组成,蚕豆饲料较巢菜籽饲料、苦瓜籽饲料和浸泡蚕豆在脆化草鱼生产养殖上更具有可行性。     

Silymarin inhibits adipogenesis in the adipocytes in grass carp <Emphasis Type="Italic">Ctenopharyngodon idellus</Emphasis> in vitro and in vivo

In this study, two experiments were performed to explore the function of silymarin in adipogenesis in grass carp (Ctenopharyngodon idellus) using in vitro and in vivo models. In experiment 1, differentiated grass carp pre-adipocytes were treated with silymarin for 6 days. Treatment with 100 μg mL^?1silymarin (SM100 group) significantly reduced triglyceride accumulation at day 6. The adipogenic gene expression levels of PPARγ, C/EBPα, SREBP1c, FAS, SCD1, and LPL, and the protein expression level of PPARγ were significantly down-regulated in the SM100 group. Additionally, the SM100 group had significantly lower reactive oxygen species production and reduced glutathione contents compared with the control in vitro. In experiment 2, the juvenile grass carp (mean body weight= 27.4 ± 0.17 g) were fed six isonitrogenous and isocaloric diets in a factorial design containing 0, 100, or 200 mg kg^?1 silymarin (SM0, SM100, SM200) associated with either 4 or 8% lipid levels (low lipid, LL, and high lipid, HL, respectively) for 82 days. The results demonstrated that dietary silymarin supplementation significantly reduced the elevated intraperitoneal fat index in grass carp fed with high-lipid diets, and the gene expression of adipogenesis (PPARγ, FAS) when supplemented with dietary silymarin was notably lower than when no silymarin was supplemented under the high-lipid diets. Thus, our data suggest that silymarin suppressed lipid accumulation in grass carp both in vitro and in vivo, and the effect might be due to an influence on the expression of adipogenesis factors and ROS production partly associated with effects on antioxidant capability.     

Effect of waterborne zinc exposure on lipid deposition and metabolism in hepatopancreas and muscle of grass carp <Emphasis Type="Italic">Ctenopharyngodon idella</Emphasis>

The aim of the present study was to explore the effect of waterborne zinc (control, 0.85, 2.20, 3.10 mg/l, respectively) exposure on lipid deposition and metabolism in the hepatopancreas and muscle of grass carp Ctenopharyngodon idella. The lipid content, Zn accumulation, and the activities and expression levels of several enzymes involved in lipid metabolism were determined in hepatopancreas and muscle. Waterborne Zn exposure reduced growth performance and increased Zn accumulation in both tested tissues. In hepatopancreas, Zn exposure increased lipid content, the activities of lipogenic enzymes, such as 6PGD, G6PD, ME, ICDH and FAS, as well as the mRNA expression level of G6PD, 6PGD, ICDH, FAS and SREBP-1. But the activity of CPT I and the mRNA expression of HSL, CPT Iα1a, CPT Iα2a and PPARα were down-regulated by Zn exposure. In contrast, in muscle, waterborne Zn exposure decreased lipid deposition, activities of 6GPD, ICDH and ME, as well as the mRNA expression level of G6PD, ICDH, ME, FAS and SREBP-1. However, the activity of CPT I as well as the mRNA expression level of PPARα, HSL, CPT Iα2a, CPT Iα1b and CPT Iβ were up-regulated by Zn exposure. Our results indicate that waterborne Zn increases lipid content by up-regulating lipogenesis and down-regulating lipolysis in hepatopancreas. But, in muscle, waterborne Zn reduces lipid accumulation by up-regulating lipolysis and down-regulating lipogenesis. Differential patterns of lipid deposition, enzymatic activities and genes’ expression indicate the tissue-specific regulatory mechanism in fish.     

Effects of dietary non‐protein energy source levels on growth performance,body composition and lipid metabolism in herbivorous grass carp (Ctenopharyngodon idella Val.)

A study was conducted to determine the effects of dietary non‐protein energy sources on growth, tissue lipid accumulation and lipid metabolism‐related genes expression of grass carp. Triplicate groups of fish were fed for 9 weeks on four isonitrogenous (300 g kg^?1) experimental diets with four levels of non‐protein energy (6.52 kJ g^?1 control diet, 5.32 kJ g^?1 high‐CEL diet, 8.46 kJ g^?1 high‐CHO diet and 8.53 kJ g^?1 high‐LIP diet respectively). Increasing dietary non‐protein energy source levels did not improve the growth, and the high‐CEL diet reduced the growth of grass carp. The high‐CHO diet tended to induce high hepatosomatic index, with high fat and glycogen content of liver. However, the high‐LIP diet caused the high mesenteric fat index, but did not increase liver fat. The mRNA abundance and activities of hepatic lipogenic enzymes were significantly increased in the high‐CHO diet group, whereas the opposite tendencies were observed in the high‐LIP diet group. Peroxisome proliferator‐actived receptor‐α (PPARα) in liver and PPARγ in mesenteric adipose tissue were up‐regulated in the high‐CEL diet group. Lipoprotein lipase (LPL) gene expression was significantly increased both in liver and mesenteric adipose tissue of fish fed the high‐LIP diet, while the LPL gene expression was up‐regulated in liver but down‐regulated in mesenteric adipose tissue of fish fed the high‐CEL diet. These findings suggest that an increase in dietary non‐protein energy sources alters the genes expression of lipid metabolism and increased lipid deposition.     

Protein‐sparing capability of dietary lipid in herbivorous and omnivorous freshwater finfish: a comparative case study on grass carp (Ctenopharyngodon idella) and tilapia (Oreochromis niloticus × O. aureus)

Two, 8‐week feeding trials were conducted to compare protein‐sparing capability of dietary lipid in herbivorous grass carp (Ctenopharyngodon idella) and omnivorous tilapia (Oreochomis niloticus × O. aureus). Utilizing a 2 × 3 factorial design, experimental diets containing two levels of crude protein (380 and 250 g kg⁻¹) and three levels of lipid (0, 40 and 100 g kg⁻¹) were formulated for use in both feeding trials. Growth performances showed better response of both fish fed 380 g kg⁻¹ protein diet than those fed 250 g kg⁻¹ protein diet. Despite the dietary protein level, weight gain (WG), specific growth ratio (SGR), feed conversion ratio (FCR) and protein efficiency ratio were much higher (P < 0.05) for grass carp fed 40 g kg⁻¹ lipid diet than those fed 100 g kg⁻¹ lipid diet; however, there were no significant differences in tilapia fed the two diets. The feed intake of grass carp fed lipid‐free diet was the lowest, but it tended to decrease with increase in dietary lipids in tilapia. Lipid retention (LR) was negatively correlated with dietary lipid concentration of both fish. Viscerosomatic index (VSI), hepatosomatic index (HSI), intraperitoneal fat ratio (IPF) and whole‐body and liver lipid content positively correlated with dietary lipid concentration of both fish. Plasma parameters and liver enzymes activities were also positively correlated with dietary lipid concentration of both fish. Liver lipid contents were higher and enzymes activities were lower in grass carp when compared with tilapia. These data suggested that there was no evidence of a protein‐sparing effect of dietary lipids in grass carp. Tilapia has relatively higher capacity to endure high dietary lipid level compared to grass carp.     

基于肝脂和1H-NMR技术的草鱼肝胰脏及血清代谢组学分析

为了探讨草鱼肝胰脏脂质过量蓄积的生化基础和促进草鱼的健康养殖,采用1H-NMR分析技术对肝脂含量分别为3 %~4 %和14 %~16 %的两组草鱼的肝胰脏和血清进行了代谢组学分析。结果表明,从草鱼肝胰脏和血清中分别检测到了58种和47种代谢物。葡萄糖、别嘌呤二醇、牛磺酸、乳酸、谷氨酸、肌酸、丙氨酸、sn-甘油-3-磷酸胆碱、甘氨酸、石碳酸、次黄嘌呤、乙酸、赖氨酸、亮氨酸、缬氨酸为两组草鱼肝胰脏主要差异代谢物;其中,肝脂含量为14 %~16 %的草鱼肝胰脏中葡萄糖和别嘌呤二醇的含量明显高于肝脂含量为3 %~4 %的草鱼组,但乳酸和多种氨基酸含量则低于肝脂含量为3 %~4 %的草鱼组。乳酸、葡萄糖、肌酸、柠檬酸、亮氨酸、丙酮酸、缬氨酸、脯氨酸、鸟嘌呤核苷、异亮氨酸、谷氨酸、sn-甘油-3-磷酸胆碱、丙氨酸、赖氨酸、甘氨酸为两组草鱼血清主要差异代谢物;其中肝脂含量为14 %~16 %的草鱼血清中葡萄糖、柠檬酸、脯氨酸、谷氨酸、sn-甘油-3-磷酸胆碱、精氨酸以及甘氨酸7种代谢物含量高于肝脂含量为3 %~4 %的草鱼组,血清乳酸等含量则明显低于肝脂含量为3 %~4 %的草鱼组。肝脂含量为14 %~16 %的草鱼组其体内糖的有氧氧化和糖酵解途径均受到了明显的抑制,同时存在氨基酸代谢异常,这应该是导致草鱼肝胰脏脂质过量蓄积的重要原因之一。     

饲料蛋白质、脂肪、碳水化合物水平对草鱼生长和组织营养成分组成的影响

采用蛋白质、脂肪、碳水化合物含量不同的７种颗粒饲料，饲养初始体重约１６ｇ的草鱼，经６０天后取样分析，发现草鱼相对生长率随饲料蛋白质添加量的升高而显著上升；高蛋白质饲料一定程度上升高全鱼和肌肉的粗蛋白含量，并显著增加肝胰脏脂质，主要是中性脂质的积累。全鱼、肌肉和肠－肠系膜脂肪含量随饲料脂肪添加量增加而显著升高。这表明，饲料蛋白质添加量是影响草鱼肝脏脂质积累的主要因素     

草鱼鱼种对胆碱需要量的研究

用不含胆碱的饲料饲养草鱼鱼种，草鱼鱼种生长减慢，饲料效率降低，肝脏脂肪浸润，血浆总脂，甘油三脂，胆固醇和磷脂含量降低，随着饲料中胆碱含量的添加，草鱼生长和饲料效率改善，肝脏脂肪含量降低，血浆总脂、甘油三脂、胆固醇，磷脂含量回升。当饲料中胆碱添加量达到０．３％以上时，草鱼生长率最高，肝脏脂肪含量，血浆总脂、甘油三脂，胆固醇，磷脂与摄食天然饲料（浮萍）的草鱼基本相同。在本研究条件下，建议草鱼鱼种饲料中     

草鱼蛋白质和脂肪代谢对饥饿胁迫的响应

实验选取平均体质量(31.86±1.47) g的草鱼, 随机分为2个实验组, 对照组(CG)和饥饿组(SG), 每组3个平行, 饥饿处理15、30、45和60 d, 测定饥饿对鱼体的生长、肌肉生化组成、血液生化指标以及蛋白质代谢的影响。结果表明: 饥饿组肥满度、脏体比、肝体比显著低于对照组。随着饥饿时间的延长, 草鱼肌肉中的水分含量逐渐增加, 脂肪和蛋白质含量呈现降低趋势, 脂肪含量在4个时期没有明显的差异(P>0.05), 水分和蛋白质含量分别呈现差异性增加和降低的趋势。血清总蛋白在饥饿15 d时与对照组没有明显的差异(P>0.05), 其后3个时期对照组显著高于饥饿组(P<0.05), 但饥饿组后3个时期趋于稳定。随着饥饿时间的延长, 白蛋白、总胆固醇和甘油三脂含量在4个时期与对照组都有明显变化(P<0.05), 饥饿组呈现先降低后升高再降低的波浪形变化。丙氨酸氨基转移酶活性在15、60 d时与对照组没有明显的变化(P>0.05), 在30 d时先降低, 45 d时显著升高(P<0.05)。随着饥饿时间的延长, 与对照组相比RNA︰DNA在肌肉中没有明显的差异(P>0.05), 在肝胰脏中与对照组呈现显著性差异, 随着时间的延长饥饿组呈现先降低后增高的趋势。谷氨酸脱氢酶活性在肌肉中于饥饿15 d时与对照组没有明显差异(P<0.05), 其后比对照组显著增加, 随着时间的延长饥饿组谷氨酸脱氢酶活性呈现上升的趋势; 在15、45 d时与对照组没有明显的变化(P>0.05), 在30、45 d时显著升高(P<0.05)。肝胰脏中谷氨酸脱氢酶活性在4个时期比对照组有显著的增加; 与肌肉相比, 肝胰脏和血清中谷氨酸脱氢酶活性是一种有效的反应蛋白质代谢的指标。草鱼对体内贮能物质(蛋白质和脂肪)的动用并不是简单地与饥饿时间呈线性相关, 而是出现周期性和阶段性起伏的变化。     

水飞蓟素对四氯化碳致鲫肝(细胞)损伤的保护和抗氧化作用

为了评价水飞蓟素(Silymarin, SM)对鲫(Cyprinus carpio)肝(细胞)的保护和抗氧化作用,分别从体外和体内两个方面探讨其作用效果.在体外,利用8 mmol/L的四氯化碳(CCl4)作用肝细胞4 h构建鲫肝细胞体外损伤模型,用不同质量浓度的水飞蓟素(100、300和600μg/mL)对鲫肝细胞进行前处理(CCl4损伤前加药)、后处理(CCl4损伤后加药)和前后处理(CCl4损伤前后均加药),然后检测细胞活力和细胞上清中谷丙转氨酶(GPT)、谷草转氨酶(GOT)、乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)和丙二醛(MDA)含量.在体内,用含水飞蓟素的饲料(0.1、0.5和1.0 g/kg)饲喂鲫60 d,再腹腔注射30%四氯化碳-植物油混合液,然后检测血清和肝组织匀浆中谷丙转氨酶(GPT)、谷草转氨酶(GOT)、乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)等生化指标.研究结果表明,水飞蓟素不同程度地抑制 CCl4损伤引起的肝细胞培养上清中 GPT、GOT、LDH活性和 MDA含量的升高,提高 SOD活性及肝细胞的存活率.体内研究发现,0.5和1.0 g/kg水飞蓟素显著降低CCl4损伤导致的血清中GPT、GOT、LDH活性升高,显著提高总蛋白(TP)、白蛋白(Alb)含量,有效提高肝中谷胱甘肽(GSH)含量、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)、总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性,降低丙二醛(MDA)含量(P<0.05或P<0.01);而0.1g/kg的水飞蓟素除了抑制LDH显著升高外,对其他指标均无效果.综合以上结果认为,水飞蓟素对鲫肝有保护作用,可防治鱼类肝(细胞)损伤,该保护作用可能与其抗氧化作用有关.