维生素C缺乏对豚鼠抗氧化能力及红细胞膜流动性的影响

目的　观察维生素C(以下简称VC)缺乏对豚鼠血浆抗氧化酶类、脂质过氧化产物及红细胞膜流动性的影响。方法　每日通过灌胃给幼年豚鼠不同剂量VC以构建动物模型,VC干预剂量分别为0 (缺乏组)、7 5、12 5、2 5 0mg kgbw补充组,干预时间为2 0天。干预结束后收集血样,分离获取血浆及红细胞,测定血浆超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH Px)及丙二醛(MDA)含量;采用荧光偏振法,以DPH为探针,检测红细胞膜流动性。结果　各组血浆SOD差异无显著性;缺乏组GSH Px活力较每日7 5mg kgbwVC补充组降低了2 0 .8% ;与各VC补充组比较,缺乏组血浆MDA水平明显升高(P <0 .0 5 ) ,红细胞膜流动性明显降低(P <0 .0 1)。结论　维生素C缺乏可导致豚鼠血浆GSH Px含量降低,红细胞膜流动性下降,MDA水平增高。     

核酸抗氧化作用的研究

为了解核酸对人体抗氧化作用的影响 ,对某核酸胶囊进行了动物和人体实验研究。采用老龄大鼠抗氧化试验 :取老龄雌性SD大鼠 3 2只 ,分低、中、高剂量组和老龄对照组 ,每组 8只。剂量组饮用核酸胶囊配制成的饮水 ,对照组则饮用普通水 ,连续饮用 50d。第 51天测血清丙二醛 (MDA)含量、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶 (GSH -Px)活性 ;人体试食试验 :选取 50～ 65岁居民 12 0人 ,试食组和对照组各60人。受试者每天服用 6粒胶囊。试食组服用核酸胶囊 ,对照组服用除核酸外其余成分均相同的胶囊 ,为期两个月。于第 61天 ,测血清MDA、SOD和GSH Px。结果显示 ,老龄大鼠抗氧化试验显示各剂量组大鼠血清MDA含量均明显低于对照组 (P <0 0 1) ,低、中剂量组血清SOD活力明显高于对照组 (P <0 0 1,P <0 0 5) ,各剂量组大鼠血清GSH -Px活力均明显高于对照组 (P <0 0 1) ;人体试食试验显示试食组血清SOD活力高于对照组 (P <0 0 5) ,而血清MDA、GSH -Px与对照组比较无显著性差异 (P >0 0 5) ,试食组的食欲、精神、气力三项主观指标比对照组的有明显改善 (P <0 0 5)。提示核酸胶囊对老龄大鼠有明显抗氧化作用 ;而单独的核酸可以提高人体SOD活性 ,并对人体食欲、精神和气力有促进作用     

维生素C、E联合作用对交通警察体内脂质过氧化物的影响

目的:探讨维生素E、维生素C联合作用对交通警察体内脂质过氧化水平的影响。方法:对1 4 7名交通警察(接触组)、98名不接触有害因素作业的健康人员(对照组) ,测定血清中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物歧化酶(GSH -Px)活性、丙二醛(MDA)的含量;接触组服维生素E、维生素C 3周后重新测定其相同指标。结果:接触组体内SOD和GSH -Px活性明显低于对照组,差异有显著性,血清中MDA含量高于对照组,差异有显著性(P <0.0 1 ) ;接触组服药后体内的SOD和GSH—Px活性明显高于服药前,差异有显著性(P <0.0 1 ) ,血清中MDA含量低于服药前,差异有显著性(P <0. 0 1 )。结论:维生素E、维生素C联合作用能对抗交通警察接触有害因素造成的脂质过氧化作用     

补充β-胡萝卜素对大鼠抗氧化能力及红细胞膜流动性影响的研究

目的:通过补充不同剂量β-胡萝卜素(β-C),探讨其对机体抗氧化能力和红细胞膜流动性的影响。方法:Wistar大鼠分为β-C缺乏组(β-C1组),每天补充β-C0.071(β-C2组),0.355(β-C3组),4.28(β-C4组)和15.0mg/kg(β-C5组)4个剂量组,均喂不含VA饲料8w。采用荧光法测定大鼠血浆和肝脏中VA含量,分析血液中SOD、MDA和GSH-Px含量及活性,用荧光偏振度P值和微粘度η值评价红细胞膜的流动性。结果:补充8w干预后,β-C缺乏组大鼠血浆中VA含量为135μg/L,明显低于β-C补充各组(P<0.01),肝脏VA水平仅为0.761μg/g;β-C补充达15.0mg/(kg·d)时,肝脏VA储存量最高,分别是β-C1组和β-C2组的7.7倍(P<0.01)和3.86倍(P<0.01)。抗氧化能力分析结果显示,4.28mg/(kg·d)组血浆中SOD的含量较其他4组均降低(P<0.05),GSH-Px活性明显升高,脂质过氧化物MDA的含量明显下降(P<0.01),红细胞膜流动性明显提高,表现为荧光偏振度P和微粘度η值均明显低于β-C1组、β-C2组和β-C5组(P<0.05)。结论:大鼠每天摄入0.355mg/(kg·d)以上剂量的β-C,即可满足机体对视黄醇的生理需要并在肝脏中保持一定量的储存,4.28mg/(kg·d)的β-C补充则能够发挥较好的抗氧化作用,提高红细胞膜的流动性,而过高剂量补充无明显效果。     

番茄红素对大鼠体内抗氧化系统功能的影响

目的　观察番茄红素 (lycopene ,LP)对大鼠抗氧化酶系统的影响。方法　大鼠饲喂番茄红素 4周后处死 ,测定血清和肝匀浆的超氧化物歧化酶 (SOD)活性、过氧化氢酶 (CAT)活性、谷胱甘肽过氧化物酶(GSH -Px)活力、总抗氧化能力 (T -AOC)、丙二醛 (MDA)及还原型谷胱甘肽 (GSH)含量。结果　各番茄红素给药组的大鼠血清和肝组织的SOD活性、GSH -Px活力及T -AOC上升 ,MDA含量降低 ,与空白组相比 ,在统计学上差异有显著性 (P <0 0 5 )。结论　番茄红素可以提高大鼠机体的抗氧化能力 ,抑制脂质过氧化     

贫血孕妇维生素A、维生素B_2和铁营养状况及抗氧化水平的调查分析

目的分析孕期贫血妇女的血浆维生素A(VA)、维生素B2(VB2)和铁营养状况及抗氧化水平。方法将孕中期妇女分成非贫血组(Hb≥110g/L,36人)和贫血组(HB80~105g/L,426人),经知情后同意参加。采用24小时膳食回忆法了解受试者每日主要营养素摄入情况,采集空腹静脉血5ml,分析血浆VA、VB2和铁蛋白(SF)水平,超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性,丙二醛(MDA)和红细胞膜流动性的变化。结果贫血孕妇VA、VB2摄入不足,分别为推荐摄入量(RNIs)的58·7%和57·2%,铁的来源仍为吸收率低的植物性食物。贫血孕妇的血浆VA(1·25μmol/L)和铁蛋白(20·57μg/L)水平明显低于非贫血孕妇(VA1·57μmol/L,SF33·16μg/L,P<0·05),全血谷胱苷肽还原酶活性系数(BGRAC)(1·79)水平高于非贫血组(1·52);SOD(77·1U/ml)和GSH-Px(61·9U)活性低于非贫血组(SOD92·2U/ml,GSH-Px71·6U,P<0·05);MDA(4·58nmol/ml)和红细胞膜的P和η值(P=0·2622,η=2·7465)明显高于非贫血组(MDA3·78nmol/ml,P=0·2360,η=2·3658,P<0·05)。且随贫血程度的加重,VA、铁蛋白水平、SOD和GSH-Px活性进一步下降,BGRAC、MDA、P和η值明显升高。结论妊娠中期贫血妇女血浆VA、VB2、铁蛋白及抗氧化能力均明显低于非贫血孕妇。且随贫血程度的加重而降低。     

高海拔地区心血管疾病与微量元素硒及相关生物活性物质的临床研究

目的 :探讨微量元素硒 (Se)及相关生物活性物质在高海拔地区心血管疾病中的作用。方法 :测定 4 7例心血管疾病患者和 2 0例健康人体内血清Se、血浆谷胱甘肽过氧化物酶 (GSH -Px)活力 ,丙二醛 (MDA)含量及相关临床指标。结果 :心血管病组血清Se含量及GSH -Px活力显著下降 (P <0 0 1) ,MDA含量升高 (P <0 0 5 ) ,心肌酶中肌酸磷酸激酶 (CK -MB)和心肌钙蛋白 (CTn -I)明显高于对照组 (P <0 0 5 )。结论 :血清Se减少时 ,高海拔地区心血管疾病患者体内存在着抗氧化能力降低和脂质过氧化反应增强。提示临床可使用亚硒酸钠和抗氧化剂     

甲壳质对老龄小鼠LPO含量和SOD、GSH-Px活性的影响

目的　探讨甲壳质对老龄雄性昆明种小鼠LPO含量和SOD、GSH -Px活性的影响。方法　经口给药 14d后 ,用TBA法测定肝脏中LPO含量 ;用NBA法测定红细胞中SOD活性 ;用DTNB法测定全血中GSH -Px活性。结果　甲壳质对LPO含量的影响除 6 4 0mg/kg·bw剂量组与老龄组比较有极显著性差异 (P <0 0 1)外 ,其余 2个剂量组与老龄组比较均具有显著性差异 (P <0 0 5 )。甲壳质对老龄SOD、GSH -Px活性的影响除 8 0mg/kg·bw剂量组与老龄组比较差异显著 (P <0 0 5 )外 ,其余 2个剂量组与老龄组比较均具有极显著性差异 (P <0 0 1)。结论　甲壳质具有明显降低老龄小鼠LPO含量和提高SOD、GSH -Px活性作用     

茶多酚抗动脉粥样硬化机制研究

目的　观察茶多酚在高脂饲料诱发家兔动脉粥样硬化过程中各种抗氧化和氧化指标的动态变化。方法　选取 1 5～ 2 0kg的家兔 2 4只 ,随机分为 4组 :正常对照组、动脉粥样硬化模型组、低剂量茶多酚组和高剂量茶多酚组。分别于实验前、6周末和 12周末测定血清谷胱甘肽过氧化物酶 (GSH -Px)、红细胞超氧化物歧化酶 (RBC -SOD)活性和血清丙二醛 (MDA)含量。 12周末空气栓塞处死家兔 ,迅速剥离主动脉弓 ,进行病理学检查。结果　动脉粥样硬化模型组家兔血清MDA升高 ,GSH -Px、RBC -SOD活性下降 ,主动脉弓内膜下充满泡沫细胞和粥样斑块 ;而茶多酚能降低血清中MDA含量 (P <0 0 5 ) ,诱导家兔体内GSH -Px、RBC -SOD活性增强 (P <0 0 5 ) ,在一定程度上减轻高脂饲料诱发的家兔动脉粥样硬化程度。结论　抗氧化活性可能是茶多酚预防和改善动脉粥样硬化作用的重要机制之一。     

河北甜杏仁对D-半乳糖诱导衰老模型大鼠的影响

目的　研究河北甜杏仁对D 半乳糖 (D gal)诱导衰老模型大鼠的影响。方法　给D 半乳糖衰老模型大鼠饲以不同杏仁剂量 ( 32 5、6 5、97 5g kg饲料 )的饲料 ,30天后 ,测定大鼠血清中丙二醛 (MDA)水平、超氧化物歧化酶 (SOD)、谷胱甘肽过氧化物酶 (GSH Px)的活力以及红细胞膜脂质流动性。结果　与衰老组比较 ,高、中剂量组大鼠血清中MDA明显降低 (P <0 0 1) ,SOD、GSH Px活力明显提高 (P <0 0 1) ,红细胞膜脂质流动性明显增强 (P <0 0 1)。而低剂量组各项指标均没有明显变化 (P >0 0 5 )。结论　甜杏仁具有一定的抗氧化、延缓衰老的作用     

微量营养素补充对儿童机体抗氧化及DNA氧化损伤影响的研究

目的通过营养调查了解农村儿童抗氧化营养素的摄入情况和观察补充五种营养素对儿童机体抗氧化能力及淋巴细胞DNA氧化损伤的影响。方法选择某农村9～11岁健康儿童82名,随机分为补充营养素组(补充组)和对照组,每组41名,采用24h膳食回忆法进行膳食调查。补充组儿童每日补充抗氧化营养素片[含维生素A(VA)600μg、维生素E(VE)100mg、维生素C(VC)300mg、β胡萝卜素(βC)1mg和亚硒酸钠(Se)200μg],而对照组则服用相同颜色和包装的安慰剂,试验期为8周。分别于补充前和补充结束时采集血样,分析两组血浆VA、VE、VC、βC、Se、谷胱甘肽过氧化物酶(GSHPx)、超氧化物歧化酶(SOD)、丙二醛(MDA)水平以及淋巴细胞DNA自发性损伤和H2O2(5、10、25μmol/LH2O2)诱导的氧化损伤。结果膳食调查结果表明,农村儿童VA、VC和硒摄入量偏低,分别为推荐营养素摄入量(RNI)的50.6%、65.6%和67.3%。营养素补充8周后,补充组儿童血浆中βC、VA、VE、VC和Se的水平与对照组相比分别提高了13.4%、32.8%、11.5%、46.9%和24.6%(P<0.01)。GSHPx酶的活性达到161.7酶活力单位/ml,明显高于补充前(100.4酶活力单位/ml)和对照组(110.2酶活力单位/ml)(P<0.01),而血浆中MDA的水平由补充前7.2nmol/ml下降到干预后的4.6nmol/ml(P<0.01)。补充组血浆中SOD水     

维生素E补充对外周血细胞活性的影响及机制研究

目的观察不同剂量维生素E(VE)补充对大鼠外周血淋巴细胞增殖活性和抗DNA氧化损伤能力以及红细胞膜流动性的影响。方法将48只Wistar大鼠随机分为对照组和VE1、VE2及VE3三个VE补充组,各组VE摄入量分别为每天7.5、50、200和750IUkgbw,实验期为8周。实验结束后无痛处死动物并留取全血,分别测定血浆VE和MDA含量,分析红细胞膜GSHPx活性、红细胞膜流动性、淋巴细胞转化率及DNA氧化损伤。结果3个干预组血浆VE水平较对照组明显升高(P<0.05);50IUkgbw·dVE(VE1)组血浆MDA含量为(2.29±0.55)nmolml,显著低于其它三组(P<0.05),红细胞膜GSHPx活性为(367.17±129.86)Umgprot,明显高于其它三组(P<0.05);与对照、VE2、VE3组相比,VE1组淋巴细胞转化率分别提高了261.86%、199.23%、412.97%(P<0.05),10μmolLH2O2诱导的DNA氧化损伤程度显著降低(P<0.05);VE1组红细胞膜P、η值明显低于其它三组(P<0.05),即该组膜流动性显著提高。结论本实验揭示VE能明显改善红细胞膜流动性、提高淋巴细胞DNA抗氧化能力及增殖活性的有效补充剂量为50IUkgbw·d;补充剂量过大时未观察到类似作用,甚至显示细胞功能下降。     

β-胡萝卜素对大鼠DNA氧化及烷化损伤影响的研究

目的　研究β-胡萝卜素(β- C)对大鼠DNA氧化及烷化损伤的影响,初步探讨其抗氧化作用机制。方法　将大鼠随机分为5组,分别为β- C缺乏组(β-C1组)、补充0 . 0 71mg (kg·d) (βC2组)、0 . 35 5mg (kg·d) (βC3组)、4 . 2 8mg (kg·d) (βC4组)、15 . 0mg (kg·d) (βC5组)。微量荧光法测大鼠血浆中VA含量;单细胞凝胶电泳(SCGE)观察淋巴细胞DNA氧化损伤状况;高效毛细管电泳法测尿中O6 甲基鸟嘌呤(O6 MeG)的排出量。结果　经8周干预后,四个βC补充组血浆中VA的水平为2 76～30 6 μg L ,缺乏组血浆中VA的含量为135 μg L ,明显低于补充组(P <0 . 0 1)。DNA损伤结果显示:缺乏组大鼠淋巴细胞DNA自发性损伤明显高于补充组(P <0 . 0 1)。H2 O2 诱导的淋巴细胞氧化损伤,4 .2 8mg (kg·d)组淋巴细胞氧化损伤明显低于其他4个组(P <0 . 0 1)。β- C各补充剂量组的O6 MeG的排出量在第6周和第8周时均明显低于缺乏组(P <0 . 0 5 )。O6 MeG排出量并未随着补充剂量的增加而减少,4 .2 8mg (kg·d)组尿中O6 MeG排出量在第8周时最低。结论　β- C较长时间缺乏可导致DNA自发损伤、H2 O2 诱导的氧化损伤以及烷化损伤均明显增加;大剂量β-C15 . 0mg (kg·d)补充对DNA损伤无明显防护作用,适量摄入β- C 4 . 2 8mg (kg·     

补充抗氧化维生素对老年机体红细胞功能改善效果的研究

目的研究抗氧化维生素E(VE)、维生素C(VC)联合不同剂量β-胡萝卜素(β-C)补充,对老年机体红细胞溶血度、红细胞膜ATP酶和红细胞膜流动性的影响。方法经知情同意后选择300名60~75岁的老年人,随机分为5组,1~4组补充VC 300mg/d+VE 200mg/d的同时,再分别补充β-C 16.7、8.4、5.6和0.0mg/d,对照5组补充VE 5mg/d,连续补充16周。补充前、后分别抽取清晨空腹静脉血,用H2O2氧化诱导溶血法测红细胞溶血度,酶学比色法测红细胞膜ATP酶活性,荧光偏振法测红细胞膜流动性。结果干预后1~4组老年人红细胞溶血度(分别为38.8%、39.9%、37.6%和40.9%)显著低于其干预前(分别为54.5%、57.1%、56.4%和55.4%)(P<0.01)和干预后第5组(55.7%)(P<0.01);干预后第1组红细胞膜Na+-K+-ATP酶0.72μmol/(mg·h)、Ca2+-Mg2+-ATP酶0.85μmol/(mg·h)显著高于干预后第5组[分别为0.49μmol/(mg·h)和0.61μmol/(mg·h)](P<0.05);干预后第1~4组红细胞膜荧光偏振度ρ值、1至3组微粘度η值均明显高于其干预前(P<0.01),也高于干预后第5组(P<0.01或P<0.05)。结论抗氧化VE、VC联合不同剂量β-C补充可降低老年机体H2O2诱导的红细胞溶血度,提高红细胞膜ATP酶的活性,改善老年机体红细胞膜的流动性。     

Vitamin E supplementation protects erythrocyte membranes from oxidative stress in healthy Chinese middle-aged and elderly people

Elderly people are subject to higher levels of oxidative stress than are young people. Vitamin E, as a powerful antioxidant residing mainly in biomembranes, may provide effective protection against oxidative membrane damage and resultant age-related deterioration, especially in the elderly. We hypothesized that appropriate levels of vitamin E supplementation would protect erythrocyte membranes from oxidative stress and thus improve membrane fluidity in healthy middle-aged and elderly people. To test this, we conducted a 4-month double-blind, randomized trial in which 180 healthy subjects (55-70 years old) were randomly divided into 4 groups: group C (control), and 3 treatment groups in which daily doses of 100 mg (VE1), 200 mg (VE2), and 300 mg (VE3) dl-α-tocopheryl acetate were administered. We measured plasma α-tocopherol concentration, malondialdehyde, and superoxide dismutase levels, erythrocyte hemolysis, and erythrocyte membrane fluidity at the beginning and end of the trial. After 4 months supplementation, plasma α-tocopherol concentrations in the 3 treatment groups had increased by 71%, 78%, and 95%, respectively (all P < .01), and significant decreases in plasma malondialdehyde concentrations were observed in these groups (all P < .05). Erythrocyte hemolysis was decreased by 20% to 38% after vitamin E supplementation (all P < .05), and in addition, groups VE2 and VE3 showed dramatic improvements in erythrocyte membrane fluidity (P < .01). Surprisingly, superoxide dismutase activity also decreased significantly in the treatment groups (all P < .05). In summary, vitamin E supplementation apparently alleviates oxidative stress in healthy middle-aged to elderly people, at least in part by improving erythrocyte membrane fluidity and reducing erythrocyte hemolysis.     

Supplementation with iron and riboflavin enhances dark adaptation response to vitamin A-fortified rice in iron-deficient, pregnant, nightblind Nepali women

BACKGROUND: Nightblindness affects 16-52% of pregnant women in areas of Nepal and in some cases persists after vitamin A treatment. Iron and riboflavin affect vitamin A utilization and photoreceptor function, respectively, and pilot data in the study population showed a high prevalence of iron and riboflavin deficiencies. OBJECTIVE: The objective was to assess the effect of supplemental iron and riboflavin on pupillary threshold (PT) and plasma retinol in nightblind, pregnant Nepali women given vitamin A-fortified rice. DESIGN: Nightblind pregnant women were randomly assigned to receive, 6 d/wk under supervision for 6 wk, a vitamin A-fortified rice curry dish providing 850 microg retinal activity equivalents/d with either a 30-mg Fe and 6-mg riboflavin (FeR + VA) capsule or a placebo control (VA only) capsule. Hemoglobin, erythrocyte riboflavin, and plasma ferritin and retinol were measured before and after the intervention. Dark adaptation was assessed by PT score. RESULTS: Women who were iron deficient at baseline (n=38) had significantly greater improvement in PT score with iron and riboflavin supplementation than without (P=0.05). Iron and riboflavin supplements significantly reduced the prevalences of riboflavin deficiency (from 60% to 6%; P<0.0001), iron deficiency anemia (from 35% to 15%; P<0.007), and abnormal PT (from 87% to 30%; P<0.05) from baseline. Mean increases in erythrocyte riboflavin (P<0.0001) and plasma ferritin (P=0.01) were greater in the FeR + VA group than in the VA only group. CONCLUSIONS: Iron deficiency may limit the efficacy of vitamin A to normalize dark adaptation in pregnant Nepali women. Further studies are needed to assess the effect of simultaneous delivery of iron and vitamin A for the treatment of nightblindness.     

Adult cockatiels (Nymphicus hollandicus) at maintenance are more sensitive to diets containing excess vitamin A than to vitamin A-deficient diets

The purpose of this experiment was to examine the physiological responses of adult cockatiels at maintenance to dietary vitamin A (VA) concentrations, and to identify concentrations associated with deficiency and toxicity. Adult cockatiels at maintenance (n = 22, 2-3 y of age) were fed a diet of 0, 600, 3000 or 30,000 microg VA/kg (0, 2000, 10,000 or 100,000 IU), and monitored for signs of VA deficiency or toxicity for up to 706 d. The analyzed diet concentrations were 0, 835, 2815 and 24,549 microg/kg, respectively. After 269 d, birds fed the 30,000 microg/kg VA diet had greater plasma retinal concentrations, markedly intensified vocalization patterns, pancreatitis and multifocal accumulation of lymphocytes in the lamina propria of the duodenum compared to birds fed the 600 microg/kg diet (P < 0.05). The 3000 microg/kg VA diet induced increased plasma retinol, splenic hemosiderosis and altered vocalization patterns (P < 0.05), although not as striking as those induced by the 30,000 microg/kg VA diet. The secondary antibody response was reduced after 225 d and vocalization patterns were altered in birds fed 0 microg/kg VA (P < 0.05), but after almost 2 y there were no changes in body condition, plasma retinol, organ pathology or classical signs of deficiency such as squamous metaplasia of nasal epithelia. Thus, adult cockatiels at maintenance were more susceptible to VA toxicity than to VA deficiency and concentrations > or = 3000 microg VA/kg diet can cause toxicity. It is possible that disturbances in VA nutrition contribute to the widespread incidence of behavioral problems reported in companion birds.     

Estimation of the dietary vitamin A requirement of juvenile grass shrimp, Penaeus monodon

Two growth experiments were conducted to estimate the minimal dietary vitamin A requirement for juvenile grass shrimp, Penaeus monodon. In expt. 1, purified diets containing 0, 1,500, 3,000, 15, 000, 30,000, 45,000 and 60,000 retinol equivalent (RE)/kg (i.e., 0, 5,000, 10,000, 50,000, 100,000, 150,000, 200,000 IU/kg) of supplemental vitamin A (retinyl acetate) were fed to P. monodon (mean initial weight 0.97 +/- 0.01 g) for 8 wk. In expt. 2, diets with 0, 600, 1,200, 1,800, 2,400, 3,000, 3,600, and 4,500 RE/kg (i.e. , 0, 2,000, 4,000, 6,000, 8,000, 10,000, 12,000, 15,000 IU/kg) of supplemental vitamin A were fed to the shrimp (mean weight 0.68 +/- 0.01 g) for 6 wk. The basal unsupplemented diet contained 54 RE vitamin A/kg, and supplemental levels were confirmed by analysis. Each diet was fed to three replicate groups of shrimp. In expt. 1, shrimp fed diets supplemented with 300 RE vitamin A/kg had significantly greater weight gain (P < 0.05) than those fed the unsupplemented control diet and diets supplemented with >===" BORDER="0">30,000 RE vitamin A/kg. Survival rate was higher in shrimp fed diets supplemented with 1,500-30,000 RE vitamin A/kg than shrimp fed the control diet. Highest blood triglyceride concentration and body lipid concentration were in shrimp fed diets supplemented with 45,000 and 60,000 RE vitamin A/kg, respectively. Eye vitamin A concentration and hepatopancreatic total lipid concentration in shrimp generally increased as dietary vitamin A supplementation increased. In expt. 2, feed efficiency was highest in shrimp fed diets supplemented with 2,400, 3,000, 3,600 and 4,500 RE vitamin A/kg, followed by shrimp fed diets with 600 and 1,200 RE vitamin A/kg and finally the unsupplemented control group. Shrimp fed diets supplemented with vitamin A had significantly higher survival percentages than those fed the unsupplemented control diet. Weight gain percentage of the shrimp analyzed by broken-line regression indicated that the minimal dietary vitamin A concentration in growing P. monodon is 2,511 RE/kg ( approximately 8, 400 IU/kg).