水产动物营养与饲料学-双语教学课件chapter1-5-Vitamins.ppt
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水产动物营养与饲料学-双语教学课件chapter1-5-Vitamins.ppt
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Chapter1-5Vitamins,1.General2.Fat-solublevitamin3.Water-solublevitamin,Generalorganiccompoundsrequiredintraceamountsfromanexogenoussource(usuallythediet)Functionindependentofenzymes,orinsomecasessuchasvitaminK,mayhavecoenzymeroles(辅酶的作用)normalgrowthreproductionhealthVitaminsareclassifiedasfatsolubleandwatersoluble.,FatSolubleVitaminsVitaminAVitaminDVitaminEVitaminK,WatersolublevitaminsprimarilycoenzymefunctionsvitaminBcomplexVB1(thiamin-HCl,硫胺素)VB2(riboflavin,核黄素)VB3(calciumpantathenate,泛酸)VB5(nicotinicacid,烟酸)VB6(pyridoxine,吡哆素)VB7,Folicacid(retinal)VB12(cyanocobalamin,氰钴素)choline(胆碱)inositol(肌醇)requiredinlargerquantitiesandhavevitaminCfunctionsotherthancoenzymes(不作辅酶)(ascorbicacid),biotransformationCholinechannelcatfishmethyldonors(methionine)choline¥38.5-39.0/kg¥5.0/kg(50%),Factorsaffectingthevitaminrequirements
(1)Size
(2)Age(3)growthrates(4)variousenvironmentalfactors(5)nutrientinterrelationships(相互关系),fairlywiderangesinrequirementvaluesforgrowthinthesamespecies(seeTable1-15)EX.VitaminErequirementinrainbowtroutRequirementResponseCriteria25IU/kgWG,absenceofdeficiencysigns(ADS,未出现缺乏症)30IU/kgWG,ADS50IU/kgascorbicacidstimulatedlipidperoxidation(AASLP,维C刺激下的脂肪过氧化)100IU/kgmaximumliverstorage(MLS,肝脏最大积累量),Inaddition,therequirementvaluesdeterminedbymaximumliverstorageorbasedoncertainenzymedata(表1-15中根据肝脏最大储存量或些酶的数据而测定的需求值),areoftenmuchhigherthantherequirementvaluesbasedonweightgainandabsenceofdeficiencysigns(经常大大高于根据增重率和缺乏症而测定的数据);,AsummaryofvitamindeficiencysignsinAppendixTableA-3,2.Fat-SolubleVitaminsAbsorptionandstoragealongwithdietaryfatsconditionsfavorableforfatabsorptionalsoenhancetheabsorptionoffat-solublevitaminsstoredbyanimalsifdietaryintakeexceedsmetabolicneedsproduceatoxiccondition(hypervitaminosis,维生素过剩症)Itisunlikelytooccurunderpracticalconditions.,thenutritionalhistoryofexperimentalfishpriortotheiruseinrequirementstudiesbecomescriticalThetimerequiredtodepletefishoftheirstoredfat-solublevitaminsishighlyvariable(鱼用于消耗体内储存的脂溶性维生素时间差异很大).Differenceinvitaminintakepriortoanexperimentmayberesponsibleforsomeoftheconflictingfindingsontheinductionandseverityofdeficiencysigns(可能是导致维生素缺乏症现象和严重性方面存在争论的部分原因),2.1VitaminArequiredinvertebratesforregeneration(再生)ofthelight-sensitivecompoundrhodopsin(视紫红质)intheretina(视网膜)oftheeye.propergrowth,reproduction,resistancetoinfection(抗感染),andthemaintenanceofdifferentiatedepitheliaandmucussecretions(上皮分化及粘液分泌),VitaminAinthreeforms
(1)asanalcohol(retinol)(视黄醇)
(2)analdehyde(retinal)(视黄醛),(3)andanacid(retinoicacid)(视黄酸)Infreshwaterfishthereversiblereactionsofoxidationandreductionretinol3-dehydroretinol(视黄醇3-脱氢视黄醇)retinolretinal(视黄醇视黄醛)3-dehydroretinol3-dehydroretinal(3-脱氢视黄醇3-脱氢视黄醛),Tilapiaretinol3-dehydroretinolChannelcatfish-carotene(胡萝卜素)vitaminA1andA2in1:
1ratioonlyifthedietaryconcentrationexceeded2,000IU/kgCold-waterfish-caroteneasavitaminAprecursor(利用胡萝卜素为维生素A前体).,Tilapia-caroteneandcanthaxanthin(角黄素)biotransformedvitaminA1inliverdihydroxyearotenoids(二羟胡萝卜素)astaxanthin(虾青素)zeaxanthin(玉米黄素),tunaxanthin(胡萝卜二醇)bioconvertedvitaminA2InmammalsCarotenoidshavebeenfoundtofulfillfunctionsindependentofvitaminA(具有多种与维生素A无关的生物功能).,VitaminAdeficiencyRainbowtroutanemia(贫血),twistedgillopercula(鳃盖扭曲),anhemorrhagicintheeyesandbaseoffins(眼和鳍基出血)Brooktroutpoorgrowth,highmortality,eyelesions(损伤)edematouseyes(水肿)displacedlens(晶状体移位)anddegenerationoftheretina(视网膜退化),inchannelcatfishfed0.4mgof-carotenen/kgofdietfor3yearsdevelopedexophthalmia(突眼症),edema(水肿),andhemorrhagickidney(肾出血).incommoncarpfedavitaminA-dificientdietafter8to11weeks,anorexia(厌食),palebodycolor(体色发白),hemorrhagicskinandfins(皮肤和鳍出血),exophthalmia(突眼),andtwistedgillopercula(鳃盖扭曲)occurred.,Rapidlygrowingyellowtailfingerlings(幼鱼)fedavitaminA-deficientdietdevelopeddeficiencysignsin20daysincludingarrestedgrowthofgillopercula(鳃盖生长抑制),darkpigmentation(黑色素沉着),anemia(贫血),andhemorrhage(出血)intheeyesandliver,accompaniedbyhighmortality(伴随高的死亡率).VitaminAaddingformsinfishfeedstheacetate(乙酸酯),palmitate(棕榈酸酯),orpropionateester(丙酸酯)intheformoffree-flowingbeadlets(自由流动的微粒)inamultivitaminpremix(多维预混料).,1.2VitaminDSourcesofvitamonD
(1)ergocalciferol(麦角钙化醇)(D2,whichoccurspredominantlyinplants主要存在于植物)
(2)cholecalciferol(胆钙化醇)(D3,whichoccurinanimals).BothformsofDarehydroxylated(羟基化)inthelivertothe25-hydroxy(羟基)forms.The25-hydroxy-D3(25-羟基-D3)isfurtherhydroxylatedinthekidneyto1,25-dihydroxyvitaminD3(1,25-二羟基-D3),1,25-dihydroxy-D3isthebiologicallyactiveformofvitaminDresponsibleforfacilitatingmobilization(动员),transport(转运),absorption(吸收),anduseofcalciumandphosphorus(钙磷)inconcertwith(协同作用)theactionsofparathyroid(甲状旁腺)hormoneandcalcitonin(降钙素).Cholecalciferol(胆钙化醇)hasbeenshowntobeatleastthreetimesmoreeffectivethanergocalcirerol(胆钙化醇)inmeetingthevitaminDrequirementofrainbowtrout.,VitaminD2wasutilizedaswellasvitaminD3upto1,500IU/kgofdiet,buthigherconcentrationsofvitaminD2depressedweightgainandfeedefficiencyinchannelcatfishrearedincalcium-freewater(但是更高浓度的维生素D2抑制饲养在无钙水体中的斑点叉尾蛔的生长和饲料效率).,VitaminD-deficientinrainbowtrout,fedadietexhibitedpoorgrowth,elevatedliverlipidcontent(肝脂含量增加),impairedcalciumhomeostasismanifested(体内钙平衡破坏)bytetany(痉挛)ofwhiteskeletalmuscle(白骨骼肌),andultrastructural(亚显微结构)changesinthewhitemusclefibersoftheepaxialmusculature(轴肌白纤维).,However,inasimilarstudyalsowithrainbowtrout,nohypocalcemiaorchangesinboneash(低钙血和骨骼灰分变化)wereobserved.Alordosis-likedroopytailsyndrome(类似于脊椎前凸下垂综合症)observedinvitaminD-deficienttroutwassuggestedtoberelatedtoanepaxialmuscleweakness(与轴肌虚弱有关).InchannelcatfishfedavitaminD-deficientdietfor16weeksshowedpoorgrowth,loweredbodycalciumandphosphoruslevels(体内钙磷水平降低),andloweredtotalbodyash(体内总灰份减少),butvertebralashlevel(脊椎灰分水平)wasnotsignificantlyaffectedbyvitaminDdeficiency.,infingerlingbrooktrout(溪红点鲑幼鱼)fed3.75106IUvitaminD3/kgdietfor40weekshadhypercalcemia(高钙血)andincreasedhematocritlevels(血细胞比容水平增加),butnodifferenceinratesofgrowthandsurvival.However,notdetectanyincidenceofrenalcalcinosis(没有发现肾结石现象)inrainbowtroutfedadietcontainingupto1106IUvitaminD3/kgdiet.Supplementation(添加)of50,000IUvitaminD3/kgdietsignificantlydepressedthegrowthrate(抑制生长率)ofchannelcatfish.,Bycontrast,adietof1106IUvitaminD3/kghasbeenreportedtoshownotoxiceffects(无毒性作用)inchannelcatfishrearedincalcium-freewaterfor14weeks.SupplementationformVitaminD3isaddedtofishfeedseitherinabeadletwithvitaminA(同维生素A一起以微粒状)orasaspray(喷雾干燥粉)ordrum-driedpowder(滚筒干燥粉)inamultivitaminpremix(多维预混料).,1.3VitaminEagenericdescriptor(统称)forallthemoleculesthatpossessthebiologicalactivityof-tocopherol(具有-生育酚生物活性的所有分子).NaturalformsofvitaminEare,alld-stereoisomers(d型立体异构体)andconsistofasubstitutedaromaticring(被置换的芳香环)andalongisoprenoidsidechain(和一个长的类异戊二烯侧链).,ThereareeightnaturallyoccurringcompoundswithvitaminEactivity(有八种自然存在的具有维生素E活性的化合物):
d-;d-;d-;d-toeopherols,whichdifferinthenumberandpositionofthemethylgroupsinthearomaticring(芳香环上各自甲基团数目和位置不同);andtheircorrespondingtocotrienols(和各自相应的生育三烯醇).Thecompoundwiththehighestbiopotencyisd-tocopherol(具有最高生物效力的是d-生育酚).,OneIUofvitaminEisdefinedas(一个国际单位(1u)的维生素E被定义为)thebiologicalactivityof1mgofDL-tocopheryl(1毫克DL-生育酚的生物活性).Functionsinvitroasaverygoodantioxidant(抗氧化剂)inamannersimilartoseveralsyntheticantioxidants(其作用方式与几种人工合成抗氧化剂相似).Invivo,vitaminEandselenium(硒)(viaglutathioneperoxidase)(与谷胱甘肽过氧化酶协同作用)functionaspartsofamulticomponentantioxidantdefensesystem(作为多成分抗氧化防御系统的组成部分).,Thissystemprotectsthecellaganisttheadverseeffectsofreactiveoxygenandotherfreeradicalinitiators(保护细胞免受活性氧和其它自由活性基团的损害)Theseradicalinitiatorsaregeneratedfromtheoxidationofpolyunsaturatedmembranephospholipids,criticalproteins,orboth(这些活性氧和自由基团是由膜磷脂中的高度不饱和脂肪酸或关键蛋白质(或二者)的氧化产生的).,VitaminEdificiency(维生素E缺乏症)inchinooksalmon,Atlanticsalmon,channelcatfish,commoncarp,rainbowtrout,andyellowtail.ThedeficiencysignsofVEaresimilarandincludemusculardystrophy(肌肉营养不良)involvingatrophy(萎缩)andnecrosis(坏死)ofwhitemusclefibers;edema(水肿)ofheart,muscle,andothertissueduetoincreasedcapillary(毛细血管)permeability(渗透性),whichareoftengreenincolorasaresultofhemoglubinbreakdown(由于血红蛋白分解而呈绿色),anemia(贫血)andimpairederthropoiesis(红细胞生成受阻);,depigmentation(褪色)andceroidpigment(蜡样质沉着)intheliver.Theincidence(发生率)andseverity(严重性)ofthesedeficiencysignshavebeenshowntobeenhancedwhendietsdeficientinbothvitaminEandselenium(饲料同时缺乏维生素E和硒时)inAtlanticsalmon,rainbowtrout,andchannelcatfish.TheseobservationsdemonstratedasignificantinteractionbetweenseleniumandvitaminEinthenutritionoffish(硒和维生素E在鱼的营养中存在明显的协同作用),Erythrocytefragility(红细胞脆性)hasbeenusedasanindicatorofvitaminEstatusinsomeanimals.Peroxidehemolysis(过氧化溶血)ofredbloodcellshasbeenusedtodeterminevitaminEdeficiency(被用作维生素E状态的指标)inrainbowtrout.invitro(在体外)ascorbicacidstimulatedlipidperoxidationinlivermicrosomesofrainbowtroutaccuratelyreflected-tocopherolstatus(肝脏微粒体中维生素C诱导的脂肪过氧化反应准确反映了生育酚的状态).,ThislatterprocedurehasalsobeenusedtoassessvitaminEstatusinchannelcatfish(这一方法也被用于评估斑点叉尾回的维生素E状态).Whenhighconcentrationsofdietarypolyunsaturatedfattyacidsareinvolvedinthedietsofcommoncarpandrainbowtrout(饲料中加入大量不饱和脂肪酸时),therequirementforvitaminEisincreased(维生素E需求增加).,VitaminE-deficientrainbowtrouthavebee
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