intestine, previouslyperfusedwithaclaycontainingsolution. Eventhoughkaoliniteconsumptionappearedheterogeneous, histologicalobservationsrevealedasignificantincreaseinthe thicknessofthevillicausedbylargevacuolesatthebaseof theabsorptivecells.Othermorphologicalchangesincludea lengtheningoftheapicalmicrovilli andanincreased mitochondrial replication.Furthermore,significantincreases wereobservedintheabsorption ofLCFAsafterintestinal perfusionwithclaysolution,andintheexpressionoffatty acidbindingprotein(FABP) after28daysofkaolinite ingestion.
Theseresultsindicate thatanimalscanbenefitfromclay complementationwhenavailable.Thisingestionstimulatesthe absorption ofLCFAsmostprobablythroughendocytosisand theirrapidbindingbyFABP.Thiscanactasanintracellular buffertopreventfatrefluxintotheintestinallumen.Never-
A12.51
Influenceofwater salinityandaltitude onthetolerance of amphibianearlylifestagestonitrite
C.Shinn,A.Marco,(EstaciónBiológicadeDoñana); L.Serrano,(UniversidaddeSevilla)
Highconcentrationsofnitriteinaquaticenvironmentsaretoxic fora numberofamphibianspecies.Chlorideionsareknownto partiallyinhibitnitrite(NO−)toxicityinsaltwaterfishandare hypothesisedtodothesameinamphibians.Newlyhatched tadpolesofBufocalamita,RanapereziandHylameridionalis fromDoñanaNationalPark(DNP;altitude20m)andRana perezifromGredosMountains(altitude1900m)weresubjected toaseriesofsodiumnitrite(NaNO2)concentrations(0–20mg N-NO2-/L)forupto20days.
−
theless,bloodaluminumlevelsappearedhigherinclay-eating
Byday8at5mg/LN-NO2
allR.perezilarvaefromDNP
ratscomparedtothecontrolgroup,indicatingthatkaoliniteis
dissociatedinthelumen,andthataluminumpassesdirectly throughtheintestinalbarrier.
weredeadwhilstBufocalamita larvalmortalityrateswere
considerably lower at that concentration after 15 days of exposure.However,atday15nodeathswereregisteredat
5mg/LN-NO−
forH.meridionalisandat20mg/LN-NO−
thisspeciespresentedintermediatemortalityrates.R.perezi
larvae from Gredos Mountains displayed an LC50 below
0.5mgN-NO−/Lafter16daysofexposure.
Eggsandtadpolesofallthreespeciesweresubjectedaseriesof
A12.50
Validation ofthehepaticportal veincannulationtechnique usingAtlantic salmon(SalmosalarL.)
nitriteconcentrationsinbrackishwater.ThepresenceofCl− ionsincreasedsurvival,activityandgrowthoflarvaeexposedto nitrite.
Rana perezi populations living at altitude appear to be
−
E.Eliason,A.Farrell,(UniversityofBritishColumbia);A.
significantlymore sensitive to NO2
pollution than coastal
Kiessling,A.Karlsson,B.Djordjevic(NorwegianUniversity
ofLifeSciences)
Cannulationofthehepaticportalveininfishispotentially a valuabletechniqueforbothfishnutritionists andphysiolo- gists.Combining dorsalaortaandhepatic portalvein cannulationtechniquesenablestheexamination ofnutrient uptake and hepatic metabolic transformation, as well as
populations, although variation in temperature and initial
developmentalstagemayexplainsomeofthisvariation. Low salinitylevelsappeartoattenuatethetoxicityofnitrite to developingamphibians. Thisfindinghasecological signifi- canceforendangeredspeciesofamphibianslivinginbrackish conditions.
systemicphysiologicalchangesassociatedwithgutfunction(suchasacid–basebalanceandionandosmoticregulation)in
greaterdetailthanpreviouslypossible.Thisstudyassessed thehepaticportalveincannulationtechniqueandsubsequent recoveryfromsurgeryinAtlanticsalmon(Salmo salarL). Withinthe1-to3-daypost-surgeryperiod,hematocritlevels weremaintainedandbloodvariables, includingcortisol, returnedtobaselinelevels,indicating thatthistechniqueisa viableandusefulmethodtostudythedigestive physiologyof fish. We also report on the appearanceprofilesfor amino acidsinbloodsampledsimultaneouslyfromthehepaticportal veinanddorsalaortafollowingamealtoillustrate the differential effectsoflivermetabolismontheaminoacid profilesforpre-andpost-hepaticbloodsamples.Supported byNSERCCanadaandtheNorwegian ResearchCouncil centerofexcellence,AquacultureProteinCentre(APC).
A12.52
Sexualdimorphism ofmusclegrowthinalargeflatfish,the
Atlantic halibut (HippoglossushippoglossusL.)
Ø.Hagen,V.Vieira,I.Johnston,(UniversityofSt.Andrews); C.Solberg,(BodøUniversity College)
Atlantichalibut(HippoglossushippoglossusL.)isanimportant foodfishthatcanreach100kginthewild.Itiscurrentlybeing farmedonasmallscaleinseveralcountriesincludingScotland, NorwayandIceland.For largeflatfishspecies,suchashalibut, thelargenumberofmuscle fibrespresent andpotential differencesinmusclecellularitybetweendorsalandventral andleftandrightsidesofthetrunkcomplicate studiesofmuscle growth.Inthepresentstudy,22wildandfarmedhalibutwere studiedranging from2to97.000g.Statisticalmethods forthe
determinationofmaximumfibrenumber(FNmax)aredescribed,