Nutritionisoneofthemostimportantfactorsinfluencingthegrowthoffarmedfish.Theeffectofdietongrowth,diseaseresistanceandimmunesuppressioniswellestablished,includingover-andunderfeeding,buttheeffectofnutritiononstressislesswellunderstood.Whenfisharestressed,theirabilitytoresistattackisweakened,andstressisconsideredaprimarycontributingfactortoimpairedhealthinculturedfish.Dietarycarbohydratesarewidelyincludedinfishfeedstoimprovetheirphysicalqualityandtoprovideaninexpensivenon-nitrogenousenergysource.Theymayinducenutritionalproblems,however,asexcessivelevelsofcarbohydratesreducegrowthrateandareoftenaccompaniedbypoorfeedutilization.Highbloodglucoselevelsandelevatedhepaticglycogendepositionareamongthemostfrequentlydescribedmetabolicdisturbances.Inadditiontochangesingrowthandintermediatemetabolism,excessdietarycarbohydrateshavebeenspeculatedtoinfluencethestressresponsesoffish.Theadrenergicresponseandhypothalamus–pituitary–intrarenal(HPI)axisareactivatedbystress.TheHPIresponseresultsinincreasedplasmacortisol,levelsofwhicharewidelyusedasanindicatorofstressinfish.Theeffectsofdietarycarbohydratelevelsoncirculatingcortisolhavenotbeenextensivelystudiedandresultshavebeeninconsistent.cellsurvivalduringstress,thusprotectingcellsfromdamageandrestoringnormalstructureandfunction.HSP70isalsowidelyusedasstressbiomarkers.Toestablishifstressisinducedbyhighdietarycarbohydrates,plasmacortisollevelsandHSP70expressionweremeasuredina)feddifferentcarbohydratediets.Atotalof168carp(g)weredividedintotwogroups,withthreereplicates.TheNSgroupwasfedanormaldiet(35%carbohydrate),whiletheHSgroupwasfedahighcarbohydratediet(50%carbohydrate).Fishweremaintainedinaquariawithanautomatictemperature-controlledsystemofrecyclingwaterfor5–10weeks.PlasmacortisolandHSP70expressionintheliver,heart,spleenandkidneyweredeterminedat0,6,12,24and48hafterfasting.compare.Furthermore,plasmacortisolandHSP70expressioninliverwasincreasedat48haftera24-hfast.A50%carbohydratedietappearstoinducestressinallogynogeneticcruciancarpbutthereasonforfluctuatinglevelsof