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Gradual Provision of Live Black Soldier Fly (Hermetia illucens) Larvae to Older Laying Hens: Effect on Production Performance, Egg Quality, Feather Condition and Behavior

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  • Scothorst Feed Research B.V.

Abstract and Figures

Feather pecking is a key welfare challenge in laying hen husbandry. Feeding of live Hermetia illucens larvae could provide a possible solution to reduce feather pecking in hens. This research investigates effects of dispensing live H. illucens larvae to non-beak trimmed older laying hens on production performance, behavior and welfare. Control treatment hens were provided a commercial diet, while larvae treatment hens were provided live H. illucens larvae (using special dispenser) on top of a soy-free diet. Feather condition, production performance and egg quality were measured during the initiation (67 weeks age) and termination (78 weeks age) of the trial. Behavior of birds was monitored using video recording. Feed conversion ratio, body weight gain and egg laying parameters were similar for both treatments. At termination of the trial, larvae-fed hens exhibited better feather condition in comparison to control hens (p = 0.004). Behavioral observations indicated that larvae provision influenced the number of birds on floor during morning and afternoon hours. In conclusion, live H. illucens larvae could successfully replace soy in diets of older laying hens (in combination with local plant proteins). Provisioning of these insects also had a positive effect on the feather condition of laying hens with intact beaks.
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Animals2020,10,216;doi:10.3390/ani10020216www.mdpi.com/journal/animals
Article
GradualProvisionofLiveBlackSoldierFly
(Hermetiaillucens)LarvaetoOlderLayingHens:
EffectonProductionPerformance,EggQuality,
FeatherConditionandBehavior
LauraStar
1
,TariqueArsiwalla
2
,FrancescMolist
1
,RaymondLeushuis
2
,MonikaDalim
2

andAmanPaul
2,
*
1
R&D,SchothorstFeedResearchB.V.,8218NALelystad,TheNetherlands;LStar@schothorst.nl(L.S.);
Fmolist@schothorst.nl(F.M.)
2
ProductDevelopment,ProtixB.V.,5107NCDongen,TheNetherlands;
TariqueArsiwalla@hotmail.com(T.A.);Raymond.Leushuis@protix.eu(R.L.);
Monika.Dalim@protix.eu(M.D.)
*Correspondence:amanpaul@mail.com;Tel.:+31162782501
Received:16January2020;Accepted:26January2020;Published:28January2020
SimpleSummary:Innature,hensspendconsiderableamountsoftimeeatingliveinsects.Thisis
consideredastheirnaturalbehaviorandmaypositivelycontributetoanimalwelfare.However,
layinghensgenerallyhavelimitedaccesstoinsectsincurrentintensivefarmingsystems.Hermetia
illucenslarvaearenutritiousandcanbeindustriallyproducedusingtheprinciplesofcircular
agriculture.InEurope,legislationallowsthefeedingofliveinsectstopoultry,andcouldpossibly
beusedtoreplacesoyindietsoflayinghensasproteinsource.Themajorityofsoymealusedin
EuropeoriginatesfromNorthandSouthAmericancountries.IncreasingsoyplantationsinSouth
Americancountriesisoftenlinkedtodeforestationandsocialissues.Thisresearchevaluatedeffects
ofincludingliveH.illucenslarvae,asreplacementofsoyinthedailyration,onproduction
performance,eggquality,behaviorandfeatherconditionofolderlayinghens.LiveH.illucenslarvae
canbeusedincombinationwithlocalplantproteinstosuccessfullyreplacesoyindietsofolder
layinghens.FeedinghensliveH.illucenslarvaealsohadapositiveeffectonthefeathercondition
ofbirds.
Abstract:Featherpeckingisakeywelfarechallengeinlayinghenhusbandry.Feedingoflive
Hermetiaillucenslarvaecouldprovideapossiblesolutiontoreducefeatherpeckinginhens.This
researchinvestigateseffectsofdispensingliveH.illucenslarvaetononbeaktrimmedolderlaying
hensonproductionperformance,behaviorandwelfare.Controltreatmenthenswereprovideda
commercialdiet,whilelarvaetreatmenthenswereprovidedliveH.illucenslarvae(usingspecial
dispenser)ontopofasoyfreediet.Feathercondition,productionperformanceandeggquality
weremeasuredduringtheinitiation(67weeksage)andtermination(78weeksage)ofthetrial.
Behaviorofbirdswasmonitoredusingvideorecording.Feedconversionratio,bodyweightgain
andegglayingparametersweresimilarforbothtreatments.Atterminationofthetrial,larvaefed
hensexhibitedbetterfeatherconditionincomparisontocontrolhens(p=0.004).Behavioral
observationsindicatedthatlarvaeprovisioninfluencedthenumberofbirdsonfloorduring
morningandafternoonhours.Inconclusion,liveH.illucenslarvaecouldsuccessfullyreplacesoyin
dietsofolderlayinghens(incombinationwithlocalplantproteins).Provisioningoftheseinsects
alsohadapositiveeffectonthefeatherconditionoflayinghenswithintactbeaks.
Keywords:Hermetiaillucens;livefeeding;olderlayinghens;productionperformance;eggquality;
feathercondition
Animals2020,10,2162of13
1.Introduction
Ancestorsofmodernpoultrylivedinsocialgroupsof20to30chickens.Incurrentnoncage
systems,theflocksizesaremuchlarger.Layinghensarenotabletorememberorrecognizeallflock
matesinsuchsystemsandthereiscompleteabsenceofsocialhierarchy[1].Thisresultsinfeather
pecking,whichisoneofthegreatestchallengesincommerciallayinghenhusbandry[2].Atpresent,
noncagesystemsareprevalentinEuropeandNorthAmerica.Furthermore,infutureSouth
American,AsianandAfricancountriesarealsoexpectedtoadoptnoncagepoultrysystems[3].
Therefore,impactofseverefeatherpeckingwillfurtherincrease.
Layinghenslearntopeckatyoungage[4].Severefeatherpeckingisoftenevidentinoldlayer
hens[4,5].Provisioningofpeckingsubstrateatyoungagemayreducethelikelihoodofseverfeather
peckingatmaturity[6].However,suchprovisiondoesnotcompletelyeliminatetheriskofsevere
featherpeckingduringadulthood[7].Somestudieshaveindicatedthatpeckingismoresevereinold
layinghens(>70weeksofage)whencomparedtoyounghens(25weeksofage)[8,9].Thismakes
ensuringthewelfareofoldlayinghensmorechallenging.Someauthorshavealsoindicatedthat
inabilityofchickentoexpresstheirnaturalbehaviorcanresultinaggressivebehaviorandincreased
pecking[10].Presentationofliveinvertebratetoconsuminganimals(naturalcarnivoresor
omnivores),providesthemanopportunitytoexpresstheirnaturalbehavior[11].Expressionof
naturalbehaviorislikelytobepleasurablefortheanimal[12].Chickensareeffectiveforagersoflive
insects[13],sinceinsectsarepartofthenaturaldietofchickens.Freerangechickensspendabout
37%oftheirtimelookingforandeatinginsects[14].Insectsnotonlypresentamovingstimulito
attracttheattentionofchickens,butarealsonutritious[15–18].
Liveinsects,includingblacksoldierflylarvae(Hermetiaillucens)arealreadyapprovedfor
poultryfeedinginEurope[19].Blacksoldierflylarvaehavegainedspecialstatusamongstinsects
duetotheirunique:(a)abilitytoconsumeawiderangeoforganicsidestreams;and(b)nutritional
profile,especiallytheproteincomposition[20].
Arecentlypublishedreportindicatedthatinclusionofdriedblacksoldierflyprepupaemeal
improvedtheeggweightandeggshellthicknessincomparisontoacontroldiet(noprepupaemeal
inclusion).However,nodifferencesinproductionperformancewereobserved[21].Areviewarticle
publishedin2019compilesliteraturerelatedtoinclusionofblacksoldierflylarvaemealinpoultry
feed[22].However,tothebestoftheauthorsʹ knowledge,thereisnopeerreviewedliterature
studyingtheinclusionofliveblacksoldierflylarvaeinlayingdiets.Itisexpectedthatprovisionof
liveblacksoldierflylarvaewillnotadverselyaffecttheproductionperformanceandeggquality
parameters.Anothertopicthatremainstobeinvestigatedistheprovisioningofliveblacksoldierfly
larvaeinrelationtothewelfareofolderlayinghens(wherewelfareismorechallengingthanyounger
birds).Currentresearchwasconductedtoevaluatetheeffectofsteadyandrandomprovisioningof
liveblacksoldierflylarvaetoolderlayinghenson:(a)productionperformance;(b)eggquality;(c)
feathercondition;and(d)birdbehavior.
2.MaterialsandMethods
2.1.LayingHensandHousingManagement
Olderlayinghens(DekalbWhite;65weeksofage)arrivedatSchothorstFeedResearch(SFR;
Lelystad,theNetherlands)inthelastweekofDecember2018.Thesehenswereallocatedtoaviary
penswithwoodshavingsonthefloorandallowedtoadapt(acclimatize)foraperiodof2weeks.
Henswere67weeksofageduringtheinitiationofthetrial.Beforearrivingattheexperimental
facilitieshenswerehousedinanaviarysystem(Vencomatic,Eersel,theNetherlands)with330birds
perpen.
Onlyhensthatwereactiveandshowednoclinicalsignsat67weeksagewereincludedinthe
trial.Henswerenotidentifiedbyaseparateindividualcode,rathertheyweregroupedandidentified
Animals2020,10,2163of13
usinguniquepennumber.Afterinitiationofthetrial,henswereexcludediftheygotsickormet
humaneendpoints.Humaneendpointsaredefinedassituationsinwhichlayinghenswere
clinicallysickwithoutprospectsofrecovery,severelyinjured,orwhenhenswereunabletostand
upright.Beaktreatmentoflayinghens(toavoiddamagebyseverepecking)isnotallowedinthe
Netherlands,soallbirdsinthistrialhadintactbeaks.
Feedingtrialswererealizedintwoidenticalhousesthatwerewindowless,artificiallylighted,
andcentrallyheated(targettemperature:20±2°C).Layinghenswereaccommodatedinaviarypens
of1.5mlength(includinglayingnest),2mwideand2.3minheight.Henswereaccommodatedata
densityof22hens/pen.Penswereequippedwithperches(approx.18cm/hen),afeederbin(ad
libitumfeed,approx.5cm/henfeederspace)andsixnippledrinkersperpen(adlibitumwater).
Beddingconsistedoffreshwoodshavings.
Penswereinspectedeverydayduringthetrialsforspecificobservations(e.g.,healthofthebirds)
andrecorded.Thehenswerenotvaccinatedduringthetrial.
2.2.BlackSoldierFlyLarvaeandLarvaeDispenser
LiveblacksoldierflylarvaeweresuppliedbyProtixB.V.(Dongen,theNetherlands).Larvae
wereproducedinGMP+andSecureFeedcertifiedfacilityunderHACCP(HazardAnalysisCritical
ControlPoints)conditions.Freshandlivelarvaeweresuppliedonaweeklybasis,andwerestored
inacoolanddryplaceuntilconsumed.Thenutritionalcompositionofthelivelarvaeasdeclaredby
themanufacturerisindicatedinTable1.
Table1.Nutritionalcompositionoflivelarvae(asinbasis,providedbysupplier).
NutrientsLiveLarvae
Moisture(g/kg)700.0
Crudeprotein(g/kg)135.0
Crudefat(g/kg)105.0
ThelarvaedispenserusedduringthestudywasalsosuppliedbyProtixB.V.(Dongen,the
Netherlands).DesignofthedispenserisindicatedinFigure1.Thelarvaedispenserwasdesigned
suchthatapproximately275goflivelarvaecouldbedispensedfromthefourexitsofthedispenser
(equallyandrandomly)duringa6hperiod.Thedispenserconsistedofabufferthatstoredrequired
amountsoflarvaeforonedayoffeeding.Larvaegraduallyfellfromthebufferintothedispenser
unitwhichfurtherbifurcatedthelarvaeintooneofthefourdischargepoints.Thesizeandvolume
ofthedispenserwasdesignedkeepinginmindthenumberofhens(sothateverychickengotthe
sameproportionoflarvae)anddimensionsofthepen.
Figure1.Liveblacksoldierflylarvaedispenser.
2.3.ExperimentalDiets
Animals2020,10,2164of13
Commerciallayingmashdiet(containingsoy)andaspecialsoyfreedietweresuppliedbyABZ
Diervoeding(Leusden,theNetherlands).Theingredientsandcalculatedcompositionofdietsare
presentedinTable2andTable3,respectively.Bothdietswereformulatedtomeetthenutritional
requirementsofolderlayinghens.
Table2.Ingredientcompositionofexperimentaldiets.
%IngredientsCommercialMashDietSoyFreeMashDiet
Maize30.0030.00
Wheat34.6135.52
Soybeanmeal>48%CP9.700.00
Sunflowerseedmeal38%CP<1%CF6.006.00
Rapeseedmeal(SE)2.507.42
Poultryfat2.362.07
Maizeglutenmeal>60%CP2.225.16
Alfalfa16–19%CP1.020.00
Potatoprotein0.001.89
Limestone8.888.90
Monocalciumphosphate0.230.23
Sodiumbicarbonate0.250.27
Potassiumbicarbonate0.030.32
Salt0.020.00
Premix11.001.00
LysineHCl(L79%)0.130.21
Methionine(DL99%)0.030.00
Premixred0.500.50
Phytase0.260.27
NSPenzyme0.250.25
1Containing:Cu(CuSO4.5H2O)1,000mg/kg;Fe(FeSO4.H2O)4000mg/kg;Mn(MnO)10,000mg/kg;
Zn(ZnSO4.H2O)4400mg/kg;I(Ca(IO3)2anhydrous)100mg/kg;Se(Na2SeO3)15mg/kg;vit.A750,000
IU/kg,vit.D3150,000IU/kg;vit.E1250IU/kg;pantothenicacid500mg/kg;niacin1000mg/kg;vit.B6
100mg/kg;vit.B122000μg/kg;biotin4000μg/kg;vit.K3200mg/kg;choline20,000mg/kg;DL
methionine100g/kg.
Table3.Calculatednutrientcompositionofexperimentaldiets(asinbasis).
NutrientsCommercialMashDietSoyFreeMashDiet
Energy(kcal/kg)2800.002800.00
Moisture(g/kg)112.00111.00
Ash(g/kg)124.00121.00
Crudeprotein(g/kg)158.00160.00
Crudefat(g/kg)50.0048.30
Crudefibre(g/kg)32.0032.70
Starch(g/kg)387.00396.00
Ca(g/kg)38.0038.00
P(g/kg)3.934.01
Na(g/kg)1.501.50
Cl(g/kg)1.801.80
K(g/kg)6.476.48
Lysine(g/kg)16.406.40
Methionine+cysteine(g/kg)16.086.34
Threonine(g/kg)14.544.80
Tryptophan(g/kg)11.541.41
1Basedonapparentfecaldigestibility.
Animals2020,10,2165of13
2.4.StudyDesignandFeedingRegime
Arandomizedcompleteblockdesignwasusedfortheexperimentwithtwotreatments(control
andlarvaefed)andeightreplicates(22hens/replicateatthestartofthetrial).Blockingwasapplied
tothepositionofpensintheexperimentalfacility.Thetrialwasconductedforadurationof12weeks.
Controlgroups(GroupA)wereprovidedwithsoycontainingcommerciallayingmashdiet.The
larvaefedgroup(GroupB)wereprovidedwithasoyfreediet.Bothgroupswereprovidedad
libitumfeedandwater.Onthetopofsoyfreediet,GroupBhenswerealsoprovidedwith12glive
larvaeperhenperday(10%ofdailyfeedintake)usinglarvaedispenserdescribedinSection2.2.
Larvaewereprovidedat11.30ameachday,andthedispenser(Figure1)selfemptiedat
approximately5.30pm.
2.5.ProductionPerformanceandMortality
Thefollowingproductionparametersweremeasuredduringthestudy:(1)bodyweightgain
frominitiationuntiltheendofthefeedingtrial;(2)weeklyfeedintake/pen;(3)weeklynumberof
eggs/penandeggweight/pen;(4)layingrate,eggmassandfeedconversionratiowerecalculated
fromtheabovedata.Mortalitywasrecordeddaily.Hensthatweresick,severelywounded,orcould
notstanduprightwereeuthanized.
2.6.EggQuality
Qualityparameters,i.e.,eggshellbreakingstrength,elasticityofshellandHaughunitwere
evaluatedforteneggs/penduringinitiationandterminationofthetrial.Theseparameterswere
evaluatedbyInstituteofQualityMeasurementinEggs(Amersfoort,theNetherlands).
2.7.FeatherCondition
Layinghens(5birds/pen)wererandomlychosenandevaluatedforfeatherconditionduring
initiationandterminationofthefeedingtrial.Featherconditionwasscoredbetween0(intactfeathers
withnoinjuriesorscratches)to5(completelydenudedarea).Neck,back,rumpandbellyweretaken
intoaccountforscoring,becauseoftheirassociationwithfeatherpeckingbehavior[23,24].
2.8.BirdBehavior
Videoobservationsweremadein2pens(1fromGroupAand1fromGroupB)torecordand
analysehenbehavior.TheschemeusedforvideoobservationismentionedinTable4.Video
recordingsweremadetohaveundisturbedobservations.Behaviorwasscoredbycountingthe
numberofbirdsontheflooratanintervalofevery5minduringtheobservationperiod.Video
observationswererecordedtounderstandtheinfluenceoflarvaeprovisioningonbirdsʹbehavior.
Table4.Videoobservationregime.
PeriodCorresponding
ObservationDayMorningAfternoon
BeginningoftrialFirstday(18/01/2019)
11.00amto12.00pm12:00pmto3:00pm2
BeginningoftrialSecondday(20/01/2019)
TerminationoftrialSecondlastday(05/04/2019)
TerminationoftrialLastday(06/04/2019)
130minbeforeandafterloadingofdispenser;2Nointerruptiontime.
2.9.DataExclusionParametersandStatisticalAnalysis
Aspecificobservationwasmarkedoutlierandexcludedfromthedatasetbeforestatistical
analysis,iftheresidual(fitted—observedvalue)wasgreaterthan2.5timesstandarderrorofthe
residualsofthedataset(ANOVA).Ifaspecificobservationonfeedintake,layingrate,oreggweight
Animals2020,10,2166of13
wasconsideredoutlier,itwasnotusedforthecalculationofcorrespondingfeedconversionratioand
eggmass(wereexcluded).
ExperimentaldatawereanalysedusingGenStat®version19.1(VSNInternationalLtd.,Hemel
Hempstead,UK).Feedintake,layingrate,eggmassandweight,feedconversionratio,mortality,egg
qualityparametersandfeatherscoreswerecomparedbetweentwotreatmentsusingANOVA.Pen
wastheexperimentunit.Generalmodelwas:
Yij=μ+Blocki+Treatmentj+eij(1)
With:
Yij=responseparameter;μ=overallmean;Blocki=blockeffect(i=1to8);Treatmentj=effectof
treamentgroup(j=1,2);eij=residualerror;Valueswithp≤0.05wereconsideredstatisticallydifferent.
2.10.AnimalEthics
ThetrialwasrealizedaccordingtotheguidelinesoftheAnimalandHumanWelfare
Codes/LaboratorypracticecodesintheNetherlands.TrialprotocolwasapprovedbytheSchothorst
FeedResearchInstituteEthicsReviewCommittee.
3.Results
3.1.ProductionPerformance
Resultscorrespondingtofeedintake,layingrate,eggweight,eggmassandmortalityrateare
presentedinTable5andTable6.GroupB(larvaefedhens)hadasignificantlylower(p=0.029)feed
intakeincomparisontoGroupA(control).FeedintakeindicatedinTable5isbasedonintakeof
mashdiets(larvaeintakebyGroupBnottakenintoaccount).GroupBhensreceivedapproximately
12goflarvaeperhenperday(g/h/d).ThereforetotalfeedintakeforGroupBwasabout135g/h/d,
whichwasnotdifferentfromGroupA.Larvaeconsistofapproximately70%moisture,soondry
matterbasis,feedintakeofGroupBwas127g/h/d,whichisnumericallylowerthanthecontrol
treatment(significantdifferenceswerenotcalculated).Layingrate,eggweight,eggmassand
mortalityratedidnotdifferbetweentreatments.
FeedconversionratiosofbothtreatmentsarealsoindicatedinTable5.Inlinewithalowerfeed
intake,GroupBalsoshowedasignificantlylowerfeedconversionratio(p=0.004).Iflarvaeintake
byGroupBhensistakenintoaccountonadrymatterbasis,feedconversionratioofGroupBis
estimatedtobe2.452.ThisvalueisnumericallylowerthanthefeedconversionratioofGroupAand
isonlysignificantatthe10%levelofconfidence(p=0.071).
Table5.Productionperformanceandmortalityrateoflayinghensfedacommercialdiet(GroupA)
orasoyfreediet+livelarvae(GroupB)from67to78weeksofage.
TreatmentFeedIntake2
(g/h/d)
LayingRate
(%)
Egg
Weight(g)
EggMass
(g/d)
Mortality
(%)
FeedConversion
Ratio(g/g)
GroupA133a83.363.1152.582.82.534
GroupB123b81.963.3251.791.12.391
SEM12.5381.8930.1531.1930.8450.0238
pvalue0.0290.6010.3530.6570.1970.004
a,bValueswithoutacommonsuperscriptinacolumndiffersignificantly(p≤0.05).1SEM=Standard
errorofmeans.2IntakeoflarvaebyGroupBwasnottakenintoaccount.
Animals2020,10,2167of13
Table6.Totalcrudeproteinandfatintakebylayinghensfedwithacommercialdiet(GroupA)ora
soyfreediet+livelarvae(GroupB)from67to78weeksofage(asinbasis).
ParametersGroupAGroupB
Nutrientcompositionofdiets1
Crudeprotein(g/kg)158.0160.0
Crudefat(g/kg)50.048.3
Energy(kcal/kg)2800.02800.0
Nutrientcompositionoflarvae2 
Crudeprotein(g/kg)‐135.0
Crudefat(g/kg)‐105.0
Totalfeedandnutrientintake 
Feedintake(g/h/d)133.1123.3
Larvaeintake(g/h/d)012.0
Crudeproteinintake(g/d)21.021.3
Crudefatintake(g/d)6.667.21
1Valueprovidedbythesupplierofmashfeedandlivelarvae.2Nutrientcompositionofthelarvae
basedonprovidedinformationoflarvaesupplier.
Bodyweightoflayinghenswasdeterminedduringtheinitiation(67weeksofage)and
termination(78weeksofage)ofthetrial.BodyweightofhensduringthetrialisindicatedinTable
7.GroupAhensshowedanaverageweightlossduringthetrial,whileGroupBhensshowedan
averageweightincrease.However,therewasnosignificantdifferencebetweenthetwoexperimental
groups.
Table7.Bodyweight(g)oflayinghensfedacommercialdiet(GroupA)orasoyfreediet+livelarvae
(GroupB)from67to78weeksofage.
Treatment67Weeks(g)78Weeks(g)
GroupA16691660
GroupB16641675
SEM111.116.2
pvalue0.7520.529
1SEM=Standarderrorofmeans.
3.2.EggQuality
Eggqualityparametersweredeterminedduringtheinitiationandterminationofthetrial.
ValuesobtainedforqualityparametersarementionedinTable8.Therewerenodifferencesbetween
eggshellstrength,elasticityandHaughunitbetweeneggsfromGroupsAandBhens.
Table8.Qualityparametersofeggsfrom67and78weeksagelayinghensfedacommercialdiet
(GroupA)orasoyfreediet+livelarvae(GroupB).
TreatmentEggWeight2(g)BreakingStrenght(N)Elasticity(N/S)HaughUnit
67weeks78weeks67weeks78weeks67weeks78weeks67weeks78weeks
GroupA63.5462.8637.738.953662379.375.6
GroupB63.8063.0739.538.754159579.577.0
SEM10.6070.8250.8711.0389.2019.430.7761.875
pvalue0.7680.8560.1810.8860.7100.3470.8360.619
1SEM=Standarderrorofmeans.2Eggweightdeterminedonlyforeggsusedforqualitymeasurement.
3.3.FeatherCondition
Thefeatherconditionscoresofthelayinghensdeterminedduringtheinitiationandtermination
ofthetrialareindicatedinTable9.Olderlayinghensalreadyhadfeatherdamageduringthe
Animals2020,10,2168of13
initiationofthetrial.InitialfeatherdamageofGroupBwasnumericallyhigherthanGroupA(no
significantdifferences,p=0.06).Attheendofthetrial,featherdamageofGroupBwassignificantly
lesscomparedtoGroupAhens(p=0.004).Somehensinbothgroupsstartedtomoltduringthetrial,
whichismarkedbyrenewingoffeathers.Duringtheinitiation,allthescoredhenshadabaldbelly
(correspondingtoscore4or5).However,duringterminationfivelayinghenswerescored≤2for
belly.Ifthesemoltedhensaretakenintoaccount,featherconditionscoreforGroupsAandBcould
beadjustedto3.3and2.6,respectively.Evenafteradjustmentofthescore,featherdamageofhens
fromGroupBwassignificantlylesscomparedtohensfromGroupA(p<0.05).
Table9.Featherconditionscoreoflayinghensfedacommercialdiet(GroupA)orasoyfreediet+
livelarvae(GroupB)from67to78weeksofage.
TreatmentFeatherScore
2
67Weeks(g)78Weeks(g)
GroupA3.42.9
a
GroupB3.62.2
b
SEM
1
0.0770.107
pvalue0.0600.004
a,b
Valueswithoutacommonsuperscriptinacolumndiffersignificantly(p≤0.05).
1
SEM=Standard
errorofmeans.
2
Featherconditionscorefrom0(intactfeathers,noinjuriesorscratches)to5
(completelydenudedarea)werescoredforneck,back,rumpandbellyperhen.Averagefeather
conditionscorewascalculatedandanalysed.
3.4.BirdBehavior
Videoobservationsofbirdbehaviorweremadeduringtheinitiationandterminationofthetrial.
AnalyticaldatarevealedhighercountsofhensonfloorduringmorninghoursinGroupB(when
larvaewereloadedindispenser)whencomparedtoGroupA(Figure2).Whereas,forGroupAhigher
countsofhensonfloorwereobservedduringafternoonhourswhencomparedtoGroupB.
Figure2.NumberofhensobservedatthefloorareaofpeninGroupA(control)andGroupB(larvae
fed)attheinitiation(18/01/2019and20/01/2019)andtermination(05/04/2019and06/04/2019).
Observationswereperformedinmorning(afterloadingoflarvaeindispenser,approx.11.00amto
12.00pm)andafternoon(2.00pmto3.00pm).Redarrowsindicatetimeoflarvaesupply.
4.Discussion
4.1.EffectonProductionPerformance
Animals2020,10,2169of13
GroupsAandBhenshadafeedintakeof133and123g/h/d,respectively(withoutaccounting
larvaeintakebyGroupB).Thereductioninmashfeedislinkedtothenutritionalqualityoflive
larvae,whichareabletocompletetheproportionofproteinandfatindiets(Table6).Livelarvae
usedduringthecurrentstudyoriginatedfromGMP+andSecurefeedcertifiedfactoryandwere
grownusingHACCPprinciples,indicatinghighnutritionalquality.
Afteradjustingthelarvaeintakebylayinghens,thefeedconversionratiooflarvaefedhenswas
numericallylowerthancontrolhens.Eventhoughthedifferenceswerenotsignificant,butpvalue
(0.071)approachedtheborderlineofsignificance.
TherewerenodifferencesinthelayingrateandeggweightbetweenGroupsAandB.Itappears
thatlivelarvaeinclusioninsoyfreedietsmadefromlocalingredients(inthiscaserapeseedmeal)
hadnoadverseeffectoneggproduction.InEurope,soyisthemajorsourceofproteinusedinpoultry
dietformulations[25].Approximately32gsoymealisconsumedbyhenstolayeverysingleegg[26].
ThemajorityofsoybeingusedforthispurposeoriginatesfromAmericancountries.Accordingto
someestimates,79%ofsoymealconsumedinEUoriginatesfromSouthAmerica[27]withBrazil
alonesupplyingmorethan40%ofthetotalconsumption[28].ImportofsoyfromSouthAmerican
countrieshasbeenasubjectofdebateinrecentyears.Increasingsoyplantationsinthesecountries
hasbeenfrequentlyassociatedwithdeforestation,whichfurthertranslatesintoincreasingthreatto
indigenouspeopleandhumanrightviolations[29].Majordriversofsoytradelinkeddeforestation
inSouthAmericaare:(1)increasingprofitperhectarefromsoyplantation;(2)developmentof
infrastructurefore.g.,roadstofacilitatesoytransport;and(3)badlyfabricatedregulations[26].This
scenarioindicatestheurgentneedtofindsoymealsubstitute.Insectscouldbegrownusingwide
rangeofagrofoodindustrybyproducts,servingasanimportantpillaroflocalcirculareconomy
[20].FromtheoutcomesofthisstudyitissuggestedthatliveHermetiaillucenslarvae(inadditionto
otherplantproteinsources)couldbesuccessfullyusedforthereplacementofsoyinEuropean
poultrydietswithoutdetrimentaleffectsonproductionperformance,behaviorandwelfareofolder
layerhens.
AslightaverageincreaseinbodyweightwasobservedforGroupBhens(contrarytoGroupA
hens).However,therewerenosignificantdifferencesinbodyweightbetweenbothgroups.For
layinghensatthisage,bodyweightgainhasverylittlesignificance.Bodyweightgainismore
significantforbroilerindustry,whichcouldbeasubjectoffuturework.
4.2.EffectonEggQuality
Eggqualityparameters(i.e.,shellstrength,eleasticityandHaughunit)wereunchangedwithor
withoutinclusionoflarvaeindiets.Thisfindingaddstothebodyofevidencethatblacksoldierfly
larvaetogetherwithalocalplantproteinsourcecanreplacesoyinpoultrydiets.
Apreviousresearchalreadyinvestigatedtheimpactofblacksoldierflylarvaeproteinmeal
baseddietsonqualityofeggsproducedbylayinghens[30].At5%inclusionlevels,bettereggshell
strengthwasobservedincomparisontozeroinclusionlevels.Inthecurrentstudy,12glarvae
togetherwith123.3gmashfeed,correspondsto1.3%blacksoldierflylarvaeproteininclusion.
Therefore,inthefutureitcouldbeinterestingtoinvestigatetheeffectofincreasedlarvaeinclusion
ratesoneggquality.Studieshavealsoindicatedthebeneficialeffectofblacksoldierflyproteinmeal
inclusiononyolkcolor,γ‐tocopherol,lutein,β‐caroteneandcholesterolcontent[30,31].Inclusionof
livelarvaeontheconcentrationofthesemoleculescouldbeanothersubjectoffutureresearch.
4.3.EffectonFeatherCondition
Duringtheinitiationofthetrial,featherdamageoflarvaefedhenswasnumericallyhigherthan
controlhens(nosignificantdifferences).However,thepvaluewas0.06,indicatingdifferencenear
significanttrend.Outcomesofcurrentresearchindicatethatprovisionofliveblacksoldierflylarvae
inarandomandcontrolledmannerresultedinreductionoffeatherdamageinolderlayinghens.
Eventhoughlarvaefedhensstartedwithbadfeatherscore(incomparisontocontrolhens),these
hensendeduphavingsignificantlybetterfeatherscoreduringtheterminationoftrials.
Animals2020,10,21610of13
Gentlepeckingisnormalinlayinghensandresultsinlittleornofeatherdamage[32].Feather
peckingisaffectedby:(a)internalfactors:geneticstrain,age,hormonalstate,fearfulnessandsocial
motivations;and(b)externalfactors:floorsubstrate,flocksize/density,lightintensityanddiets[33].
Amongstthesefactors,relationbetweenageandfeatherpeckingisparticularlyimportantforegg
producersandconsumers.Layinghensarecommonlyusedforeggproductionuntil86weeks[34,35]
andintheNetherlandsitisevenincreasinglycommontokeepwhitelayinghensuntil95to100weeks
ofage(withoutmolting).Inlayinghensofageabove65weeks,severefeatherpeckingisextremely
common[8,33].Somewidelyusedcommercialsolutionstorestrictpeckinginvolveeithertrimming
ofthebeaksorkeephensinsmallandconfinedgroups.However,thesetechniqueshavetheirown
welfareissues[36].ThefirstsolutionisnotallowedintheNetherlands,wherethestudywas
performed.Therefore,alllayinghensusedhadintactbeaks,contributingtothepoorfeather
conditionoftheolderlayinghenatthestartofthetrial.Otherpathwaystoreducefeatherpecking
include:offeringenrichments(naturalsubstratetopeckat),lowerstockingdensity(facilitatinghens
torememberflockmates),andadaptedfeedformulation(increasingproteinslevelsindiet)[37].
However,allthesesystemsstillincludeusageofsoybaseddiets.
Alternativessuchasfreerangesystemsarealsoconsideredeffectiveinreducingfeather
pecking.Astudyindicatedthatfreerangechickensspendaboutonethirdoftheirtimeeatinginsects,
whichprovidesthemwithanaturalsubstratetopeckat[14].However,recentfindingshaveindicated
thathighmortalityinafreerangesystemisnegativeinrelationtoanimalwelfare[38].Normally,
layinghensinclosedsystemshavelittleaccesstoliveinsects(besidespestinsects).Providinga
sufficientamountoflarvae(throughaspeciallydesignedlarvaedispenser)toeachhenoffereda
naturalsubstratetopeckatanddistractthelayinghensfrompeckingateachother.Similareffects
werealsoobservedinyoungturkeypoults.Feedingliveblacksoldierflylarvaeresultedinreduced
featherpeckingonbackandtailbase[39].Itcouldalsobeoffutureinteresttostudytheeffectof
providingliveblacksoldierflylarvaetolayingpulletsondevelopmentofpeckingbehavior.
4.4.EffectonBirdBehavior
Livelarvaefedhens(GroupB)countsonthefloorwerehigherduringthemorningthanthe
afternoon.GroupAhens(control)countsonthefloorwerelowerinthemorningcomparedtoGroup
Bhens.However,GroupAhenscountsonthefloorwerehigherintheafternooncomparedtoGroup
Bhens.Itmightbesuggestedthatthesupplyoflarvaeinthemorningfulfilledtheneedoflaying
henstoshowfeedsearchingbehavior(i.e.,theirbehaviorwasrewarded).Resultsfromthecurrent
researchindicatethatprovisionofliveblacksoldierflylarvaecouldfacilitatehensinexpressingtheir
naturalbehavior.Expressionofnaturalbehaviorisalsolinkedtoreducedfeatherpeckingincaseof
layinghens[40]andwillcontributetobirdwelfare.
Researchershaveindicatedthathigherpeckingactivityhasbeenobservedinlayinghensduring
morninghours[41].Thesebirdsspendamoretimebeingquiet,sittingandrestingduringthe
afternoon[42].Videoobservationsforlarvaefedhensalsoindicatedhigherbirdcountsonthefloor
duringmorninghours.Besides,thesebirdshadabetterfeatherconditionattheendofthetrial.It
couldbehypothesizedthatlarvaefedbirdsspendmoretimepeckingatlarvaethanateachother.
Additionally,larvaeavailabilityinthemorningwassatisfying,providingthemanopportunityto
restduringtheafternoon.Lastly,inthefuture,itcouldalsobeofinteresttooptimizethelivelarvae
provisiontimetosufficientlysatisfythehens.Liveinsects,particularlyblacksoldierflylarvae,are
alreadyapprovedforpoultryfeedinginEurope.Severalcompaniesarenowengagedinthebusiness
ofrearingblacksoldierflylarvaeusingfoodindustrybyproducts.Theseinsectsarenowbeing
viewedasimportantpillarsofcirculareconomy[20].Asaresult,thereisasubstantialinterestin
feedingblacksoldierflylarvaetolayinghensandbroilers[30,31,39,43].Thisstudyprovidesan
interestingfirstinsightregardingthesuccessfulinclusionofliveblacksoldierflylarvaeindietsof
olderlayinghens.However,thisstudyispotentiallyincompletewithoutevaluationof(a)
performanceandfeatherpeckingdevelopmentinyounglayinghens;(b)nutritionaleggquality;(c)
otherwelfaretraits;and(d)additionalcostsinvolvedinrelationtothebenefits.Furthermore,this
studycouldalsobeexpandedtobroilers,breederflocksandturkeys.
Animals2020,10,21611of13
5.Conclusions
Thereisagrowinginterestinutilizationofliveblacksoldierflylarvaeforfeedingpoultry.
Literatureindicatesthattheseinsectsarenutritiousandtheirfarmingcouldfacilitatecircular
economy[20].Moreover,theseinsectscouldalsohelpinsolvingsomewelfareissuesrelatedto
poultryfarming,e.g.,featherpecking[43].Keepingthisinmind,thecurrentstudywasrealizedto
studytheeffectof:(a)feedingsoyfreedietscontainingcombinationoflocalplantproteinsandblack
soldierflylarvaetoolderlayinghensonproductionperformanceandeggquality;and(b)effectof
dispensingliveblacksoldierlarvaetoolderlayinghensonfeatherconditionandhenbehavior.
Resultsobtainedduringthestudyindicatedthatreplacingsoywithliveblacksoldierflylarvae
andlocalproteinsourceshasnoadverseeffectonproductionperformanceandeggquality.
Additionally,randomandsteadyprovisionoflarvaetoolderlayinghenswithintactbeakshada
positiveeffectonfeathercondition.
AuthorContributions:Conceptualization,L.S.andF.M.;methodology,L.S.;formalanalysis,L.S.;investigation,
L.S.;writing—originaldraftpreparation,L.S.andA.P.;writing—reviewandediting,L.S.,F.M.,T.A.,M.D.,and
R.L.;supervision,L.S.andF.M.Allauthorshavereadandagreedtothepublishedversionofthemanuscript.
Funding:Thisresearchreceivednoexternalfunding.
Acknowledgments:AuthorsarethankfultoDr.EricSchmitt,animalcaretakersandprojectofficeofSchothorst
FeedResearchandMaiBoonmawong(studentatVanHallLarensteinUniversityofAppliedSciences),fortheir
helpandsupportduringthetrial.Authorsarealsoverygratefultotheguesteditorsofthisjournalspecialissue
foracknowledgingthescientificqualityofthisresearchandexemptingthepublicationfee.
ConflictsofInterest:ThisresearchwassponsoredbyProtix.Thesponsorisanindustrialscaleproducerofblack
soldierflylarvae.Thesponsorhadnoroleinthedesignofthestudy;inthecollection;analyses;orinterpretation
ofthedata.However,sponsorofthisstudy,dohavearoleinwritingofthemanuscriptandtimingofsubmission.
Mainmotivationbehindthismanuscript,istoinformtheaudienceaboutpossibleroleofliveinsectsinchicken
welfare.
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©2020bytheauthors.LicenseeMDPI,Basel,Switzerland.Thisarticleisanopenaccess
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(CCBY)license(http://creativecommons.org/licenses/by/4.0/).
... In contrast to the meal form, less is known about the inclusion of unprocessed whole BSFL in poultry rations on acceptance, nutrient intake and utilization, performance and health of the birds. Chickens are excellent foragers of insects as these are among their natural feed sources (Star et al., 2020). Feeding experiments indicated that diets containing insects are highly interesting for poultry species (Moula et al., 2018;Nascimento Filho et al., 2020;Star et al., 2020;Tahamtani et al., 2021). ...
... Chickens are excellent foragers of insects as these are among their natural feed sources (Star et al., 2020). Feeding experiments indicated that diets containing insects are highly interesting for poultry species (Moula et al., 2018;Nascimento Filho et al., 2020;Star et al., 2020;Tahamtani et al., 2021). The use of whole BSFL as feed for poultry may be particularly important in organic farming and low-input systems (e.g., local farming with less feed processing and transportation), and where insect production could be integrated into production cycles (e.g., insects farming with locally available organic residues as feed substrate) (Nyakeri et al., 2017). ...
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... In contrast to the meal form, less is known about the inclusion of unprocessed whole BSFL in poultry rations on acceptance, nutrient intake and utilization, performance and health of the birds. Chickens are excellent foragers of insects as these are among their natural feed sources (Star et al., 2020). Feeding experiments indicated that diets containing insects are highly interesting for poultry species (Moula et al., 2018;Nascimento Filho et al., 2020;Star et al., 2020;Tahamtani et al., 2021). ...
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A feeding experiment was conducted to investigate the impact of feeding defrosted whole black soldier fly larvae (BSFL) to broilers in increasing levels in the ration on blood metabolites, carcass characteristics (CC) and on changes in fatty acid (FA) composition in plasma, muscle and abdominal fat. Day-old chicks (Ross-308; n=252) were assigned to one of four groups each with 6 replicate pens (10-11 birds/pen). The birds were fed either a demand-oriented age-specific control (CON) diet and had no access to BSFL, or fed CON plus BSFL at 10% (L10), 20% (L20) or 30% (L30) of CON feed intake. At weeks (wk) 4 and 6, birds (2 per pen) were slaughtered to collect blood, breast muscle, and abdominal fat samples and to determine CC. Plasma triglyceride concentrations increased in a dose dependent manner with increasing levels of whole BSFL compared with CON (P<0.05). The L30 and L20 had higher plasma non-esterified FA concentrations than CON (P<0.05). There were no differences in slaughter weight and CC between groups (P>0.05). Broilers fed 30% BSFL had the highest saturated FA proportion in plasma, muscle and abdominal fat and the lowest monounsaturated FA proportion in abdominal fat tissue (P<0.05). The levels of total polyunsaturated FA in plasma and abdominal fat were lower in L30 than in CON (P<0.05). In plasma, muscle and abdominal fat, the proportion of conjugated linoleic acid (isomer C18:2cis-9, trans-11) was highest in L30 followed by L20 and L10 compared with CON (P<0.05). Overall, whole BSFL could be included in broiler diets up to 20% to promote sustainability in broiler farming without adverse effects on slaughter weight, meat quality and FA compositions, whereas, the highest inclusion level (i.e. 30%) of whole BSFL in the daily ration was associated with altered FA composition in plasma, fat and meat.
... It accounts for not only the physical needs to be met but also ethological and psychological ones, and promotes the role of positive mental experiences. One example of the latter is foraging for food: searching for insects through scratching is a positive experience for poultry and therefore contributes to their welfare, 12 in line with the Five Domains model. This is not, however, what is achieved by promoting the use of insect PAP for animals confined indoors in intensive systems. ...
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The European Union has started considering alternative feed, such as insect protein, to supply the livestock industry. Insect-derived protein as animal feed is increasingly seen as a solution to diminish the use of imported soy linked to deforestation and to supplement the use of fishmeal from depleted oceans. In the EU’s commitment to tackle the climate crisis, the promises of insect farming have been embraced by policy makers but it does not seem to be the sustainable solution the EU is looking for.
... This contradiction would be due to the very high level of larvae meal incorporated and their method of analysis. In a recent study, Star et al. (2020) found no significant effect on the Haugh unit with the inclusion of soldier fly larvae in the hen's diet but found the period of their experiment too short. The same authors supported their results by reporting the age and laying phase of their laying hens. ...
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Although the egg is one of the foods offering nutrients of high biological value, the diet of layer chickens can change these characteristics. The aim of this study was to evaluate the effect of a long-term dietary replacement of fish meal with maggot meal of black soldier fly larvae on egg quality of hens. A total of 480 one-day-old Isa brown chicks were randomly assigned to 4 dietary treatment groups. The groups were named T0 (8% fish meal), T1 (4% maggot meal and 4% fish meal), T2 (6% maggot meal and 2% fish meal), and T3 (8% maggot meal). Each treatment group had 6 replicates of 20 chicks each. Data were collected on the eggshell quality parameters between 22 and 56 weeks of age. The results indicated that egg weight, shell weight, shape index, shell index, egg surface area, egg volume, density, yolk pH, albumen pH, yolk and albumen moisture content, yolk color, and yolk height were not influenced by the use of larval meals. Although the proportion of the yolk increased with age, there was no interaction between the use of fly larvae and the duration of its use for the collected parameters. However, the proportion of albumen, Haugh’s unit in T1 and T3 treatments were higher than those of T0 and T2. The proportion of egg yolk, the yolk to albumen ratio, and the count of cracked eggs of T0 and T2 varied significantly compared to T1 and T3. Total egg fat decreased significantly as a result of the use of maggot meal. Total cholesterol, High-density lipoprotein (HDL) cholesterol, Low-density lipoprotein (LDL) cholesterol, and LDL/HDL ratio were lower in groups fed larvae meal, compared to the control group. It was concluded that the use of black soldier fly larvae meal during the entire rearing cycle and period of layers did not adversely affect the eggshell quality and nutritional content of the eggs.
... The replacement of the traditional diet by BSFL affected not only the health but also the behaviour of birds. Star et al. (2020) found that older laying hens fed on live BSFL exhibited better feather and BSFL reduced the feather pecking of hens. ...
Thesis
Since the suitability of BSFL as animal feed depends on the nutritional composition of their rearing substrate and it is possible to modify the nutrient composition of BSFL by adjusting their rearing substrate. Five experiments were conducted and the main conclusion is listed below: 1.Using 50% Schizochytrium microalgae residue as the substrate increased the amount of DHA in BSF pre-pupae. 2.BSFL decreased the amount of olive pomace waste with retention of lauric acid and protein in their bodies, BSFL and 75% will be the optimal percentage of this waste to use as the cheapest rearing substrate for BSFL. 3.Using bird manure as a substrate for BSFL are better than mammal manure to increase the amount of PUFAs and other chemical compositions of BSF pre-pupae. Using manure made EAAI of BSF pre-pupae satisfying source for fishes and shrimps than fishmeal and soybean meal. 4.The optimal percentage of using quail manure as a substrate for BSFL was 40%. Using 100% quail manure as a feeding media for BSFL decreased the amount of total fat and saturated FAs with accumulating the amount of MUFAs, especially OA and biosynthesize POA of BSF pre-pupae. 5.Applying Se-rich silkworm pupae residue for feeding BSFL raised the amount of ALA by hundred times than using 50% Schizochytrium microalgae residue. Moreover, using Se-rich silkworm pupae increased the amount of protein in BSF pre-pupae, but the Se content kept constant in the body of BSFL. Finally, all the organic wastes evaluated in this study could be used as rearing substrates for BSFL to achieve a sustainable circular economy by replacing the source of protein (fishmeal and soybean meal), source of lipid (fish oil), or both of them. * Innovative points of the study 1.The present study found that the composition of BSFL could be manipulated with the adjustment of the rearing substrate, such as Schizochytrium microalgae residue and Se-rich silkworm pupae residual, which makes it possible to produce high-quality BSFL product intentionally. 2.The present study found that bird manure rather than mammal manure could be a good rearing substrate for BSFL production with better nutritional value.
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This study presents a life cycle assessment (LCA) comparing laying hen to broiler chicken production. Sustainability and protein conversion efficiency are considered. The protein-to-protein conversion was calculated per 1t of feed protein consumed by birds and per 1kg of protein in end products for human consumption. Additionally, a part of the commercial feed was replaced by live black soldier fly larvae, reared on Gainesville diet, and fruit and vegetable waste (FVW). Results of the LCA showed significant differences in integrated impacts between different production systems and different chicken feeds but not between different insect feeds. The most environmentally friendly scenario is insect (FVW) fed broiler. In protein conversion efficiency (PCE) assessment, laying hen production achieved better PCE than broiler chicken when protein quality is considered. Main influencing factors on results were feed production, composition, and protein content. Due to many assumptions made, results should be viewed critically.
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This paper aimed to review the recent advances in using insect meal in poultry nutrition to assess the suitable species, dietary inclusion level, and nutrients profile, advantage, and disadvantage as well. More than 50 research articles, review articles, short communications, and book chapters were obtained from various online databases i.e. Google Scholar, PubMed, and Scopus, using the following keywords insect breeding and insects in poultry nutrition, black soldier fly Hermetia illucens (BSF). The selected black soldier fly larvae (BSFL), and pupa (BSFP) are based on growing interest due to easy breeding, valuable protein resource, and economic value. The urgent needs for alternative and locally available feed resources have been substantially increased after the COVID-19 crisis due to different reasons such as lockdown, close of boards, airports, and seaports. Most developing countries are dependent on imported feedstuffs for animal nutrition which was greatly influenced during COVID-19, affecting animal feed chain supply for farm species. That has raised the need for alternative/nonconventional local protein sources to sustain animal protein production. The BSF is a promising and candidate feed resource based on recently published broilers, laying hens, Japanese quail, and ducks' studies.
Chapter
Insects have application in poultry feed because of their capacity to sustainably repurpose wastes into nutrient-dense feeds, combined with the demand for poultry meat and eggs in the diets of the growing human population. Additionally, poultry naturally consumes insects, thus insects may enhance poultry welfare. Several insects are commercially reared including the house cricket (Acheta domesticus L.), yellow mealworm (Tenebrio molitor L.), and black soldier fly larvae (Hermetia illucens L.). Insect nutrient concentrations are affected by species, stage of development, feedstock on which they are raised, and processing method. Insects are a concentrated source of energy and protein with an excellent balance of essential amino acids, of which methionine levels are higher than standard corn and soybean meal sources commonly utilized in poultry diets. Because they are readily eaten and well utilized by poultry, insects are an effective source of nutrition in poultry feed for a burgeoning world population.
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The use of insect live larvae as environmental enrichment has recently been proposed in broiler chickens, but the concomitant administration of black soldier fly (BSF) and yellow mealworm (YM) has never been tested yet. Therefore, the present study aims to evaluate the effects of live BSF and YM larvae as environmental enrichments for broiler chickens by means of plumage status, behaviour, leg health, and excreta corticosterone metabolites (CM). A total of 180 4-day old male Ross 308 broiler chickens were randomly distributed in 3 experimental treatments (6 replicates/treatment, 10 birds/replicate) and fed for 35 days as follows: 1) control (C, commercial feed), 2) BSF: C + 5% of the expected daily feed intake [DFI] live BSF larvae and 3) YM: C + 5% of the expected DFI live YM larvae. Feathering, hock burn (HB) and footpad dermatitis (FPD) scores (end of the trial), as well as behavioural observations (beginning of the trial [T0] and every 11 days [T1, T2 and T3] during morning, larvae intake and afternoon) through video recordings, were assessed, and excreta samples collected to evaluate the CM. Feathering, HB and FPD scores, and excreta CM were unaffected by insect live larvae administration ( p > 0.05). In the morning, the insect-fed birds displayed higher stretching, wing flapping, ground pecking (at T1 and T3), as well as lower preening (at T1 and T2), than the C group ( p < 0.05). During the larvae intake, higher scratching, wing flapping and ground pecking, as well as lower stretching, preening and laying down, were observed in the insect-fed (scratching, stretching and laying down) or YM-fed (wing flapping, ground pecking and preening) groups than the C birds ( p < 0.05). In the afternoon, insect live larvae administration increased wing flapping (YM) and laying down (BSF and YM), as well as decreased ground pecking (YM, p < 0.05). In conclusion, the administration of insect live larvae as environmental enrichment (especially YM) was capable of positively influencing the bird welfare through the stimulation of foraging behaviour, increase in activity levels, and reduction in bird frustration, without affecting the plumage status, leg health, and excreta CM.
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