ArticlePDF Available

Abstract

Background: starch is an important energy source for ruminants nutrition. This carbohydrate is often used to improve rumen fermentation, optimizing digestion of structural carbohydrates and increasing protein flow to the small intestine. Microbial and digestive enzymes are involved in starch digestion, generating products that can positively or negatively affect animal performance and health, depending on the starch contents of the diet. Objective: to describe the basic characteristics of starches, the factors affecting its nutritional availability, and its effects in ruminants. Conclusion: a number of factors affect starch digestibility, including granule size, amylose/amylopectin ratio, proportion of farinaceous and vitreous endosperm, presence of starch-lipid and starch-protein complexes, and physical-chemical processing of the feed. Ingestion of large amounts of starch can trigger ruminal acidosis. However, its rational use in the diet has positive effects on methane emissions, and in milk yield and composition.
Rev Colomb Cienc Pecu 2016; 29:77-90
Revista Colombiana de Ciencias Pecuarias
Original articles
77
Literature Review
Starch in ruminant diets: a review¤
Almidones en la alimentación de rumiantes: revisión de literatura
Amido na alimentação dos ruminantes: revisão de literatura
Luis M Gómez1,2,3*, MVZ, MSc, (c)Dr. Sc; Sandra L Posada2, Zoot, MSc, Dr. Sc; Martha Olivera3, MV, Dr. Sc.
1Departamento de Investigación y Desarrollo, Grupo Nutri-Solla, Solla S.A., AA 1272, Itagui, Colombia.
2GRICA Research Group, Facultad de Ciencias Agrarias, Universidad de Antioquia, AA 1226, Medellín, Colombia.
3BIOGENESIS Research Group, Facultad de Ciencias Agrarias, Universidad de Antioquia, AA 1226, Medellín, Colombia.
(Received: April 15, 2015; accepted: November 11, 2015)
doi: 10.17533/udea.rccp.v29n2a01
¤ Tocitethisarticle:GómezLM,PosadaSL,OliveraM.Starchinruminantdiets:areview.RevColombCiencPecu2016;29:77-90.
* Correspondingauthor: LuisM Gómez.Director ofResearch andDevelopment, SollaS.A. Company.Carrera42 No.33-80 Itagui,Colombia. Tel+574
4448411.E-mail:lmgomezo@solla.com
Summary
Background:starchisanimportantenergysourceforruminantsnutrition.Thiscarbohydrateisoftenused
toimproverumenfermentation,optimizingdigestionofstructuralcarbohydratesandincreasingproteinow
tothesmallintestine.Microbialanddigestiveenzymesareinvolvedinstarchdigestion,generatingproducts
thatcanpositivelyornegativelyaffectanimalperformanceandhealth,dependingonthestarchcontentsofthe
diet. Objective: todescribethebasiccharacteristicsofstarches,thefactorsaffectingitsnutritionalavailability,
anditseffectsinruminants.Conclusion:anumberoffactorsaffectstarchdigestibility,includinggranulesize,
amylose/amylopectinratio,proportionoffarinaceousandvitreous endosperm,presence ofstarch-lipidand
starch-proteincomplexes,andphysical-chemicalprocessingofthefeed.Ingestionoflargeamountsofstarch
cantriggerruminalacidosis.However,itsrationaluseinthediethaspositiveeffectsonmethaneemissions,
andinmilkyieldandcomposition.
Keywords: acidosis, amylopectin, amylose, digestibility, lactation, methanogenesis.
Resumen
Antecedentes: el almidónes unimportante recursoenergético parala alimentaciónde rumiantes.Este
carbohidratoesfrecuentementeempleadoparaelmejoramientodelosparámetrosdefermentaciónruminal,
loqueoptimiza elaprovechamiento de loscarbohidratos estructurales eincrementa elujode proteínaal
intestinodelgado.Ensudigestiónparticipanenzimasmicrobianasydigestivas,lascualesgenerandiferentes
78
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
productosqueimpactanpositivaonegativamenteeldesempeñoproductivoylasaluddelanimal,dependiendo
del nivel de almidón en la dieta. Objetivo: describirlascaracterísticasbásicasdelosalmidones,losfactores
queafectansudisponibilidadnutricionalylosefectosdesuutilizaciónenlaalimentacióndelosrumiantes.
Conclusión:existeunsinnúmerodefactoresqueafectanladigestibilidaddelalmidón,entreellos,eltamaño
delgránulo,la relaciónamilosa/amilopéctina,laproporcióndeendospermofarináceoyvítreo,lapresencia
decomplejosconlípidosyproteínas,ysuprocesamientofísico-químico.Laingestióndegrandescantidades
dealmidónpuededesencadenaracidosisruminal;noobstante,suempleoracionalenladietadelosrumiantes
tieneefectospositivossobrelaemisióndemetano,ylaproducciónycalidaddelaleche.
Palabras clave: acidosis, amilopectina, amilosa, digestibilidad, lactancia, metanogénesis.
Resumo
Antecedentes: oamidoéuma importantefonte deenergianaalimentaçãodos ruminantes.Este carboidrato
é geralmente utilizado para melhorar os parâmetros de fermentação no rúmen, o que otimiza a utilização dos
carboidratosestruturaiseaumentao uxodeproteínaparao intestinodelgadodoanimal.Nasuadigestãoestão
envolvidas enzimas digestivas e microbianas, as quais geram diferentes produtos que impactam positiva ou
negativamenteodesempenhoprodutivoe asaúdedoanimaldependendo doníveldeamidona dieta.Objetivo:
descreverascaracterísticasbásicasdoamido,factoresqueafectamasuadisponibilidadenutricionaleosefeitosdasua
utilizaçãonaalimentaçãoderuminantes.Conclusão: diversosfatoresafetamadigestibilidadedoamido,incluindo
otamanhodogrânulo,arelaçãoamilose/amilopectina,aproporçãodeendospermafarináceoevítreo,aformação
decomplexoscomlipídeoseproteínaseoseuprocessamentofísico-químico.Aingestãodegrandesquantidades
deamidopodeprovocaracidoseruminal,noentanto,asuautilizaçãoracionalnaalimentaçãoderuminantestem
efeitospositivossobreasemissõesdemetano,aproduçãodeleiteeasuaqualidadecomposicional.
Palavras chave:acidose, amilopectina, amilose, digestibilidade, lactação, metanogênese.
Introduction
Starch–thelargestreservoirofplantpolysaccharides-
playsanimportantroleingerminationandgrowth,
anditssynthesisissecondonlytothatofcellulose.
Starchisthemainenergycomponentusedinruminant
feeds due to its availability (Ortega and Mendoza,
2003). It is often included in the diet to improve
ruminal fermentation, allowing for a better use of
structuralcarbohydratesandtoincreaseproteinow
tothesmallintestine(Huntingtonet al.,2006).Starch
sourcesare expensive,sotheymustbeusedwisely
tobecost-effective.Itisimportanttounderstandthe
structural characteristics of starch, its ruminal and
post-ruminal digestion and the factors affecting its
digestibility in order to improve performance and
prot of livestock systems. This review describes
starch,thefactorsaffectingitsnutritionalavailability,
anditseffectsinruminantfeedingandnutrition.
Description of starch
Composition
Starches are mainly α-glucans composed of
two types of molecules: amylose and amylopectin
(SantanaandMeireles,2014;Table1).Amyloseisa
linearD-glucosepolymercontainingabout99%α-1,4
links(Parker andRing,2001).Amylopectin,which
has95%α-1,4linksand5%α-1,6links(Stevneboet
al.,2006),isthemostabundantcomponentofstarches
(Figure 1). On the other hand, amylose content in
starchusuallyuctuatesfrom200to300g/Kg.Some
starch-richfeedssuchaswaxycerealsusuallycontain
negligibleamountsofamylose,whilehigh-amylose
sourcesmaycontainupto700gamylose/Kg.Cereals
suchaswheat,maize,barley,andricecancontaina
waxygenederivedfromnaturalmutationsofgenes
encoding granule bound starch synthase, which is
requiredforamylosesynthesis(Svihuset al.,2005).
Structure
Starchgranulesareformedbyconcentricallygrowing
layersalternatingsemi-crystallineandamorphouslms
(Figure1).Thesemi-crystallineregionismoreabundant
in amylopectin and is more impervious to enzymatic
attackbecauseofits resistance to entryofwater.The
amorphous region is rich in amylose and has lower
densitythanthecrystallinearea,whichfacilitateswater
ow and enzyme attack; however, it is abundant in
hydrogenbonds(Perezet al., 2009).
79
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
Table 1. Properties of starch components.
Characteristic Component
Amylose Amylopectin
General structure Linear Branched
Branch sites Nonea1 per 20 to 25 glucose units
Polymerization degreeb
Molecular weight
~1.000
1 x 105-1 x 106 g/mol
~10.000-100.000
1 x 107-1 x 109 g/mol
Stability in solution Low High
a There is a type of branched amylose with 1 or 2 α-1,6 links per molecule.
b Number of glucose residues per molecule.
Adapted from Parker and Ring, 2001.
Figure 1. (A) Structure of starch granules, represented by organized laminar forms. Amorphous rings (composed mainly of amylose)
separate layers in the semi-crystalline regions (composed primarily of amylopectin). Modied from Perez et al., 2009. (B) Amylopectin
structure according with the cluster model by Myers et al., 2000. Glucan chains are depicted by solid lines while intersections between
them indicate branch linkages. The dotted lines show the limit of amylopectin side chain clusters with unbranched chains associated in
tightly packed double helices. a) depicts the amorphous areas separating amylopectin side chain clusters.
A
B
80
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
Structural alterations
Gelatinization. It is the permanent alteration
of the granule structure by breaking its hydrogen
bonds. Starch absorbs water during gelatinization,
theexpansionbreaks the hydrogenbondsreleasing
someoftheamylosebyleaching,thusbirefringence
is reduced and starch becomes more soluble
and exposed to enzyme activity (Rooney and
Pugfelder,1986).Inexcessofwater,moststarches
gelatinise at temperatures higher than 80 °C. The
gelatinisationtemperatureishigherforsmallstarch
granules. Amylose-rich cereals are more resistant
togelatinisationthancereals with normal andhigh
amylopectin levels (Svihus et al., 2005). Table 2
shows gelatinization values for several foods and
processing methods. The degree of gelatinization
is higher for extruded vs. pelleted food since the
temperatureusedintheprocessishigher(upto250°C
vs.60-95°C;Caballero,2010).
Table 2. Starch gelatinization under several processing methods
in various feeds.
Food Gelatinization (%)1Processing
Corn 17.06 Unprocessed
Sorghum 12.47 Unprocessed
Yucca 7.59 Unprocessed
Concentrate 1 32.49 Pelleting
Concentrate 2 32.55 Pelleting
Concentrate 3 31.92 Pelleting
Corn 79. 3 Extruded
1Assessed by an enzymatic method (Medel et al., 1999).
Retrogradation. It is dened as the reversible
returnofasolubilized,dispersedoramorphousstate
toacrystallineorinsolubleform,whichlimitsstarch
digestibility. Amylose is the main component that
facilitatesretrogradation(Biliaderis,2009).
Sources of starch
Cereal grains and roots
Cerealgrainsare a major source of starch used
inanimalfeeds.Cereals are composed ofpericarp,
endosperm and germ (Figure 2). The pericarp
comprises3to8%ofthekernelweight,althoughit
canbeupto 25% in oats(Everset al.,1999).It is
mostlycomposed(90%)ofhighlyligniedberand
thestarchcontentislessthan10%(Liet al.,2007),
thuspericarpdigestibilitydoesnotexceed40%(Van
Barneveld,1999).
Figure 2.Corn kernel composition.Adapted from Eckhoff
andWatson(2009).
Theendospermrepresentsbetween60and90%of
thegrain.Itisthemorphologicalstructurecontaining
the starch. It also contains proteins, phospholipids
andash,butlittleneutraldetergentber(NDF)and
phosphorus (P; Eckhoff and Watson, 2009). The
endospermlayers,fromtheoutsidein,arealeurone,
peripheralendosperm,horny(orvitreous)andoury.
Boththeperipheraland the horny endospermhave
starch granules surrounded by a matrix abundant
in hydrophobic proteins called prolamines and
non-starch polysaccharides (PNAs; β-glucans,
arabinoxylans, and pectins), which are relatively
impermeabletowaterandenzymaticactivity(Zeoula
andCaldasNeto,2001;Giubertiet al.,2014).Grains
exhibitinghighproportion of peripheral and horny
endospermarecalledvitreousorhorny,whilethose
abundantinoury endosperm arecalledopaqueor
soft(ZeoulaandCaldasNeto,2001).
Non-conventional sources
Starchrepresentsanimportant fraction in many
crops.Mostcereals(i.e.corn, wheat, rice, oat, and
barley) contain between 60 and 80% starch, while
legumes (chickpea, bean, pea) contain from 25 to
81
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
50%, tubers (potato, cassava, cocoyam, arrowroot)
from 60 to 90%, and some green fruit (banana,
mango) contain as much as 70% (Santana and
Meireles,2014).Asincereals,thelargestproportion
ofstarchcorrespondstoamylopectinandthesmallest
to amylose (17-30%; Hu et al., 2010). Amylose
represents14to19%ofstarchincassava,between2
and22%inpotato,andapproximately37%inplantain
(Knowleset al.,2012).Amylopectininstarchfrom
potatoislessbranchedcomparedtocereals(Alvani
et al.,2011).Itisalsohighlyexpandable(Vasanthan
andBhatty,1996) and gelatinizes atrelatively low
temperature(between64.4 and 69.9 °C) compared
tootherstarches(Hernandez-Medinaet al.,2008).
Table3showsamyloseandamylopectinconcentration
indifferentstarchyfoodsandconcentratesfedtodairy
cattle.Differencesinamylose/amylopectinratioaffect
therateofruminalorintestinaldigestion.Digestionrate
ofamylopectinis usuallyhigherthanthat of amylose
(Knowleset al.,2012).
Tab le 3. Amylose and amylopectin content in various feeds.
Source Amylose (%) Amylopectin (%)
Corn 29.24 70.76
Sorghum 29.55 70.45
Yucca 19.84 80.16
Concentrate 1 (C1)* 21.17 78.83
Concentrate 2 (C2) 22.22 77.78
Concentrate 3 (C3) 20.25 79.75
Concentrate 4 (C4) 24.89 75.10
*Isoenergetic and isoproteic concentrates (C) for dairy cattle formulated
with four carbohydrate sources: corn (C1), sorghum (C2), yucca (C3), citrus
pulp (C4). Assessed using the method described by Gibson et al. (1997).
Ruminal and post-ruminal digestion of starch
Once it reaches the rumen, starch is degraded
mainly by amylolytic bacteria and by fungi and
protozoato alesserextent(Huntington,1997).The
α-1-4andα-1-6endoandexoamylasesproducedby
rumenmicroorganismshavetheabilitytohydrolyze
amylose and amylopectin glycosidic linkages,
releasingdifferentoligosaccharides(Table4).
The post-ruminal process of starch degradation
begins with pancreatic α-amylase secretion, which
hydrolyzes amylose and amylopectin into dextrins
andlinearoligosaccharideswithtwotothreeglucose
units. The process is completed by the action of
oligosaccharidases(maltaseandisomaltase)secretedin
theintestinalmembrane(OrtegaandMendoza,2003).
Inruminants,thesite of starchdigestionaffects
thesubstratesabsorbed.Ruminaldigestiongenerates
volatilefattyacids(VFA)forabsorptionandprovides
energyformicrobialproteinsynthesis(Huhtanenand
Sveinbjörnsson,2006). Decreasedrumendigestibility
ofstarchisdesirabletopreventfromacidosisandto
increasethesupplyofglycogenicsubstrates(Svihus
et al.,2005). Starchdigestioninthesmallintestine
implies greater energetic efciency compared with
ruminaldigestionduetoreducedmethaneproduction
and fermentation heat losses and higher efciency
of metabolisable energy utilisation (Huhtanen and
Sveinbjörnsson, 2006). Nevertheless, the increased
energyefciencyfromhigherstarchdigestioninthe
small intestine is offset by the increase in hindgut
fermentation,becauseonlyVFAareabsorbedfrom
thehindgutwhereasmicrobialmatterisexcretedin
feces.Adecrease inruminalstarchdigestion isnot
associated with an increase in its small intestinal
Table 4. Enzymes involved in starch hydrolysis.
Enzyme Link End product
Phosphorylase α -1-4 glycosyl Glucose 1 phosphate
Alpha-amylase α -1-4 glycosyl Linear and branched oligosaccharides
Beta-amylase α -1-4 glycosyl Maltose and limit dextrins
Amyloglucosidase α -1-4 glycosyl and α -1-6 glycosyl Glucose
Isoamylase α -1-6 glycosyl Lineal chains of α -1-4 glucans
Pullulanase α -1-6 glycosyl Lineal chains of α -1-4 glucans
Adapted from Tester et al., 2004.
82
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
digestion,butitisassociatedwithhigherhindgutand
lowertotaltractdigestibility(Larsenet al.,2009).
Forthisreason,rumenisconsideredtheprimary
site of starch digestion. Ruminal digestion usually
accountsfor 75to80% oftheintake, andabout35
to60%ofthestarch entering the small intestine is
degraded.About35to50%ofthestarchthatescapes
digestion in the small intestine is degraded in the
hindgut(Harson,2009).Accordingtoameta-analysis
byMoharreryet al.(2014),ruminalstarchdigestibility
variesgreatly(from 224to942 g/Kg).Theauthors
alsonotedthatstarchconsumptionadverselyaffected
ruminalstarchdigestibility,obtaininganegativeslope
of1.4%perKgincreaseindailystarchintake.Table
5 presents the content and ruminal digestibility of
various starch sources used in livestock.
Table 5. Starch content and ruminal digestibility of several starch
sources commonly used as feed supplements in dairy cattle.
Grain Starch (%) Rumen digestibility (%)a
Corn1,2 76.0 72 - 89.9
Sorghum1,2 71.3 60 - 78.4
Wheat1,2 70.3 88.3 - 88.1
Barley1,2 64.3 80.7 - 84.6
Oats1,258.1 92.7 - 94.0
Yucca380.0 91.0
a Variability is explained by grain treatment (grinding, rolling, aking).
1 Herrera-Saldana et al., 1990. 2Huntington, 1997. 3Vearsilp and Mikled, 2001.
Factors affecting starch digestibility
Granule size
Thisisalimitingfactorinstarchdigestionbecause
therelationship betweenstarchvolumeandsurface
area,andthussubstrate-enzymecontact,decreasesas
granulesizeincreases(Sviluset al.,2005).Cereals
withsmallgranules,suchasoatsandrice,aremore
digestiblethancorn, wheat andpotato,whichhave
longgranules(Bednaret al.,2001;Sviluset al.,2005).
Amylose/amylopectin ratio
Several studies have shown that amylose/
amylopectinratioisnegativelycorrelatedwithstarch
digestion(Bednaret al.,2001).Amyloseisinserted
intoamylopectinmoleculesincreasingtheamountof
hydrogen bonds within the starch molecule, which
negatively impacts the ability of expansion and
enzymeactivity(Caldas-Netoet al., 2000).Likewise,
starchgranuleswithhighamylosecontentaremore
pronetoretrogradation(Sviluset al.,2005).
Floury versus vitreous endosperm
Severalresearchers(Correaet al.,2002;Ngonyamo-
Majeeet al.,2008)havereportedaninverserelationship
betweenstarch digestibilityandvitreousness.Allen
et al.(2008),studiedruminalandduodenal-stulated
cows using corn with vitreous endosperm content
varyingbetween25and66%.Theyfoundthatfeeding
cornwith66%ofvitreousendospermreducedruminal
digestionin19.1%andoveralldigestionin7.1%.
Starch-lipid complexes
Quantitatively,lipids are the major non-starch
compoundsinstarchgranulesandcanbefoundas
freefattyacids(mostly palmiticandlinoleicacid)
and lysophospholipids (Svihus et al., 2005). In
cereal grains, a portion of amylose has insoluble
starch-lipidcomplexes,whichformhelicalstructures
that provide greater adhesion between molecules,
dininish starch swelling (Vasanthan and Bhatty,
1996), decrease their solubility (Rooney and
Pugfelder,1986)andreducetherateofenzymatic
digestion(Croweet al., 2000).Cassavaandpotato
starch contain a smaller percentage of lipids
compared with cereal starch (Zeoula and Caldas
Neto,2001;Alvaniet al.,2011).
Starch-protein complexes
The proteinaceous matrix surrounding starch
granulesaffectsstarchdigestibility.Digestibilityis
negativelyassociatedwiththepresenceofprolamins.
Prolaminsarestorageproteinsthatreceiveadifferent
nameforeach cereal,namelyzein(corn), karins
(sorghum), gliadin (wheat), hordeins (barley),
secalins(rice),andavenines(oats).Usually,wheat,
oats, rice and barley have fewer prolamins than
cornand sorghum(Momanyet al.,2006; Giuberti
et al.,2014).
83
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
Zeinsaccountfor50to60%oftheproteininthe
wholegrainand are locatedattheperiphery of the
cell.Flouryendospermislowinzeincomparedwith
vitreous endosperm (Giuberti et al., 2014). Zeins
arenotsolubleintherumenenvironment(Lawton,
2002).Starchdigestionrequiresthatrumenbacteria
degradezeinsrstviaproteolysis,beforestartingthe
amylolyticactivity(Cotta,1998).
Processing of cereal grains
Grain processing using temperature, humidity
andpressurefacilitatebinding of bacteria tostarch
granules,increasingits digestibility (Huntington et
al., 2006). Common processing includes grinding,
pelleting, dry rolling, steam rolling (addition of
water before rolling), and steam aking. All these
processes aim to break grain barriers such as the
pericarp and the protein-starch matrix, allowing
accessof microorganismstostarchgranules.These
processesalsoreducetheparticlesize,andincrease
surfaceareaandmicrobialcolonization(Giubertiet
al., 2014). The response to processing varies with
differentgrains,withsorghum>corn>oats=barley>
wheat(Huntingtonet al.,2006).
Gelatinizationofstarchmakesitmorewater-soluble
anddigestible.AccordingtoHuntington(1997),steam
akingofcornimprovesruminal,post-ruminalandtotal
tractdigestibilitycomparedwithdryrolling(85vs.70%,
92vs.69%,and99vs.90%,respectively).According
toSveinbjörnssonet al.(2007),heattreatmentincreases
starchdegradationduring8hofin vitro incubation,as
follows:0.155vs.0.870forpurepotatostarch,0.491vs.
0.815forpeas,0.686vs.0.913forbarley,and0.351
vs.0.498formaize.
Only a fraction of starch is gelatinazed during
steamconditioningand pelleting offeeds(from10
to200gstarch/Kg).Theexpanderprocessing,onthe
otherhand,addsupto80gwater/Kgwhilethediet
reachesahighpressureandtemperaturesabove100°C,
thusresultinginbetween220and 350 g starch/Kg
gelatinizedduringthisprocess.The extrusion adds
evenmorewater(upto180gwater/Kg)andthediet
issubjectedto evenhighertemperatures(>110°C)
underhighpressure,thusresultinginmorecomplete
gelatinisation and disintegration of starch granules
(Svihus et al.,2005).ThiswasevidencedbyOffner
et al.(2003),whoreported0.607,0.663,0.743,0.746,
0.819, 0.830, and 0.867 effective degradabilities
foruntreated, cracked, ground, pelleted, expanded,
steamakedandextrudedcorn,respectively(passage
rate0.04h-1).Graintypealsoinuencestheresults.
Steamakingofcorneliminatedtheadverseeffects
ofvitreousendospermandprotein-starchmatrix on
digestibilityincomparisonwithdryrolling.Thiswas
contrary to the results obtained for barley, a grain
withahighlydigestibleprotein-starchmatrix,where
nodifferencewasobservedbetweenbothtreatments
(Engstromet al.,1992).
Starch source
The highest effective degradability of starch
in cereal grains was obtained for oats, wheat and
barley,being lower for corn and sorghum. Corn
and especially sorghum have a high proportion
of peripheral and horny endosperm resulting in
increased resistance to microbial activity (Rooney
andPugfelder,1986),unlikewheatandoats,which
have higher proportion of floury endosperm. In
addition, corn and sorghum have a denser protein
matrix(Kotarskiet al.,1992).Thein vitro experiment
byLanzaset al.(2007)measuredfractionalgasrates,
as a measure of starch digestion (Huhtanen and
Sveinbjörnsson,2006),reporting0.26,0.24,0.15,and
0.06h-1 ratesforwheat,barley,corn andsorghum,
respectively(p<0.001).
Cassavahashighereffectivedegradabilitythan
cornandsorghumduetoitslackofpericarp,protein
matrix,hornyandperipheralendosperm;aswellas
lowproportionoflipids,lackofassociationsbetween
starchandprotein,lessamylose,moreamylopectin,
lesshydrogenbonding,andgreaterswelling when
subjected to chemical processes. Cassava starch
is composed exclusively of amylopectin in the
crystalline region and amylose in the amorphous
region, which prevents excessive formation of
hydrogenbondswithamylopectin,allowingamylose
to be readily leached. This is contrary to cereals,
whichhaveamyloseinthecrystallineregion(Zeoula
andCaldasNeto,2001).Effectivedegradabilityof
corn,sorghumandcassava,reported by Offner et
al.(2003),was 0.597,0.603y0.802, respectively
(passagerate0.06h-1).
84
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
Physiological restrictions of the small intestine
Starch digestibility in the small intestine is
limited.Asdigestaowincreases,starchdigestibility
decreases (Huntington et al., 2006). Factors that
limitstarchdigestibilityincludecontrolledglucose
absorption,decientenzymeaccessibilitytostarch
granules,alterationsinruminalandintestinalpH,and
lackofsynchronybetween starch ow throughthe
intestineandamylasesecretion(Owenset al.,1986).
Starchdigestion efciencyinthesmallintestine
variesbetweensources.Tothiet al.(2003)reported
higher digestibility for barley starch in the small
intestine compared with cornstarch, resulting in
higher small intestine absorption in terms of g/Kg
starchingested.
Starch and ruminal acidosis
Starchfermentationincreasesvolatilefattyacids
(VFA) and lactate production, which can reduce
ruminal pH and kill cellulolytic microorganisms,
leadingtodecreasedberdigestibilityanddrymatter
(DM) intake. Additionally, it can cause metabolic
disorders such as acute and sub acute ruminal
acidosis, rumenitis, laminitis, liver abscesses and
polyencephalomalacia(Plaizieret al.,2009).
The risk of ruminal acidosis increases when
starchdigestionrate increases.Thisratevaries with
graintypeandprocessingandgenerallyoccursinthe
followingorder:wheat(32%h)>oat>barley(29%h)
>potato(5%h)>corn(2%h)andsorghum(Callison
et al.,2001;Mosaviet al.,2012).Krauseet al.(2002)
reportedlowerruminalpHinlactatingcowsfedhigh
moisture corn vs. dried corn. Gulmez and Turkmen
(2007) observed a decrease of ruminal pH (<6) in
lactatingcowswhencornwasreplacedbywheat.They
alsoobservedlowpH(<5.8)over13continuoushours
whenwheatwastheonlysourceofstarch.
Cassavaisused asareadily fermentableenergy
source for ruminants. It has a high rate and extent
of ruminal degradation, as evidenced by Khampa
andWanapat(2006)whocomparedcassavavs.corn
supplementation at 1 and 2% of live weight. They
found that 2% cassava supplementation lowered
ruminalpH(5.3vs.6.4)andcellulolyticbacteria(2.3
vs.5.9x107).
Starch and methanogenesis
Ruminal digestion of ber-rich diets increases
hydrogen and carbon dioxide production, which
are substrates for methanogenesis. Moreover,
starch-rich diets change the bacterial ecology by
favoring propionic-acid producing bacteria over
methanogens (Bannink et al., 2006; Ellis et al.,
2008).Propionicacidproductionfromdicarboxylic
acids(aspartate,malate,fumarate)viathesuccinate
pathway is thermodynamically more efficient
than methanogenesis (Offner and Sauvant, 2006).
Moreover,rapidly-fermentingdietsreducemethane
productionbydecreasingruminalpH,whichaffects
thegrowthofmethanogens,protozoa (Hook et al.,
2011)andcellulolyticbacteria(Sunget al.,2007),
andincreasespassagerate,whichreducesprotozoans
and,thereby,interspecieshydrogentransfer(Kumar
et al.,2013).
Agle et al. (2010) reported that diets with higher
proportionofnon-structuralcarbohydrates(52and72%)
resultedinnumerically lowermethaneemissions(1.5
vs.3.4g/hour,respectively),althoughresultsshowed
nodifferenceduetohighvariability.Arecentstudyin
grazingHolsteinFriesiancowsfoundthatconcentrate
level (2, 4, 6, and 8 Kg/cow/day) had no impact on
methane emissions (287, 273, 272, and 277 g/day,
respectively). However, when it was associated with
DMandenergyconsumption,methanedecreasedwith
increasinglevelsofconcentrate(gCH4/KgDM:20,19.3,
17.7,and18.1;CH4-E/grossenergyintake:0.059,0.057,
0.053,and0.054,respectively).Theydemonstratedthat
concentratesupplementationtograzingcowsincreased
milkproductionanddecreasedmethaneemissionsper
unitofmilkproduced(Jiaoet al.,2014).Aguerreet
al.(2011)foundthatchangingforage:supplement
ratio(F/S)from68:32to47:53reducedmethane
emissionsfrom648to538g/cow/day.Pirondiniet
al.(2015)evaluatedtheeffectofstarch(23.7and
27.7%DM)onmethaneemissionsindairycows,
ndingloweremissionsforstarch-richdiets(415
vs. 396 g/d, respectively). Finally,Hatew et al.
(2015) investigated the effect of starch (270 vs.
530g/Kg concentrateDM)andfermentationrate
85
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
(fastvs.slow)indairycows.Theyfoundnodifferences
inmethaneproducedperKgoffat-correctedmilkand
protein,orper KgDMconsumed, orasafraction of
thegrossenergyconsumed.However,thehighstarch
diet(46.9vs.43.1g/Kg)hadlessruminalmethane
per Kg of fermentable organic matter (42.6 vs. 47.4
g/Kg).Haleset al.(2012)evaluatedtheeffectofcorn
processing. They found that Jersey animals eating
steamedcornakesproducedlessmethanethanthose
eatingdryrolledcorn(58.77vs.74.31L/animal,11.65
vs. 14.06 L/KgDMintake,2.47 vs. 3.04% ofgross
energyconsumed,and3.30vs.4.18% of digestible
energ y consu med). The reduction was explained by
differences in ruminal fermentation, changi ng the
placeofdigestion(fromtherumentotheintestine),or
decreasedruminalpH.Scarceliteratureisavailableon
theeffectofstarchsourceandprocessingonmethane
emissions.InastudyreportedbytheCCRP(2012)a
reductionofmethaneemissionsincowsfedground
wheat(219gmethane/day,11.1gmethane/KgofDM
consumed)vs.groundcorn(424and19.5gmethane,
respectively).
The difference in methane production per starch
vs. cellulose unit does not depend on the chemical
composition,asboth carbohydratesarehydrolyzedto
glucosebeforefermentation.Conversely,hemicellulose
polymerincludessugarswith5to6carbons,whichcould
lead to changes in the fermentation prole (different
proportionsofVFA)andmethaneemissions.Ratherthan
thechemicalcomposition,thedifferences in methane
production from starch, cellulose and hemicellulose
appear to be a function of the microbial species that
degrade each substrate. Fermentation patterns and
methaneproductionvaryasmicrobialspeciesadaptto
changes in dietary substrates and ruminal conditions.
Additionally,associative effects between nutrients
inuence methane production, which means that this
gascanbeestimatedforthedietandnotforindividual
ingredients(Knappet al.,2014).
Relationship between starch and milk
composition and yield
Effect on milk yield and fat content
Milk yield response depends on the starch
source(Khorasaniet al.,2001) and its degradation
rate. Mosavi et al. (2012) compared milk yield in
Holstein cows consuming wheat, barley,maize or
potatoes. They found a reduced milk yield for the
diet added with potatoes, and attributed it to its
lower digestibility. Supplementation with rapidly
degradablestarchesinrumen-suchasbarley,wheat
or cassava- increases yield but reduces milk fat
(Sutton, 1989). Poore et al. (1993) found a milk
yieldincreaseof3.4Kg/dayand0.4%fatreduction
whenruminaldigestibilityincreasedfrom48to72%.
Milkfatreductionisassociatedwithchangesinthe
fermentationprole,causedbyarelativereductionin
lipogenicvs.glycogenicprecursors(Reynoldset al.,
1997).Rumenpropionateincreaseswhileacetateand
butyratedecreasewheningestionofrapidlydegradable
starchexceeds7Kg/day(Casperet al.,1990).Jurjanz
et al.(1998)evaluatedstarchsourceand level(wheat
orpotatopeels;<5,6,or>7.5Kg/d)onmilkyieldand
composition.Highstarchconsumptionfrom potato
peels(>7.5Kg/day)leadtoslowerruminaldegradation
andincreasedmilkfatcontent(+3.3g/Kg)compared
towheat.Fedinloweramounts,thestarchsourcedid
notaffectmilkfatsynthesis.Thelowerrateofstarch
degradationcouldhavereleasedmorefatprecursors.
Mosavi et al.(2012)alsoobservedslowerruminal
degradation for corn starch compared with wheat,
barley or potato, as well as increased acetate and
butyrateproductionalongwithhighermilkfat(3.43%
vs.3.12,3.09,and3.13%,respectively).Contraryto
thesendings,Chanjulaet al.(2004)didnotobserve
differences in milk production and compositional
qualitybyaddingcorn(lowdegradability)orcassava
(highdegradability)attwoinclusionlevels(55vs.
75%).
AccordingtoKennellyandGlimm(1998),milkfat
isreducedduetheinhibitoryeffectofmethylmalonyl
CoA(synthesizedfrompropionicacid)onfattyacid
synthesisinthemammarygland.MethylmalonylCoA
accumulation competitively inhibits malonyl CoA
(VanSoest,1994).
Reynoldset al.(1997)associatedmilkfatdecrease
withincreasedlevelsofplasmaglucoseandinsulin
in animals fed high amounts of the supplement.
Insulinlowerslipolysisandpromoteslipogenesisin
adiposetissue,reducingfattyacidsavailabilitytothe
mammarygland,thusdecreasingmilkfat.According
to Van Soest (1994), lipogenesis in adipose tissue
86
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
is insulin dependent, which is not the case for the
mammarygland.
Thereductioninmilkfatcanalsobeexplainedby
increasedtrans-unsaturatedfattyacidsintherumen
(Gaynoret al.,1995).Cerealgrainsarehighinlinoleic
and oleic acid. A ruminal pH decrease due to the
dietcandisturbbiohydrogenationofunsaturated18
carbonfatty acidsincreasingtransC18:1fattyacid
(transisomersresultfromincompletemicrobialbio-
hydrogenationoflinoleicacidintostearicacid).Itis
knownthatruminalandmilkincreaseintransC18:1
iscorrelatedwithlowmilkfatlevelsincowsfedhigh
graindiets(Griinariet al.,1998).Corncontainsahigh
concentration of linoleic (C18:2) and octadecanoic
acid (trans C18:1),whichinhibit biohydrogenation
andreducelipogenesisinthemammarygland.
AccordingwithMontoyaet al.(2004),theoptimal
content of nonstructural carbohydrates (NSC) for
maximizingmilkyieldisbetween30and38%ofthe
diet. Those researchers supplemented cows with 4
Kgofacommercialconcentrateand0,6,and12Kg
offreshpotatoes,thusNSCaccountedfor7.2,12.4,
and17.9%ofDMintake.Milkyieldwashigherfor
the potato treatments (17.2 vs. 15.8 liters/cow/day;
p=0.004).Nevertheless,nodifferencewasobserved
fortheinclusionof6vs.12Kgpotatoes,whichcould
beassociatedwithalimitedabilitytousepotatoNSC.
Theirstudyfoundnodifferencebetweentreatmentsfor
fatpercentageand production(p>0.05).Pimentel et
al.(2006)alsoevaluatedcassavasupplementationon
milkyieldandcomposition.Theyreplaced0,25,50,
and75%ofcornwithcassava,ndingalineardecrease
of30and1.15g/dayinmilkyield(correctedfor3.5%
fat)andfatproduction,respectively.Accordingtothe
authors,theviabilityandlevelofcornsubstitutionwith
cassavawilldependonalowcostofsubstitutionthat
compensatesfortheexpecteddecreaseinproduction.
Dann et al. (2014) evaluated three starch levels
(17.7, 21.0, and 24.6%) in Holstein cows using
increasing levels of ground corn. They found that
solids-corrected milk yield was not affected by the
diet, averaging 40.8 Kg/d. They concluded that
starch content did not affect rumen fermentation or
performance.Theirhigheststarchlevel(onaDMbasis)
was between 23 to 30%, which follows within the
recommendedrangeforlactatingcows(Grant,2005).
Delahoyet al.(2003)conductedtwoexperiments
assuming that supplements such as steam-flaked
corn(SFC)andnon-forageber(NFF)sourcesmay
provide benets over corn. In the rst experiment,
animalswereassignedtoacracked-corn(CC)orto
asteam-akedcorn(SFC)supplement.Inthesecond
experiment,animalswereofferedgroundcorn(GC)
ornoforagesourcesofber(NFF).No differences
wereobservedinmilkyield(24.3and27.5Kg/dfor
experiments1and2,respectively),explainedbyalack
ofdifferenceinnetenergyconsumptionforlactation,
which exceeded the requirements (Experiment 1).
Anotherfactorthatcouldexplaintheseresultsisthe
qualityofthepasture,whichdidnotreducethepH,a
targettoimprovebyNFFinclusioninExperiment2.
Effect on the protein content
Dietsrichinnonstructuralcarbohydratesincrease
ruminalammonianitrogenutilizationandmicrobial
protein synthesis (Svihus et al., 2005). Therefore,
whendietaryenergyincreases,metabolizableprotein
is also increased. Mosavi et al. (2012) evaluated
theeffectof four starch sourcesonmilkproteinin
Holstein cows. While protein levels of milk were
similar (3.03, 3.10, 3.14, and 3.04%) for wheat,
barley,corn and potato supplements, respectively,
milkproteindifferedin favor of wheat, barley and
corn,comparedtopotato(1.08,1.06,1.06,and0.98
Kg/d,respectively; p=0.02).GozhoandMutsvangwa
(2008)foundnodifferenceinmilkproteinforanimals
feddietsbasedonwheat,barleyorcorn,buthigher
milk protein was observed for diets based on corn
vs. oats. On the contrary, other studies comparing
slowversusfastruminaldegradingstarchesfoundno
differencesin milkprotein(Khorasaniet al., 2001;
Silveira et al.,2007;Cabritaet al.,2009).
It has been suggested by Huhtanen and
Sveinbjörnsson(2006)thatenhancedstarchdigestion
in the small intestine increases milk protein,
perhapsbysparingaminoacidsfrombeingusedfor
gluconeogenesisintheliver.Theyreportastudyin
whichmilkproteinyieldwasslightlybutsignicantly
higherformaizecomparedwithbarleysupplements.
Contrarytothisconcept,increasingstarchdigestion
intherumenisconsideredadvantageousintermsof
milkproteinyield,sinceitincreasestheenergysupply
formicrobialproteinsynthesisandthemetabolisable
87
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
protein ow to the small intestine (Thair, 2012).
Finally, Reynolds (2006) reports a study in which
therewasnoevidencethatthesiteofstarchdigestion
increasedmilkproductionorchangeditscomposition.
Final thoughts
Rumenfermentationofstarch-althoughitreduces
energy efciency over the enzymatic digestion in
the intestine- determines its nutritional value for
ruminants. The rate and extent of ruminal starch
digestion alters pH, cellulolytic activity, microbial
proteinsynthesis,methaneemissionsand,eventually,
animalproduction.Thereisa considerablebodyof
researchon degradation potential of various cereal
grains, but little information on non-traditional
sourcesofstarchthatcouldreplacecerealgrainswhen
availabilityandcostsarecompetitive.Thestructural
traitsofstarch fromthesesources,their interaction
withothercomponents,andtheeffectofprocessing
should be examined. In vitro digestion techniques
constituteastartingpointforstudyingtheextentand
kineticsofstarchdegradationfromnon-conventional
sources.
Starch is the main energy component used in
ruminants feed to modulate ruminal fermentation
andpromote sync with the nitrogen sources. More
researchisrequiredtoevaluatetheeffectofusingone
ormoresources of starch —with different degrees
of degradability and processing— on protein use
efficiency, milk yield and compositional quality.
Studiesshouldfocusonadditionlevelsandnutrient
composition of the forage base according with the
stage of lactation and energy requirements of the
animal.
Acknowledgements
The Administrative Department of Science,
TechnologyandInnovation(Colciencias,Colombia,
call 569 of 2012. Code 1115+569-33874) and
the Sustainability Strategy 2014-2015 (CODI,
UniversidaddeAntioquia,Colombia)supportedthe
research project entitled “Evaluación in vitro e in
vivodediversasestrategiasnutricionalesparamitigar
las emisiones de metano y su impacto productivo,
reproductivo y económico en ganadería de leche
especializadaenelnortedeAntioquia”,whichmade
possiblethisliteraturereview.
Conict of interest
Theauthorsdeclaretheyhavenoconictsofinterest
withregardtotheworkpresentedinthisreport.
References
Agle M, HristovAN, Zaman S, Schneider C, Ndegwa PM,
VaddellaVK.Effectofdietaryconcentrateonrumenfermentation,
digestibility,andnitrogenlossesindairycows.JDairySci2010;
93:4211-4222.
AguerreMJ,WattiauxMA,Powell JM, Broderick GA,Arndt C.
Effectofforage-to-concentrateratioindairycowdietsonemission
ofmethane,carbondioxide,andammonia,lactationperformance,
andmanureexcretion.JDairySci2011;94:3081-3093.
AllenMS,LonguskiRA,YingY.Endospermtypeofdryground
corngrainaffectsruminaland total tract digestion of starchin
lactatingdairycows.JDairySci2008;91(E-Suppl.1):529.
AlvaniK,QiX,TesterRF,SnapeCE.Physico-chemicalproperties
ofpotatostarches.FoodChem2011;125:958-965.
BanninkA,KogutJ,DijkstraJ,FranceJ,KebreabE,VanVuuren
AM,TammingaS.Estimationof the stoichiometry of volatile
fatty acid production in the rumen of lactating cows. J Theor
Biol2006;238:36-51.
Bednar GE, PatilAR, Murray SM, Grieshop CM, Merchen NR, 
Fahey GC. Starch and ber fractions in selected food and feed
ingredientsaffecttheirsmallintestinaldigestibilityandfermentability
andtheirlargebowelfermentabilityinvitroinacaninemodel.JNutr
2001;131:276-286.
Biliaderis CG. Structural transitions and related physical
propertiesofstarch.In:BeMillerJ,WhistlerR,editors.Starch:
ChemistryandTechnology.3thed.AcademicPressUSA;2009.
p.293-372.
CaballeroDJ.Efectodelusodealimentobalanceadopeletizado
desdeelinicio hasta el engordeenlagranja porcina el Hobo,
SantaCruz deYojoa,Honduras.Tesisde pregrado.Zamorano,
Honduras. 2010; [Access date: March 9, 2015]. URL: http://
bdigital.zamorano.edu/bitstream/11036/236/1/T2917.pdf.
CabritaARJ,ValeJMP,BessaRJB,DewhurstRJ,FonsecaAJM.
Effectsofdietarystarchsourceandbuffersonmilkresponsesand
rumenfattyacidbiohydrogenationindairycowsfedmaize-based
diets.AnimFeedSciTechnol2009;152:267-277.
CaldasNetoSF,ZeoulaLM,BrancoAF,DoPradoIN,DosSantos
GT,FregadolliFL,KassiesMP,DalponteAO.Mandiocaeresíduos
dasfarinheirasnaalimentaçãoderuminantes:Digestibilidadetotal
eparcial.RevBrasZootec2000;29:2099-2108.
88
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
Callison,SL,FirkinsJL,EastridgeML,HullBL.Siteofnutrient
digestion by dairy cows fed corn of different particle sizes or
steam-rolled.JDairySci2001;84:1458-1467.
CasperDP,SchingoetheDJ,EisenbeiszWA.Responseofearly
lactationdairycowsfeeddietsvaryinginsourceofnonstructural
carbohydrateandcrudeprotein.JDairySci1990;73:1039-1050.
ChanjulaP,WanapatM,WachirapakornC,RowlinsonP.Effect
ofsynchronizingstarchsourcesandprotein(NPN)intherumen
onfeedintake,rumenmicrobialfermentation,nutrientutilization
andperformanceoflactatingdairycows.AsianAustJAnimSci
2004;17:1400-1410.
CCRP,ClimateChangeResearchProgram.Effectofstarchbased
concentrateswithdifferentdegradationcharacteristicsonmethane
emissions.Reducingemissionsfromlivestockresearchprogram.
Australian Government, Department ofAgriculture, Fisheries
andForestry.2012.
Correa CES, Shaver RD, Pereira MN, Lauer JG, Kohn K.
Relationshipbetweencornvitreousnessandruminalinsitustarch
degradability.JDairySci2002;85:3008-3012.
CottaMA.Amylolyticof selected speciesof ruminal bacteria.
AppEnvironMicrobiol1998;54:772-776.
Crowe TC, Seligman SA, Copeland L. Inhibition of enzymic
digestionofamylose byfreefatty acidsin vitrocontributes to
resistantstarchformation.JNutr2000;130:2006-2008.
DannHM,TuckerHA,CotanchKW,KrawczelPD,MooneyCS,
GrantRJ,EguchiT.Evaluationoflower-starchdietsforlactating
Holsteindairycows.JDairySci2014;97:7151-7161.
Delahoy JE, Muller LD, Bargo F, Cassidy TW, Holden LA.
Supplementalcarbohydratesourcesforlactatingdairycowson
pasture.JDairySci2003;86:906-915.
EckhoffSR,WatsonSA.CornandSorghumstarches:Production.
In: BeMiller J, Whistler R, editors. Starch: Chemistry and
Technology.3thed.AcademicPressUSA;2009.p.373-439.
Ellis JL, Dijkstra J, Kebreab E, BanninkA, Odongo NE,
McBrideBW,FranceJ.Aspectsofrumenmicrobiologycentralto
mechanisticmodellingofmethaneproductionincattle.JAgricul
Sci2008;146:213e33.
Engstrom DF,Mathison GW,Goonewardene LA. Effect of
beta-glucan,starchandbercontentandsteamvsdryrollingof
barley-grainonitsdegradabilityandutilizationbysteers.Anim
FeedSciTechnol1992;37:33-46.
EversAD, O’Brien L, Blakeney AB. Cereal structure and
composition.AustJAgricRes1999;50:629-650.
GaynorPJ,WaldoDR,CapucoAV,ErdmanRA,DouglassLW,
TeterBB.Milkfatdepression,theglucogenictheoryandtrans-C
18:1fattyacids.JDairySci1995;78:2008-2015.
GibsonTS,Solah VA, McCleary BV.Aprocedureto measure
amylose in cereal starches and ours with concanavalinA. J
CerealSci1997;25:111-119.
Giuberti G, GalloA, Masoero F, Farraretto LF, Hoffman PC,
ShaverRD.Factors affectingstarch utilization inlarge animal
foodproductionsystem:Areview.Starch2014;66:72-90.
GozhoGN,MutsvangwaT.Inuenceofcarbohydratesourceon
ruminalfermentationcharacteristics,performance,andmicrobial
proteinsynthesisindairycows.JDairySci2008;91:2726-2735.
Grant,R.2005.Optimizingstarchconcentrationsindairyrations.
ProcTri-StateDairyNutrConf,FortWayne,IN,2005.p.73-79.
GriinariJM,DwyerDA,McGuierMA,BaumanDE,Palmquist
DL, Nurmela KV. Trans- octadecenoic acids and milk fat
depressionin lactatingdairy cows.J DairySci 1998;81:1251-
1261.
GulmezBH,TurkmenII.Effectofstarchsourceswithdifferent
degradationratesonruminalfermentationoflactatingdairycows.
RevueMédVét2007;158:92-99.
HalesKE,ColeNA,MacDonaldJC.Effectsofcornprocessing
methodanddietaryinclusionofwetdistillersgrainswithsolubles
on energy metabolism, carbon-nitrogen balance, and methane
emissionsofcattle.JAnimSci2012;90:3174-3185.
Hatew B, Podesta SC, Van Laar H, Pellikaan WF,Ellis JL,
DijkstraJ,BanninkA.Effectsofdietarystarchcontentandrate
offermentationonmethaneproductioninlactatingdairycows.
JDairySci2015;98:486-499.
HarsonDL.Understandingstarchutilizationinthesmallintestine
ofcattle.Asian-AustJAnimSci2009;22:915-922.
Hernández-Medina M, Torruco-Uco JG, Chel-Guerrero L,
Betancur-AnconaD.Caracterizaciónsicoquímicadealmidones
de tubérculos cultivados en Yucatán, México. Cienc Tecnol
Aliment2008;28:718-726.
Herrera-Saldana R, Huber TJ, Poore MH. Dry matter, crude
protein,andstarchdegradability of ve cereal grains. JDairy
Sci1990;73:2386-2393.
Hook SE, Steele MA, Northwood KS, WrightAD, McBride
BW.Impactofhigh-concentratefeedingandlowruminalpHon
methanogensandprotozoa intherumenofdairycows.Microb
Ecol2011;62:94-105.
Hu G, Burton C, Yang C. Efcient measurement of amylose
contentincerealgrains.JCerealSci2010;51:35-40.
Huhtanen P, Sveinbjörnsson J. Evaluation of methods for
estimatingstarchdigestibilityanddigestiónkineticsinruminants.
AnimalFeedSciTechnol2006;130:95-113.
HuntingtonGB.Starchutilizationbyruminants:frombasicsto
thebunk.JAnimSci1997;75:852-867.
HuntingtonGB,HarmonDL,RichardsCJ.Sites,rates,andlimits
ofstarchdigestionandglucosemetabolismingrowingcattle.J
AnimSci2006;84:E14-E24.
Jiao HP, Dale AJ, Carson AF, Murray S, GordonAW, Ferris
CP.Effectofconcentratefeedlevelonmethaneemissionsfrom
grazingdairycows.JDairySci2014;97:7043-7053.
89
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
JurjanzS,Colin-SchoellenO,GardeurJN,LaurentF.Alterationof
milkfatbyvariationinthesourceandamountofstarchinatotal
mixeddietfedtodairycows.JDairySci1998;81:2924-2933.
Kennelly JJ, Glimm DR. The biological potential to alter the
compositionofmilk.CanJAnimSci1998;78(Suppl):23.
KhampaS,WanapatM.Inuencesofenergysourcesandlevels
supplementationonruminalfermentationandmicrobialprotein
synthesisindairysteers.PakistanJNutrition2006;5:294-300.
KhorasaniGR,Okine EK,KennellyJJ. Effectsofsubstituting
barleygrain withcorn onruminal fermentationcharacteristics,
milkyieldandmilkcompositionofHolsteincows.JDairySci
2001;84:2760-2769.
KnappJR,LaurGL,VadasPA,WeissWP,TricaricoJM.Enteric
methaneindairycattleproduction:Quantifyingtheopportunities
andimpact of reducingemissions. JDairySci 2014;97:3231-
3261.
KnowlesMM,PabonML,CarullaJE.Useofcassava(Manihot
esculenta Crantz) and other starchy non-conventional sources
inruminantfeeding.RevColomCiencPecu2012;25:488-499.
KotarskiSF,WaniskaRD,ThurnKK. Starchhydrolisis bythe
rumenmicroora.JNutr1992;122:178-190.
Krause KM, Combs DK, Beauchemin KA. Effects of forage
particlesize andgrainfermentabilityinmid-lactationcows.II.
RuminalpH andchewing activity.JDairy Sci2002; 85:1947–
1957.
Kumar S, Dagar SS, PuniyaAK, Upadhyay RC. Changes in
methaneemission, rumen fermentationin responsetodiet and
microbialinteractions.ResVetSci2013;94:263-268.
LanzasC,FoxDG,PellAN.Digestionkinetics ofdriedcereal
grains.AnimFeedSciandTechnol2007;136:265-280.
LarsenM, LundP,WeisbjergMR,HvelplundT.Digestionsite
ofstarchfromcerealsandlegumesinlactatingdairycows.Anim
FeedSciandTechnol2009;153:236-248.
LawtonJW.Zein:Ahistoryofprocessinganduse.CerealChem
2002;79:1-18.
Li L, Blanco M, Jane JL. Physicochemical properties of
endosperm and pericarp starches during maize development.
CarbohydrPolym2007;67:630-639.
Medel P, Salado S, de Blas JC, Mateo GG. Processed cereals
indietsforearly-weanedpiglets.AnimalFeedSciandTechnol
1999;82:145-156.
MoharreryA,LarsenM,WeisbjergMR.Starchdigestioninthe
rumen, small intestine, and hind gut of dairy cows –A meta-
analysis.AnimFeedSciTechnol2014;192:1-14.
MomanyFA,SessaDJ,LawtonJW,SellingGW,HamakerSA,
WilletJL. Structural characterization of alpha-zein.J Agric
FoodChem2006;54:543-547.
MontoyaNF,PinoID,CorreaHJ.Evaluacióndelasuplementación
con papa (Solanum tuberosum) durante la lactancia en vacas
holstein.RevColCiencPec2004;17:241-249.
MosaviGHR, FatahniaF,MirzaeiAlamoutiHR,MehrabiAA,
DarmaniKohH.Effectofdietarystarchsourceonmilkproduction
andcompositionof lactatingHolsteincows. SAfr JAnim Sci
2012,42:201-209.
MyersAM,MorellMK,JamesMG, BallSG. Recentprogress
toward understanding biosynthesis of the amylopectin crystal.
PlantPhysiol2000;122:989-997.
Ngonyamo-MajeeD,ShaverRD,CoorsJG,SapienzaD,Lauer
JG.  Relationship between kernel vitreousness and dry matter
degradability for diverse corn germplasm.  II.Ruminal and
post-ruminal degradabilities. Anim Feed Sci Technol 2008;
142:259-274.
OffnerA, Bach A, Sauvant D. Quantitative review of in situ
starchdegradationintherumen.AnimFeedSciTechnol2003;
106:81-93.
OffnerA, Sauvant D. Thermodynamic modeling of ruminal
fermentations.AnimRes2006;55:343-365.
OrtegaME,MendozaG.Starchdigestionandglucosemetabolism
intheruminant:areview.Interciencia2003;28:380-386.
Owens FN, Zinn RA, KimYK.  Limits to starch digestion in
theruminant’ssmallintestine.JAnimSci1986;63:1634-1648.
ParkerR,RingSG.Aspectsofthephysicalchemistryofstarch.
JCerealSci2001;34:1-17.
PerezS, BaldwinPM,GallantDJ.Structuralfeaturesof starch
granulesI.In:BeMillerJ,WhistlerR,editors.Starch:Chemistry
andTechnology.3thed.AcademicPressUSA;2009.p.149-192.
PimentelRR,AndradeFM,ChavesAS,deLimaLE,RamosVR.
Substituição do milho pela raspa de mandioca em dietas para
vacasprimíparasemlactação.RBrasZootec2006;35:1221-1227.
Pirondini M, Colombini S, Mele M, Malagutti L, Rapetti L,
GalassiG,CrovettoGM.Effectofdietarystarchconcentration
andshoilsupplementationonmilkyieldandcomposition,diet
digestibility,and methaneemissionsin lactating dairy cows.J
DairySci2015;98:357-372.
Plaizier JC, Krause DO, Gozho GN, McBride BW. Subacute
ruminalacidosisindairycows:thephysiologicalcauses,incidence
andconsequences.VetJ2009;176:21-31.
PooreMH,MooreJA,SwingleRS,EckTP,BrownWH.Response
oflactatingHolstein cowstodiets varying inbersource and
ruminalstarchdegradability.JDairySci1993;76:2235-2243.
ReynoldsCK.Productionandmetaboliceffectsofsiteofstarch
digestionindairycattle.AnimFeedSciTechnol2006;130:78-94.
ReynoldsCK,SuttonJD,BeeverDE.Effectsoffeedingstarch
to dairy cattle on nutrient availability and production. In:
GarnsworthyPC,WisemanJ,editors.Recentadvancesinanimal
nutrition Nottingham University Press. Nottingham 1997. p.
105-134.
RooneyLW,PugfelderRL.Factorsaffectingstarchdigestibility
withspecial emphasison sorghumandcorn.JAnimSci1986;
63:1607-1623.
90
Rev Colomb Cienc Pecu 2016; 29:77-90
Gómez LM et al. Starch in ruminant diets: a review
SantanaA,MeirelesA.New starchesarethetrendforindustry
applications:areview.FoodandPublicHealth2014;4:229-241.
SilveiraC,Oba M, BeaucheminKA, Helm J.Effectof grains
differinginexpectedruminalfermentabilityontheproductivity
oflactatingdairycows.JDairySci2007;90:2852-2859.
Stevnebo,SahlstromS,SvihusB.Starchstructureanddegreeof
starchhydrolysisofsmallandlargestarchgranulesfrombarley
varietieswithvaryingamylosecontent.AnimFeedSciTechnol
2006;130:23-38.
SungHG,KobayashiY,ChangJ,HaA,HwangIH,HaJK.Low
ruminalpHreducesdietaryberdigestionviareducedmicrobial
attachment.Asian-AustJAnimSci2007;20:200-207.
Sutton JD.Altering milk composition by feeding. J Dairy Sci
1989;72:2801-2814.
SveinbjörnssonJ,MurphyM,UdénP.Invitroevaluationofstarch
degradationfromfeedswithorwithoutvariousheattreatments.Anim
FeedSciTechnol2007;132:171-185.
Svihus B, UhlenAK, Harstad OM Effect of starch granule
structure, associated components and processing on nutritive
valueofcerealstarch:Areview.AnimFeedSciTechnol2005;
122:303-320.
TesterRF,KarkalasJ,QiX.Starchstructureanddigestibilityenzyme-
susbstraterelationship.WorldsPoultSciJ2004;60:186-195.
ThairMN.Effectsofthelevel,typeandprocessingofcerealgrains
indietsfordairycows.DoctoralThesis.SwedishUniversityof
AgriculturalSciences,2012;[Accessdate:September4,2015].
URL:http://pub.epsilon.slu.se/8984/1/tahir_mn_120823.pdf
TothiR,LundP,WeisbjergMR,HvelplundT.Effectofexpander
processing on fractional rate of maize and barley starch
degradationintherumenofdairycows estimatedusingrumen
evacuationand insitutechniques.Anim FeedSci andTechnol
2003;104:71-94.
VanBarneveldSL.Chemicalandphysicalcharacteristicsofgrains
related to variability in energy and amino acid availability in
ruminant:areview.AustJAgricRes1999;50:651-666.
VanSoestPJ.Nutritionalecologyoftheruminant.2thed.O&B
Books,Corvalis;1994.
VasanthanT,BhattyRS.Physicochemicalpropertiesofsmall-and
large-granulestarchesofwaxy,regularandhighamylosebarleys.
CerealChem1996;73:199-207.
VearsilpT,MikledC.Siteandextentofcassavastarchdigestion
inruminants.InternationalWorkshoponCurrentResearchand
Developmenton UseofCassavaasAnimalFeed. KhonKaen,
UniversityThailand2001; [Accessdate:March9,2015] URL:
http://www.mekarn.org/procKK/choc.htm
Zeoula LM, Caldas Neto SF.Recentes avanços em amido
na nutrição de vacas leiteiras. In: Simposio Internacional em
bovinoculturadeleite.AnaisLavras2001:Lavras:Universidad
FederaldeLavrasp.249-84
... At the ruminal level, these carbohydrates define the speed and extent of fermentation (Cone 1998). Sugars, like the soluble fraction of starches, are rapidly fermented, which increases cell mass, production of volatile fatty acids and synthesis of microbial protein (Gómez et al. 2016). LI Jian-nan et al. (2014) reported a starch disappearance rate from the dried and milled sweet potato tuber of 27.6 % h -1 in the first two hours of incubation in the rumen, which decreased as the incubation time increased. ...
... Another aspect that supports the responses obtained with FSPT is its high starch content, which, like MCG, allowed diets high in this nutrient, on average 37.1 %, dry basis, a level that produces a decrease in ruminal pH and an increase in the production of propionic acid, a glucogenic compound that favors the animal response (Zavaleta 2007). It has also been showed that this effect on pH decreases methanogenesis, a process that involves energy expenditure, favors bacterial growth, increases the passage rate and saves energy (Stern et al. 1994 andGómez et al. 2016). ...
... When considering some chemical and ruminal characteristics that affect the animal response, the sweet potato tuber have an average starch content slightly velocidad y extensión de la fermentación (Cone 1998). Los azúcares, al igual que la fracción soluble de los almidones, son de rápida fermentación, lo que aumenta la masa celular, producción de ácidos grasos volátiles y síntesis de proteína microbiana (Gómez et al. 2016). LI Jian-nan et al. (2014) informaron una tasa de desaparición del almidón del tubérculo de camote seco y molido de 27.6 % h -1 en las primeras dos horas de incubación en el rumen, la que disminuyó a medida que aumentó el tiempo de incubación. ...
Article
Full-text available
The productive response to the substitution of milled corn grain by fresh sweet potato tuber (I. batatas) in a ration destined to fattening steers was evaluated. A completely random design with a 3 x 2 factorial arrangement was used. The study lasted 78 days and three substitution levels were evaluated on a dry basis: 0, 50 and 100 % (TL0, TL50 and TL100, respectively), and two evaluation periods. The diets were isoenergetic and isoprotein. A total of four crossbreed males, with an average initial weight of 358 + 23 kg were used per treatment. The live weight gain was 1.620, 1.670 and 1.756 kg animal day-1 for TL0, TL50 and TL100. The intake of dry matter, fresh tuber and crude protein was 2.66, 2.67 and 2.76 kg; 0.00, 0.76 and 1.56 kg DM; 0.303, 0.296 and 0.305 kg; while the metabolizable energy intake resulted 29.50, 29.16 and 29.00 MJ 100 kg of live weight day-1 and the food conversion, 6.88, 6.68 and 6.62 kg of dry matter intake per kg of live weight gain-1 for TL0, TL50 and TL100. The cost of the fresh sweet potato tuber and the substitution of the milled corn grain was $ 0.18 and 0.40 kg dry-1 (US dollars). With respect to TL0, the feeding cost was reduced by 18.0 and 28.3 % with TL50 and TL100. It is concluded that the fresh sweet potato tuber proved to be a competitive and economically viable nutritional alternative, as an energy source for the replacement of 100 % of the corn grain in diets for fattening male cattle.
... 984. 13), and ether extract (EE, no. 920.39) content. ...
... which is in the normal range of rumen ecology (pH 6.20-7.00) [13]. In the present study, different modification methods influenced the ruminal pH at 2 and 4 h of incubation time, and the lowest value occurred in the untreated group. ...
Article
Full-text available
Simple Summary Cassava chips (CSC) have typically been used as an energy source for ruminant rations in tropical regions due to their high starch content and higher degradability rate in the rumen, which is higher than 90%. However, inconsistencies in production and fluctuations in prices encourage animal nutritionists to search for alternatives to CSC. The introduction of new tuberous plant species may help improve local feed diversity while also reducing feed shortages in particular areas. The winged bean tuber (WBT) has a high proportion of starch that might be able to replace CSC as an energy source. Moreover, it was discovered that steamed WBT might be useful for improving feed efficiency, which could lower rapid starch degradability and maintain rumen pH when compared to the WBT raw material. Abstract This research assessed the impact of cassava chips (CSC) and winged bean tubers (WBT) with various starch modification methods on the chemical composition, ruminal degradation, gas production, in vitro degradability, and ruminal fermentation of feed using an in situ and in vitro gas production technique. Experimental treatments were arranged for a 2 × 5 factorial, a completely randomized design with two sources of starch and five levels of modification treatments. Two sources of starch were CSC and WBT, while five modification treatments of starch were: no modification treatment, steam treatment, sodium hydroxide (NaOH) treatment, calcium hydroxide (CaOH2) treatment, and lactic acid (LA) treatment. The starch modification methods with NaOH and CaOH2 increased the ash content (p < 0.05), whereas the crude protein (CP) content was lower after treatment with NaOH (p < 0.05). Steam reduced the soluble fraction (a) and effective dry matter degradability of WBT in situ (p < 0.05). In addition, the WBT steaming methods result in a lower degradation rate constant in situ (p < 0.05). The degradation rate constants for the insoluble fraction (c) in the untreated CSC were higher than those of the other groups. Starch modification with LA reduced in vitro dry matter degradability at 12 and 24 h of incubation (p < 0.05). The starch modification method of the raw material showed the lowest pH value at 4 h (p < 0.05). The source of starch and starch modification methods did not influence the in vitro ammonia nitrogen concentrations, or in vitro volatile fatty acids. In conclusion, compared to the CSC group and untreated treatment, treating WBT with steam might be a more effective strategy for enhancing feed efficiency by decreasing or retarding ruminal starch degradability and maintaining ruminal pH.
... This retrograde starch resists amylase activity [8,22]. Resistant starch resists enzymatic degradation due to α-1,4 linked glucose (amylose) in crystalline lattices [40]. ...
... HMT-treated cassava altered VFA proportions in the rumen after 48 h, where acetate and butyrate increments were observed. This observation was in contrast to a previous study that showed that starch increased propionate but decreased acetate content [40]. High RS content may have caused this finding; RS is often classified as a dietary fiber [45] due to its resistance to the enzymatic hydrolysis of α-amylase and pullulanase in vitro. ...
Article
Full-text available
Background and aim: Resistant starch (RS) is difficult to digest in the digestive tract. This study aimed to evaluate the effects of heat-moisture treatment (HMT) on RS in cassava and examined its impact on rumen fermentation. Materials and methods: Cassava flour was used as a raw material and used in a randomized block design with four different cycles of HMT as the treatments and four different rumen incubations in vitro as blocks. Treatments included: HMT0: without HMT (control), HMT1: one HMT cycle, HMT2: two HMT cycles, and HMT3: three HMT cycles. Heat-moisture treatment processes were performed at 121°C for 15 min and then freezing at -20°C for 6 h. Analyzed HMT cassava starch characteristics included components, digestibility, and physicochemical properties. In in vitro rumen fermentation studies (48 h incubation) using HMT cassava, digestibility, gas production, methane, fermentation profiles, and microbial population assessments were performed. Results: Heat-moisture treatment significantly reduced (p < 0.05) starch, amylopectin, rapidly digestible starch (RDS), and slowly digestible starch levels. In contrast, amylose, reducing sugars, very RDS, RS, and protein digestion levels were significantly increased (p < 0.05). Additionally, a reduced crystallinity index and an increased amorphous index were observed in starch using Fourier-transform infrared analyses, while a change in crystalline type from type A to type B, along with a reduction in crystallinity degree, was observed in X-ray diffraction analyses. Heat-moisture treatment significantly (p < 0.05) reduced rumen dry matter (DM) degradation, gas production, methane (CH4 for 12 h), volatile fatty acid (VFA), and propionate levels. In addition, acetate, butyrate, and acetate/propionate ratios, as well as population of Streptococcus bovis and Bacteroides were significantly increased (p < 0.05). However, pH, ammonia, and organic matter digestibility were unaffected (p > 0.05) by HMT. Conclusion: Cassava HMT altered starch characteristics, significantly increased RS, which appeared to limit rumen digestion activity, decreased rumen DM degradation, gas production, VFAs, and CH4 production for 12 h, but increased S. bovis and Bacteroides levels.
... In the present study, the responses of energy sources on the performance variables corroborate with the findings of previous research published by other authors. Corn has a high energy content provided by starch and is therefore the main energy ingredient used in diet formulations for lactatin contributes to the optimization of rumen fermentation as it synchronizes with nutrients from forage degradation which in turn stimulate microbial growth and feed consumption (GÓMEZ et al., 2016). As a result, cows that were fed with corn-based diets had the highest nutrient consumption averages. ...
... Corn has a high energy content provided by starch and is therefore the main energy ingredient used in diet formulations for lactating cows. Starch contributes to the optimization of rumen fermentation as it synchronizes with nutrients from forage degradation which in turn stimulate microbial growth and feed consumption (GÓMEZ et al., 2016). As a result, cows that were fed ed diets had the highest nutrient consumption averages. ...
Article
Full-text available
The present study aimed at assessing the effects of hepatoprotective agents in diets that contain sources of energy on milk production, milk composition, and nutrient partition in lactating cows. Sixteen Holstein x Gir crossbred mid-lactation cows with an average body weight of 553 ± 85 kg were used in this study. These animals were allocated in a 4x4 Latin square design. A 2x2 factorial arrangement was employed in this feeding experiment. In each treatment, cows received diets with or without a hepatoprotective agent and variable in ground corn grain or citrus pulp as energy sources. Evaluated parameters included nutrient intake and digestibility, milk production, milk composition, energy balance, and nitrogen balance. Performance and nutrient balance variables were assessed and no interaction was observed between the hepatoprotective compounds and the dietary sources of energy. Dry matter intake, milk production and net energy for lactation were higher in corn as an energy source whereas milk fat content was higher in citrus pulp diets. There was a reduction in protein and casein contents in the milk of cows that was supplemented with an hepatoprotective agent. In this study, the hepatoprotective agent improved nitrogen balance in dairy cows. The use of the hepatoprotective compounds in the diet of these lactating cows in confinement reduced the milk protein fraction and favored a higher nitrogen balance in these animals. Retention of nitrogen compounds in the metabolism of lactating cows under confinement is influenced by hepatoprotective agents. dairy cows; liver; milk production; nutrients balance
... The physicochemical grain properties and a variety of other factors may affect the digestibility of a feed (Gómez et al., 2016). Cereal grains and legumes are exceptionally rich in nutrients, especially dietary fiber, B vitamins, minerals, as well as phytochemicals all potentially health-beneficial. ...
Conference Paper
Full-text available
The fattening of broilers in Serbia is partially organized through contract production in small family farms that fatten broilers for the needs of large companies. The article contains an economic analysis of this small family farm, which produces about 12 000 kg of chicken meat per year on a small area of 120 m2, with one family member involved all the time and other members helping as needed. Fattening broilers on the farm is organized in two ways: contract fattening up to 1 kg for 25 days and fattening up to 3.5-4 kg for 56 days. In the case of fattening broilers up to 25 days of age, on average, feed costs account for 45%, day-old chicks for 26%, and labor costs for 22%. For broilers up to 56 days of age, the largest average share is feed costs 62.4% and labor costs 26.2%. The price of fattened broilers did not change during the fattening period, so the realized production value was the same in one fattening method and similar in the other fattening method, while cost of production increased in each fattening round, which affected the reduction of contribution margine. In addition to the increase prices of feed mixtures, positive economic results were achieved on the farm, and with contract production, secure purchasing was ensured and risks in production were reduced.
... Após o rompimento dessa estrutura através de processamento ou mastigação do grão, a taxa de fermentação dos grânulos de amido é determinada pela quantidade de matriz proteica que circunda os grânulos de amido (ANTUNES, RODRIGUEZ, 2006). O processamento do grão como a moagem atua aumentando a área de superfície dos grãos, reduzindo a interação da matriz proteica com os grânulos de amido e aumentando a solubilidade do amido em água por meio do rompimento das pontes de hidrogênio das moléculas de amilose e amilopectina dos grânulos de amido, que facilita a adesão e digestão enzimática pelas bactérias ruminais (GÓMEZ, POSADA, OLIVERA, 2016). ...
Article
Three corn genotypes (hard, semi-hard and semindented) ground in a 10 mm diameter sieve and separated into four particle sizes (greater than 1400 µm; between 1400 and 850 µm; between 850 and 420 µm; and smaller than 420 µm) were evaluated. Starch degradation was verified after incubations in the rumen of cattle, at times of 3, 6, 9, 15, 24 and 48 hours. Corn genotypes with lower vitreousness showed higher solubility, rumen passage rate and rumen degradation. Genotypes in smaller particles showed higher degradations than larger particles. Corn with low vitreousness associated with finer grinding showed better ruminal starch fermentation.
... The DM and CP intake from sheep fed cashew nut bran was lower than recommended by NRC (2007), for animals in a similar category to those used in this research (74.2 and 5.84 g/kg BW 0.75 for DM and CP intake, respectively). Probably, the digestion of the cashew nut bran diet also was affected by the complex interactions among starch, lipid, and protein (Gómez et al., 2016). In consequence, the digestibility of OM, CP, and carbohydrates fractions (NFC and TC), but not fiber fraction, also decreased resulting in major effects on energy metabolism (lower intake of ME, DE, and energy balance). ...
Article
Full-text available
This research evaluated the effects of biscuit bran and cashew nut bran as energy source and additional energy level on intake, digestibility, feeding behavior, energy partitioning, N balance, and blood parameters on ewes. Twenty Morada Nova cull ewes breed (average age of 3 years old and initial body weight of 30.1 ± 3.56 kg) were distributed in a completely randomized design in a 2 × 2 factorial scheme of two energy sources (biscuit bran vs. cashew nut bran) and two levels of energy above 10% and 25% of the recommended energy requirements. The inclusion of cashew nut bran above 10% of the recommended energy promoted a lower crude protein (CP) and ethereal extract intake (P < 0.01) than cashew nut bran above 25% of the recommended energy. The interaction between energy source × energy level did not affect digestibility and energy partition on ewes (P > 0.05). The diet containing cashew nut bran above 10% of the recommended energy presented lower metabolizable energy intake and energy balance (P < 0.05). Regarding N balance, the cashew nut bran diet above 10% of the recommended energy decreased N intake (P = 0.01), N absorbed (P < 0.01), and N balance (P = 0.04). Partial replacement of corn with the byproduct biscuit bran or cashew nut bran is a possible nutritional strategy. Ewes fed with 210 g/kg of biscuit bran presented greater CP intake and improvement of the protein use with the reduction of plasma levels of urea.
... Enzymes involved in starch degradation in the rumen.The substrate in brackets indicates that fermentation depends on the enzyme source. 1 From Korarski, et al.[29], Robyt et al.[30], Fogarty[31], Vthinen[32].2 From Gomez et al.[33]. ...
Article
Full-text available
Carbohydrates (e.g., starch and cellulose) are the main energy source in the diets of dairy cows. The ruminal digestion of starch and cellulose is achieved by microorganisms and digestive enzymes. In order to improve their digestibility, the microbes and enzymes involved in starch and cellulose degradation should be identified and their role(s) and activity known. As existing and new analytical techniques are continuously being developed, our knowledge of the amylolytic and cellulolytic microbial community in the rumen of dairy cows has been evolving rapidly. Using traditional culture-based methods, the main amylolytic and cellulolytic bacteria, fungi and protozoa in the rumen of dairy cows have been isolated. These culturable microbes have been found to only account for a small fraction of the total population of microorganisms present in the rumen. A more recent application of the culture-independent approach of metagenomics has acquired a more complete genetic structure and functional composition of the rumen microbial community. Metagenomics can be divided into functional metagenomics and sequencing-based computational metagenomics. Both approaches have been applied in determining the microbial composition and function in the rumen. With these approaches, novel microbial species as well as enzymes, especially glycosyl hydrolases, have been discovered. This review summarizes the current state of knowledge regarding the major amylolytic and cellulolytic microorganisms present in the rumen of dairy cows. The ruminal amylases and cellulases are briefly discussed. The application of metagenomics technology in investigating glycosyl hydrolases is provided and the novel enzymes are compared in terms of glycosyl hydrolase families related to amylolytic and cellulolytic activities.
Article
The performance of a corn steam flaker was evaluated to improve steam‐flaked corn (SFC) quality and investigate its feeding effects on nutritional value, productive performance, digestibility coefficients, and economic efficiency of growing rabbits. The flaker performance was studied as a function of change in steaming time, steam chest temperature and roll gap. Performance evaluation of the flaker was carried out in terms of flake thickness (FT), flake density (FD) and processing index (PI) as well as rabbit feeding trials. Experimental results clarified that values of FT, FD and PI are in the optimal limits under conditions of 118°C steam chest temperature, 40 min steaming time and 0.80 mm roll gap. Steam flaking is an acceptable process for rabbit feeds as SFC with optimal FD of between 0.36 and 0.39 kg/L corresponding to a PI of between 50.14% and 54.32% significantly improve the nutritional value of SFC compared with whole corn grain by 1.31%, 1.26% and 160.75% respectively. Also, SFC severely decreased the total count of harmful bacteria, fungi count and mortality rate compared to whole corn grain. Rabbits fed SFC processed to the density of 0.36 kg/L of the diet had better body weight gain, feed conversion ratio, organic matter digestibility, net revenue and economic efficiency of 9.29%, 8.89%, 4.65%, 15.62% and 15.43% compared with rabbit fed whole yellow corn grain respectively. In conclusion, it is convenient to entirely substitute whole corn grain with SFC to be utilised in rabbits' diets where achieved the best feeding effects results.
Article
Full-text available
Abstract Background The high amount of soluble carbohydrates and the reduced dry matter content in cactus pear can cause excessive fermentation, resulting in nutrient losses, when it is preserved in the silage form. Thus, the association of cactus pear with elephant grass in the production of mixed silages may reduce nutritional losses during the ensiling process. Thus, the aim was to evaluate the mineral profile, carbohydrates fractionation, nitrogen compounds, and in vitro gas production of elephant grass silages associated with a cactus pear levels (0, 150, 300, and 450 g/kg on dry matter basis). The study was carried out in a completely randomized design, with 4 treatments and 5 replications, totaling 20 experimental silos. Results The increase in cactus pear levels in elephant grass silages composition provided an increase in the contents of K (P = 0.013), Ca (P
Chapter
The ready availability of corn at low and steady prices, its storability from season to season, and its high starch content led to the development of commercial processes for the recovery of corn starch. Although grain sorghums are a major world crop, they are considered to be inferior to corn for food, feed, or industrial uses. They require less water than corn for growth; therefore, they are grown in the arid regions. The principles of steeping and milling corn for the separation of starch are universal because they are dictated by the nature of the corn kernel and the properties of its components. Feed products produced during grain sorghum starch production have names and protein contents similar to the com starch feed by-products. Milo (sorghum) steep liquor has been used as an ingredient in liquid feed supplements for beef cattle feeding. As grain sorghums are brown in color and contain condensed tannins, all the feed products are dark brown in color. Therefore, they are used almost exclusively in ruminant feeds.
Chapter
Corn has been the staple food for countless generations of natives of North and South America. Corn has reached its present state of development through continual mutations, hybridizations, segregations and selections by random, natural processes, and by conscious selection. A number of types have developed by this process, which differ primarily in the structure of the grain. Grain sorghum (Sorghum bicolor Moench) is a cereal grain also known in some localities as milo, milo maize, or kaffir corn. The sorghum plant resembles the corn plant, but the grains, about the size and shape of No. 5 shot, are borne on a terminal, bisexual rachis (head). Mature corn or sorghum kernels are unique, well-organized entities that exist for the purpose of reproducing the species. Descriptions of their structures and compositions are helpful in understanding the process of disruption that is achieved during the wet-milling process. Grain sorghums are considered to be inferior to corn for food, feed, or industrial uses. They require less water for growth than corn and, therefore, are grown in more arid regions. The wet-milling of grain sorghum is similar to that of corn, although novel methods of extracting starch from sorghum have recently been investigated. Wet milling, as a process to recover starch, is essentially a method of disrupting the corn or sorghum kernel in such a way that the component parts can be separated in an aqueous medium into relatively pure fractions.
Article
Small- and large granule starches were isolated from pin-milled and air classified fractions of waxy (SB 89528), regular (Condor), and high-amylose (Glacier) barleys, and their physicochemical properties were investigated. The isolations contained 95-97% starch, 0.1-0.3% protein, and 0.1-0.2% ash. Scanning electron microscopy showed that the starch granules were oval to round in shape with diameter ranges of 2-10 μm for small and 12-26 μm for large granules. The starches had A-type X-ray diffraction patterns, typical of cereal starches. The differences in the physicochemical properties such as X-ray diffraction relative intensities, swelling factor, amylose leaching. Brabender pasting, differential scanning calorimetry thermal characteristics, and resistance to acid and α-amylase hydrolysis were greater among the three genotypes than between the small and large-granule starches from the same genotype. The large granule barley starches may be substituted for corn starches because their physicochemical properties are generally similar.
Article
Matching production of milk components to demand improves the biological efficiency and ultimately enhances the overall profitability of the dairy industry. Consumer demand for the major components of milk has changed considerably over the past two decades. To align production with demand successfully, the dairy industry must be able to respond to changes in consumption patterns. A better understanding of the biological control of milk protein, fat and lactose synthesis is necessary before the dairy industry can fully exploit the potential to alter milk composition. The topic of this review is the current state of knowledge about using dietary intervention or genetic-based techniques to alter the composition of bovine milk. The usefulness of the two approaches is evaluated. The methods are also assessed in terms of both their present and anticipated abilities to exploit the biological potential to alter the composition of milk. The scope of the article covers the details of current approaches and relevant difficulties, as well as expected advances that should contribute to the development of more refined and therefore more effective methods for selectively altering milk composition. Progress in targeted modification of milk components depends upon an increased understanding of lactation biology, particularly the genetic basis of milk component synthesis. Bioactive and functional components of milk are discussed in terms of target compositions for milk and implications for human health. Advances in knowledge about ruminant nutrition and genetics will allow the dairy industry to modify milk composition and better match consumer demand, especially for components perceived as healthy.
Chapter
The functional properties of starch depend on a number of integrated factors, which include polymer composition, molecular structure, interchain organization, and minor constituents such as lipids, phosphate ester groups, and proteins. Chemical, enzymic, and physical modification of starch, with either preservation or destruction of the native granule, broaden the functionality-imparting properties of different starches. The greatest challenge is to relate physicochemical properties and functions of starch with information on various levels of structure. There is a diversity of structures depending on starch source, amylose-amylopectin ratios, lipid, moisture and plasticizer contents, and thermo-mechanical histories. In addition to difficulties in describing and quantifying the structural morphology of starch materials, the ultra structural level of starch also presents a great challenge. This chapter discusses some aspects of phase transition behavior and other material properties of starch, particularly as they pertain to the structural order and interactions of the starch polysaccharides with water, lipids, and other solutes. Understanding the thermally induced structural transitions of starch is helpful in controlling its physical properties and processing behaviors (e.g. plasticization, viscosity), as well as in designing products with improved properties (e.g. texture, stability). The description of the state and phase transition behavior of starch systems is focused on with an emphasis on their molecular organization and their response to various environments (temperature, solvent, other cosolutes). Selected material properties are also discussed in an effort to demonstrate structure-function relationships of this biopolymer mixture in pure systems and in real food products.