A. O. Vet. Fak. Derg.
31 (3) : 517-525 ı984
THE EFFECT OF FEED TEXTURE O~ BROILER PERFORMA:\"CE
Erol Şengör* Basi1 E.F. Bayne**
Yem Dokusunun Broiter Performansına Etkisi
Özet: Yemin tavuklara pellet haliııde verilmesi, dökme to;;.)'em verilme-sine nazaran daha iyi bir l-iiyüme sağlaniaktadır. Pellet yem ile geııellikle daha £l'i bir biiyiime elde edilebilmesine rağmen, bundan bazı sapmalar da olabilmektedir. Pilicin )ıaşı, pe/let yem yenilmesini etkileyen bir faktör olarak gösterilmiştir. Pellet tanelerinin büyüklüğü pilicin biiyükliiğüne göre a)'arlanmrılıdır. Pilicin büyükıÜğii ö'nemli Mçiide )'aşa bağlıdır.
Daha iyi biiyümeyi sağlayan tek faktö'r )'emin fiziksel şekli dl!ğildir. Pel-let yapma sırasında bazı kimyıasal değişiklikler meydana gelebilmektedir. Ras-)'onun içindeki bütün yem hammaddeleri pellet yapma işleminden aynı Mçiide
etkilenmemektedir.
Pellet yem, yem yemeyi uyarmaktadır. Pellet yem yiyen piliçler dö"kme toz yem yiyenlere nazaran daha fazla yem tüketirler. Alınan yemin, ihtiyacın
üzerin-de olan kısmı yemüzerin-den yararlanmayı artırmaktadır.
Pellet yem yfyen piliçler yemi daha hızlı yerler ve yem yeme işlemini dök-me tozyemyiyenlerden daha önce tamamlarlar. Yem yeme işleminin kendisi belli bir miktar enerji harcanmasını gerektirdiğinden, pellet yem yfyenler diğerlerinden daha fazla eneıji tasarruf ederler. Pellet yem yenilerek tasarruf edilen bu fazla enerji, prodüktif enerji olarak ağırlık kazancı artması şeklinde yansımış olabilir.
Summary: Offering fted to poultry in pelleted form rather than in mash form has been shown to give a better growth response. While a growth response is generally obtained on textured feed it is not invariably so. Age of
1 Dr. University of Ankara, Faculty of Veterinary Medicine, Dept. of Animal Hus-bandry. Ankara-Turkey.
2 Louglıry College of Agriculture, I'oultry Department. CooksıoWIl, BT80 9 AA. Co-Tyrone, :\"ortlıern Ire1and, United Kingdom.
sıl! EROL ŞENGÖR - DASİL E.F. RA YNE
tlze bird waJ s/iowil m a factor to influence tlze textll1'ed food intakc. Size of the pellet should be clzanged according to tlze size ~f the bird. Size of the bird, on the other hamI, is generally assor.iated with the age.
PIz)'sical form
~f
feed is not tlze only factar to give beller growtlz response. ehemical clzanges mayaıso occ1lre in tlze feed during pelleting process. Not all the in<~redients in aration are affected equally by pelleting. Pelleted food stimulates the food intake. Birds on pelleted food consume morefood than that on mash food. The increase infeed intake above maintenance requirement improl'es tlze ejficieney offood coıwersion.Birds on pelleted food can eat faster, so they can finislz their eating earlier .than the birds on mash. Since certain amOlmt of energy is needed for eating process itself, birds on pelleted food wıll save more energ)'. This saved eneı;!!,)' ma)' then be riflected as higher bod)' weight gain.
Introduction
In the current days Turkey has eagerly started to go into an
ex-port business. Poultry products will apparently contribute a
consi-derable size to this e£Tort. Competition with the other poultry product
exporter countries forees one to evaluate every single facility to
pro-duce evcn chcaper procluet. One of the faeility to produee more
meat by using the same amount of food is fed the broilers with the pelleted food instead of mash form.
Thc presentation offood to broilers in textured form (ie. as erumbs
and pellets) is common commercial praetice in the developed countries.
The superiority of textured rations compared to rations presented in
mash form cither in improving the rate of growth or improving
e£Ti-cieney of food conversion or both, has been well documented. Despite
of the several evidenees, pelleted food unfortunately has not been
com-monly used in Turkey.
Poultry fCed ingredients, such as wheat, maize and 'soyabean an~
important constituents of human diets partieularly in developing
countrics. For this reason in the developing world, poultry produetian
costs are high, and profit margins can be slim relative to those found
in extensive livestock farming enterprises. It is, therefore, very much
important to evaluate every possibility for increasing production
THE EFFECT OF FEED TEX[TURr:: ON BRODlLER PERFORMANCE 51?
The effect of feed texture on live weight
Offering fecd to poultry in peııcted from rather than in mash form
has been shown to gi"e a better growth response. The initial work
re-ported by Heywang and Morgan (7) demonstrated this response with
white leghorn stock. These authors noted that 12 weeks body wcights
of both cockerels and puııets were approximately i i.') % of the body
weights of mash fcd controls. Since this work alcrted researchers to
this growth response the body weight advantages occuring from
pel-let fed birds have bem rcpeatedly demonstrated (3, 5, i i, i 3,
ı
6)."Vhile a bctter grov\'th response is generaıı)' obtained on textured
feed it is not invariably so. Calet (4) in an exceııent review of the
literature identified several factors responsible for variations in results
induding the age of the birds being fed. Ziegenhagen et ai. (2 i) were
early workers able to demonstrate that chicks prcferred mash rather
than pellets at age s up to 14 days and that by 28 days a preference for
pcllets could be demonstrated. A similar early preference \Vas
de-monstrated by SavOl'y (I 5) which, he speculated, ma)' have been
due to the difficulty of swallowing pellets by very young chicks. The
peııets usccl \Yere 3.2 mm in diameter, a size commonly used in
com-mercial practice in the developed countries. If this was indeed the
case, then feeding asmaller pellet from day-old ma)' be superior to
mash feeding. An intercsting study by Wilson and Ncsbeth (20) using
a very smail bird, the quail, was able to sh~w that feeding a peııet of
3 mm diameter but eut to lengths of 2.5 mm or less was able to
sup-port superior rates of growth from day-old to 3.') days of age. However,
it is apparent that he was using an unsereened pellet with a partide
size ranging from a smail crumble to the pellet size deseribed.
~ever-theless, their \York illustrates weıı that given a suitable partide size in
textmed feed, growth rates can be obtained which are superior to
mash fed birds. it can be argued that anather reason, other than the
case of swallowing, may account for the early growth superiority
re-ported with mash fed birds. It may be that birds prefer mash because
of the interest aroused by variations in the colour and partide size
of the feed compared with the more uniform characteristics of a pellct.
it has long becn observcd that birds wiıı select out certain partides
from mash. Howevcr, the ability to select will directly reflect the
fine-ness to which a mash is ground. it seems that any means of
520 EROL ŞENGÖR - BASiL E.F. BAYNE
is this ability to stimulate food intake that is the primary advantagc
of pelleted food.
Whilc the physical form in which a ratian is prescnted to the bird
is of importance, it is not the only faetor involved in improving growth
rate. it has been shown that benefieial effeets oceur as a result of chemi. cal changes whieh seem to take place in the feed during the pelleting
process (1, 19). When whole pellets, reground pellets and the
unpel-lcted mash were fed to birds it has been observed that the ",hale
pel-lcts and the reground pellets fed in mash form produce a signifieantly
greater growth response when compaı-ed to the unpelleted mash. At
28 days birds on pellets and reground pellets wcre of almost identical
average weight whercas the unpelleted mash fed birds weighed 5
%
lcss (1).
Summers et aL. (19) enquired further into the benefits obtained
from the pelleting process itself by using com (a high energy
ingredi-ent), wheat br an (a law energy ingredient) and wheat short s (a medium
energy ingredient). These ingredients were processed by steam pelleting
and were then reground to a mash form before including in the ration.
Either the reground sample or an original unprocessed mash sample
was mixed 50 :50 with a com, soya diet and then fed as a mash can ta i-ning no processed ingredients, a mash contaii-ning processed ingredients
and as steam pellets containing no processed ingredients (tablc I).
Table 1. The effect of regrinding afıer steam pelleıing on growth and metabolisable energy of eorn, wheat ,horts and bran
- - -- •__ ••" - ••- - _. _. _ •• -_._.- - _. -, --- ._-- ,--- __ O- ._•••
Average Weighı (g) Metabolisable Energy (kcalj g) ----_._---_ ..-. ----"---,._---_. 1. 70 2.05 2.20 2.16 3.61 3.51 259 303 314 303 248 i 267
i Corn i \"heat i "Vheat . Corn '\,Vheaı i Wheaı i
, i i i .
, ! Shorts i ıkan i . Slıorts i Bran i
' .__ '._. __ . ' i i i: i ! 231 233 i 164 3.45 2.10 1.46 :Vlash With unprocessed ingredienı Mash \Vith processed ingredienı Pellet "Vith ıınprocessed i ingredil'nı - ._---- - _...- -
---~ot only did the processed ingredients result in greater average
live weight but it was apparent that the difference could not be so.lely
pre-THE EFFECT OF FEED TEXETURE ON BRODlLER PERFORMANCE 521
sentcd. Measurement of the metabolisable energy of the ration showed that the pelleted and proeessed rations had eonsistently higher energy lcvels supporting the view that ehemiea! changes occurred on pelleting which partially aceount for the increase in body weight.
The evidenee suggests that not all ingredients in aration are af-fCcted equally by the pelleting process. In the initial work, Allred ct ai. (2) were ablc to show that pelleted and reground com alone in a basaıration was affeeted by the pelleting process in such a way that growth \vas improved, but not significantly so. When rations contained pelleted and reground soya bean oil meal or oat mill feed or a combi-nation of thcm both, there was no growth response compared with that obtained on an unpeleted basal diet. However, when pelleted reground com was fed in combination with either or both of the two other ingredients, pelleted and reground soyabean oil meal or oat mill feed, growth was significantly better. A highly significant response was obtained when the ration_was fed in pelleted form rather than in mash form.
Several possibilities have been advaneed to exp!ain the benefi-cial growth effeets that arise as a result of the pelleting process per se. The increase in temperature and in pressurl' during pelleting have been proposed as being primarily responsible. When com was steamed, . water soaked and the n autoclaved but not pelleted, this heat only
treat-ment did not produee signifieantly better growth than when birds wc re fed a control ratian (2). Although these results suggest that pressurl' exerted on the fe ed as it is forced through the die is of major impor-tance, it does not deny the fact that temperature during the pellet-ing process is of importance in specific instanees. For example, it is commercial practice to pellet fe ed elite breeding stock where the heat treatment may effectively kill any Salmonellae which may be conta-minating the fe ed and heat treatment mayaıso destroy toxic factors or other growth inhibiting fact'ors
(ı,
9).A claim that the growth responses noted in birds fed pellets and reground pellets as opposed to mash was due to mechanical rather than chemical changes in the feed was advanced by Hamm et ai. (6). This conclusion was supported by Bolton (3) who determined that the crude protein, oil, total carbohydrate and the available carbohyd-rate levels did not change as a result of the pelleting process and he attributed better growth to increased consumption of pelleted [ood.
522 EROL ŞENGÖR - BASiL E.F. BA YNE
As already noted, Summers ct aL. (I 9) found metabolisablc energy
\cvcls to be increased as a result of peUeting, an observation not
sup-ported by H usser and Robblce (8). No significant change in gross
cnergy of the grain dry matter of peUeted feed was reported by Sibbald
(17) hut !ıe did obsef\-'C true metabolisablc energy (TME) to be
chan-ged by cold peııeting but not significantly so and the changes differed between grains. The TME of oats actuaııy fell on cold peUeting. In
bter work (18) the relevance of TME was questioned. The argument
\Vas advanced that during the peUeting process the grain kernels wc re
further broken and the e£feets observed mal' have been due to the
disruption of the kernels on peııeting and the resultant greater surface
areas exposed to the digestive process rather than to the production
of pellets themselves. According to Calct (4) the effect of pressing alters not only the cell waıı but the whole ceU structure making maize starch
in particular much more susceptiblc to be damaged by amylase. This
altcration in the starch grains may explain the better energy
availa-bility measured in eereals. This supports the vicw that the beneficial dfects of pcııeting mal' be due to mechanical faetors rather than chemi-cal changes.
Evidence that food intake was involved in producing the grmvth
res-ponsc was providcd by Hamm and Stephenson (5). These authors
found that when the food intake of peııets and reground peııets was
limited to the same Icvcl of mash intake in the controls, no growth
res-ponse was obtained with food that had bcen pelleted suggesting the
greater voluntary intake on pelleted food above the maintenanee
re-qııirement is a major factol'. In almost all the trials cited by Calct (4), in his review, an inerease in food intake assoeiated with pellet feeding \Vas noted. This inerease in intake can be explained in terms of
palat-ability. The work ofZiegenhagcn ct aL. (21) referred to earlier,
eon-e\ıdcd that although young ehicks preferred mas!ı to pellets up to 14
days of age, as the birds grew in size such that they were able to con-sume peııets easily, preference for peUets cmerged. This preferenee for pelleted feeds amongst old er birds has been notcd by other \Yorkers in
free choic~ feeding experiments (4, 12). '
An alternative explanation whieh mal' partiaUy explain the
im-proved growth rates aehieved on peııets may involve the rapidity with
whieh birds can eonsume peııets as opposed to mash . .Jensen ct aL.
THE EFFECT OF FEED TEXETURE ON BRODILER PERFORMANCE 523
birds fed mash and pellets went to the fe cd trough each day. How-ever, the time spent at the trough on eaeh visit varied markedly. 1tlash fed birds spent 14.3
%
of their day eating while those fed pellets only 4.7%
.Since the cating procedure itself requires a certain amount of energy it can be postulated that birds on peııets will save more energy as they spend lcss time eating. This saved energy may be refleeted as productive energy in improved body weight gain. This suggestion that pelleting increases the productive energy of the feed by deercasing the time spent fCeding is supported by Savory (IS).The effeet of feed texture on effideney of food eonversion
it has been argued that the extra food consumed over and above the maintenance requirement will be direetly reflected in increased growth. This being the case, the efficiency with which this extra con-sumption wiıı be converted to extra weight gain will be high, thereby raising the overaıı efficiency with whieh the peııeted food intake is converted into weight, any improved efficiene)' therefore being as-soeiated with increased body weight when peııets are fed. This link between better growth and improved food conversion has be:'n de-monstrated in experiments comparing pellet and mash feeding sys-tems at 28 days of age (I, 14) but in not all cases can such a link be shown to exist beyand aıı dau bt.
The majority of authors who showed significantly better foo d conversion when the diet was pellcted concluded that this improvement in food conversion efficiency may be due to less energy being expan-ded by the bird when eating pellets and this saved energy being con-verted into body weight (LO, 15). Alternatively, this improvement in efficieney of food conversion may be due to an increased feed intake on peııets above maintenance requirement (5, 8). Allred et aL. (I) eoncluded that better food conversion observed on peııeted rations may be due to same chemical change during the pelleting process pos-sibly by the inactivation of a growth inhibitor in the ratian.
Other authors have observed no significant improvement in the ef-ficiency of food conversion by peııeting the ratian (I 4, 20). Runnels et aL. (14) could show no significant food conversion improvement at 56 days of age by peııeting the ratian, yet was able to demonstrate a significant improvement at 28 days of age. Wilson and Nesbeth (20)
524 EROL ŞENGÖR - BASiL E.F. BAYNE
showed identicaI food conversion cfricicncy at 35 days of age by using
bobwhite quails.
Condusion
There is no recent Iiterature which warrants changing the
conclu-sion of Calct (4.) that on a scientific leveı, the reason for the efficiency
of peııets are not yet completely understood. Yet it is undeniable that
in general growth benefits do arise when peııeted food is fed. If these
benefits cannot be completely and satisfactorily explained at a
scien-tific levcl one has to look towards the effect of the peııeting on food in-take to offeT parti al explanation.
in the absence of any conclusiye evidence for the occurence of
chemicaI or mechanical changes to whoııy explain the increase in
growth associated with peııet feeding, the definitc practical value
of peııet feeding may be considered to be due to the ability of peııets to increase the bird's appetite.
There İs no evidence that the peııeting process impairs the effi-ciency of feed conversion. On balance, the literature suggests that food
conversion on peııeted rations wiıı be slightly bettcr than that
obtai-ned on mash fed ratİons.
Bibliography
1. Alıred, j.8., jensen, L.S. and McGinnis, j. (l9')7): Faetors affee/ing the response of ehicks and po/llts to feed pelleting. Poıılt. Scİ., 36: 517-523.
2. Allred, j.8., Fry, R.E., jensen, L.S. and McGinnis, j. (1957): St/ldies with chieks on im/novement iıı nutr;tive value oIfeed iııgredieııls by pelleıiııg. POlılı. Scİ., 3r,: 1284-.1289. 3. Bolton, W. (1960): The diges.ibility of Illash and pellets by chicks. J.Agrİc. S,İ., 55: 14
ı-142.
4. Caıet, C. (1965): The relative value of pıllels rers/ls mash ıınd grain in /Jo/lltry nutritio/l. World's Poult. Scİ.,.l. 21: 235'2.
5. Hamm, D. and Stephenson, E.L. (1959): The pelleting respoı/seiııbroilerfeediııg. Poulı. Scİ., 38: 1211.
6. Hamm, D., jaen, E., Tollett,j. and Stephenson, E.L. (1960): Broiler andpoult raıiOl/s ejfeets oj pelletiııg waler soaking the grain, el/0'me addi/iol/s, and limited feediııgs. Arkansas Exp. SIn. Bu1I. 631.
THE EFFECT OF FEED TEXETlJRE ON BRODlLER PERFORMANCE 525
7. Heywang, B.W. and Morgan, R.B. (1944): A comparison of a pel/eted aııd ııııpel/eted all-mruh diel jor growiııg ehieken\. Poulı. Sci., 23: 16-20.
tl. Hussar, N. and Robblee, A.R.(I%21: f.1feels of I,elietiııg Ol!Ihe utilisalioıı offeed by ıhe
growing clıirketl. Poııll. Sci., 11: 1189-1493.
9. Hutton, K. and Armstrong, D.G. (1976): Gereal processiııg. in: Feed encrgy sourccs for livestoek. pp 47-63. Ed. by H. Swan and D. I.ewis. London., Buııerworths.
LO. jensen, L.S., Merrili, L.H., Reddy, C.V. and McGinnis, j. (1962): GbservaıioılS
Ol!catiııg palle,."s aııd rale ojjood paJJage ofbirdsfed lJel/eıed and unpel/eted diets. Poull. Sci., 41 :
141.1-1419
i i. jensen, L.S., Ranit, G.O., Wagstaff, R.K. and McGinnis, J. (1965): Proleil! and Iysine requiremenls ofdel'e!ol,ing twkeys as in/lııenred by lJelieting. Poulı. Sei., 44: 1435-1441.
12. Pepper, W.F., Slinger, S.j. and Summers, j.D. (1960): Sludies with elıiekens and tur-keys011 ıhe relationship helwren faı, lIIıidmıified faclors and pelieıing. Paul ı. Sei., 39: 66-74.
13. Proudfoot, F.G. and Sefton, A.E. (1978): Feed texlure (lIıd lighUrerıtmeııt effeeıs011 the
l,erjoTlnanee of ehiekeıı hmilers. Poııll. Sci., 57: 408-4 i6.
14. Runnels, T.D., Malone, G.W. and Klopp, S. (197(i): The inflııenee ofjeed lexlııre on broi!er I,erformanee. Poull. Sci., 5:,: 1958-196 i.
15. Savory, C.). (1974): Growıh and hehavioıır of clıieks fed on pellets or mash. Bril. Poulı. Sei., 15: 281--286.
ili. Şengör, E. (1982): The effect oj !ighıiııg regime, feed lalllTe and leeder space allowanee on hroiler per/armmıee. :\1. Agr. du'sis. Unspublished. The Faculıy of Agriculture and Food
Science, TIl(' Qııcen's University of Bdfası. Narthcm Ircland. U.K.
17. Sibbald, I.R. (197G): The eflect oj eold pelieting on Ihe true melaholisahle energy wlııes of eereal grains fed to adıılt rooslers and a comlJarison of ohserved wil/Z predicted melaholisahle eııaıu erılııe. Poull. Scİ., 5.'i: 970-974.
18. Sibbald, I.R. (1977): 7he effect qf steam pelietiııg on the lrue metaholisable energy valııes ofpol/ltry diets. Poulı. Sci., 56: IG86-1688.
19- Summers, j.D., Bentley, H.U. and Slinger, S.). (I %8) : Influetlee of method of I,elietiııg on uliiisatirJ/l of etlugylrom com, wheaı, shorls al!d hran. Cen:al Chem. 45: (i 12.
20. Wilson, H.R. and Nesbeth, W.G. (I 980) : Pelleıs versus mash f~r slarling Bobwhite ql/ail. Pou]ı. Sci., 59: 932-931.
21. Ziegenhagen, E.H., Corman, L.B. and Hayward, ).W. (1917): Feed parlıcle size as afaetor affeetiııg I,erjormanee of tl/rke).s l,olllIs. l'oult. Sei., 26: 212-214.
