MATERIALS AND METHODS Study area: This study was conducted in 2007 in an open-sided house with curtains at the University of

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1 Interntionl Journl of Poultry Science 8 (1): 35-39, 2009 ISSN Asin Network for Scientific Informtion, 2009 Effect of Different Feed Regimes During the Strter Stge on Productivity nd Crcss Chrcteristics of Mle nd Femle Ross 308 Broiler Chickens D.J. Novel, J.W. Ng mi, D. Norris nd C.A. Mjiorgu Deprtment of Animl Production, University of Limpopo, P Bg X1106, Soveng 02, South Afric Astrct: An experiment ws conducted to determine the effect of different feed restriction regimes during the strter stge (14-21 dys) on productivity nd crcss chrcteristics of mle nd femle Ross 308 chickens. A 3 (feeding levels: d-liitum intke, 50% d-liitum intke nd 5% d-liitum intke) 2 (mle nd femle chickens) fctoril rrngement in complete rndomized design ws used. Feed restriction ffected (p<5) live weight of chickens t the ge of 21 dys nd mle chickens were hevier (p<5) thn femles t the sme ge. Chickens on 5% d liitum feeding ttined complete compenstion in live weight t 42 dys of ge while those on 50% d liitum feeding did not. However, mle chickens ttined higher (p<5) live weights thn femle chickens t 42 dys of ge. It is suggested tht 5% d liitum restriction feeding during the strter stge from 14 up to 21 dys of ge my offer some economic dvntge over d-liitum feeding regimen, minly y enhncing feed utiliztion. It my, therefore, e useful nutritionl strtegy to reduce the cost of commercil strter grin sed-diets. Key words: Ross 308 roiler chickens, strter stge feed restriction, productivity, crcss chrcteristics, ft deposition INTRODUCTION The development of lterntive fuels including io ethnol produced from mize nd io diesel from plnt oils is likely to result in n incresed cost of feed stuff for roiler nutrition since there is expecttion tht world cerel vilility for livestock especilly poultry will e highly restricted. Therefore, there is criticl need to increse efforts of reducing feed cost without compromising the finl productivity. One possile nutritionl strtegy of reducing feed cost is to restrict feed intke of the irds in the erly stge of life. Although some studies hve determined the effect of erly feed restriction on crcss ft contents nd feed efficiency (Plvnik nd Hurwitz, 1988, 1991), leg prolems nd totl mortlity (Roinson et l., 1992; Sleh et l., 1996) nd metolic diseses (Arce et l., 1992) in roiler chickens, there is little or limited informtion concerning the use of erly feed restriction s nutritionl pproch to reduce cost of poultry feed. It is, therefore, importnt to scertin such responses in roiler chickens sujected to different feed restriction regimes during the strter stge. Such informtion would e very eneficil to poultry frmers in rurl res of Limpopo province nd elsewhere. The min ojective of this study ws to determine the effect of different feed restriction regimes during the strter stge on productivity nd crcss chrcteristics of mle nd femle Ross 308 roiler chickens. MATERIALS AND METHODS Study re: This study ws conducted in 200 in n open-sided house with curtins t the University of Limpopo Experimentl Frm, Limpopo Province, South Afric. The experimentl frm is situted out 10 km northwest of the University Turfloop cmpus. The mient tempertures round the study re re ove o o 32 C during summer nd 25 C or lower during winter seson. The men nnul rinfll is etween nd mm. Birds, tretment, design nd dt collection: Mle nd femle Ross 308 roiler chickens were rised for 14 dys efore the commencement of the study. On commencement, 300 mle nd femle Ross 308 roiler chickens were rndomly llocted to 6 tretment comintions (Tle 1) with five replictions in 3 (feeding regimes: d-liitum feeding s the control, 5% d-liitum intke nd 50% d-liitum intke of mount of feed intke of d-liitum chickens of the previous dy, respectively) X2 (sexes of chickens) fctoril rrngement in complete rndomized design (SAS, 2000). There were 30 floor pens, ech contining 10 irds per repliction. Relimenttion period ws from dy 22 until dy 42. Except for the durtion of the food restriction, the irds were offered feed nd fresh wter fed d-liitum. The lighting progrm ws 24 h. The experiment ws terminted when irds were 42 dys of ge. During the experiment, the initil verge live weights of the chickens were tken t 14 dys old. Therefter, dily men live weights nd feed intke were mesured until the end of the experiment t 42 dys. Dily growth rtes nd feed conversion rtio were clculted. Mortlity ws mesured throughout the experimentl period. At dy 36, four irds were rndomly 35

2 Tle 1: Experimentl tretments Tretments SMR 0: Mle chickens without ny strter feed restriction SMR 5 : Mle chickens fed 5% of the control intke for seven dys SMR 50 : Mle chickens fed 50% of the control intke for seven dys SFR 0: Femle chickens without ny strter feed restriction SFR 5: Femle chickens fed 5% of the control intke for seven dys SFR : Femle chickens fed 50% of the control intke for seven dys 50 selected from ech repliction nd trnsferred to metolic cges for mesurement of pprent digestiility. At 42 dys old, ll remining irds were slughtered y cervicl disloction to determine the crcss chrcteristics. Nutrient nlysis: The dry mtter, nitrogen, crude protein, phosphorus nd ft contents were determined s descried y AOAC (2002). The Gross Energy (GE) of the diets nd excret smples were determined using n ditic om clorimeter (University of Kwzulu- Ntl Lortory, South Afric). The Apprent Metolizle Energy (AME) content of the diets ws clculted (AOAC 2002). Dt nlysis: Effect of different feed restriction regimes during the strter stge on productivity nd crcss chrcteristics of mle nd femle Ross 308 roiler chickens on live weight, feed intke, feed conversion rtio, digestiility, crcss chrcteristics nd mortlity were nlyzed using the Generl Liner Model (GLM) procedures of sttisticl nlysis of vrince (SAS 2000). Mens were seprted using Duncn (1955) multiple-rnge test. The effects of interctions were not included in the model ecuse erlier nlyses including ll the interctions showed tht they were not importnt. Int. J. Poult. Sci., 8 (1): 35-39, 2009 RESULTS The nutrient compositions of the strter nd grower diets re presented in Tle 2. The diets t ech phse (i.e., strter nd grower phses) were isocloric nd isonitrigenous. Prior to this experiment, the chicks were fed 23% CP strter diet tht would stisfy their nutritionl requirements ccording to the NRC (1994). Results of the effects of level of feed restriction on live weight, feed intke nd mortlity of mle nd femle Ross 308 roiler chickens t 21 dys of ge re presented in Tle 3 Level of feed restriction hd effects (p<5) on live weight nd feed intke of roiler restriction nd sex of the chickens hd no effect (p>5) chickens. Incresing the level of feed restriction reduced on nitrogen content of rest met smples of Ross 308 (p<5) live weights nd feed intkes of roiler chickens. However, level of feed restriction did not hve ny effect (p>5) on mortlity of chickens during the restriction period. Mle nd femle roiler chickens hd similr (p>5) feed intkes nd mortlity rtes. However, mle roiler chickens were hevier (p<5) thn femle chickens t 21 dys of ge. Results of the effects of level of feed restriction on feed intke, intke s percentge of live weight, growth rte, feed conversion rtio nd mortlity of mle nd femle Ross 308 roiler chickens etween 21 nd 42 dys of ge re presented in Tle 4. Level of feed restriction hd no effect (p>5) on feed intke, growth rte, feed conversion rtio nd mortlity of the roiler chickens. of the chickens hd no effect (p>5) on mortlity. However, mle roiler chickens hd higher (p<5) feed intke nd growth rte nd etter feed conversion rtio thn femle roiler chickens. When intke ws expressed s percentge of live weight, differences (p<5) in feed intke were oserved etween chickens on 5 nd 50% d liitum feeding nd those on d liitum feeding. When intke ws expressed s percentge of live weight, mle chickens hd lower (p<5) feed intke thn femle chickens. Results of the effects of level of feed restriction nd sex of the chickens on diet dry mtter nd nitrogen digestiilities, nitrogen retention nd metolisle energy re presented in Tle 5. Feed restriction levels nd sex of the roiler chickens hd no effect (p>5) on dry mtter digestiility, nitrogen digestiility nd nitrogen retention. However, chickens on 5% d liitum feeding hd lower (p<5) metolisle energy vlues thn those on d liitum feeding nd those on 50% d liitum feeding. Broiler chickens on 50% d liitum feeding nd those on d liitum feeding hd similr (p>5) metolisle energy vlues. Results of the effects of feed restriction on live weight, dressing percentge nd crcss chrcteristics of mle nd femle Ross 308 roiler chickens t 42 dys of ge re presented in Tle 6. Level of feed restriction hd no effect (p>5) on dressing percentge nd intestine lengths, s well s on weights of wing, ft pd, gizzrd nd liver. However, chickens on 50% d liitum feeding hd lower (p<5) live weights, drumstick nd rest weights thn those on d liitum feeding. Mle nd femle roiler chickens hd similr (p>5) dressing percentges nd ft pd weights. However, mle roiler chickens hd higher (p<5) intestine lengths, live weights nd thigh, drumstick, wing, rest nd liver weights thn femle chickens. Level of feed restriction nd sex of the chickens hd no effect (p>5) on rest, thigh, drumstick, wing, gizzrd nd liver weights when expressed s percentge of crcss weight of the chickens t 42 dys of ge (Tle ). Level of feed roiler chickens t 42 dys of ge (Tle 8). DISCUSSION Feed restriction during the strter period ffected live weight of the roiler chickens t the ge of 21 dys. The more severe the feed restriction the lower ws the live weight ttined t 21 dys of ge in oth mle nd 36

3 Tle 2: Nutrient composition of the strter nd grower diets (the units re in g/kg for dry mtter, g/kg DM for protein, lysine, ft, clcium nd phosphorous nd MJ ME/kg DM for energy) Diet Dry mtter Energy Nutrient protein Lysine Ft Clcium Phosphorus Strter Grower Tle 3: Effect of level of feed restriction on feed intke (g/ird/dy), live weight (g/ird) nd mortlity (%) of mle nd femle Ross 308 roiler chickens t 21 dys of ge Vrile Tretment No Live weight Feed Intke Mortlity 0% d liitum % d liitum % d liitum 100 c 348 c SE Mle Femle SE ,c :Mens in the sme column not shring common superscript re significntly different (p<5). SE: Stndrd Error femle roiler chickens. This ws expected since live weight gin depends on nutrient intke. Thus, those chickens offered lower mounts of feed ttined lower live weights. These results re similr to the findings of Leu et l. (2002) nd Oyedeji nd Atteh (2005). The level of feed restriction which Plvnik nd Hurwitz (1989) estimted just to meet mintennce energy requirements is equivlent to out 16 KJ ME/ird/dy in the 6-12 dy period, pproximtely 35% of norml feed intke. This mintennce energy level, however, must hve een overestimted ecuse the feedrestricted irds gined 2-4 g ody weight ech dy during the restricted period. It is lso possile, s suggested y some workers, tht the irds in their study, even though in negtive energy lnce, were le to gin weight due to chnge in ody composition: they used ft reserves nd deposited more len tissues (Leeson et l., 1991; Yu nd Roinson, 1992). In the present study, level of feed restriction hd no effect on mortlity of the chickens. This is similr to results reported y Oyedeji nd Atteh (2005). However, the present results re contrry to the findings of Sleh et l. (2005) who reported tht level of feed restriction hd effects on mortlity of the roiler chickens. Mle roiler chickens were hevier thn femle chickens t the end of feed restriction period. However, there were no significnt differences in intke nd mortlity. Thus, differences in live weight could not e explined in terms of differences in feed intke. It is possile tht differences in live weight my hve een due to etter feed conversion rtio in mle chickens compred to femle chickens. These results re similr to those of Zuir nd Leeson (1994). However, the present results re contrry to those reported y Leeson et l. (1991). The present results indicte tht t 42 dys of ge roiler chickens on 5% d liitum feeding ttined similr live weights to those on d liitum feeding. This mens tht there ws complete compenstion. This could only e explined in terms of higher intke expressed s percentge of live weight for those chickens on 5% d liitum feeding. However, roiler chickens on 50% d liitum feeding hd lower live weights, drumstick nd rest met weights thn those on d liitum feeding. These results indicte tht complete compenstion did not occur in roiler chickens on 50% d liitum feeding. Plvnik nd Hurwitz (1991) crried out tril in which they offered roiler chicks or turkey poults vrying levels of energy-restricted diets to determine the effect of compenstory growth on the ft content of the dominl ft pd. While the turkey poults were le to fully compenste from ll levels of restriction, the roiler chickens were only le to fully compenste from the mildest restrictions. Similrly, other workers were unle to demonstrte complete compenstory growth of roiler chickens which hd een sujected to similr degrees of feed restriction (Pinchsov et l., 1985; Plvnik et l., 1986; Clvert et l., 198; Pinchsov nd Jensen, 1989; Yu et l., 1990). Leeson et l. (1991), reported complete ody weight recovery y ll tretment groups y 42 dys of ge with no chnge in overll efficiency. Crcss chrcteristics were lso not ffected y erly life undernutrition. Jones nd Frrell (1992) restricted roiler chickens to only KJ/kg, level much more severe thn tht recommended y Plvnik nd Hurwitz (1989) nd reported complete ody weight recovery t 48 dys of ge. Plvnik nd Hurwitz (1991) showed tht milder feed restriction, which llowed 60-0% of norml growth, permits more relistic recovery. Mle roiler chickens ttined higher live weights thn femle chickens t 42 dys of ge. This is similr to the findings of Plvnik nd Hurwitz (1991). However, the present results re in contrst to the results of Lippens et l. (2000). The higher live weights oserved in mle chickens in the present study could e explined in terms of higher intke, growth rte nd etter feed conversion rtio. Additionlly, mle chickens hd longer intestines. However, the present results could not e explined in terms of higher dry mtter nd nitrogen digestiilities, intke s percentge of live weight,nitrogen retention or metolizle energy during relimenttion period. In fct, femle chickens hd higher intke vlues when intke ws expressed s percentge of live weight. These results re similr to those of Leu et l. (2002). 3

4 Tle 4: Effect of level of feed restriction on feed intke (g/ird/dy), intke s percentge of live weight, growth rte (g/ird/dy), feed conversion rtio (FCR) (g feed/g live weight gin) nd mortlity (%) of mle nd femle Ross 308 roiler chickens etween 21 nd 42 dys of ge Vrile Feed Intke s % Growth Tretment No intke of live weight rte FCR Mortlity 0% d-liitum % d-liitum % d- liitum SE Mle Femle SE ,c :Mens in the sme column not shring common superscript re significntly different (p<5). SE: Stndrd Error Tle 5: Effect of level of feed restriction on diet dry mtter nd nitrogen digestiilities (deciml), nitrogen retention (g/ird/dy) nd metolisle energy (MJ/kg DM) of mle nd femle Ross 308 roiler chickens etween 36 nd 42 dys of ge Vrile Tretment No Dry mtter digestiility Nitrogen digestiility Nitrogen retention Metolisle energy 0% d-liitum % d-liitum % d- liitum SE Mle Femle SE 0 0 5,,c :Mens in the sme column not shring common superscript re significntly different (p<5) SE : Stndrd Error Tle 6: Effect of level of feed restriction on performnce, crcss chrcteristics nd dressing percentge of mle nd femle Ross 308 roiler chickens t 42 dys of ge Vriles Intestine Live Dressing Thigh Drum Wing Brest Ft Gizzrd Liver length Tretment No Weight %ge (g) stick (g) (g) (g) (g) (g) (g) (cm) 0% dli % dli % dli SE Mle Femle SE ,,c :Mens in the sme column not shring common superscript re significntly different (p<5). SE: Stndrd Error Tle : Effect of level of feed restriction on prts when expressed s percentge of crcss weight of mle nd femle Ross 308 roiler chickens t 42 dys of ge Vrile No Thigh Drumstick Wing Brest Gizzrd Liver tretment 0% d liitum % d liitum % d liitum SE Mle Femle SE ,,c :Mens in the sme column not shring common superscript re significntly different (p<5). SE: Stndrd Error 38

5 Tle 8: Effect of level of feed restriction on nitrogen content (g/kg DM) of mle nd femle Ross 308 roiler chickens rest met smples t 42 dys of ge Tretment No Nitrogen 0% d liitum % d liitum % d liitum SE 0.53 Mle Femle SE 0.43,,c :Mens in the sme column not shring common superscript re significntly different (p<5). SE: Stndrd Error Conclusion: Feed restriction t the strter stge ffected the live weight of roiler chickens t 21 dys of ge. Chickens on 5% d liitum feeding ttined complete compenstion in live weight while those on 50% d liitum feeding did not. It is suggested tht 5% d liitum restriction feeding during the strter stge from 14 up to 21 dys of ge my offer some economic dvntge over d-liitum feeding regimen, minly y enhncing feed utiliztion. It my, therefore, e useful nutritionl strtegy to reduce the cost of commercil strter grin sed-diets. ACKNOWLEDGEMENT The Ntionl Reserch Foundtion for finncil support. REFERENCES Arce, J., M. Berger nd C.L. Coello, Control of scites syndrome y feed restriction techniques. J. Applied. Poult. Res., 1: 1-5. AOAC, Officil Methods of Anlysis. Assocition of Officil Anlyticl Chemists, Wshington, DC. Clverl, C.C., J.P. McMurtry, R.W. Roserough nd R.G. Cmpell, 198. Effect of energy level on the compenstory growth response of roilers following erly feed restriction. Poult. Sci., 66: 5. Duncn, D.B., Multiple rnge nd multiple F-tests. Biometrics, 11: Jones, G.P.D. nd D.J. Frrell, Erly life food restriction of the chicken. I. Methods of ppliction, mino cid supplementtion nd the ge t which restriction should commence. Br. Poult. Sci., 33: Leeson, S., J.D. Summers nd L.J., Cston, Diet dilution nd compenstory growth in roilers. Poult. Sci., 0: Leu, W.M.K., J.T.B. Cott, A.I.G. Oliveir nd P.B. Rodrigue, Desempenho de frngos sumetidos restrição limentr n fse inicil em diferentes sistems de crição. Ciênci Agrotecnic, Lvrs 26: Lippens, M., G. Room, G. De Groote nd E. Decuypere, Erly nd temporry quntittive food restriction of roiler chickens. 1. Effects on performnce chrcteristics, mortlity nd met qulity. Br. Poult. Sci., 41: NRC, Ntionl Reserch Council, Nutrient Requirements of Poultry. 9th Rev. Edn. Ntionl Acdemy Press, Wshington, DC. Oyedeji, J.O. nd J.O. Atteh, Response of roilers to feeding mnipultions. Int. J. Poult. Sci., 4: Pinchsov, Y., I. Nir nd I. Nitsn, Metolic nd ntomicl dpttions of hevy-odied chicks to intermittent feeding. I Food intke, growth rte, orgn weight nd ody composition. Poult. Sci., 64: Pinchsov, Y. nd L.S. Jensen, Comprision of physiologicl nd chemicl mens of feed restriction in roiler chicks. Poult. Sci., 68: Plvnik, I., J.P. McMurtry nd R.W. Roserough, Effect of erly feed restriction in roilers. I. Growth performnce nd crcss composition. Growth, 50: Plvnik, I. nd S. Hurwitz, Effect of dietry protein, energy nd feed pelleting on the response of chicks to erly feed restriction. Poult. Sci., 68: Plvnik, I. nd S. Hurwitz, Erly feed restriction in chicks: Effects of ge, durtion nd. Poult. Sci., 6: Plvnik, I. nd S. Hurwitz, Response of roiler chickens nd turkey poults to food restriction of vried severity during erly life. Br. Poult. Sci., 32: Roinson, F.E., H.L. Clssen, J.A. Hnson nd D.K. Onderk, Growth performnce, feed efficiency nd the incident of skeletl nd metolic disese in full-fed nd feed-restricted roiler nd roster chickens. J. Applied Poult. Res., 1: Sleh, K., Y.A. Atti nd H. Young, Effect of feed restriction nd reed on compenstory growth, dominl ft nd some production trits of roiler chicks. Archiv fur Geflugelkunde, 60: Sleh, E.A., S.E. Wtkins, A.L. Wldroup nd P.W. Wldroup, Effects of erly quntittive feed restriction on live performnce nd crcss composition of mle roiler grown for further processing. J. Applied Poult. Res., 14: SAS, Proprietry softwre relese 8.1. Sttisticl Anlysis Systems Institute, Inc., Cry, North Croline, USA. Yu, M.E., F.E. Roinson, M.T. Clndini nd L. Bodnr, Growth nd ody composition of roiler chickens in response to different regimes of feed restriction. Poult. Sci., 69: Yu, M.E. nd F.E. Roinson, The ppliction of short-term feed restriction to roiler chicken production: A Rev. J. Applied Poult. Res., 1: Zuir, A.K. nd S. Leeson, Effect of erly feed restriction nd relimenttion on metolichet production nd chnges in digestive orgns in roiler chickens. Poult. Sci., 3: