Performance Comparison and Lysine Requirements of Seven Commercial Brown Egg Layer Strains During Phase One

Transcription

1 Interntionl Journl of Poultry Siene 7 (8): 806-8, 008 ISSN Asin Network for Sientifi Informtion, 008 Performne Comprison nd Lysine Requirements of Seven Commeril Brown Egg Lyer Strins During Phse One P. Gunwrdn, D.A. Rolnd, Sr. nd M.M. Brynt Deprtment of Poultry Siene, Auurn University, Auurn, Alm 36849, USA Astrt: This study ws 3 7 ftoril rrngement of 3 lysine levels (0.97, 0.88 nd 0.747) nd seven ommeril rown egg lyer strins. The ojetive of this experiment ws to determine the effet of inresing dietry lysine on performne, egg omposition, egg solids, egg qulity nd profits in seven ommeril rown egg lyer strins nd to determine the lysine requirement during phse one (from - 36wk of ge). This experiment lsted 6 weeks. Seven strins of hens (n = 40 of eh strin) t week of ge were rndomly divided into tretments (8 replites of 0 irds/tretment). The results showed tht there were no intertions etween lysine nd strin on ny prmeter. Lysine hd signifint effets on egg weight, egg mss, feed onversion, perent lumen solids, yolk olor, shell olor, lumen weight, egg shell nd lumen omponents. There were signifint strin effets on egg prodution, feed onsumption, egg weight, egg mss, feed onversion, speifi grvity, yolk weight, shell olor, shell, lumen nd yolk omponents, yolk, lumen nd whole egg solids. Strin hd the est overll performne. All strins peked in prodution over 94% nd were lying 94-96% t 36 weeks of ge. Averge egg weight (-36wk) ws 60.3g, vrying from g etween strins. Averge feed intke ws.3g/hen/dy vrying from g/hen/dy etween strins. Averge egg weight of hens fed diets ontining the highest lysine level ws.04g hevier thn the hens fed the diets ontining the lowest lysine level. Inresing dietry lysine from % signifintly improved feed onversion from.0-.06g feed/g egg nd inresed egg mss from g/hen/dy. Averge lysine intke of hens fed 0.97% level ws 03mg/hen/dy vrying from mg/hen/dy etween strins. Beuse egg pries nd ingredient pries often hnge, there n e no fixed dietry lysine level for optiml profits. Key words: Brown lyer Strin, lysine requirement, shell olor Introdution Brown-egg-lying hens predominte in mny prts of the world, nd their use is rpidly growing in the USA nd other South Amerin ountries s well. Different rown strins hve different prodution hrteristis, egg omponents, egg solids, nd egg qulity (Wu et l., 008). Some strins my e enefiil for further proession suh s dried nd liquid egg prodution where s some strins my e enefiil for tle egg prodution. Severl ommeril Brown-egg-lyer strins re urrently used y egg produers. Protein (lysine) is the mjor nutrient representing high perentge of totl ost of the diets. Liu et l. (005) nd Wu et l. (007) reported tht inresing Protein (lysine) level signifintly improved egg prodution, egg weight; egg mss, feed onsumption, feed onversion, egg speifi grvity nd ody weight of hens. As hens ge, the nutrient requirement dereses (Sell et l., 987 nd Wu et l., 005). If the nutrient ontents of diets fed to old hens re the sme s tht of diets fed to young hens, some of nutrients my e wsted nd ost of prodution my inrese. It is importnt for ommeril leghorn industry to know the lysine requirement, vrition in strin performne, nd if there re ny intertion etween strin nd lysine on performne. Hens re normlly fed lysine rnging from % during phse one. Current high ost of protein (lysine), emphsize the need to know the lysine requirement for optiml performne nd profits. However very few studies hve een onduted to determine the lysine requirement ross rown egg lyer strins during phse one. Egg qulity hs eome n importnt spet of egg mrketing s retil outlets re now demnding high stndrds for onventionl internl nd externl qulity hrteristis. Throughout the world, preferene for shell olor in tle eggs differs nd is sed minly on the visul pperne of the egg. Although shell olor hs little to do with the nutritionl vlue of tle egg, uniformity of olor of rown eggs, together with ertin minimum depth of olor re importnt onsidertions for onsumers. Ple-shelled eggs re often deemed uneptle using some highly produtive strins to e rejeted. Egg shell olor etween strins hs reeived very limited or no reserh ttention (Odsi et l., 007). Even though rown egg lying hens re not used for liquid nd reker egg industry, there my e potentil of using them in future. Inresing mino ids suh s methionine nd lysine signifintly inrese perent 806

2 Gunwrdn et l.: Dietry Lysine nd Brown Egg Lyers lumen in Hy-line W-36 hens during phse (Shfer et l., 998 nd Novk et l., 004). It might e enefiil for the egg proessing industry to know how to mnipulte dietry lysine to improve liquid egg nd dried egg prodution. There re very few if ny studies ville on the effet of dietry lysine on egg omposition nd egg solids of rown egg lyers. Tehnologil dvnes in genetis, mngement, niml helth nd ehvior hve llowed lying hens to hve etter feed effiieny, lrger egg size nd longer persistene of prodution. Thus it is neessry to ondut reserh in nutritionl requirement determintion nd in optimiztion of the use of nutrients, so tht lying hens n hve the mximum geneti potentil expression (Willim et l., 005). Therefore the ojetive of this experiment ws to determine the effet of inresing dietry lysine on performne, egg omposition, egg solids, egg qulity, in seven ommeril rown egg lyer strins nd to determine the nutrient (lysine) requirements tht llow for the est performne in phse one (from -36wk of ge). Mterils nd Methods This study ws 3 x 7 ftoril rrngement with three dietry lysine levels (0.97, 0.88 nd 0.747) nd seven ommeril rown egg lyer strins. The seven rown ommeril or experimentl egg lying strins (otined from Centurion poultry In. ) were identified s strin -7. Strin 5 ws the Bovns Brown lssi. Ingredients nd nutrient omposition of experimentl diets re shown in Tle. Feed nd feed ingredient smples were nlyzed for mino ids. Dietry energy (840MEkl/kg) ws mintined the sme in ll diets. Energy nd lysine levels of experimentl diets were determined to meet the minimum nutrients requirements speified y (NRC, 994). In this experiment, seven rown egg lying strins (totl n = 680) t week of ge were rndomly ssigned into tretments (8 replites of 0 hens per tretment). The tril lsted 6 weeks. Hens were housed two per ge in 40.6 x 45.7m ge. Eh replite onsisted of five djoining ges. Replites were eqully distriuted into upper nd lower ge levels to minimize ge level effet. All hens were housed in n environmentlly ontrolled house with temperture o mintined s lose to 6 C s possile. Pullets were housed t 8 week of ge. Light ws inresed y 5 minutes per week from hours per dy to 6 hours per dy. The house hd ontrolled ventiltion nd lighting (6h/d). All hens were supplied with feed nd wter d liitum. Animl housing nd hndling proedures during experimenttion were in ordne with guidelines of Auurn University s Institutionl Animl Cre nd Use Committee (IACUC). Feed onsumption ws reorded weekly nd lulted verge dily feed onsumption, egg prodution ws reorded dily nd egg weight nd Tle : Ingredients nd nutrient ontent of the experimentl diets Ingredient (%) Diet Diet Diet 3 Corn Soy en mel Hrd shell Limestone Dilium phosphte Poultry oil NCl Vitmin Premix Minerl Premix DL-Methionine Totl Clulted Anlysis ME (Kl/kg) Crude protein C Aville phosphorus N Methionine+Cystine Lysine Hrd shell = lrge prtile limestone (pssing US mesh #4 nd retined y US mesh #6) CCO 3 supplied y Frnklin Industril Minerls, Lowell,FL. Provided per kilogrm of diet: Vitmin A (s retinyl ette), 8,000 IU; holeliferol,,00icu, vitmin E (s DL-lph-toopheryl ette), 8IU; vitmin B, 0.0mg; rioflvin, 5.5mg; D-lium pentotheni id, 3mg; niin, 36mg; holine, 500mg; foli id, 0.5mg; vitmin B (thimin mononitrte), mg; pyridoxine,.mg; iotin, 0.05mg; vitmin 3 K (mendione sodium isulfte omplex), mg. Provided per kilogrm of diet: mngnese, 65mg; iodine,mg; iron, 55mg; opper, 6mg; zin, 55mg; selenium, 0.3mg. speifi grvity were reorded one every two weeks. Egg weight nd egg speifi grvity were mesured using ll eggs produed during onseutive dys. Feed onsumption ws determined y sutrting the ending feed weight of eh trough (eh replite) from eginning feed weight weekly. Egg speifi grvity ws determined using 9 grdient sline solutions vrying in speifi grvity from in unit inrements (Holder nd Brdford, 979). Mortlity ws determined dily nd feed onsumption ws djusted ordingly. Body weight ws otined y weighing 3 hens per replite t the end of the experiment. Egg mss (g of egg/hen per dy) nd feed onversion (g of feed/g of egg) were lulted from egg prodution, egg weight nd feed onsumption. Egg omponents were mesured using 3 rndomly seleted eggs from eh tretment replite t the middle nd end of the experiment. Eggs were weighed nd roken. The yolks were seprted from the lumen. Before yolk weight ws determined, the hlz ws removed y foreps. Eh yolk ws rolled on lotting pper towel to remove dhering lumen. The shells were lened of ny dhering lumen nd dried for 5 dys. Alumen weight ws lulted y sutrting the weight of yolk nd shell from the whole egg weight. 807

3 Gunwrdn et l.: Dietry Lysine nd Brown Egg Lyers Three eggs from eh tretment replite were onsumption. Feed onsumption of Strin 5 ws rndomly olleted t the middle nd t the end of the signifintly higher thn those of strin, 4 nd 7 ut experiment for mesuring solids. The yolk nd lumen ws similr to strin, 3 nd 6. There ws no signifint were mixed nd 5-6g of homogente ws pipetted into effet of dietry lysine on feed onsumption. This result n luminum dish with weight reorded to 0.00g. The ws in greement with Wu et l., 007, who reported o smple ws dried in n oven for 4h t 40.5 C (AOAC, tht there ws no signifint effet of dietry protein 990) nd then weighed. Three eggs whih rndomly (lysine) on feed onsumption with Hy-line W-36 hens. seleted from eh tretment replite were used to nlyze yolk nd lumen solid. After yolk ws Egg prodution: There ws signifint strin effet on seprted from lumen, three yolks nd lumen per egg prodution (Tle ). Strin hd the highest egg replite were mixed seprtely. The proedure for prodution wheres strin hd the lowest. Dietry nlyzing lumen nd yolk solid ws the sme lysine did not signifintly ffet egg prodution nd s the proedure for whole egg solid ontent. Yolk olor there ws no signifint intertion etween strin nd nd hugh units were mesured (3 eggs from eh dietry lysine on egg prodution. This result ws in tretment replite) t the middle nd t the end of the greement with Btemn et l., 00, 00 nd 003 experiment using n egg multitester EMT-500 who reported tht there ws no signifint intertion (Rootmtion,o, Ltd. Tokyo, Jpn). Hugh units were etween strin nd lysine on egg prodution with white lulted from the reords of lumen height nd egg leghorns. Wu et l., 007 lso reported tht there ws weight using the formul: no effet of dietry lysine on egg prodution HU = 00 log 0 (H-.7 W +7.56) Egg mss: Signifint strin nd dietry lysine effets were oserved on egg mss (Tle ). Strin hd the where HU = Hugh unit, H = height of the lumen (mm) highest egg mss mong seven strins. Inresing nd W = egg weight (g). Shell olor ws mesured (3 dietry lysine linerly inresed egg mss from eggs of eh tretment replite) t the middle nd t 54.3g resulting in 4.88% inrese in egg mss. the end of the experiment using CHROMA METER CR- There ws no signifint intertion etween strin nd 300 (Minolt o, Ltd. Osk, Jpn). The egg shell olor dietry lysine on egg mss. reported s L*, * nd *. The L* vlue represents lightness nd rnges from 0-00, with 0 orresponding Egg weight: Both dietry lysine nd strin hd to lk nd 00 to white. Redness-greenness nd signifint effet on egg weight (Tle ). Strin 4 hd yellowness-lueness, were mesured y * nd *, the lowest egg weight. Dietry lysine linerly inresed respetively. egg weight y 3.44% from g. There ws no Dt were nlyzed y ANOVA using pro mixed of signifint intertion etween strin nd dietry lysine Sttistil Anlysis System (SAS Institute, 000) for on egg weight. This result ws onsistent with the rndomized omplete lok with ftoril rrngement previous reports tht there ws no signifint intertion of tretments. Dietry lysine nd strins were fixed, etween strin nd lysine on egg weight with white wheres loks were rndom. The ftoril tretment leghorns (Btemn et l., 00, 00, 003). rrngement onsisted of three dietry lysine levels nd seven strins. The following model ws used to nlyze Feed onversion: Dietry lysine nd strin signifintly the dt: effeted feed onversion. However there ws no intertion etween strin nd lysine on feed onversion Y ijk = µ + " i + $ j + ("$) ij + P k +, ijk (Tle ). Strin hd the est feed onversion wheres strin hd the worst. Hens fed high lysine diets hd Where Y ijk = individul oservtion, µ = overll men, " i etter feed onversion thn hens fed low lysine levels. = dietry lysine effet, $ j = strin effet, ("$) ij = intertion This result ws in greement with tht of Liu et l. (005) etween dietry lysine nd strin, P k = effet of lok,, ijk nd Wu et l. (007) who reported inresing dietry = error omponent. If differenes in tretment mens lysine improved feed onversion with Hy-line W-36 hens. were deteted y ANOVA, Dunn s multiple rnge test ws pplied to seprte mens. A signifine level of Egg speifi grvity, finl ody weight nd mortlity: P= 0.05 ws used for nlysis. There ws signifint effet of strin on egg speifi Centurion poultry, In. Lexington, GA grvity. However dietry lysine or intertion etween Deguss Corportion, Allendle, NJ Results nd Disussion Feed onsumption: There ws no signifint intertion etween strin nd dietry lysine on feed onsumption (Tle ). There ws signifint strin effet on feed lysine nd strin hd no signifint effet on egg speifi grvity (Tle 4). Egg speifi grvity of strin ws signifintly greter thn tht of the other six strins. There ws no signifint effet of dietry lysine, strin or intertion etween strin nd lysine on ody weight nd mortlity. 808

4 Gunwrdn et l.: Dietry Lysine nd Brown Egg Lyers Tle : Effet of lysine on feed intke, egg prodution, egg mss, feed onversion nd egg weight of seven rown egg lyer strins during first yle phse (wk to 36 wk of ge) Feed Egg Feed intke Egg mss onversion Egg Lysine (g/hen Prodution (g of egg/h (g of feed/g Weight (%) Strin per dy) (%) per dy) of egg) (g) Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Strin Pooled SEM Proility Lysine NS NS < < Strin < < < < Lysine Strin NS NS NS NA NA Mens within olumn nd under eh min effet with no ommon supersripts differ signifintly (P = 0.05). Inresing dietry lysine signifintly inresed perent redution in orn use, s the level of protein inresed. lumen, perent lumen solids nd lumen weights This result ws in greement with tht of Krunjeew. (Tle 3). However, inresing dietry lysine deresed (97), who reported tht inresing dietry lysine from perent shell. There ws no signifint intertion %, signifintly deresed yolk olor from etween lysine nd strin on perent omponents, with white leghorn hens. perent solids or lumen, yolk nd shell weight (Tle Strin hd the est overll performne (Tle ). 3). Strin hd signifint effet on perent egg Compred to rown egg lying hens of other six strins, omponents, perent egg solids nd yolk weight (Tle Strin hens hd the est effiieny in utilizing nutrients 3). Strin 5 nd strin nd 7 hd the highest nd to produe one grm egg (Tle 5). The est lowest perent yolk respetively. Strin,, 6 nd 7 hd performne of ll seven strins ws otined with hens highest perent lumen nd strin, hd the highest fed diets ontining 0.097% lysine. Strin 5 (Bovns perent shell. Strin 4 hd the highest yolk nd whole rown lssi) hens onsumed 0.0g protein, 063mg egg solids wheres strin,, 4 nd 5 hd the lysine, 798mg TSAA nd 39kl ME per hen dily or highest lumen solids. 0.36g protein, 9.3mg lysine, 4.5mg TSAA nd Both dietry lysine nd strin hd signifint effet on 5.98kl ME per g egg for the est performne (Tle shell olor (Tle 4). Strin 4 nd 5 hd the drkest nd 5). Strin 5 required 5% more protein, 7% more TSAA, lightest shell olor respetively (Tle 4). Inresing nd 33% more lysine thn the vlues reommended y dietry lysine signifintly deresed yolk olor due to NRC (994). 809

5 Gunwrdn et l.: Dietry Lysine nd Brown Egg Lyers Tle 3: Effet of lysine on egg omponents, egg solids, nd lumen, yolk nd shell weights of seven rown egg lyer strins during first yle phse (wk to 36 wk of ge) % Egg omponents % of solids Alumen, Yolk, Shell weight (g) Lysine (%) Strin Yolk Alumen Shell Whole egg Alumen Yolk Alumen Yolk Shell d Strin Strin d Strin Strin Strin d Strin e Strin Pooled SEM Proility Lysine NS 0.00 NS < NS NS Strin < NS < NS Lysine x Strin NS NS NS NS NS NS NS NS NS Mens within olumn nd under eh min effet with no ommon supersripts differ signifintly (P = 0.05). Tle 4: Effet of lysine on speifi grvity, ody weight, mortlity, shell olor [lightness (L*), redness (*), yellowness (*] nd egg qulity of seven rown egg lyer strins during first yle phse (wk to 36 wk of ge). Egg Egg qulity Speifi Body Grvity Weight Mortlity Egg shell olor Hugh Yolk Lysine (%) Strin (Unit) (Kg) (%) L* * * Unit olor d Strin d Strin d Strin e Strin e Strin d Strin de Strin Pooled SEM Proility Lysine NS NS NS NS Strin NS NS < < < NS NS Lysine x Strin NA NS NS NS NS NS NS NS - Mens within olumn nd under eh min effet with no ommon supersripts differ signifintly (p < 0.05). A higher L* vlue mens lighter olor; higher * vlue mens redder olor; higher * vlue mens more yellow olor. Tle 5: Nutrient requirement of seven rown egg lyer strins fed diets ontining 0.97% lysine during first yle phse (wk to 36 wk of ge) Strin Strin Strin 3 Strin 4 Strin 5 Strin 6 Strin 7 Nutrients required per hen dily Protein (g) Lysine (mg) TSAA (mg) Dietry energy (kl) Nutrients required to produe one grm egg Protein (g) Lysine (mg) TSAA (mg) Dietry energy (kl) Hy-line rown nd Bovns rown strins re the most mngement guide ( ) nd.6% more populr rown egg lying strins in the world. protein, 0.% more TSAA nd 8.4% more lysine thn Compring the nutrient requirements of Hy-line rown the vlues reommended y Bovns rown with the nutrient requirements of strin 5 (Bovns rown mngement guide (008), respetively. lssi), the Bovns rown lssi (strin 5) required The Eonometri Feeding nd Mngement Progrm 3.9% more protein, 8.7% more TSAA, nd 7.6% more developed y Rolnd et l. (998, 000) ws used to lysine thn the vlues reommended y Hy-line rown lulte profits t different dietry lysine levels nd egg 80

6 Gunwrdn et l.: Dietry Lysine nd Brown Egg Lyers Tle 6: Nutrient requirement of seven rown egg lyer strins fed diets ontining 0.88% lysine during first yle phse (wk to 36 wk of ge) Strin Strin Strin 3 Strin 4 Strin 5 Strin 6 Strin 7 Nutrients required per hen dily Protein (g) Lysine (mg) TSAA (mg) Dietry energy (kl) Nutrients required to produe one grm egg Protein (g) Lysine (mg) TSAA (mg) Dietry energy (kl) Tle 7: Nutrient requirement of seven rown egg lyer strins fed diets ontining 0.747% lysine during first yle phse (wk to 36 wk of ge) Strin Strin Strin 3 Strin 4 Strin 5 Strin 6 Strin 7 Nutrients required per hen dily Protein (g) Lysine (mg) TSAA (mg) Dietry energy (kl) Nutrients required to produe one grm egg Protein (g) Lysine (mg) TSAA (mg) Dietry energy (kl) Tle 8: Influene of dietry lysine on profits of Bovns rown lssi ( Strin 5) hens during first yle phse (wk to 36 wk of ge) Prie spred Diet 0 ents 5 ents 30 ents 37 ents 5 (Lysine %) Returns ($/dozen) Bsed on feed prie of $06.44 per to for the 0.97 lysine diet, $ 0.65 per ton for the 0.88 lysine diet, nd $99.8 per ton for the lysine diet. Bsed on n Urner Brry egg prie of 3 ents/doz. for hek nd peewee, 40 ents/doz. for smll, 57 ents/doz. for medium, 67 ents/doz. for lrge, 68 ents/doz. for extr lrge nd 69 ents/doz. for jumo eggs. 3 Bsed on n Urner Brry egg prie of 3 ents/doz. for hek nd peewee, 40 ents/doz. for smll, 65 ents/doz. for medium, 80 ents/doz. for lrge, 8 ents/doz. for extr lrge nd 84 4 ents/doz. for jumo eggs. Bsed on n Urner Brry egg prie of 3 ents/doz. for hek nd peewee, 40 ents/doz. for smll, 57 ents/doz. for medium, 87 ents/doz. for lrge, 9 ents/doz. 5 for extr lrge nd 0 ents/doz. for jumo eggs. Returns (R) were lulted using the eqution R = UBEP-R-C-dC, where UBEP = Urner Berry Egg Prie, NR = nest run into pkge produt delivered, PC = prodution ost nd FdC = feed ost s desried y Rolnd et l.(998, 000). pries (Tle 8). Current feed pries were used. Prie spreds, etween medium nd lrge eggs were 0, 5, 30 nd 37 ents/dozen. Mximum profits per dozen of eggs were otined in Bovns rown lssi hens (Strin 5) fed the lowest lysine diet (0.747%) t smll (0 nd 5 ents/dozen) prie spreds (0.00 nd 0.40 $/dozen) wheres, highest profits were otined y feeding the high lysine diet (0.97%) t lrger (30 nd 37 ents/dozen) prie spreds (0. nd $/dozen). Sine feed pries nd egg prie vry, there n e no fixed dietry lysine level for optiml profits during phse ( wk to 36 week of ge). In this study, nutrient requirement of Bovns rown lssi hens (strin 5) for optiml performne ws otined with the highest dietry lysine level (0.97). However, nutrient requirement for optiml profits vry ording to the urrent ingredient nd egg pries. Aording to the profit nlysis (Tle 8) highest profits with lrger prie spreds were otined with the highest dietry lysine diet (0.97%) wheres with smller prie spred, highest profits were otined with the lowest lysine diet (0.747%). In ddition to the lysine requirement for optiml profits vrying with ingredients nd egg pries, the lysine requirement for optiml performne nd profits lso vries with energy intke (Tle 5, 6 nd 7); this omplites efforts to determine requirements for optiml performne nd profits. In onlusion, the results showed tht there were no intertions etween lysine nd strin on ny prmeter. Lysine hd signifint effets on egg weight, egg mss, feed onversion, perent lumen solids, yolk olor, shell olor, lumen weight, egg shell nd lumen omponents. There were signifint strin effets on egg prodution, feed onsumption, egg weight, egg mss, feed onversion, speifi grvity, yolk weight, shell olor, shell, lumen nd yolk omponents, yolk lumen nd whole egg solids. All strins peked in 8

7 Gunwrdn et l.: Dietry Lysine nd Brown Egg Lyers prodution over 94% nd were lying 94-96% t 36 weeks of ge. Averge egg weight (-36wk) ws 60.3g, vrying from g etween strins. Averge feed intke ws.3g/hen/dy vrying from g/hen/dy etween strins. Averge egg weight of hens fed diets ontining the highest lysine level ws.04g hevier thn the hens fed the diets ontining the lowest lysine level. Inresing dietry lysine from % signifintly improved feed onversion from.0-.06g feed/g egg nd inresed egg mss from g/hen/dy. Averge lysine intke of hens fed 0.97% level ws 03mg/hen/dy vrying from mg/hen/dy etween strins. Beuse egg nd ingredient pries nd energy intke often hnge, there n e no fixed dietry lysine level for optiml profits. Referenes th AOAC., 990. Offiil methods of Anlysis. 5 ed. Assoition of Anlytil Chemists, Wshington, DC. Btemn, A., M.M. Brynt nd D.A. Rolnd Sr., 00. Nutrient requirements of Dekl White, Dekl Sigm nd Bovns White hens for optimum profits in ool environment in Phse I. Poult. Si., 8: 8. Btemn, A., M.M. Brynt nd D.A. Rolnd Sr., 00. Nutrient requirements of Dekl White, Dekl Sigm nd Bovns White hens for optimum profits in ool environment in Phse I. Poult. Si., 8: 8. Btemn, A., M.M. Brynt nd D.A. Rolnd Sr., 003. Eonometris feeding of ommeril lyers: 6. Strin omprison (Dekl nd Bovns White) of nutrient requirements for performne nd optimum profits (Phse III). Poult. Si., 8: 3. Bovns rown mngement guide North Amerin Edition, 008. Holder, D.P. nd M.V. Brdford, 979. Reltionship of speifi grvity of hiken eggs to numer of rked eggs nd perent shell. Poult. Si., 58: Hy-line vriety rown ommeril mngement guide, Krunjeew, H., 97. Effet of protein nd energy levels on lying performne of strins of different ody weights. Aust. J. Exp. Agri., : Liu, Z., G. Wu, M.M. Brynt nd D.A. Rolnd, Sr., 005. Influene of dded syntheti lysine in low-protein diets with the methioine plus ystine to lysine rtio mintined t J. Appl. Poult. Res., 4: Ntionl Reserh Counil, 994. Nutrient Requirements of Poultry. 9 Rev. Ed. Ntionl Ademy Press, Wshington, DC. Novk, C., H. Ykout nd S. Sheideler, 004. The omined effet of dietry lysine nd totl sulfur mino id level on egg prodution prmeters nd egg omponents in Dekl Delt lying hens. Poult. Si., 83: Odsi, A.Z., R.D. Miles, M.O. Bln nd K.M. Portier, 007. Chnges in rown egg shell olor s the hen ges. Poult. Si., 86: SAS Institute, 000. SAS/STAT User s Guide. SAS Institute In., Cry, NC. Sell, J.L., R. Angel nd F. Esrino, 987. Influene of supplementl ft on weight of eggs nd yolks during erly egg prodution. Poult. Si., 66: Shfter, D.J., J.B. Crey, J.F. Prohsk nd A.R. Sms, 998. Dietry methionine intke effets on egg omponent yield, omposition, funtionlity nd texture profile nlysis. Poult. Si., 77: Willim, N.S., H.S. Rostgno, P.R. Sores, M.A. Silv nd L.F.U. Velsquez, 005. Nutritionl requirements in methionine + ystine for white-egg lying hens during the first yle of proution. Int. J. Poult. Si., 4: Wu, G., M.M. Brynt, R.A. Voitle nd D.A. Rolnd, Sr., 005. Effet of dietry energy on performne nd egg omposition of Bovns white nd Dekl white hens during phse. Poult. Si., 84: Wu, G., P. Gunwrdn, M.M. Brynt, R.A. Voitle nd D.A. Rolnd, Sr., 007. Effet of dietry energy nd protein on performne, egg omposition, egg solids, egg qulity nd profits of Hy-Line W-36 hens during phse. Int. J. Poult. Si., 6: Wu, G., P. Gunwrdn, M. Brynt, R. Voitle nd D. Rolnd, Sr., 008. Effet of method nd dietry energy on post molt performne of two strins of single om white leghorn hens. J. Appl. Poult. Res., 7: -0. Wu, G., M.M. Brynt, P. Gunwrdn nd D.A. Rolnd, Sr., 007. Effet of nutrient density on performne, egg omponents, egg solids, egg qulity, nd profits in eight ommeril leghorn strins during phse one. Poult. Si., 86: Rolnd, D.A. Sr., M.M. Brynt, J.X. Zhng, D.A. Rolnd Jr. S.K. Ro nd J. Self, 998. Eonometri feeding nd mngement. Mximizing profits in Hy-line W-36 hens y optimizing totl mino id intke nd environmentl temperture. J. Appl. Poult. Res., 7: Rolnd, D.A. Sr., M.M. Brynt, J.X. Zhng, D.A. Rolnd Jr. nd J. Self, 000. Eonometri feeding nd mngement of ommeril Leghorns: Optimizing profits using new tehnology. Pges: in: Egg Nutrition nd Biotehnology. J.S. Sim, S. Nki nd W. Guenter, ed. CABI pulishing, CAB Int., Wllingford, UK. 8