Interntionl Journl of Poultry Science 4 (7): 44-448, 005 ISSN 68-8356 Asin Network for Scientific Informtion, 005 Evlution of Seprte nd Comined Effects of Choline nd Betine in Diets for Mle Broilers P.W. Wldroup nd C.A. Fritts Poultry Science Deprtment, University of Arknss, Fyetteville AR 770, USA Astrct: A study ws conducted to evlute the effects of supplementtion of corn-soyen mel sed diets with etine nd choline on live performnce nd rest met yield of mle roiler chicks. Diets formulted to meet nutrient levels of top roiler compnies were supplemented with either 0 or 000 mg/kg etine in comintion with either 0 or 000 mg/kg choline. Betine supplementtion ws crried out either for the full 49 d feeding tril or initited t 35 d of ge. Ech dietry tretment ws ssigned to eight replicte pens of 60 mle chicks of commercil strin. At 4 nd 49 d of ge smples of irds were processed under commercil conditions nd dressing percentge nd rest yield determined. The results of this study indicte little or no positive enefit in terms of ody weight gin, feed conversion, or mortlity from the ddition of etine to nutritionlly dequte corn-soyen mel sed diets for roiler chicks in situtions where disese chllenge from coccidiosis is not mjor issue. Improvements in dressing percentge were otined from etine supplementtion nd in rest yield from choline supplementtion t 4 d of ge ut not t 49 d of ge. Therefore, ge of ird might e considertion for using these supplements s irds processed t younger ges might e more responsive to these nutrients. Further studies re needed to evlute the potentil effect of ge on response to choline nd etine. Key words: Broilers, etine, choline, processing yield, rest met Introduction Mny studies hve exmined the interreltionship etween choline nd methionine (Mrvel et l., 944; Clndinin et l., 946; Gerry et l., 948; Sunde et l., 95; West et l., 95; Fetherston nd Stephenson, 960; Quillen et l., 96; Pesti et l., 980; Bker et l., 983; Miles et l., 983; Tillmn nd Pesti, 986; Grci- Neto et l., 000) nd etween etine nd methionine (Rostgno nd Pck, 996; Schutte et l., 997; Kidd et l., 997; Virtnen nd Rumsey, 996; Esteve-Grci nd Mck, 000; McDevitt et l., 000) to determine if these compounds cn spre the needs of the chick for methionine, with considerle vrition in results. While some studies (Virtnen nd Rosi, 995; Virtnen nd Rumsey, 996) suggest tht the response to etine ws greter thn tht otined from the ddition of methionine, others hve filed to demonstrte tht the methionine content of the diet could e reduced y supplementtion with etine (Rostgno nd Pck, level of methionine in the diet. From this study it ws difficult to determine the reltive contriutions of etine nd choline to this response. The present study ws designed to evlute the individul nd comined contriutions of etine nd choline to enhncement of rest met yield in mle roilers grown for further processing. Mterils nd Methods Diets were formulted using corn nd soyen mel of known crude protein nd moisture content to meet the nutrient levels of the top five compnies in populr griculturl survey The nutrient stndrds used for formultion re shown in Tle nd the composition of the diets for the vrious ge periods is shown in Tle. For ech ge period, lrge tch of the sl diet ws prepred nd liquots used for mixing the vrious test diets. Diets were fortified with complete vitmin nd trce minerl premixes otined from locl poultry 996; Schutte et l., 997; Esteve-Grci nd Mck, compnies. 000; McDevitt et l., 000). However, severl studies Dietry tretments consisted of x 3 fctoril suggest tht ddition of etine my improve rest rrngement of tretments with two choline levels (0 or met yield (Schutte et l., 997; Wllis, 999; Esteve- 000 mg/kg supplementl choline) nd three etine Grci nd Mck, 000; McDevitt et l., 000; Remus, tretments (0, 000 mg/kg from 0 to 49 d, 0 to 35 00). A recent study from our lortory (Wldroup et followed y 000 mg/kg to 49 d). Becuse much of the l., 005) concluded tht ddition of 000 mg/kg etine, development of rest muscle tkes plce during the 000 mg/kg choline, or the comintion of 500 mg/kg of ltter stges of growth it might e possile to otin the etine nd 500 mg/kg of choline, fed continuously from sme improvements y supplementing the finisher diets one dy of ge, resulted in significnt improvement in with etine, thus the reson for feeding only from 35 to rest met yield of mle roilers, independent of the 49 dys in the ltter tretment. Choline ws supplied s 44
Tle : Nutrient content of diets from top roiler compnies Nutrient Unit Strter Grower Finisher Finisher 0-6 d 6-30 d 30-4 d 4d-mkt ME Kcl/l 36.00 394.00 46.00 460.00 Crude protein % 0.93 9.6 7.0 6.08 Lysine %.3.09 0.93 0.88 TSAA % 0.96 0.85 0.76 0.76 Tryptophn % 0.5 0. 0.0 0.8 Arginine %.5.3.7.08 Threonine % 0.85 0.76 0.68 0.64 Nonphytte P % 0.43 0.37 0.34 0.33 Clcium % 0.83 0.85 0.76 0.76 Sodium % 0.3 0.0 0. 0.0 Tle : Composition (g/kg) nd nutrient content of diets formulted to stndrds of top roiler compnies Ingredient Strter Grower Finish Finish 0-4 d 4-35 d 35-4 d 4-56 d Yellow corn 6. 655.37 78.36 7.44 Soyen mel (48% CP) 3.75 76.0 8. 98.36 Diclcium phosphte 0.39 7.7 5.7 4.77 Poultry oil 6.67 3.3 0.69 36.73 Ground limestone 8.70 0.86 0.6 0.4 Feed grde slt 5.4 4.67 4.76 4.68 Constnt ingredients 4.5 4.5 4.5 4.5 L-Lysine HCl (98%).88.7.30.9 L-Threonine 0.90 0.57 0.65 0.64 L-Arginine.93.0.39.6 DL-Methionine (98%) 3.08.39.06.6 Vrile 3.00 3.00 3.00 3.00 TOTAL 000.00 000.00 000.00 000.00 3 Nutrient composition ME kcl/l (C) 36.00 394.00 46.00 460.00 Crude protein, % (C) 0.93 9.7 7.0 6.08 Crude protein, % (A).45 0.6 7.84 6.43 Lysine, %(C).4.09 0.93 0.88 Lysine, % (A).6. 0.96 0.9 TSAA, %(C) 0.96 0.85 0.76 0.76 TSAA, % (A).0 0.93 0.84 0.8 Threonine, %(C) 0.85 0.76 0.68 0.64 Threonine, % (A) 0.88 0.79 0.7 0.67 Nonphytte P, %(C) 0.43 0.37 0.34 0.33 Clcium, %(C) 0.84 0.85 0.76 0.75 Sodium, %(C) 0.3 0.0 0. 0.0 Contins 0.5 g/kg BMD-50 (Alphrm, Inc., Fort Lee NJ 0704), 0.75 g/kg Con 60 (Elnco Animl Helth division of Eli Lilly & Co., Indinpolis IN 4685).0 g/kg of vitmin premix (provides per kg of diet: vitmin A 774 IU; choleclciferol 04 IU; vitmin E 6.53 IU; vitmin B 0.03 mg; rioflvin 6.6 mg; nicin 39 mg; pntothenic cid 0 mg; mendione.5 mg; folic cid 0.9 mg; thimin.54 mg; pyridoxine.76 mg; d-iotin 0.066 mg; ethoxyquin 5 mg; Se 0. mg),.0 g/kg trce minerl mix (provides per kg of diet: Mn (from MnSO 4 H0) 00 mg; Zn (from ZnSO 4 7H O) 00 mg; Fe (from FeSO 4 7H O) 50 mg; Cu (from CuSO 4 5H0) 0 mg; I from C(IO 3) H0), mg. Vrile mounts of choline, etine, nd wshed uilders snd. 3 C = clculted from NRC (994) djusted to crude protein nd moisture content of ingredients used in formultion; A = Anlyzed y Ajinomoto Hertlnd Lysine LLC, Chicgo IL. dry 60% choline chloride product while etine ws dded s crystlline 97% product. Choline nd etine nlyses of the mixed diets were conducted y commercil lortory specilizing in these ssys. The sl diet in ech period ws nlyzed for crude protein nd mino cid content. The house used in this study ws n insulted steel truss uilding of commercil design with 3 ft curtin sidewll contining 48 pens with 56 ft per pen. New softwood shvings over concrete floors served s litter. 443
Tle 3: Choline content (mg/kg) of experimentl diets Feeding period Bsl diet + 000 mg/kg Choline ------------------------------------------------ ----------------------------------------------------- Clculted Anlyzed Anlyzed 3 Difference Strter 39 35 40 905 Grower 60 0 080 860 Finisher 04 35 03 898 Finisher 990 5 933 88 3 Clculted from NRC (994). Anlyzed y Dnisco Animl Nutrition, St. Louis MO. Difference etween nlyzed level of sl diet nd choline supplemented diets. Tle 4: Betine content (mg/kg) of experimentl diets Feeding Bsl + 000 mg/kg period diet etine Strter Bdl 08 Grower Bdl 05 Finisher Bdl 036 Finisher dl 07 Anlyzed y Dnisco Animl Nutrition, St. Louis MO Bdl = elow detection limits. Temperture ws controlled y thermostticlly controlled gs rooders, djustle sidewll curtins, nd exhust fns. Ech pen ws equipped with two tue feeders nd one utomtic wter fount. For the first seven dys supplementl feeders nd wterers were used. Incndescent lights supplemented nturl dylight to provide 3 hr light dily. Mle roilers of commercil strin were otined from locl htchery where they hd een vccinted in ovo for Mrek s disese nd hd received vccintions for Newcstle Disese nd Infectious Bronchitis post htch vi corse spry. Sixty chicks were ssigned t rndom to ech pen. Cre nd mngement of the irds followed recommended guidelines (FASS, 999). Ech of the six tretments ws fed to eight pens of chicks, rndomly distriuted throughout the house. Body weight y pen ws otined t 4, 35, 4, nd 49 d with feed consumption during ech period determined. Birds were checked twice dily; ny ird tht died or ws removed to llevite suffering ws weighted nd the weight used to djust feed conversion (FCR; grms of feed per grm of gin). At 4 nd 4 d five irds per pen, selected from mong 5 irds mrked y toe slit t dy-old, were processed to determine dressing percentge nd prts yield. After hr fst the irds were plced in coops nd trnsported pproximtely one mile to the processing plnt. They were weighed nd processed with utomted eviscertion s descried y Fritts nd Wldroup (005). Due to the utomtic eviscertion it ws not possile to determine dominl ft content. The eviscerted crcsses were weighed nd plced in chiller with ir gittion for one hour. The crcsses were removed, hung on shckles, nd llowed to drin for 30 min. The crcsses were then deoned y trined technicins to determine prts yield. Pen mens served s the experimentl unit for sttisticl nlysis. Dt were sujected to ANOVA using the Generl Liner Models procedure of the SAS Institute (99). When significnt differences mong tretments were found, mens were seprted using repeted t- tests using the LSMEANS option of the GLM procedure. Min effects of etine progrm nd choline ddition were exmined long with the interction of etine progrm nd choline ddition. Dt for 4 nd 35 d comined the results of the irds fed no etine with those who did not receive etine until 35 d of ge. Mortlity dt were trnsformed to prior to nlysis; dt re presented s nturl numers. Results Anlysis of the sl diet indicted tht the levels of crude protein nd essentil mino cids were in good greement with clculted vlues (Tle ). The nlyzed choline content of the sl diet ws lso in good greement with clculted vlues (Tle 3). Amount of dded choline ws determined y difference y sutrcting the totl choline content of the supplemented diets from tht otined on the sl diet; dded choline vlues were slightly under the expected vlue of 000 mg/kg ut verged 874 mg/kg over the entire study. Anlyzed etine content of the test diets ws in good greement with expected vlues (Tle 4) with n verge of 044 mg/kg over the entire study. Thus, the test diets were considered to contin the expected levels of nutrients. The effects of etine feeding progrm nd choline supplementtion on ody weight t different ges re shown in Tle 5. Feeding 000 mg/kg of etine from 0 to 49 or from 35 to 49 d hd no significnt influence on ody weight t ny ge. There ws significnt effect of choline supplementtion on ody weight t 4 d, with significnt reduction in BW from irds fed 000 mg/kg of choline. However, there ws significnt interction of etine nd choline supplementtion t oth 4 nd 49 d of ge. The ddition of 000 mg/kg of choline to diet of chicks tht hd not een fed etine or to the diet of chicks tht hd een feed 000 mg/kg of etine from dy of ge hd no effect on BW of chicks; however, when 000 mg/kg choline ws dded to the diet of chicks tht 444
Tle 5: Effect of supplementl etine nd choline on ody weight of roilers (mens of eight pens of 60 irds per tretment. Dt from irds fed diets with no etine from 0 to 35 d were comined t 4 nd 35 d) Mesurement Betine Progrm Supplementl choline (mg/kg) ------------------------------------------------------------------------------------- None 000 Men 4 d BW (kg) None 0.463 0.459 0.46 0-49 d 0.46 0.466 0.464 Men 0.46 0.463 35 d BW (kg) None.068.068.068 0-49 d.03.05.04 Men.046.047 4 d BW (kg) None.800.809.804 0-49 d.789.770.780 35-49 d.876 c.77.80 Men x.8 y.768 49 d BW (kg) None 3.3 3.38 3.346 0-49 d 3.40 3.38 3.365 35-49 d 3.469 3.309 3.389 Men 3.394 3.340 Mesurement -------------------------------------------------- Proility > F ------------------------------------------------- Betine Choline Bet x Cho CV 4 d BW 0.6 0.84 0.6 4.34 35 d BW 0.09 0.93 0.5 3.70 4 d BW 0.6 0.04 0.03 3.40 49 d BW 0.56 0.0 0.03 3.9 Time of ddition of 000 mg/kg etine. Mens with common superscripts do not differ significntly (P<0.05). xy Mens with common superscripts do not differ significntly (P<0.05). hd not een fed etine until 35 d of ge, there ws significnt reduction in BW t oth 4 nd 49 d of ge. Feed conversion from 0 to 4 d ws numericlly improved (P = 0.08) nd from 0 to 49 d ws significntly improved (P < 0.0) y feeding 000 mg/kg etine from dy of ge ut not when fed from 35 d (Tle 6). Overll, choline supplementtion hd no significnt effect on feed utiliztion ut the ddition of 000 mg/kg choline to the diet significntly reduced feed conversion t 4 d when fed in diets in which etine feeding ws initited t 35 d. This interction ws not oserved t 49 d of ge. Mortlity ws very low during the study (Tle 7). There ws no indiction of ny effect of etine or choline on mortlity t ny ge during the study, nor ws their ny interction of the two nutrients. The chicks were plced on new litter nd the diets contined n nticoccidil nd citrcin methylene dislicylte. Exmintion of ded or culled irds y qulified poultry pthologist did not revel ny indiction of prolems with coccidiosis or intestinl necrosis. The effects of etine feeding progrm nd choline supplementtion on crcss prmeters re shown in Tle 8. Feeding 000 mg/kg of etine eginning t one dy of ge resulted in significnt improvement in dressing percentge t 4 d ut not t 49 d. Addition of etine hd no significnt effect on rest yield t 4 or 49 d of ge. Addition of 000 mg/kg of choline significntly improved rest yield t 4 d ut not t 49 d. Discussion No ttempts were mde in the present study to reduce the methionine content of the diet y supplementtion with choline or etine s previous work from our lortory (Wldroup et l., 005) nd elsewhere (Rostgno nd Pck, 996; Schutte et l., 997; Esteve- Grci nd Mck, 000; McDevitt et l., 000) demonstrted no methionine spring effect for etine in corn-soyen sed roiler diets. No improvement in ody weight over the course of the present study ws oserved s result of supplementing the diets with 000 mg/kg of etine. A negtive effect on ody weight t oth 4 nd 49 d of ge ws oserved when 000 mg/kg choline ws dded to diets of chicks tht hd een fed etine from 35 d of ge fter receiving no etine supplementtion for the first 35 d. This effect ws not oserved when choline ws dded to diets of chicks tht hd een receiving 000 mg/kg of etine from dy old. Feed conversion over the 49 d feeding period ws significntly improved y continuous ddition of 000 mg/kg etine, ut not when fed only for 35 to 49 d of ge. The negtive effect of choline supplementtion of diets of chicks tht hd een fed etine from 35 d of ge fter receiving no etine supplementtion for the first 35 d ws lso oserved on feed conversion t 4 d of ge ut not t 49 d. It is possile tht some competition for metolic pthwys my tke plce 445
Tle 6: Effect of supplementl etine nd choline on feed conversion y mle roilers (mens of eight pens of 60 irds per tretment. Dt from irds fed diets with no etine from 0 to 35 d were comined t 4 nd 35 d) Mesurement Betine Progrm Supplementl choline (mg/kg) ------------------------------------------------------------------------------------ None 000 Men 0-4 d FCR None.00.9.96 0-49 d.76.89.83 Men.88.9 0-35 d FCR None.63.605.609 0-49 d.597.599.598 Men.605.60 0-4 d FCR None.765.740.753 0-49 d.738 c.76.73 35-49 d.739.786.76 Men.747.75 0-49 d FCR None.873.854.863 x 0-49 d.84.833.83 y 35-49 d.849.844.847 x Men.845.843 Mesurement ----------------------------------------------------- Proility > F --------------------------------------------------- Betine Choline Bet x Cho CV 0-4 d FCR 0.37 0.96 0.60.96 0-35 d FCR 0.6 0.65 0.59.56 0-4 d FCR 0.08 0.73 0.0. 0-49 d FCR 0.0 0.88 0.35.94 Time of ddition of 000 mg/kg etine. Mens with common superscripts do not differ significntly (P<0.05). xy Mens with common superscripts do not differ significntly (P<0.05). Tle 7: Effect of supplementl etine nd choline on mortlity of roilers (mens of eight pens of 60 irds per tretment. Dt from irds fed diets with no etine from 0 to 35 d were comined t 4 nd 35 d) Mesurement Betine Supplementl choline (mg/kg) Progrm ------------------------------------------------------------------------------------ None 000 Men 0-4 d Mortlity (%) None.5 0.83.04 0-49 d 0.00 0.00 0.00 Men 0.63 0.4 0-35 d Mortlity (%) None.08.5.67 0-49 d 0.83 0.00 0.4 Men.46 0.63 0-4 d Mortlity (%) None 0.83.67.5 0-49 d 0.83 0.83 0.83 35-49 d 3.33 0.83.08 Men.67. 0-49 d Mortlity (%) None 0.83.67.5 0-49 d 0.83 0.83 0.83 35-49 d 3.33 0.83.08 Men.67. Mesurement ----------------------------------------------- Proility > F -------------------------------------------------- Betine Choline Bet x CHO CV 0-4 d mortlity 0.3 0.69 0.06.5 0-35 d mortlity 0.8 0.33 0.8.4 0-4 d mortlity 0.5 0.54 0.9.50 0-49 d mortlity 0.5 0.54 0.9.50 Time of ddition of 000 mg/kg etine. CV of trnsformed mens. 446
Tle 8: Effect of supplementl etine nd choline on crcss prmeters of roilers (mens of eight pens of five irds per time period) Mesurement Betine Supplementl choline (mg/kg) Progrm ----------------------------------------------------------------------------- None 000 Men 4 d dressing percentge None 70.88 70.8 70.85 xy 0-49 d 7.9 70.96 7.44 x 35-49 d 70.49 70.54 70.5 y Men 7.0 70.78 4 d rest yield None 5.73 6.58 6.5 0-49 d 6.30 6.44 6.37 35-49 d 6.3 6.74 6.5 Men 6. 6.58 49 d dressing percentge None 70.48 7.88 7.8 0-49 d 69.98 70.5 70. 35-49 d 70.40 7.3 70.86 Men 70.9 7.5 49 d rest yield None 7.4 7.4 7.4 0-49 d 6.9 6.40 6.66 35-49 d 6.40 6.98 6.68 Men 6.8 6.84 Mesurement ----------------------------------------------- Proility > F ------------------------------------------ Betine Choline Bet x Cho CV 4 d Dressing percentge 0.0 0.0 0..7 4 d Brest yield 0.35 0.03 0.38 6.05 49 d Dressing percentge 0. 0.09 0.66 5.56 49 d Brest yield 0.7 0.93 0.6 6.7 Time of ddition of 000 mg/kg etine. Mens with common superscripts do not differ significntly (P<0.05). xy Mens with common superscripts do not differ significntly (P<0.05). etween choline nd etine tht my require some supplementtion nd in rest yield from choline djustment period; this is worthy of further investigtion. supplementtion ut not t 49 d of ge. Therefore, ge In contrst to previous reports from our lortory of ird might e considertion for using these (Wldroup et l, 005) nd elsewhere (Schutte et l., supplements s irds processed t younger ges might 997; Wllis, 999; Esteve-Grci nd Mck, 000; e more responsive to these nutrients. Further studies McDevitt et l., 000; Remus, 00) tht etine re needed to evlute the potentil effect of ge on supplementtion my improve rest met yield, there response to choline nd etine. ws no indiction of improvements in rest yield in the present study. Addition of 000 mg/kg etine from dy References of ge significntly improved crcss dressing Allen, P.C., H.D. Dnforth nd P.C. Augustine, 998. percentge t 4 d of ge ut not t 49 d. Addition of 000 mg/kg of choline significntly improved rest yield t 4 d ut not t 49 d. Due in lrge mesure to its osmoregultory functions (Kidd et l., 997; Kettunen et l., 00, 00), etine ppers to e of enefit in chicks infected with coccidiosis (Mtthews et l., 997; Augustine et l., 997; Allen et l., 998; Augustine nd Dnforth, 999; Mtthews nd Southern, 000; Wldenstedt et l., 999). Chicks in the present study received n nticoccidil in the diet nd were grown on new litter with no pprent prolems with coccidil infection. In conclusion, the results of this study indicte little or no positive enefit in terms of ody weight gin, feed conversion, or mortlity from the ddition of etine to corn-soyen mel sed diets for roiler chicks in Dietry modultion of vin coccidiosis. Int. J. Prsitol., 8: 3-40. Augustine, P.C. nd H.D. Dnforth, 999. Influence of etine nd slinomycin on intestinl sorption of Met nd glucose nd on the ultrstructure of intestinl cells nd prsite development stges in chicks infected with Eimeri cervulin. Avin Dis., 43: 89-97. Augustine, P.C., J.L. McNughton, E. Virtnen nd L. Rosi, 997. Effect of etine on the growth performnce of chicks inoculted with mixed cultures of vin Eimeri species nd on invsion nd development of Eimeri tenell nd Eimeri cervulin in vitro nd in vivo. Poult. Sci., 76: 80-809. Bker, D.H., K.M. Hlpin, G.L. Czrnecki nd C.M. situtions where disese chllenge from coccidiosis is Prsons, 983. The choline-methionine not mjor issue. At 4 d of ge improvements in dressing percentge were otined from etine interreltionship for growth of the chick. Poult. Sci., 6: 33-37. 447
Clndinin, D.R., W.W. Crvens, J.G. Hlpin nd E.B. Miles, R.D., N. Ruiz nd R.H. Hrms, 983. The Hrt, 946. Supplementry vlue of methionine, interreltionship etween methionine, choline, nd cystine, nd choline in prcticl soyen oil mel sulfte in roiler diets. Poult. Sci., 6: 495-498. strter rtion. Poult. Sci., 5: 509-56. Ntionl Reserch Council, 994. Nutrient Esteve-Grci, E. nd S. Mck, 000. The effect of DL- Requirements of Poultry. 9th rev. ed. Ntionl methionine nd etine on growth performnce nd Acdemy Press, Wshington DC. crcss chrcteristics of roilers. An. Feed Sci. Pesti, G.M., A.E. Hrper nd M.L. Sunde, 980. Choline- Tec., 87: 85-93. methionine nutrition of strting roiler chicks. Three FASS, 999. Guide For the Cre nd Use of Agriculturl models for estimting the choline requirement with Animls in Agriculturl Reserch nd Teching. st economic considertions. Poult. Sci., 59: 073- rev. ed. Federtion of Animl Science Societies, 08. Svoy IL. Quillen, E.C., G.F. Coms, R.D. Creek nd G.L. Fetherston, W. R. nd E.L. Stephenson, 960. Dietry Romoser, 96. Effect of choline on the methionine interreltionships etween methionine, glycine, requirements of chickens. Poult. Sci., 40: 639-645. choline, protein level, nd energy content of the Remus, J., 00. Betine for incresed rest met chick diet. Poult. Sci., 39: 03-09. yield. Int. Poult. Prod., 9: -3. Fritts, C.A. nd P.W. Wldroup, 005. Modified Rostgno, H.S. nd M. Pck, 996. Cn etine replce phosphorus progrm for roilers sed on supplementl DL-methionine in roiler diets? J. commercil feeding intervls to sustin live Appl. Poult. Res., 5: 50-54. performnce nd reduce totl nd wter-solule SAS Institute, 99. SAS User s Guide: Sttistics. phosphorus in litter. J. Appl. Poult. Res., sumitted Version 6.03 edition. SAS Institute, Inc., Cry, NC. for puliction. Schutte, J.B., J. de Jong, W. Smink nd M. Pck, 997. Grci-Neto, M., G.M. Pesti nd R.I. Bklli, 000. Replcement vlue of etine for DL-methionine in Influence of dietry protein level on the roiler mle roiler chicks. Poult. Sci., 76: 3-35. chicken s response to methionine nd etine Sunde, M.L., P.E. Wiel, W.W. Crvens nd C.A. supplements. Poult. Sci., 79: 478-484. Elvehem, 95. A reltionship etween ntiiotics, Gerry, R.W., C.W. Crrick nd S.M. Huge, 948. vitmin B, nd choline nd methionine in chick Methionine nd choline in simplified chick rtion. growth. Poult. Sci., 30: 668-67. Poult. Sci., 7: 6-68. Tillmn, P.B. nd G.M. Pesti, 986. The response of Kettunen, H., S. Peurnen, K. Tiihonen nd M. Srinen, mle roiler chicks to corn-soy diet supplemented 00. Intestinl uptke of etine in vitro nd the with L-methionine, L-cysine, choline, sulfte, nd distriution of methyl groups from etine, choline, vitmin B. Poult. Sci., 65: 74-748. nd methionine in the ody of roiler chicks. Comp. Virtnen, E. nd L. Rosi, 995. Effects of etine on Biochem. Phys., 8A: 69-78. methionine requirement of roilers under vrious Kettunen, H., S. Peurnen nd K. Tiihonen, 00. environmentl conditions. Pges 88-9 in: Betine ids in the osmoregultion of duodenl epithelium of roiler chicks, nd ffects the movement of wter cross the smll intestinl Proceedings of the Austrlin Poultry Science Symposium, University of Sydney, Sydney NSW, Austrli. epithelium in vitro. Comp. Biochem. Phys., 9A: Virtnen, E. nd G. Rumsey, 996. Betine 595-603. Kidd, M.T., P.R. Ferket nd J.D. Grlich, 997. Nutritionl nd osmoregultory functions of etine. World s Poult. Sci. J., 53: 6-39. Mrvel, J.A., C.W. Crrick, R.E. Roerts nd S.M. Huge, 944. The supplementry vlue of choline nd methionine in corn nd soyen oil mel chick rtion. Poult. Sci., 3: 94-97. supplementtion cn optimize use of methionine, choline in diets. Feedstuffs 68: -3 (Oct. 7). Wldenstedt, L., K. Elwinger, P. Theo nd A. Uggl, 999. Effect of etine supplement on roiler performnce during n experimentl coccidil infection. Poult. Sci., 78: 8-89. Wldroup, P.W., M.A. Motl, F. Yn nd C.A. Fritts, 005. Effects of etine nd choline on response to Mtthews, J.O. nd L.L. Southern, 000. The effect of methionine supplementtion in roiler diets dietry etine in Eimeri cervulin-infected chicks. Poult. Sci., 79:60-65. Mtthews, J.O., T.L. Wrd nd L.L. Southern, 997. formulted to industry stndrds. J. Appl. Poult. Res., sumitted for puliction. Wllis, I.R., 999. Dietry supplements of methionine Interctive effects of etine nd monensin in increse rest met yield nd decrese uninfected nd Eimeri cervulin-infected chicks. Poult. Sci., 76: 04-09. McDevitt, R.M., S. Mck nd I.R. Wllis, 000. Cn etine prtilly replce or enhnce the effect of methionine y improving roiler growth nd crcse chrcteristics. Br.Poult.Sci., 4: 473-480. dominl ft in growing roiler chickens. Aust. J. Exp. Agri., 39: 3-4. West, J.W., C.W. Crrick, S.M. Huge nd E.T. Mertz, 95. The reltionship of choline nd cystine to the methionine requirement of young chickens. Poult. Sci., 30: 880-885. 448