EFFECT OF PHOTOPERIOD AND TRYPTOPHAN AMINO ACID SUPPLEMENTATION ON PINEAL GLAND HORMONE (MELATONIN) AND ITS RELATION TO PERFORMANCE IN LOCAL STRAIN.

Transcription

1 Egypt. Poult. Sci. Vol (30) (IV): ( ) EFFECT OF PHOTOPERIOD AND TRYPTOPHAN AMINO ACID SUPPLEMENTATION ON PINEAL GLAND HORMONE (MELATONIN) AND ITS RELATION TO PERFORMANCE IN LOCAL STRAIN. 1- EFFECT ON LAYING HEN PERFORMANCE. By El-Slmoney, A. E. 1, Btt, A. M. El-Neney 2, S. F. Hssn 1 Rg E. Ad El-Krim 1 nd E. H. Adull 1 1 Deprtment of Poultry Breeding Rese, 2 Deprtment of Poultry Nutrition Rese. Animl Prod. Res. Inst, Agric Rese. Centre, Ministry. Of Agric.Giz, Egypt..Received: 15/08/2010 Accepted: 25/08/2010 Astrct: This study ws conducted to investigte the effect of photoperiod, tryptophn supplementtion nd their interction on Dokki-4 lying hens performnce, feed conversion rtio, egg production, egg qulity,, immune response, lood constituents, pinel glnd hormone nd economicl efficiency. A totl numer of 297 lying hen t 24 weeks of ge were used in this study. At 24 weeks of ge hens were distriuted into 9 experimentl tretments in (3x 3) fctoril design up to 36 wks of ge through three photoperiod groups (control) L1: dy light, L2: L1+ 2 hours light nd L3: L1+ 4 hours nd three levels of tryptophn (Trp) supplementtion. The control (R1) ws 0.19%, R2= 0.21% Trp nd R3= 0.23 %. The otined results could e summrized s follows: 1-Light hd significnt effect on ody weight gin BWG (L3 ws greter thn tht exposed to L1 or L2 for BWG3 (32-36wks), egg numer EN {EN3 (32-36wks) nd EN4 (24-36wks)}, egg production EP {EP3 (32-36wks) & EP4 (24-36wks)} nd egg mss EM (EM3). - There were no significnt effects of photoperiod on EN, EP t nd wks of ge,), egg weight EW, dily Trp intke (mg/ hen / d), Trp intke (mg/ EC, nd protein intke (g / g feed). - The group of hens of L2 photoperiod significntly incresed plsm gloulin (P<0.05) compred to L1. Tretment L1 nd L2 exhiited the highest white lood cells (WBC s) thn L3. The verge of meltonin (MLT) levels (pg/ ml) ws lower during the light periods

2 El-Slmoney, et l nd higher in the middle of the drk period. Hens of L1 re likely to hve higher MLT levels thn L2 nd L3. 2- Levels of Trp hd significnt effect for ll studied dietry tretments studied on EP, EM nd lumen weight compred to the control group. EW were incresed significntly y the ddition of R2 compred with the R1 nd R3. - Trp per grm of EM ws significntly incresed s the level of dietry Trp incresed. - The tretment of R2 ws the est supplemented level where recorded lowering totl lipids nd cholesterol compred to the other tretments. - Plsm MLT, T 3 nd T 4 were incresed significntly y R3 nd R2 compred with the R1. Level of Trp exhiited the highest WBC s thn control group. 3- The interction mong lighting periods nd Trp level in diet indicted tht egg production percentge nd egg mss were significntly improved y tryptophn supplementtion t R2 in L1 nd L2. While, egg weight nd feed conversion were significntly improved y tryptophn supplementtion t R2 in ll light periods. - The est levels for decresing cholesterol ws R2 nd R3 inclusion levels of Trp in ll light periods. - The totl count of WBC s incresed y incresing Trp level compred with the control group. Plsm meltonin, T 3 nd T 4 were significntly improved y ll dietry Trp in ll light periods. It could e concluded tht dietry Trp (R2) nd lighting period (L2) might hve positive effects on performnce, Economic efficiency nd helth sttus of the lying hens. Also, dding Trp (R2) in diets of lying hens ws economiclly etter in production nd immunity without dverse effect on hen. INTRODUCTION Light density nd length of lighting period represent effective stimuli for nimls. It is known tht vrition in lighting modifies growth nd ctivity of endocrine glnds nd thus induces iochemicl nd ehviorl chnges of orgnisms. Light ply n importnt role in the control of ctivity ptterns (Yno et l., 1974). Lincoln et l. (1980) nd Irhim, (2005) reported tht chnges in photoperiod re recognized s the mjor determinnts of the timing of reproduction nd other endocrine-ssocited 928

3 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. events in irds nd mmmls. Incresing dylight resulted in erlier onset of ly, less feed consumed per hen to pek egg production, erlier ge t pek egg production, higher pek egg production, nd more totl eggs per hen thn produced y hens in regimen with n 8- hr photoperiod supplied y dylight eginning t 12wk of ge (Brke nd Bughmn, 1989). Moore nd Siopes (2000) found tht totl white lood cell (WBC) counts in Jpnese quil incresed significntly during shorter photoperiod (8L: 16D) compred to longer photoperiod (16L: 8D) nd constnt lighting. Tryptophn (Trp) is n essentil dietry mino cid for chickens tht is necessry for mximum growth nd feed efficiency. Trp is eqully second or third limiting in typicl diets for hen. In diets consisting primrily of corn, it is the first limiting mino cid ecuse of the low Trp content nd vilility in corn (Bker et l., 1969). The Trp content in the diet is importnt for optiml growth performnce, nd relile requirement estimtes hs impertive when formulting diets sed on the idel protein concept. Limited reserch hs een conducted on the Trp requirement of the lying hen nd the reported literture revels lrge differences. Trp plys n importnt role in the rin s precursor of the neurotrnsmitter serotonin, which hs mjor effect on the feeding ehvior of nimls mong its mny functions (Blundell nd Lthm, 1978, Tckmn et l., 1990, Mullen nd Mrtin, 1992). Ohtni et l. (1989) nd Jensen et l. (1990) suggest tht supplementl L-tryptophn improves the egg production rte in lying hens. In generl, cerel feedstuffs such s corn, whet nd rley re reltively low in tryptophn (Ryozo nd Mkoto (2007). Bender (1983) hve shown tht the oxidtive pthwy of tryptophn metolism is inhiited y estrogen in rts. Recently, it hs een suggested tht decresed egg production nd egg shell qulity oserved lte in the lying yer of hens my e relted to incresed estrogen concentrtion in the plsm (Edens et l., 1985). Tryptophn is n essentil mino cid in poultry nd is required for wide vriety of metolic ctivities. Becuse its concentrtion in orgnisms is mong the lowest of ll mino cids, it cn esily ply rte-limiting role in protein synthesis. Aprt from eing structurl component of ll proteins it is precursor for synthesis of two hormones, serotonin nd meltonin. These hormones generlly ct in the clssic check nd lnce mode with serotonin predominting during periods of ctivity (usully dylight) nd meltonin predominting during periods of rest (usully nighttime). In chickens, the dptive control of circdin rhythms y serotonin nd meltonin is well known prticulrly tht relted to rhythms ssocited with lood pressure, ody temperture, feed intke, growth nd repir of tissues. 929

4 El-Slmoney, et l In ddition to ll forementioned, Trp hs lso een linked with nicin iosynthesis in chickens (Corzo et l., 2005). Trp serves s the precursor of serotonin, meltonin, tryptmine nd coenzymes (NAD nd NADP) s well s meeting the mjority of the requirement for nicotinic cid (Sinio et l., 1996). By its involvement in such diverse pthwys, Trp nd its metolites regulte neuroehviorl effects such s ppetite, sleeping-wking-rhythm, impulsivity, ggression, sexul ehvior, nd pin perception. Trp hs the potentil to ffect ehviors such s ggression, feed intke nd stress through its impct on serotonin synthesis s well s through its impct on cortisol relese (Rodwell, 1979). Wethli nd Morris (1978) investigted the Trp requirement for three different strins of lying pullets, nd from these dt developed method to clculte the optimum Trp intke using the mrginl cost of Trp nd the vlue of eggs. Also conducted severl studies on the Trp requirement for older irds. Their estimted optimum Trp intke rnged from 179 to 184 mg/hen per d. They concluded tht the Trp required per dy does not decrese during the first lying yer, despite decrese in rte of egg output. Therefore, the present study ws conducted to investigte, firstly the effect of different lighting period nd feeding tryptophn levels on lying hens performnce, production, immunity nd secondly: to determine est comintion of lighting periods long with the used tryptophn levels of Dokki 4 chicken strin. MATERIALS AND METHODS This experimentl work ws crried out t the Poultry Frm of Skh Sttion, Animl Production Reserch Institute, Agriculture Reserch Center. A totl numer of 297 Dokki-4 lying hens ( locl strin) t 24 weeks of ge of nerly BW (gm) ±SE initil live ody weight were housed nd were rndomly divided into 9 groups in 3X3 fctoril design. Three lighting periods: L1, the dy lights (The verge length of the dy light out 14 hrs in the month of July nd August, nd hrs in the month of Septemer), L2, the dy light+ 2 hours nd L3, the dy light+ 4 hours of sodium vpor lmps set to deliver 50 lx t ird height white fluorescent. Three levels of Trp (R1, R2 nd R3) ws used,, the first level (R1) ws equl 0.19% Trp ccording to the Agriculture Ministry Decree in (2001) nd used s control, while R2 (R %=0.21%) nd R3: (R %=0.23%Trp). L- Trp ws dded to the sl diet t the expense of n iso-nitrogenous equivlent of L-Glu. Ech group ws represented y 33 irds 930

5 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. in three replictes, su-divided into three replictes of 11 irds ech (10 hens nd 1 cock). All irds were kept under similr mngement conditions in lying pens for ech replicte where fresh wter ws supplied ll time nd ll irds were fed on the experimentl diets d-li for 12 weeks. The sl diet ws formulted to e iso-nitrogenous (16 % CP) nd isocloric (2744 kcl/kg diet). The sl diet ws supplied to meet the lyers requirements of the Agriculture Ministry Decree (2001). Ingredients nd clculted nlysis of the sl diet re presented in Tle (1). Birds were weighted t the eginning of the experiment (24 weeks of ge) nd the initil ody weight were recorded nd then every 4 weeks till the end of the experiment 36 wks of ge nd ody weight gin (BWG) ws clculted to determine ody weight chnge. Egg numer (EN) nd egg weight (EW) were recorded monthly to clculte egg production (EP% = EN*100/28 dy). Egg mss (EM= EP* EW). Feed intke (FI) ws recorded every 4 wks from ech pen nd clculted s (g / hen / dy). Feed conversion rtio (FCR) ws clculted y FI / EM. Egg content (EC) ws clculted y multiplying EP y EW minus shell weight. The dily intke of Trp ws clculted y multiplying its content in the feed y feed consumption. Protein intke (g / g feed) ws clculted. Dividing dily Trp intke y dily output of EC yielded vlue for milligrms of Trp per grm of EC. The mount of Trp consumed per grm of EM ws clculted y dividing dily Trp intke y totl EM. Egg qulity ws mesured ech four weeks; five eggs from ech replicte were collected weighted, roken nd seprted into shells, yolks (Y) nd lumen. The weights of lumen (Alw) nd shell thickness (Sh. T mm) were recorded nd clculted s percentges of egg weight. Five lood smples were collected from ech experimentl group t the end of the experiment. Aout 5 ml. of lood from ech ird ws drwn from the wing vein in heprinized tues in the morning (etween 8 nd 10 O'clock) efore feeding. Plsm lood smples were centrifuged t 3000 rpm for 20 minutes. White lood cells (WBC s) were counted in fresh lood smples using hemocytometer s the method descried y Hwkey nd Dennett (1989). Plsm ws decnted nd stored frozen t -20 C until the time of nlysis. Blood ws nlyzed to determine totl protein, lumin (Al), gloulin (Glo), totl lipids nd cholesterol using commercil kits. The first leeding ws set to e in the middle of drk cycle nd the plsm smples were used for hormonl ssys (meltonin (MLT, T 3 nd T 4 ). The second leeding ws set to e in the middle of light cycle nd the plsm smples were used for hormonl ssys (Blood smples (5 ml) were collected from the rchil vein of ech hen t midtime of the light period nd the drk 931

6 El-Slmoney, et l period nd the plsm smples were used for hormonl ssys (meltonin (MLT, T 3 nd T 4 ) using commercil kits. The dt were nlyzed y the Lest Squres Mens method descried y SPSS (1984). Mens were seprted y using Duncn's multiple rnge test (Duncn, 1955). The hen requirement from Trp for EP, EC nd BW chnge ws determined y using roken-line regression s descried y Noll nd Wiel (1989). RESULTS AND DISCUSSION Live ody weight nd ody weight gin:- Dt presented in Tle (2) show tht hens of L3 were hevier in BW thn L1 nd L2 t 32 nd 36 wks of ge. While, BW t 24 nd 28 wks of ge were nerly similr in ll lighting tretments. This reduction in growth for irds in L2 compred to L3 my e due to the decrese in FI lthough the differences etween tretments were not significnt. There ws highly positive correltion etween BW nd FI. Hn Khlil et l. (2007) reported tht ody weight t 22 weeks of ge hd incresed significntly (P<0.05) for locl Bndrh mles grown under the first lighting regimen (light regimen grdully incresed from 8h/d to 16h/d) compred to those grown under the second lighting regimen ( schedule light resemles the nturl dy light of open sided houses (grdully incresed from 10h/d to 14h/d). The experiment confirmed tht growth of the domestic fowl cn e influenced y light. They dded tht ll-night lights my hve ided erly growth in this experiment y providing the chicks more opportunity to feed. Body weight gin from 24 to 36 wks (BWG4) of hen exposed to L3 ws greter thn those exposed to L1 or L2 lighting periods, the differences in this respect, were significnt (P<0.01) during BWG1 (24-28 wks of ge) nd BWG4, significnt (P<0.05) during BWG2 (28-32 wks) nd BWG3 (32-36 wks) in Tle (2). Gordon, (1994) suggested tht there re mny potentil welfre enefits ssocited with longer dylights, such s decresed sleep, higher physiologicl stress, or reduced immuneresponsiveness. Hn Khlil et l. (2007) showed tht ody weight gin t (10-22 wk of ge) hd incresed significntly (P<0.05) for locl Bndrh mles grown under the first lighting regimen compred to those grown under the second lighting regimen. Our results indicted tht ws smll difference etween the length of light hours (2-4 hours) ws its impct smll on ody weight nd ody weight gin. 932

7 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. Hens fed diet supplemented with R2 nd R3 recorded higher BW thn those fed either control, ut no significnt differences mong dietry tretments were oserved for ody weight. These findings gree with the results of Ohtni et l. (1989). Hens fed diet supplemented with R2 nd R3 recorded higher BWG thn those fed either control during the ll periods except to BWG2 (Tle 2). Thus, the improvement in weight gin ws independent of FI. Therefore, it might e expected tht incresed dietry Trp would increse feed intke through the influence of Trp on the synthesis nd relese of serotonin, which would in turn influence FI through gstric emptying. However, dietry Trp decrese FI in the present experiment. These findings gree with the results of Hn et l. (1991) who oserved 40% improvement in weight gin when digestile tryptophn ws incresed from 1.5 to 2.1 g/kg in chicks. Corzo, et l. (2005 ) Showed tht ody weight gin improved s Trp incresed. Ryozo nd Mkoto (2007) reported tht ody weight gins in Trp group were significntly higher thn tht in the control group. But not gree with Smith nd Wldroup (1988) nd Roserough (1996) who s oserved no weight gin response of chicks to n increse in dietry tryptophn. Antr et l. (2004) indicted tht the level of dietry Trp did not ffect BW gin. The effect of interction mong lighting periods nd Trp levels on BW nd BWG were significnt during ll periods studied s shown in tle (2). Egg Weight (EW):- No significnt effect ws detected due to the length of photoperiod on EW, while the dietry Trp concentrtion hd significnt effect on EW(Tle 2) Lesson nd Summers (1980) reported tht erly light stimultion decresed egg weight due to its positive correltion with sexul mturing. On contrry to our results regrding egg weight, Keshvrz (1998) nd Hn Khlil et l. (2008) stted tht egg weight ws significntly greter for hens on the step-down light regimen compred to other experimentl light regimens. Hens fed diets supplemented with 0.21%Trp (R2) recorded significntly higher EW thn those fed either R1 or R3. These results gree with Hrms nd Russell (2000) they showed tht EW incresed s dietry Trp incresed. While Russell nd Hrms (1999), Keshvrz nd Jckson, (1992) nd Hrms nd Ivey (1993) they reported tht there were no significnt increses in EW s dietry levels of Trp incresed. The interction mong lighting periods nd Trp hd significnt effect on EW during ll experimentl periods. Brin neurotrnsmitters re intrictely linked with Trp nd its role in ody metolism. Becuse of its 933

8 El-Slmoney, et l involvement with rin serotonin, Trp hs een shown to e responsile for ffecting mood regultion, feed intke, ehvior, nd sleep ptterns (Lethwood, 1987 nd Brnyiov, 1991). Egg production:- Tle (3) shows the effect of Trp, length of dy light nd their interction on EN, EP nd EM during the lying period from (24-36) weeks of ge. There were no significnt effects etween lighting periods on EN (EN1 & EN2), EP (EP1 & EP2) nd EM (except to EM3), while significnt (P<0.05) effect were detected t (EN3, EN4, EP3, EP4 nd EM3. Hn Khlil et l. (2008) stted tht egg mss nd egg production were significntly (P<0.001) incresed for irds exposed to step -up lighting regimen compred to others exposed to other lighting regimens for Mndrh nd Bndrh hens. Keshvrz (1998) who found tht egg mss ws significntly lower for hens on the step-down regimen nd the rte of egg production remined consistently lower for hens on the step-down regimen. The dietry Trp concentrtion hd significnt effect on EN1, EN2, EP (1-4) nd EM (1-4). (Tle 3). Hens fed on R2 diet recorded significntly the est vlues of EN, EP nd EM compred with those fed either R1or R3. Russell nd Hrms (1999) reported tht egg production incresed significntly s dietry levels of Trp incresed from 0.11 to 0.15%. Jensen et l. (1990) reported n increse in EP while there ws no increse in EW from Trp supplementtion. Ohtni et l. (1989) reported tht iovilility of Trp in diets must e considered, it is possile tht the egg production improvement from L- Trp supplementtion ws due to some metolic chnges induced y L-tryptophn feeding. Also, the improvement of EP in lyers from L- Trp supplementtion of diets my e interpreted s consequence of decrese in plsm estrdiol concentrtion or decrese of estrogenic ctivity. However, plsm estrdiol levels were not determined in my present study. Pegnov nd Eder (2003) shows tht dietry tryptophn increse the dily EM of lying hens. The resons for the discrepncies mong uthors re not known ut might e relted to the type of diet nd to the ge of the experimentl hens. Antr et l. (2004) reported tht the levels of dietry Trp (0.166, nd 0.193%) did not significntly ffect EP nd EM. The interction mong lighting periods nd Trp levels in diet on EN nd EP were highly significnt (P<0.01), significnt (P<0.05) for EM t different ge. 934

9 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. Feed intke (FI): Tle (4) shows tht there were no significnt differences etween lighting periods on FI. These results re in greement with those otined y Perry (1981) who stted tht chickens cn lern to et in the drk, ut their feed intke in the drk is much reduced. They cn lso lern to increse feed intke during the light period in nticiption of the drk period, ut re limited y their crop size. Photoperiods less thn 18 h hve een oserved to decrese feed consumption (Schwen-Lrdner et l. 2006). Hn Khlil et l. (2007) found tht there were no significnt differences in feed consumption y first lighting regimen from 8h/d y hlf n hour ech week to rech 16h/d t 22 wk of ge nd second lighting regimen from 10h/d to rech 14 h/d t 22 wk of ge for Bndrh hens. Siful, et l. (2002) reported tht the dily verge feed intke (FI) were 98, 93 nd 101 g t 12L: 12D, 14L: 10 D nd 16L: 8D, respectively. Similr results were reported y Nwr nd Bhie El-Deen (2000), El-Neney (2003), El-Sudny (2005) nd Lewis et l. (2007). There ws significnt effect of Trp on FI throughout the experimentl period (Tle 4). Hens fed on R2 hd the lower FI (FI 1, FI 2 nd FI 4 ) thn those fed R1. Also, reduced FI (FI 1, FI 2 nd FI 4 ) in the R2 nd R3 minly my e due to the protein lmost equl in ll tretments (Tle 5). In the present experiment, supplementtion of Trp hd no effect in incresing the FI. However, dietry Trp decrese FI in the present experiment. This effect could e due to the function of Trp s precursor of serotonin nd good source of mino cid. Therefore, it might e expected tht incresed dietry Trp would increse feed intke through the influence of Trp on the synthesis nd relese of serotonin, which would in turn influence FI through gstric emptying. It is well known tht serotonin, which is formed in the rin; influence feed consumption of nimls (Tckmn et l. 1990; Mullen nd Mrtin 1992 nd Pegnov nd Eder 2003). Roserough (1996) reported tht supplementl Trp ffected feed intke in chickens only when fed in diet contining low level of crude protein. Furthermore, Trp supplementtion to meet dietry requirement did not result in chnges in FI or neurotrnsmitter metolism. Similr results were reported y Ohtni, et l. (1989) nd Adeol (1998) who reported tht incresed dietry Trp level did not ffect feed intke. Lycock nd Bll (1990) reported tht 0.5% supplementl Trp to n pprently dequte diet (18% CP, 0.26% Trp) in commercil lyer reeder flock tht ws suffering from hysteri incresed FI nd EP during the six-dy feeding period. Hrms nd Russell (1993) showed tht incresing dietry Trp from the sl level (0.19% totl Trp) significntly decresed ggressive pecking 935

10 El-Slmoney, et l ehvior, with 0.38% supplementl Trp eing s effective s 1.5% supplementl Trp. Differences in results could e due to the ge of irds used, reed nd durtion of tretment. Antr et l. (2004) reported tht the dily verge feed intke (FI) were90.4, 95.6 nd 90.7 g for 0.166, nd 0.193% Trp. Unfortuntely is seems tht there re very limited literture descriing the effect of lighting periods nd Trp levels on economic trits. Significnt interction effect mong lighting periods nd Trp levels on FI during ny experimentl period ws oserved. Feed conversion rtio (FCR): Results presented in Tle (4) clered tht lighting periods hd no significnt effect on FCR t ll periods except FC3. This improvement of FCR for irds in L2 my e minly due to the decrese in feed intke nd incresed T 3. Blck ( 1978) nd Blck nd Moog (1978) reported tht thyroid hormones stimulte intestinl differentition nd mturtion s indicted y cellulr chnges, increses in lkline phosphtse ctivity nd digestive enzyme ctivity. Keshvrz (1998) who reported tht feed conversion ws significntly inferior for hens on the step-down regimen thn other experimented ones. Hn Khlil et l. (2008) reported tht the step-up lighting regimen represented the est significnt improvement result (3.75 g/g) of feed conversion compred to tht sujected to hemerl (3.93 g/g), step-up intermittent (4.10 g/g) nd step-down (4.29 g/g) lighting regimens. Tle (4) showed the dt of FCR throughout the experimentl period nd significnt effect were oserved mong different Trp levels in FCR, hen feed on R2 utilized the feed s efficient s R1 nd R3 my e minly due to increse T 3 nd T 4. Hoption (2006) reported tht thyroidl hormones ply mjor role in the growth nd development of rin nd centrl nervous systems, control of severl metolic processes including crohydrte, ft, protein, vitmin nd minerl metolism. Also, Lwrence nd Fowler (1997) reported tht thyroid hormones influence the function of most orgns nd stimulte the sic metolic rte through regultion of the metolism of crohydrtes, proteins nd lipids. Ohtni, et l. (1989) reported tht verge FCR, g feed/ g eggs were 2.58, 2.46 nd 2.35 for 0, 250 nd 500 mg/kg diet Trp in lyers (Rhode Islnd Red x White Leghorn). Significnt interction effect mong lighting periods nd tryptophn levels on FCR during ny experimentl period ws oserved. 936

11 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. Effect of Tryptophn Supplementtion:- Egg Content (EC), Trp Intke nd Protein Intke:- Results in Tle (5) show tht there were no significnt effect of lighting periods on egg content, dily Trp intke (mg/ hen / d), Trp intke (mg/ EC), protein intke (g / g feed) nd Trp per grm EM. Tle (5) shows tht there were significnt differences etween dietry levels of Trp on EC, gin: Trp, Trp intke (mg/ EC), protein intke (g / g feed) nd Trp per grm EM. It ws found tht EC nd gin: Trp were significntly decresed due to illumintion of chicks with R3 compred to R1 nd R2. Tryptophn per grm of EM ws significntly higher from hens fed the diet contining 0.23% compred to 0.19% nd 0.21% Trp. Trp per grm of EM ws significntly incresed s the level of dietry Trp incresed. Similr results were reported y Antr et l. (2004). Hrms nd Russell (1998) reported tht the increse in Methionine (Met) required to produce 1g of EC my result from decrese in utiliztion of the Met t higher intkes. Another reson might e tht the hen ws using ody stores of Met, resulting in lower percentge of Met used for egg formtion t the lower output of EC. The increse in Met required per grm of EC emphsizes the importnce of considering the level of production in experiments when evluting the requirement of the hen for n mino cid. Russell nd Hrms (1999) showed tht verge EC were 44.48, 41.92, 45.65, nd g for control, 0.17, 0.19, 0.21 nd 0.23% Trp, respectively. Hrms nd Russell (2000) reported tht EC were 29.9, 39.4, 42.9, 45.1, 45.2, nd 45.2 g for 0.12, 0.14, 0.16, 0.17, 0.18 nd 0.20% Trp, respectively. The dily Trp intke incresed ech time the Trp ws incresed. This result ws lrgely due to the increse in Trp content in the diet (Tle 5). There were highly significnt differences in dily Trp intke (mg/ hen / d) of chicks received dietry levels of Trp. In generl, the dily Trp intke (mg/ hen / d) of chicks incresed when incresed dietry levels of Trp. The Trp requirement for optimum dily egg mss 235 mg Trp /d for dily egg mss of g, in verge of the models used in Dokki-4 lying hens ( locl strin) found in the present study ws distinctly higher thn the suggestions y other uthors Bry (1969), 117 mg for dily egg mss of 46 g; Morris nd Wethli (1978), 182 mg for dily egg mss of 50 g; Jensen et l. (1990), 124 to 168 mg for dily egg mss of 46 to 52 g; Schutte (1998), 180 mg for dily egg mss of 55 g; Russell nd Hrms (1999), 157 mg for dily egg mss of 55 g; Hrms und Russell (2000), 149 mg Trp per dy for dily egg mss of 50 g; Pegnov et l. 937

12 El-Slmoney, et l (2003), 198 mg Trp /d for dily egg mss of 49 g nd lso higher thn the recommendtions of the NRC (1994), 175 mg Trp per dy for rown-egg lyers with n egg production of 90%. The results of the present study lso imply tht the requirement of lying hens for Trp is presently slightly underestimted. This effect is due to the role of Trp s precursor of serotonin, which is n importnt regultor of the ppetite of mn nd nimls (Blundell nd Lthm 1978; Tckmn et l. 1990; Roc et l. 1999). This result ws lrgely due to the increse in Trp content in the diet. The Trp intke per grm of EC incresed s the Trp content of the diet incresed. Chicks received R3 hd significntly (P<0.05) Trp intke (mg/ EC) higher thn tht R2 nd R1. Hrms et l. (1997) showed tht the Met intke per grm of EC increses s the dily output of EC increses. Similr results were reported y Russel nd Hrms (1999) nd Hrms nd Russel (2000). No significnt effect of lighting periods on protein intke (g / g feed). Significnt interction effect mong lighting periods nd Trp levels on EC, gin: Trp, dily Trp intke (mg/ hen / d) nd Trp intke per grm of EC. Results otined illustrted in Tle (5) indicted tht lighting periods hd no significnt effect on Trp per grm EM. Egg qulity:- Results otined illustrted in Tle (6) indicted tht lighting periods hd no significnt effect on EW, Sh. Tmm, Alw, ESI, Al %, nd ESP % in Dokki4 strin. While Y % hd significnt effect. Lewis et l. (2007) reported tht shell strength, s mesured y deformtion, hd positive liner reltionship with photoperiod for irds rered on 6, 8, 10 or 12h photoperiods, despite n ANOVA hving shown tht 8, 10 nd 12 h tretments were not significntly different from ech other. Dietry levels of Trp hd significnt effect on Alw, Al % nd ESP %, while no significnt effects on EW, Sh. T, ESI nd Y % were detected. In greement with the present results Azzi et l. (2006), Prochsk nd Crey (1993) nd Prochsk et l. (1996) reported n increse in lumen weight nd lumen percentge with incresed lysine intke ut noted tht percentge yolk ws not significntly ffected y lysine. Shfer et l. (1996) who demonstrted tht shell thickness ws not significntly different mong Methionine (Met) level tretments rnged from 0.3 to 0.4% dietry Met. In contrst, Scheideler et l. (1996) reported liner increse in percentge yolk with incresed lysine with no ffect on lumen percentge. A similr lck of response of shell weight percentge 938

13 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. to TSAA intkes. In my opinion differences in results could e due to the ge of irds used, reeds nd durtion of tretment. As shown from Tle (6) the interction mong lighting periods nd Trp levels hd significnt differences mong ll dietry tretments, except EW. Blood Prmeters: Tle (7) indicted tht plsm totl protein, lumin, totl lipids nd cholesterol were not ffected y lighting periods. L2 significntly incresed plsm gloulin (P<0.05) compred to L1. These results were in full greement with tht otined y El-Neney (2003), Sim et l. (2004) nd Onsilr et l. (2007). Blood profiling, initilly used to detect su-clinicl disorders due to incorrect feeding, hs recently een given more widely to evlute the effects of different tretments on metolic, nutritionl nd welfre conditions of nimls (Bover et l., 2007).On the other hnd, chicks illuminted with L1 nd L2 exhiited higher WBC s thn L3 (11.98, nd 9.91) respectively. Moore nd Siopes (2000) found tht totl WBC counts in Jpnese quil incresed significntly during shorter photoperiod compred to longer photoperiod nd constnt lighting. Leung (1991) indicted tht drkness increses totl WBC numers, which could e due to incresed meltonin levels in drkness. However, the result in the current study disgrees with those of Blir et l. (1993) nd Cmpo nd Dvil (2002) who reported tht heterophil-to-lymphocyte rtio ws unffected y nerly continuous lighting schedule (23L: 1D). It is cler from Tle (7) tht dietry levels of Trp hd significntly totl protein, gloulin, A/G rtio, cholesterol nd WBC s. In this study the increse in plsm totl protein, gloulin nd WBC s concentrtion in R2 nd R3 treted hens my e due to incresing the vilility of Trp nd incresed T 3 nd T 4. WBC s in hen incresed significntly during incresed dietry levels of Trp compred to control. Hoption (2006) reported tht thyroidl hormones ply mjor role in the growth nd development of rin nd centrl nervous systems, control of severl metolic processes including crohydrte, ft, protein, vitmin nd minerl metolism. Also, Lwrence nd Fowler (1997) reported tht thyroid hormones influence the function of most orgns nd stimulte the sic metolic rte through regultion of the metolism of crohydrtes, proteins nd lipids. Corzo et l. (2005) reported tht verge lood plsm totl protein were 3.93, 3.67, 4.03 nd 4.10 in roiler for 0.12, 0.16, 0.20 nd 0.24 % Trp, respectively. Dietry levels of Trp hd insignificntly effects on lumin 939

14 El-Slmoney, et l nd totl lipids levels. Corzo et l. (2005, ) nd Emdi et l. (2010) they found tht lood plsm cholesterol showed liner decrese with incresing dietry Trp. There were significnt effect for interction mong lighting periods nd Trp levels on totl protein, gloulin, A/G rtio, cholesterol nd WBC s. While, interction etween lighting periods nd Trp levels hd insignificnt effect on lumin nd totl lipids. Plsm hormone concentrtions:- Meltonin (MLT) secretion is incresed t night, sometimes ten-fold, reltive to dylight hours. Level of MLT incresed mrkedly during the drk period thn tht during the light period (Tle 8). Hens L1 re likely to hve higher MLT levels thn L2 nd L3 hens. This result is in good greement with tht of Cogurn et l. (1987) nd Sim et l. (2004). Liou et l. (1987) found tht the rnge of plsm MLT concentrtions ws low in lying chicken during the light period ( pg/ml) nd higher during the drk period ( pg/ml). They suggested tht the rise of plsm MLT level during the drk period in the lying chicken is essentil for regulting the time of oviposition under prticulr light-drk cycle. Sim et l. (2004) showed tht the verge of MLT level in Hy-Line commercil lyers ws higher during the drk period (288.9 pg/ml) nd lower during the light period (43.0 pg/ml). MLT modultes rnge of physiologicl functions, with the most widely known nd studied eing sleep (Lydic nd Bghdoyn, 1999). Zwilsk et l. (2007) suggested tht photoperiod-dependent chnges in the MLT signl my ply n importnt role in modulting the immune function nd reproductive sttus of the turkey. Tle (8) indicted tht T 3 nd T 4 were not ffected y lighting periods, ut T 3 nd T 4 hd high levels during the drk period. This result is in good greement with tht of Scnes et l. (1979), Sim et l. (2004). Khlif nd Shoukry (1992) who found tht no significnt differences in plsm T 3. Our results re ingreement with tht otined y Smr Elngr et. l. (2007) nd El- Neney (2003). On the contrry, the present results disgree with those of Sdovsky nd Bensdoum (1971) nd Klndorf et l. (1978) who found tht T 3 nd T 4 hd high levels during the photoperiod. Level of MLT incresed y incresing dietry levels of Trp during the drk period thn light period (Tle 8). Hens received R3 hve higher meltonin levels thn hens received R1 nd R2. There ws no significnt difference in plsm T 3 during the light nd drk periods. While, there ws significnt difference in plsm T 4 during the light nd drk periods. Anderson 940

15 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. nd Hroticky (1986) reported tht the reltionship of Trp to serotonin nd meltonin, there hve een numerous studies conducted in humns involving orl Trp supplementtion s sleep id. Esten, et l. (2004) indicted tht the synthesis of serotonin nd meltonin, s well s the innte immune response, cn e modulted y orl ingestion of Trp. Soledd et l,(2004) suggests tht the tryptophn dministrtion stimulted meltonin synthesis, leding to incresed nd erlier peking plsm levels of this hormone, nd ugmented the innte immune response crried out y the peritonel mcrophges s result of the immunoregultory ction of meltonin. There were significnt effect for interction mong lighting periods nd Trp levels on meltonin (light period) nd T 4 during the light period nd drk period. While, interction etween lighting periods nd Trp levels hd insignificnt effect on T 3 during the light period nd drk period. Economicl efficiency The egg numer, egg weight nd feeding cost re generlly consider the most importnt fctors involved in chievement of mximum efficiency vlues of egg production. The results of economicl efficiency (Tle 9) showed tht L2 nd R2 incresed the economicl efficiency compred with L3 nd R3. Using R2 in diets of lying hens with lighting periods L2 improved economicl efficiency nd reltive economicl efficiency of lying hens compred with R3 s shown in Tle (9). The highest vlues of economicl efficiency of 0.65 nd 0.71 with the reltive economicl efficiencies of nd were otined with the groups fed L1 x R2 nd L2 x R2. CONCLUSION It could e concluded tht Trp supplementtion improves the growth performnce, production, immunity nd helth sttus of lying hens without ny dverse effect on hen. Also ll lood prmeters were in norml rnge. The est comintion of lighting periods nd tryptophn levels ws (L2*R2) nd economiclly etter in production nd immunity without dverse effect on ll performnce. 941

16 El-Slmoney, et l Tle.1. Composition nd chemicl nlyses of the experimentl sl diet. Ingredients % Yellow corn Soyen mel (44%) Limestone 7.60 NCl 0.30 Di-Clcium Phosphte 1.50 DL-Methionine 0.06 Premix * 0.30 Totl 100 Clculted nlyses ** Crude protein % ME, Kcl / kg 2744 C / P rtio Crude fier % 3.33 C % 3.29 P (Aville) % 0.40 Lysine % 0.90 Methionine % 0.35 Met. + Cyct 0.62 Tryptophn 0.19 *Ech 3 Kg of vitmins nd minerls premix contined : IU Vit. A, mg Vit. E, 1000 mg Vit. K3, IU Vit. D3, 1000 mg Vit. B1, mg Pntothenic cid, 10 mg Vit. B12, 1500 mg Vit. B6, 5000 mg Vit. B2, 30000mg Nicin, mg Choline chloride, 1000 mg Folic cid, 50 mg Biotin, 300 mg I, mg Mn, mg Zn, mg Fe, 4000 mg Cu, 100 mg Se nd 100 mg Co. **According to Feed Composition Tles for niml & poultry feedstuffs used in Egypt (2001). 942

17 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. Item Tle. 2. Effect of lighting, tryptophn levels nd their interction on live ody weight, ody weight gin nd egg weight of hens. Body weight (BW), g Body weight gin ( BWG), g Egg Weight (g) wks BWG1 BWG2 BWG3 BWG4 EW1 EW2 EW3 EW4 wks 24 wks 28 wks Effect of lighting periods L c L L SEM Sig. NS NS NS NS ** * * ** NS NS NS NS Effect of Tryptophn level R R R SEM Sig. NS NS NS NS ** * ** ** * * * * Interction effect etween light periods nd Tryptophn level R c 1367 c c 150 d d 306 d L1 L2 L3 R c 1361 c c 156 cd d 320 c R c c 136 d 80 cd 77 c 293 e R c 1362 c c 157 cd 78 d 68 cd 303 de R c 1379 c c c 73 c R c 169 c 72 e 74 c 315 c R c 1369 c c 157 c 79 d 71 c 307 d R c c R c 1374 c c SEM Sig. * * * * * * * * ** ** * * NS=Not significnt. * = P 0.05 ** = P 0.01.,,c,.etc. mens within the sme column with different superscripts re significntly different 943

18 El-Slmoney, et l Item Tle. 3. Effect of lighting periods, tryptophn levels nd their interction on egg numer, egg production nd egg mss. Egg Numer Egg Production, % Egg Mss EN1 EN2 EN3 EN4 EP1 EP2 EP3 EP4 EM1 EM2 EM3 EM4 Effect of lighting periods L L L c SEM Sig. NS NS * * NS NS * * NS NS * NS Effect of Tryptophn level L1 L2 L3 R R R c c c c SEM Sig. * * NS NS * * * * * * * * Interction effect etween light periods nd Tryptophn level R cd c R d c R e d e c R e cd d e e c c d c c d d e g cd d R c c R de d c R d cd R c de R f cd c d e d f d c e d de cd e de c e e d e cd c d cd f f SEM Sig. ** ** ** ** ** ** ** ** * * * * NS=Not significnt. * = P 0.05 ** = P 0.01.,,c,.etc. mens within the sme column with different superscripts re significntly different d c d c c d c e c d d c c d c c c 944

19 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. Tle. 4. Effect of lighting periods, tryptophn levels nd their interction on feed intke (g/hen/dy) nd feed conversion. Item Feed Intke, FI (g/ hen / d) Feed conversion rtio, % FI 1 FI 2 FI 3 FI 4 FCR 1 FCR 2 FCR 3 FCR 4 Effect of lighting periods L L L SEM Sig. NS NS NS NS NS NS * NS Effect of Tryptophn level R R c c R SEM Sig. * * * * * * * * Interction effect etween light periods nd Tryptophn level L1 L2 L3 R d c 4.26 de R d d c 4.55 d 3.36 c 3.76 e 3.89 f R c c c R d 4.32 c d R d e d 4.22 e 3.20 c 3.70 e 3.71 g R c c c 4.41 c R c c c R c e e R c c 4.60 SEM Sig. * * * * * * * * NS=Not significnt. * = P 0.05.,,c,.etc. mens within the sme column with different superscripts re significntly different 945

20 El-Slmoney, et l Tle. 5. Effect of lighting periods, tryptophn levels nd their interction on egg content (EC), gin/ Trp, dily Trp intke, tryptophn intke nd Trp per grm EM. Item Egg content (EC), g Gin : Trp ( mg / g) Dily Trp intke (mg/ hen /d ) Effect of lighting periods Trp Intke (mg/ EC) Protein intke (g / g feed) Trp/g EM (mg/g) L c L L SEM Sig. NS * NS NS NS NS Effect of Tryptophn level R c R R SEM Sig. * * ** * NS * Interction effect etween light periods nd Tryptophn level R c 1.39 c c 9.54 c c d R c 1.36 c c d R e 1.13 e R d c 9.53 c c d R d R de 1.21 d R c 7.75 c c d R cd c R de 1.32 c SEM Sig. * * * * NS * L1 L2 L3 NS=Not significnt. * = P 0.05 ** = P 0.01.,,c,.etc. mens within the sme column with different superscripts re significntly different. 946

21 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. Tle. 6. Effect of lighting periods, tryptophn levels nd their interction on egg qulity prmeters for Dokki4 lying hens during the experimentl period. Item Egg weight (EW) Shell thickness (Sh. T mm) Alumen weight (Alw) Egg shell index ( ESI) Effect of lighting periods Yolk, % (Y) Al,% Egg shell, % (ESP) L L L SEM Sig. NS NS NS NS * NS NS Effect of Tryptophn level R R R c SEM Sig. NS NS * NS NS * * Interction effect etween light periods nd Tryptophn level L1 L2 L3 R c c R R cd R c R c c R d R c R R cd c SEM Sig. NS * * * * * * NS=Not significnt. * = P 0.05.,,c,.etc. mens within the sme column with different superscripts re significntly different. 947

22 El-Slmoney, et l Tle.7. Effect of lighting periods, tryptophn levels nd their interction on some lood prmeters for Dokki4 lying hens fed the dietry tretments. Item Totl protein (g/dl) A l u m i n (Al, g/dl) Gloulin (Glo g/dl) A / G rtio Totl lipids (mg/l) Cholesterol (mg/dl) WBC s (10 3 ml) Effect of lighting periods L L c L SEM Sig. NS NS * ** NS NS * Effect of Tryptophn level R c R c R SEM Sig. * NS * * NS * * Interction effect etween light periods nd Tryptophn level R cd R R R d R c c R c R e R cd R cd SEM Sig. * NS * * NS * * L1 L2 L3 NS=Not significnt. * = P ** = P 0.01.,,c,.etc. mens within the sme column with different superscripts re significntly different. 948

23 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. Tle. 8. Effects of lighting periods nd tryptophn levels on plsm hormone concentrtions for Dokki4 lying hens fed the dietry tretments. Item Meltonin (pg / ml) T 3 (ng / ml) T 4 (ng / ml) T 4 / T 3 Rtio L D L D L D L D Effect of lighting periods L L L SEM Sig. NS ** NS NS NS NS * * Effect of Tryptophn level R c c R c R SEM Sig. * ** NS NS * * NS * Interction effect etween light periods nd Tryptophn level R d c c L1 R c R R d c L2 R c d d d R c c R d e c L3 R c cd c R c SEM Sig. * ** NS NS * * * * NS=Not significnt. * = P 0.05 ** = P L =Light D=Drk.,,c,.etc. mens within the sme column with different superscripts re significntly different. 949

24 El-Slmoney, et l Tle. 9. Economic efficiency of lying hens under the effect of dding tryptophn in length of dy light. ITEM PRICE/K FEED (L.E.) TOTAL FI HEN(KG) TOTAL FEED COST/ HEN (L.E) TOTAL EN/ HEN PRICE/ EGG ( L.E ) TOTAL PRICE OF EGG ( L.E ) NET REVENUE PER HEN ECONOMIC EFFICIENCY (EE) RELATIVE (EE) L L L R R R L1X R L1X R L1X R L2X R L2X R L2X R L3X R L3X R L3X R L.E = Egyptin pound. 950

25 tryptophn, photoperiod, egg production, meltonin, lying hens, immunity. REFERENCES Adeol, O. (1998). Biovilility of tryptophn in soyen mel nd tryptophn retention in the crcsses of four-week-old ducks. Poult. Sci., 77: Anderson, G. H. nd Hroticky, N. (1986). Approches to ssessing the dietry component of the diet-ehvior connection. Nutr. Rev. 44: Antr, R. S., Hrms, R. H., Shivzd, M., Fri, D. E. nd Russell, G. B. (2004). Performnce of Commercil Lying Hens when Six Percent Corn Oil Is Added to the Diet t Vrious Ages nd with Different Levels of Tryptophn nd Protein. Poult. Sci. 83: Azzi, I. A., Nsr-Allh M. M. nd Hsn, I. I. H. (2006).The response of lying hens to corn-soyen mel diets supplemented with methionine nd lysine. Egypt Poult. Sci. Vol (26) (II): Bker, D. H., Becker, D. H., Norton, H. W., Jenson, A. H. nd Hrmon, B. G. (1969). Lysine imlnce of corn protein in the growing pig. J. Anim. Sci. 28: Brnyiov, E. (1991). Effect of serotonin on food intke y piglets during the erly postntl period. Act Vet. (Brno) 60: Bender, D. A. (1983). Effects of oestrdiol nd vitmin B6 on tryptophn metolism in the rt: impliction for the interprettion of the tryptophn lod-test for vitmin Bu nutritionl sttus. Br. J. Nutr. 50: Blck, B. L. (1978). Morphologic development of the epithelium of the emryonic chick intestine in culture: influence of thyroxine nd hydrocortisone. Am. J. Ant. 153: Blck, B. L. nd Moog, F. (1978). Alkline phosphtes nd mltse ctivity in the emryonic chick intestine in culture. Dev. Biol. 66: Blir, R., Newerry, R. C. nd Grdiner, E. E. (1993). Effects of lighting pttern nd dietry tryptophn supplementtion on growth nd mortlity in roilers. Poult. Sci. 72: Blundell, J. E. nd Lthm, C. J. (1978). Phrmcologicl mnipultion of feeding ehvior: Possile influences of serotonin nd dopmine on food intke. Pges in Centrl Mechnism of Anorectic Drugs. S. Grttini nd R. Smnin, ed.rven Press, New York. 951