hensr ^ Effects of dietary barley level on the performance of Leghorn

Transcription

1 Can. J. Anim. Sci. 73: (Sept. 1993) 625 ffects f dietary barley level n the perfrmance f Leghrn hensr ^ R. M. G. Hamiltn and F. G. Prudft Research Statin, Agriculture Canada, Kentville, Nva Sctia, Canada B4N U5. Cntributin n. 2112, received 20 January 1993, accepted 25 May Hamiltn, R. M. G. and Prudft, F. G ffects f dietary barley level n the perfrmance f Leghrn hens. Can. J. Anim. Sci. 73: Three experiments were carried ut t examine the effects fdietary barley level n the perfrmance f Leghrn hens. A 4 x 2 factrial arrangement f treatments was used in exps. I and 2 where there were fur dietary barley levels (0, 15, 30 r 60%) and tw cmmercial gentypes f hens. xperiment 3 cntained a3 x 2 x 2 arrangement f treatments invlving three dietary barley levels (15, 30 r 60%), tw cultivars f barley (2- r 6-rw) and tw levels f p-glucanase supplementatin (0 and 0. I % f the diet). gg prductin. feed intake, mrtality, egg grades, bdy weight, and eggshell and interir quality data were cllected frm 140 t 490 d f age. The data frm exps. 1 and 2 were cmbined fr statistical analysis. There was a linear relatinship (P < 0.001) between dietary barley level and feed cnversin in exps. I and 2. Differences (P < 0.05) were bserved between the tw gentypes fr 140- and 490-d bdy weights, age at 50% egg prductin, hen hused egg numbers, feed cnversin and mnetary returns. Dietary barley level, in exp. 3, had a quadratic eff'ect (P < 0.05) n egg prductin (bth HD % and HH n.) and mnetary returns and a linear effect (P < 0.01) n feed cnversin. Surce f barley and dietary B-glucanase supplementatin had little eftect n perfbrmance. Diets fr Leghrn hens may cntain up t 60% barley, but ptimum prductin perfrmance ccurred at a lwer level. Key wrds: Barley, hens, B-glucanase, barley cultivar Hamiltn, R. M. G. et Prudft, F. G ffets de la prprtin d'rge dans la ratin sur les perfrmances des pules Leghrn. Can. J. Anim. Sci. 73: Tris expdriences nt 6t6 r6alis6es pur examiner les effets de la prprtin d'rge dans I'alimentatin sur les perfrmances des pules Leghrn. Un dispsitif factriel 4 x 2 daft utilisd dans 1es exp6riences 1 et 2, qui cmprtaient quatre taux d'incrpratin d'rge (0, 15, 30 u 60%) et 2 suches cmmerciales de pule. L'expdrience 3, disps6e en factrielle 3 x 2 x 2 cmpftait 3 taux d'incrpratin d'rge (15, 30 u 60%),2 cultivars d'rge (2 u 6 rangs) et 2 niveaux de suppl6mentatin en B-glucanase (0 et 0,1% de I'aliment). La prductin d'eufs, la prise alimentaire, la mrtalitd, le classement des eufs, le pids crprel et la qualit6 de la cquille et de l'int6rieur de I'euf nt 6t6 mesurds ir partir de I'Age de 140 jurs jusqu'd 490 jurs. Les dnn6es des deux premidres expdriences, r6unies pur I'analyse statistique, nt r6v6l6 un rapprt lin6aire (P < 0,01) entre la prprtin d'rge et l'indice de cnsmmatin. Des diff6rences (P < 0,05) snt apparues entre les deux suches pur le pids crprel d 140 et d 490 jurs, pur la maturitd sexuelle, pur le nmbre d'eufs prduits par pule 1g6e, pur l'indice de cnsmmatin et pur le rendement 6cnmique. Dans l'exp6rience 3, la prprtin d'rge dans I'aliment avait un effet quadratique (P < 0,05) sur la prductin d'euf (par pule/jur et par pule lg6e). ainsi que sur le rendement financier, et un effet lin6aire (P < 0,01) sur I'indice de cnsmmatin. Le type d'rge utilisd et la suppl6mentatin en p-glucanase n'avaient que peu d'effets sur la perfrmance des pules. Bien que les r6gimes alimentaires pur pules Leghrn puissent aller jusqu'ir 60% d'rge, les meilleures perfrmances nt 6ti btenues ir des niveaux d'incrpratin plus bas. Mts cl6s: Orge, pule. p-glucanase, cultivar d'rge lmentin f a trade namc, prprietary prduct r specific cquipment des nt imply its flicial endrsement by Agnculture Canada t the exclusin f ther prducts that mav be suitable.

2 626 CANADIAN JOURNAL OF ANIMAL SCINCF The ptential f barley (Hrdeum vulgare) as a feedingstuff fr pultry has been studied since the early 1900s (Cramptn 1936). Cnsiderable data have been reprted n the use fbarley in feed fr laying hens (Petersen and Lampman 1955; Arsctt et al. 1962; Sell l97l; Britzman 1985). While a range f dietary barley levels were used in these reprted studies, it is nt pssible t establish with any certainty the dietary level(s) that gave ptimum perfrmance because f the numerus differences in the experimental designs used. Generally, in these studies barley replaced ther grains, ften at nly ne level, f the experimental diets. Barley is a majr cereal grain crp f the Maritimes and in Nva Sctia accunts fr abut ne-third fthe annual ttal cereal grain prductin (Nva Sctia Department f Agriculture and Marketing 1991). With cst f transprtatin increasing in recent years, it is desirabie t use lcally grrvn feed grains, such as barley, whenever pssible t minimize prducer's feed csts. Therefre, three experiments were carried ut t determine the ptimum levels that may be incrprated int the feed f Leghrn hens. In exps. 1 and 2, dietary barley levels f 0, 15, 30 r 60% were used, while in exp. 3 the levels were 30, 45 r 60%. p-glucans in barley (Newman et al. 1987) have an antinutritinal effect when barley is used in feed fr briler chickens (Rtter et al. 1989; Campbell and Bedfrd 1992). This antinutritinal effect f B-glucans can be amelirated by the use f the enzyme, p-glucanase. in the feeds f briler chickens (Andersn et al. 1961; Hesselman et al. 1982; Classen et al. 1985; Rtter et al. 1989). Therefre, ne-half f the diets in exp. 3 were supplemented with p-glucanase. Furthermre, since the respnse fbriler chickens t dietary p-glucanase supplementatin can be influenced by the cultivar f barley used (Campbell et al. 1989), barleys frm a tw-rw and a six-rw cultivar were used in the latter exeriment. MATRIALS AND MTHODS The pullets fr each experiment were raised frm day-ld chicks in flr pens (4.93 x 2.93 m; 100 chicks pen ') as previusly described (Prudft et al. 1988). T'he care and management f the birds in the experiments being reprled were in accrdance with the guidelines f the Canadian Cuncil n Animal Care (1980). Wd shavings were used as litter material. The birds received 14 h light : l0 h dark frm husing day until the terminatin f the experiments at 490 d f age. Initially they received an intensity f 20 lx f light fr the first 48 h pst-hatching after which it was linearly reduced 1.5 lx d 't 2 lx frm 14 t 140 d. Frm 141 t 490 d the light intensity was 10 1x. Feed, as mash, and water were prvided ad libitum during the experiment (0-490 d f age). The frmulatins f the starter and grwer diets fr the three experiments were similar. The pullets received insluble grit frm 7 t 138 d and supplemental yster shell during the laying perid ( d). The traits measured included live bdy weight at 140 and 490 d. feed intake ver 28-d intervals, age at 50% egg prductin, egg quality at and d f age, and ne day's egg cliectin was graded weekly until 228 d f age and then at every 2 wk thereafter. Mrtality was recrded as it ccurred and all the dead birds were necrpsied by a veterinary pultry pathlgist. The egg quality measurements included egg specific gravity by fltatin in saline (frm t in increments f 0.004). egg weight, albumen height and the ccurrence f bld spts. Haugh units were calculated frm the egg weight and albumen height data. Mnetary returns were calculated frm the weekly prices feggs t the prducer as set by the Nva Sctia gg Bard f the eggs laid minus the csts fthe feed and the rearing cst f the pullets. xperiments I and 2 A ttal f 384 hens received treatments accrding t a randmized cmplete blck design that cntained a2 x 4 factrial cmbinatin f treatments, repeated fur times: initially there were 48 pullets per treatment. The factrs included tw gentypes f hens and fbur dietary ievels f barley (0, 15, 30 r 60%). The chicks were frm tw cmmercial gentypes, hereafter, designated C1 and C2. The cmpsitins f the experimental diets are given in Table l. Samples frm each batch f experimental diets mixed were analyzed fr Kjeldahl nitrgen accrding t the methd f Assciatin f Official Analytical Chemists (AOAC 1984). At d f age the pullets fr each experiment were transf'erred tim the flr pens and hused in wire-mesh cages (24.5 x 41.0 cm) that

3 HAMILTON AND PROUDFOOT BARLY FOR - LAY]NG H 627 Table 1. Frmulatin fdiets fr lavins hens xperiments 1 and 2 xperiment 3 Ingredient Cntrl t5% 30% 60% 30% 45% Gnd barley Gnd crn Gnd wheat Sybean meal (46.5% CP) Fishmeal (60% CP) Pultry grease Salt (idized) Gnd limestne Dicalcium phsphate DL-Methinine L-Lysine Vitamin-mineral premixt r I7.6 l t ' 60 lt t zprvided per kilgram f diet: vitamin A 9000 IU; vitamin D ICU, vitamin 8 mg, vitamin K 1.5 mg, ribflavin 6 mg, niacin 18 mg, D-calcrum pantthenate 8 mg. flic acid 1 mg, bitin 100 pg, pyridxine 5 mg, thiamine 5 mg, chline 300 mg, vitamin B,2 l5 pg. manganese 80 mg. zinc 60 mg, cpper 6,25 mg, idine 325 pg. irn 45 mg, selenium 67.5 pg, and ethxyquin 100 mg. were lcated in tw separate rms. ach rm cntained 16 grups f 12 cnsecutive cages; the experimental treatments were randmized amng these grups. The pullets were hused in April and May fr exps. I and 2, respectively. xperiment 3 During the experimental perid 768 hens initially received dietary treatments accrding t a randmized cmplete blck design that cntained a 3 x 2 x 2 factrial cmbinatin f treatments. repeated fbur times; there were initially 64 birds per treatment. The factrs rncluded three dietary levels f barley (30, 45 and 60%), tw cultivars f barley (tw-rw and six-rw) and tw levels f dietary B-glucanase additin (0 and 0.1 % f the diet). Rde and Leger were the tw- and six-rw cultivars fbarley used in the experimental diets. The p-glucanase enzyme activity was frm AVI- ZYM SX which cntained dehydrated extracts frm Aspergillus niger and Trichderma lngibrachiatum (F. Reesei) fermentatins. The minimum eruyme activities in the supplemenl used were: cellulase 27 FPU g, ', 6-glucanase 300 U g-r and xylanase 300 U g '."Th. diers shwn in Table 1 were frmulated t be isnltrgerlus and is-calric. ach batch f the experimental diets was analyzed fbr dry matter, Kjeldahl nitrgen, crude fat, ash, calcium and ttal phsphrus accrding t methds f AOAC (1984). The diets were assayed fr metablizable energy accrding t the methd f Sibbald ( I 986) using five mature Leghrn ccks per diet. The barley cultivars were analyzed fr B-glucans and nn-starch plysaccharides by the methds f Aman and Graham (1987) and nglyst and Cummings (1988), respectively. Statistics Mdules frm the statistical prgramming language Genstat 5 (Genstat Cmmittee 1987) were used t analyze the cage grup means fthe data cllected. Regressin analyses were used t evaluate the relatinships between dietary barley levels and traits f interest. Percentage data were transfrmed t arcsin angles fr analysis, but de-transfrmed fr presentatin in the tables. RSULTS xperiments I and 2 The data frm exps. I and2 were cmbined because they were replicates f each ther in time. Results frm the cmbined experiments are presented in Tables 2 and 3. Chemical analysis indicated that the crude prtein (N2 X 6.25) cntent f the diets was simiiar fr each experiment. The cmbined prtein values fr bth experiments were 18.1, 18.0, ll.l andll.5% fr 0, 15, 30 and 60% dretary levels f barley, respectively,

4 628 CANADIAN JOURNAL OF ANIMAL SCINC Table 2. fl'ects f dietary barley level and gentype n the perfrmance f Leghrn hens frm 140 t 490 d f age (exps. I and 2 cmbined) Barley Ievel 0% l SM (n : 16) Prbabilityx Gentype C2 SM (n : 32) Prbability x xp. I xp. 2 SM (n : 32) Prbability' Bdy weight Auc (g) Mrtalil' s-''ip' l.+0 d 490 d (%) (d) 1287 t97t t t l0 19 t252 18n t X L.) 1, I 0.9 L gg Feed Mnetary prductinj cnversln returns HD (%) HH (n.) (kg/12 eggs) ($/HH n.) l / r.626 t.6t7 L569 r t l 'P : egg prductin. YHD : hen day, HH : hen hused. *:ntsignificant(p>0.05)rx:p(0.05:*+:p<0.01;***:p<0.001;l:lineareffect Table 3. ffects f dietary barley level and l genrype n the shell and interir quality f eggs fim Leghrn hcns (erps. I and 2 cmbined) Barley level 0% l SM (tt - 16) Prbabilityr Gentype CI CZ SM (tt : 32) Prbability:- xp. 1 xp. 2 SM (n - 32) Prbabilityr gg weight (g) 196 d 4fl4 d l Specific gravity' Haugh units 196 d 484 d 196 d 484 d **.L s 3,*, lt r r l l ' l Bld spts (%) 196 d.184 d l l zcded values. T de-cde 897 : : l.ol99. etc. I-ntsignificant(P>0.05):+:P10.05:++-P<0.011**+-P<0.0011L:lineareffect. with a SM f These diets were The significant linear relatinship riginally frmulated t cntain 18.0% crude (P < 0.001) between dietary barley level and prtein. feed cnversin (Table 2) was primarily due

5 HAMILTON AND PROUDFOOT. BARLY FOR LAYING H 629 t lwer feed intake f hens given the 60% barley-cntaining diet cmpared t the ther diets,(34.16 vs. [average] kg feed hen '). Dietary barley level had n significant effect (P > 0.05) n the ther perfrmance traits measured. The birds frm gentype C2 were heavier at bth 140 and 490 d (57 and 207 g, respectively), reached 50% egg prductin abut 3 d later, laid abut six eggs mre, were J.8% less efficient in cnverting feed t egg numbers and returned 54Q less hen ' than thse frm gentype Cl; these differences were significant (P < 0.05 r P < 0.001). The egg grade results fr the cmbined experiments are presented in Fig. I as a stacked bar graph. Dietary barley level had n significant effect (P > 0.05) n any f the egg grades. There were significant (P < 0.05) differences between gentypes Cl and C2 fr all the grades. Gentype C2 prduced 25.4 mre xtra Large eggs and I.6, 12.4, 1.6 and 0.3 fewer Large, Medium, Small and Pee Wee eggs, respectively, than the hens frm gentype Cl. Nne f the b ), 0: z () L, l IIJ differences fr egg grades in exps. I and2 was significant (P > 0.05). gg weights and interir quality were similar amng the dietary barley levels (Table 3). A linear relatinship (P < 0.01) ccurred between the 196-d egg specific gravity (SG) and dietary barley level. gg weights at 490 d, SG at bth ages and Haugh units were % higher (P < 0.01) fr eggs frm gentype C2 than frm Cl hens. xcept fr Haugh units at 196 d which were 3.9 units higher (P < 0.001), the shell and interir quality were similar fr bth experiments. xperiment 3 The chemical cmpsitin and nutrient biavailabilities are given accrding t dietary barley level, cultivar and supplemental enzyme level in Table 4. Chemical analysis f the 12 experimental diets indicated that their crude prtein (Nr x 6.25) cntents were withrn 6.2% f each ther, crude fat within 14.0%, ash within 14.6%, calcium within 4.5% and ttal phsphrus within 5.9%. Bar 0 Bar 15 Bar 30 Bar 60 Gen 1 Gen 2 Treatments FI Other lffi Pee \NeesV)2 Small N\\ Medium [A] Lar6;e f7-l xtra Large Fig. 1. ffects fdietary barley level n gentype fr exps. I and 2. The ttal iength fthe bars equals the mean numbers f eggs laid per hen.

6 630 CANADIAN JOURNAL OF ANIMAL SCINC c a n- Table 5. Carbhydrate cmpsitin f the tw- and six rw barleys Variety e2.9 I a c I 9 tr (, + F N 1-qq9i.l -C +-O N -t r -6 -d O -^.-.i;;.- ^; - - Od r-r N6 _d.l-:q-9i d 1q.9i9\ N NC --+ d q rdn fln -N CO n-:ql9i 9 d 60 -t _/d..1 cli099\ "? 5d d -h 5r\r * rd ddc r + r--c n- Od r-@ drr -d & ' \ ^A s = 2 At ^, ll ale4 a=s* ^9 5u-. a- N< a = r - = -.1 ') YrP--1-t = asa i A"--- -;;---= a,ulp :==5;t:>> ++4 ^a,t)4()l U z a U a,u 6N il Yr- -c - v,y O =? O ' a t t' ) u O: " 9l nq i?.z I '= =r &. : s9.t t =; i 'Y at'. -. i - 3- ; Z'= 1i'a+t= F'atl' l ar. 1t>= F Cmpnent (% f DM) Starch Ttal nn-starch plysaccharide (P) Anid deterent Iinin Mixed linked beta-glucans Cellulse A rabinxy I ans Dietary fibre (P + lignin) Tw-rw Six-rw t] l n.6 The variatin amng the true DM digestibility results (Table 2) were the same (4.1 %) regardless fdietary level, barley surce and enzyme level. The TM. and AM' values ranged between % and %, respectively, f each ther. The diets were frmulated t cntain 18.0% crude prtein and 2150 kcal AM' kg -1 f feed. Analysis f the tw barley cultivars indicated that the carbhydrate cntents f these grains were similar (Table 5). In exp. 3, dietary barley level had little eff'ect (P > 0.05) n 140-d and 490-d bdy weights, mrtality and age at 50% prductin (Table 6), but had a quadratic effect n egg prductin (HD%, P P < 0.05) andmnetary returns (P < 0.01), and a linear eflect n feed cnversin (P < 0.01). Daily egg prductin peaked at apprximately 90% when the hens were abut 177 df age and subsequently declined slwly ( % duy -') t abut 15% at 490 d. Optimum egg prductin, feed cnversin and mnetary returns ccurred with the hens given the 45% barley-cntaining diet (Table 6). Barley cultivar and dietary p-glucanase supplementatin had n significant (P > 0.05) effect n the variables summarized in Table 6. Overall mrtality was lw (2.4%). As shwn in Fig. 2. the level f barley in the diets influenced the number f Large and Small eggs prduced (P < 0.05) during the experiment: the eff'ect was quadratic and linear, respectively. The hens given the 45%

7 HAMILTON AND PROUDFOOT BARLY FOR LAY1NG H Jt Table 6. Perfrmance f Leghrn hens fed diets that cntained 30,,15 r 60% barley frm either tw- r sir-rw alieties and withut r with supplemental p-glucanase Dietary level 30% barley 45% barley 60% barley SM (n : 16) Prbabilityr Surce f barley Tw-rw 1328 Six-rw SM (n : 24) 7 PrbabilitvY 0-glucanase Nne Supplemented SM (n : 24) Prbabilitvr Bdy weights (g) 140d 490d (%) 132 I t32i t.tla 1t r 320 l t961 t t I 950 l6 Mrtality Feed Age cnversin 50% P (kg/12 eggs) (d) t **.L t I.375 ] t F prductin Mnetary returns HD (%) HH (n.) ($/HH n.) **,Q *,Q l **,Q t t 'HD : hen day, HH : hen hused. r: ntsignificant(p > 0.05), *: P ( x* - P < 0.01, L: lineareffect, e: quadraticeffect.= CD, ) c; z P () L - ), lu nzvme - 'ar rr".t#3#.2 ffil Other K Pee Wees Z- Small N Medium Kt Large f-7-f xtra Large Fig. 2. Barley level and surce, and p-glucanase supplementatin fbr exp. 3 n egg grades. The ttal length f the bars equal the mean numbers f eggs laid per hen.

8 632 CANADIAN JOURNAL OF ANIMAL SCINC barley-cntaining dret laid mre Large eggs and fewer xtra Large eggs as well as mre ttal eggs. Whereas the hens given the diets cntaining the six-rw barley laid f'ewer xtra Large (P < 0.05), mre Medium (P < 0.05) and Large (P > 0.05) eggs. Althugh the hens given the diets that cntained p-glucanase prduced fewer xtra Large eggs and mre Large, Medium and Small eggs than thse receiving the nnsupplemented diets, nne fthese differences was significant (P > 0.5). Dietary treatment had little effect n the number f Pee Wee, Grade B and C, and Cracked eggs prduced. gg and shell quaiity were similar amng the dietary barley levels, except egg specific gravity at 196 d where a linear (P < 0.05) relatinship ccurred with dietary levei (Table 7). The lwer weights fr eggs frm the hens fed the 45% barley diet cmpared t thse given the 3O r 60% barley diets supprt the egg grade results. Glucanase supplementatin influenced (P < 0.05) the ccurrence f bld sts. DISCUSSION There was ne interactin between experiment and dietary barley level when the data frm exps. I and 2 were cmbined fr statistical analysis. This interactin which represented 10.1% f the ttal variatin ccurred fr age at 50% egg prductin (Table 3) and was due t the pullets in exp. 2 given the 15 and 60% barley diets reaching this level fprductin at an earlier age than the birds receiving the 0 and 30% barley diets (154.5 vs d). In exp. 1, the barley-fed pullets reache d 50% egg prductin d later than thse given the cntrl diet withut barley. An interactin (P < 0.001) between experiment and gentype fr mnetary returns accunted fr 22.0% f the ttal variatin. This interactin was due t higher mnetary returns frm gentype C2 than Cl in exp. l. while the reverse pattern ccurred in exp. 2. The differences between the analyzed and calculated values f the experimental diets are similar t thse reprted by Bltn (1959), Table 7. gg and shell quality fbr Leghrn hens fed diets that cntained 30, 45 r 60% barley frm either twr six-rw varietres and withut and with supplemental 0 glucanase Dietary level 30% barley 45% barley 60% barley SM (n : 16) Prbabilityr Surce f barley Tw-rw Six-rw SM (tt : 24) PrbabilityY gg weight (g) 196 d 484 d '7 * SpecrIrc gravlt) - Haugh units Bld spts l%t 116 d a8- d 196 d 484 d 196 d 484 d X,L l B-glucanase Nne Supplemented SM (n : 24) Prbabilityr , s zcded values. T de-cde 902 : Y : nt significant (P > 0.05), , 789 : , etc. * : P I L : linear effect. 84. l *

9 HAMILTON AND PROUDFOOT BARLY FOR LAYING H 633 Bayley et al. (1975) and l{amiltn and Sibbald (r977). The similarities in the perfrmances f the hens given diets that cntained 0, 15, 30 r 60% barley in exps. I and2 r 30, 45 r 60% barley in exp. 3 (Tables3,4,6 and 7) agree with previusly published results (Brwn and Hale 1965:' Balnave 1910 Sell 1911; Britzman 1985; Aimnen and Uusi-Rauva 1991). These researchers, hwever, used nly ne dietary level f barley that ranged frm 55 t'72% f the diet; their cntrl diets cntained crn and were generally isnitrgenus with the crrespnding barley diet. Als, in the trial f Aimnen and Niisi (1991) the prductive perfrmance f the Leghrn hens was nt affected when the barley in the cntrl diet was replaced by ats up t 66.9% f the diet. The differences in perfrmance between the tw gentypes used in exps. 1 and 2 (Tables 3 and 4) agree with the results f Prudft and Hulan (1986) wh used hens frm the same cmmercial breeding cmpanies. Aimnen and Niisi (1991) reprted that the supplementatin f barley-at diets with B-glucanase imprved egg yield and feed cnversin by 2.2 and 3.0 %, respectively, ver the nn-supplemented cntrls; these imprvements were nt significant (P > 0.05). Since lwinger and Siiterby (1987) shwed that the respnse f chicks t dietary p-glucanase supplementatin diminishes after abut 21 d f age, it is prbably nt reasnable t expect any substantial lmprvement in perfrmance when the diets f mature hens are supplemented with dietary glucanases. Aimnen and Uusi-Rauva (1991) fund that p-glucanase supplementatin f barley-at diets had a small, but significant effect n shell weight (P < 0.01) and its crrelated respnses percent shell and shell thickness; Haugh units were unaffected. The higher specific gravity f eggs at490 d (P < 0.01) frm the birds receiving the diets that cntained the six-rw barley cmpared with thse fed the tw-rw diets (Table 7) wuld be partly due t the iwer egg weight (P < 0.05) since the amunt f shell prduced by the hens in these treatments wuld be expected t be the same; egg specific gravity is crrelated with shell weight. Cntrary t a traditinal view that barley shuld nt be used t any extent in feed fr laying hens, the results f Brwn and Hale (1965) and thse presented herein indicate that the incrpratin f up t 60% barley int the feed fr Leghrn hens had little effect n egg prductin and quality, bdy weight gains and mrtality. Optimum perfrmance fr egg prductin and grades, feed cnversin and mnetary returns prbably ccurs when the feed cntains abut 45% barley. Results frm exp. 3 indicate that the cultivar fbarley and B-glucanase supplementatin may have little influence n the perfrmance f Leghm hens. ACKNOWLDGMNTS The authrs thank R. Neilsn, P. Rgers and K. Walker fr their technical assistance, G. Leslie and B. Walker fr the statistical analysis f the data,. Griffin and staff fr daily management f the hens, and D. Nash,. McGwan and Y. van Hatten fr chemically analyzing the diets. This research was supprted in part by a grant thrugh the Atlantic Pultry Research Institute frm the Canada/Nva Sctia Livestck Feed Initiative Prgram (Prject TD 066). The tw- and six-rw barley was generusly supplied by Dr. Thin-Meiw "Alex" Ch, Research Statin, Agriculture Canada, Charlttetwn, Prince dward Island. The AVIZYM SX was dnated by T. B. Kissler, Halchemix Canada Incrp., Trnt, Ontari. Sme f the pullet chicks were dnated by the Cx Brthers Hatchery, Nel, Nva Sctia. The analysis fthe barley samples fr beta glucans and nn-starch plysaccharides were dne thrugh the curtesy f Dr. H. Graham, FINNFDS Internatinal Limited, Wiltshire, U.K. Aimnen,. M. J. and Ndsi, M Replacement f barley by ats and enzyme supplementatin in diets fr laying hens. 1. Perfrmance and balance trial results. Acta Agric. Scand. 41: t'/9-t92. Aimnen,. M. J. and Uusi-Rauva, Replacement f barley by ats and enzyme supplementatin in diets fr laying hens. 2. Interir quality and chemical cmpsitin l'eggs. Acta Agric. Scand. 4l:

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