Effects of Dietary Methionine-Supplementation on the General Performance and Economic Value of Rahmani Lambs

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1 Avilble online t ISSN Effects of Dietry Methionine-Supplementtion on the Generl Performnce nd Economic Vlue of Rhmni Lmbs A. S. El-Thwy 1 *, A. M. Ismeil 2, H. A. Ahmed 3 1. Deprtment of Animl Husbndry nd Welth Development, Fculty of Veterinry Medicine, Dmnhour University. 2. Deprtment of Animl nd Poultry Production, Fculty of Agriculture, Dmnhour University. 3. Deprtment of Nutrition nd Vet. Clinicl nutrition, Fculty of Veterinry Medicine, Dmnhour University. Abstrct: Essentil mino cids such s methionine hve been incresingly included into diets of lmbs. However, few studies hve determined the effects of methionine supplementtion in the generl performnce nd economic returns of lmb production. To ddress this question, 21 wened mle Rhmni lmbs were llotted to 3 dietry tretments: control diet (C), control diet plus 3.30 g of methionine/kg concentrte feed mixture (T1), nd control diet plus 3.63 g of methionine/kg concentrte feed mixture (T2). T1-fed lmbs showed significntly higher (P < 0.05) totl body weight gin thn those fed diets C. The digestibility coefficients of dry mtter (DM), orgnic mtter (OM), crude protein (CP), ether extrct, (EE), nd nitrogen free extrct (NFE) for T1 nd T2 were significntly better (P < 0.05) thn for C. Economiclly, dietry feed T1 nd T2 incresed the net profit by Egyptin pounds /lmb nd EGP/lmb, respectively, s compred with the control diet. In ddition, the economic efficiency (verge feed cost/kg of body weight gin) ws for C nd T1 nd for T2. Totl costs were similr between the 3 dietry tretments. In conclusion, feeding growing Rhmni lmbs with 3.30 g of methionine/kg concentrte feed mixture improved their growth performnce nd rised their economic vlue. Key Words: Economics, growth, methionine, Rhmni lmbs. Introduction Feed dditives such s probiotics, chelted minerls, nd protected mino cids hve been introduced into the mrket over the pst yers to improve the nutrient vilbility, utiliztion, nd consequently, the generl performnce of ruminnt livestock. Interest in the use of probiotics s feed supplements for ruminnts hs prticulrly incresed in most recent yers. Methionine nd lysine re the most limiting mino cids for ruminnts becuse of their low concentrtions in feed proteins. Indeed, methionine is the most limiting mino cid for protein synthesis in growing lmbs (Storm nd Orskov, 1984; Nolte et l., 2004) nd steers Greenwood nd Titgemeyer, 2000). However, the biovilbility of methionine is limited due to its degrdtion in the rumen (Schwb et l., 2001). Supplementing ruminnt diets with ruminlly undegrdble proteins cn increse the flow of nitrogen nd mino cids to the smll intestine (Titgemeyer et l., 1989) nd result in improved growth nd efficiency of nitrogen utiliztion (Goedeken et l., 1990). However, feeding ruminlly undegrdble proteins cn decrese the efficiency of microbil protein synthesis nd flow of microbil mino cids to the smll intestine (Cecv et l., 1991) Compred with feeding more degrdble protein sources. Plnt proteins deficient in methionine (Schwb et l., 1986) nd ruminint nimls cnnot synthesize methionine nd, therefore, methionine must be supplied from the dietry degrdble protein nd microbil protein synthesis (Lpierre et l., 2009). The economic benefits of methionine feeding hve been poorly studied. However, the only economic study conducted so fr showed tht feeding methionine to growing lmbs increses the net profit by $6.017/lmb besides improving their growth performnce (Abdelrhmn nd Huniti, 2008). Due to indequte methionine in plnt proteins especilly in feeding of growing lmbs, we imed to test the supplementtion of methionine in the diet of Rhmni lmbs, nd study the effect of different dietry mounts of methionine on the growth performnce of lmbs. A detiled economic nlysis ws lso performed. Mterils And Methods Animls, diets, nd experimentl design Twenty-one mle Rhmni lmbs (31.67 ± 0.89 kg body weight; 7 months of ge) were included in growth performnce tril for 120 dys t the experimentl sttion of the Fculty of Agriculture, Dmnhour University, from December 2009 to April Lmbs were housed in pens with concrete floors. All lmbs were vccinted for common infectious diseses nd dewormed before the experiment strted.

2 The lmbs were rndomly divided into 3 groups, nd ech group ws ssigned to one of the following dietry tretments: control diet (C), control diet plus 3.30 g of methionine (free mino cid) /kg concentrte feed mixture (T1), or control diet plus 3.63 g methionine/kg concentrte feed mixture (T2). The composition of the concentrted feed mixture ws s follows: 17% undecorticted cottonseed mel, 8% soyben mel, 55% yellow corn, 17% whet brn, 1.5% limestone, 1.4% sodium chloride, 0.1% common slt. The essentil mino cid (methionine) nlysis ws done with Beckmn System 7300 mino cid nlyzer fter 22 h of cid hydrolysis (6 N HCI) t 110 o C (AOAC, 1995). The methionine content ws 520 mg/kg concentrted feed mixture. Lmbs in the growing tril were weighed in the morning before drinking or feeding t the beginning of the tril nd biweekly therefter. Concentrte feed mixtures were fed t the rte of 2.5% of body weight, while whet strw ws offered d lib. Concentrte feed mixtures were djusted to chnges in body weight every 2 weeks nd given twice dily t 9:00.m. nd 1:00 p.m. The offered nd refused mounts were weighed dily. Drinking wter ws vilble for nimls ll dy. Body weight chnges nd dily gin were recorded for ech niml. After the growth performnce tril, digestibility tril ws conducted on 3 nimls from ech group for 14 dys (preliminry period), followed by nother 6 dys (collection period).the nimls were fed individully ccording to the norml llownces of the experiment ssignment. During the collection period, feces were quntittively collected from ech niml. The nimls were fitted with bgs nd hrnesses for collecting feces. A plstic bg ws usully inserted into the continully ttched bg. Ech dy the plstic bg ws removed with its content of the dily feces nd weighed. A new plstic bg ws inserted. A representtive smple of feces (10%) ws tken dily nd deep freezed. Fecl collection durted for six consecutive dys fter which the dily smples belonging to the sme niml were pooled together, nd its moisture content ws estimted t 60 O C for 48 h. The dried feces smples from ech niml were mixed nd sved for chemicl nlysis. Smples (concentrte feed mixture, whet strw, nd feces) were milled through 1 mm sieve for chemicl nlysis. Dry mtter (DM) ws determined by drying the smples t 105oC for six hr nd sh by igniting the smples in muffle furnce t 600o C for 2 h. Orgnic mtter (OM), ether extrct (EE) nd crude fiber (CF) following the procedure of AOAC (2005). Nitrogen free extrct (NFE) ws clculted s (100 (CP + EE + CF + sh)). Nitrogen (N) content ws mesured by the kjeldhl method. Crude protein (CP) ws clculted s N (nitrogen) * All chemicl nlysis ws crried out in duplicte. Cell wll constituents of concentrte mixture nd whet strw were determined ccording to the method of (Vn Soest et l., 1991; AOAC, 2005).chemicl nlysis nd cell -wll constituents re presented in Tble (1) Economic evlution The costs clculted herein re totl vrible costs (TVC), which include the feed price nd feed dditive costs. Ech lmb ws quoted the sme price nd received the sme lbor, litter, veterinry cre (drugs, vccines, nd veterinry supervision), nd wter nd electrolytes. The building nd equipment deprecition vlue ws fixed for ll nimls. Hence, ll these prmeters were considered fixed costs (totl fixed costs [TFC]). The building nd equipment deprecition vlue ws clculted considering tht the building nd equipment were deprecited over 25 nd 5 yers, respectively. Furthermore, we pplied the stright-line deprecition method suggested by Snkhyn (1983) ccording to the following eqution: ([vlue of building or equipment /number of yers]/[number of cycles of the project per yer]/totl number of nimls). In ddition, totl costs (TC) were clculted s the sum of the TFC nd the TVC. The return items included the finl body weight vlue, the weight gin vlue, nd the fertilizer sle vlue. Totl return (TR) ws clculted by summtion of the sles of the lmbs nd fertilizer. Net profit (NP) ws clculted by finding the difference between the TR nd the TC. Collective nd prtil efficiency mesures were lso computed. Collective efficiency mesures included percentge of net profit to vrible nd totl costs, nd percentge of totl returns to vrible nd totl costs. Prtil efficiency mesures included percentge of feed costs reltive to totl, vrible costs, nd totl returns. Moreover, it included the percentge of totl veterinry mngement costs reltive to totl costs, nd the verge feed cost reltive to kg body weight gin. A correltion mtrix including the different production, return, nd cost prmeters ws generted to demonstrte the degree of correltion between the investigted vribles nd to determine the best vribles to introduce into the production nd cost functions. These correltions were clssified into the following groups: high positive correltion (>0.50), medium positive correltion ( ), low positive correltion (0 0.33), high negtive correltion (>-0.50), medium negtive correltion ( ), nd low negtive correltion (0-0.33). Production nd cost functions were used to ssess the effect of chnges in production, cost prmeters, nd returns in lmb production using the forwrd, bckwrd, enter, nd mixer methods of SPSS/PC+ (2001). Liner nd logrithmic production functions were computed. These production functions were intended to estimte the effects of feed dditives on the body weight of the lmbs. Liner nd logrithmic cost functions were ctegorized into the following 2 models: the first one considers the effect of body weight (independent vrible) on TC (dependent vrible); the second model considers the effect of TR (independent vrible) on TC (dependent vrible). 8

3 The best computed production nd cost functions exhibited the best cceptnce, both economiclly nd sttisticlly (ccording to the level of significnce, s determined by F-tests nd t-tests nd by the djusted coefficient of determintion R 2 ), nd the most ccurte lmb production results (El-Thwy, 2010). The djusted regression coefficient (R -2 ) ws used insted of the regression coefficient itself, becuse the number of independent vribles incresed such tht the vlue of the regression coefficient incresed nd lost its significnce. Sttisticl nlysis Sttisticl nlysis ws performed using The Sttisticl nlysis System (SAS, 2002). The differences in vlues were nlyzed by one-wy nlysis of vrince (ANOVA), followed by Duncn s multiple rnge tests. All results re expressed s the men ± stndrd error. P vlues of less thn 0.05 were considered sttisticl significnt. The sttisticl model ws represented by Y ij = μ + T i + E ij, where Y ij represents the dependent vrible; μ, the overll men; T i, the men effect of the tretment; nd E ij, the rndom residul vrition. Results And Discussion Growth nd digestibility tril The question of supplementing the methionine in the free form rther thn protected is due to supplementing ruminnt diets with ruminlly undegrdble proteins cn increse the flow of nitrogen nd mino cids to the smll intestine (Titgemeyer et l., 1989) nd result in improved growth nd efficiency of nitrogen utiliztion (Goedeken et l., 1990). However, feeding ruminlly undegrdble proteins cn decrese the efficiency of microbil protein synthesis nd flow of microbil mino cids to the smll intestine (Cecv et l., 1991) Compred with feeding more degrdble protein sources. Moreover, plnt proteins deficient in methionine (Schwb et l., 1986) nd ruminint nimls cnnot synthesize methionine nd, therefore, methionine must be supplied from the dietry degrdble protein nd microbil protein synthesis (Lpierre et l., 2009). The initil body weight, finl body weight, nd totl body weight gin of the lmbs subjected to the growth performnce experiment re listed in Tble 2. The verge initil body weights of lmbs on diets C, T1, nd T2 were kg, kg, nd kg, respectively. The finl body weight of T1-fed (53.71 kg) ws slightly higher (P > 0.05) thn tht of lmbs fed diets C (51.29 kg) nd T2 (52.43 kg). However, the totl body weight gin of T1-fed lmbs ws significntly higher thn tht of C-fed (21.86 kg versus kg; P < 0.05). This is concordnt with previously published dt (Abdelrhmn nd Huniti, 2008) showing tht methionine feeding t 4 g/lmb/dy significntly (P < 0.05) increses totl gin nd verge dily gin of growing Awssi lmbs. In the sme line, Mt et l. (2000) reported tht weight gin nd wool growth of wened Merino lmbs increses (P < 0.05) when lmbs re fed methionine t 2.5 g/dy. Lmbs fed diet T1 showed significntly higher body weight chnges ( g/lmb/dy; P < 0.05) thn C-fed lmbs ( g/lmb/dy) over the first 65 dys of the experiment (Tble 3). The sme trend ws observed during the period from dy 66 to dy 120 nd throughout the entire experiment. Averge dily feed intkes were 925 g, 959 g, nd 1009 g/lmb/d for groups C, T1, nd T2, respectively (Tble 4) from dy 0 to dy 65 of the growth tril. The verge dily feed intkes during the period from dy 66 to dy 120 nd throughout the entire experiment were similr mong the 3 groups. No significnt difference in feed conversion rtio ws found between diets C, T1, nd T2 throughout the entire period of the experiment. The results of feed intke for different dietry tretments re presented in Tble 5. The T2 diet significntly (P < 0.05) decresed dry mtter (DM) intke from concentrte or roughge compred to other control. This finding is consistent with work by Abdelrhmn nd Huniti (2008), who found tht 4 g of methionine/lmb/dy significntly decreses totl feed intke. On the other hnd, the percentge of concentrte or roughge ws unffected by feed diets contining methionine. Feeding of methionine t level of T1 nd T2 significntly (P < 0.05) incresed the coefficients of DM, orgnic mtter (OM), crude protein (CP), ether extrct, (EE), nd nitrogen free extrct (NFE). However, methionine feeding hd no significnt effect on crude fiber digestibility. In ddition, levels of methionine t T1 nd T2 significntly incresed the nutritive vlues expressed s totl digestible nutrient (TDN) nd digestible crude protein DCP, compred to the control. The increse in digestibility coefficients is good indictor of the promicrobil ctivity of methionine. Mrditi et l. (2008), Nolte nd Ferreir (2005), nd Adrin et l. (2009) hve ll suggested tht methionine stimultes rumen microorgnisms nd my even be used directly by them. i.e. micro-orgnisms required limiting mino cid especilly methionine to improve their ctivity in ruminl degrdtion of feed. Moreover, erlier work by Brkt nd Sddick (1988) stted tht the digestibility coefficients of DM, OM, CP, nd NFE nd nutritive vlues were improved when Ossimi lmbs were fed methionine t 3.30 g/kg of dry mtter feed mixture s compred to those fed methionine-free diet. Economic study In this study, the TFC ws EGP per lmb. This vlue included the price of equipment nd building deprecition (0.50 EGP nd EGP, respectively), wter nd electricity (2.00 EGP), lbor (48.00 EGP), nd veterinry mngement (3.00 EGP). As regrds the TVC (Tble 6), no significnt differences were found mong the 3 groups. Consequently, the TC of C, T1, nd T2 groups were not significntly different either (961.55, , nd 982 EGP/lmb/120 dys, respectively). 9

4 The TR vlues obtined in the form of fertilizer nd lmb sles re shown in Tble 7. Totl returns of lmbs fed diet T2 were significntly higher ( EGP; P < 0.05) thn those of lmbs fed diet C ( EGP) or T2 ( EGP). The net profits of the C nd T2 groups were significntly lower ( EGP nd EGP, respectively; P < 0.05) thn of those lmbs given diet T1 ( EGP). As presented in Tble 8, T1-fed lmbs hd significntly higher efficiency mesures (P < 0.05) thn the other groups. The percentge of net profit to TC ws 33.32% for T1, wheres the percentges for the C nd T2 groups were 31.14% nd 32.21%, respectively. The sme trend ws observed for the percentges of net profit to TVC, TR to TC, nd TR to TVC, i.e., T1 chieved significntly higher vlues thn C nd T2. Prtil efficiency mesures re presented in Tble 9. The percentges of feed costs to TC nd TVC between the groups were not significntly different (P > 0.05), the percentge of feed costs to TC for C, T1, nd T2 being 20.60%, 22.19%, nd 22.22%, respectively. The percentges of feed costs to TR were not significntly different either (P > 0.05), the percentge of feed costs to TR for C, T1, nd T2 being 15.71%, 16.64%, nd 16.95%, respectively. The percentge veterinry mngement costs to TC were 0.30% (T1) nd 0.31% (C nd T2). The verge feed cost reltive to totl gin rnged between nd nd ws not significntly different mong the groups. The correltions between body weight, weight gin, feed intke, FCR, TVC, TC, nd TR re shown in Tble 10. A medium positive correltion ws found between the initil weight nd weight gin (0.601). A high positive correltion ws demonstrted between weight gin nd TR (0.938). A low positive correltion ws found between weight gin nd feed intke (0.174). Medium positive correltions were found between weight gin nd both TVC (0.517) nd TC (0.433). However, weight gin ws negtively correlted with FCR (-0.989). Production function Effect of different rtes of methionine feeding on Rhmni lmb body weight Different mounts of methionine supplementtion hd significntly different effects (P < 0.05) on Rhmni lmb body weight. Nevertheless, pproximtely 26% of the overll chnges in body weight were ttributed to methionine supplementtion. From the eqution described below, we found tht incresing the mounts of methionine (3.30 g nd 3.36 g) by pproximtely 1% led to body weight increses of bout 0.10 nd 0.12%, respectively. Tble 1. Function Log (body weight) = log (3.30 g methionine) log (3.36 g methionine) T (35.89)* (42.17)* (34.73)* F (112.23)* R * Significnt t P < 0.05 Cost nd return functions Reltionship between body weight nd TC of supplemented methionine t different supplementtion rtes We found significnt effect (P < 0.05) between body weight nd TC when using diets C, T1, nd T2, with bout 15% of the chnges in TC ttributble to the chnge in body weight. Incresing the body weight by pproximtely 1% due to methionine supplementtion t different rtes (3.30 nd 3.36 g) led to incresed TC of bout 0.06% nd 0.09%, respectively. Tble 2. Function Log (body weight) = log (3.30 g methionine) log (3.36 g methionine) T (19.20)* (27.30)* (32.22)* F (100.89)* R Reltionship between TR nd TC in diets with different mounts of supplementry methionine A significnt reltionship (P < 0.05) ws observed between the TR nd TC vlues when using different mounts of methionine supplementtion (3.30 nd 3.36 g), with bout 18% of the chnges in TC ttributble to the chnge in the TR. An incresed in TR by bout 1% under the effects of supplemented methionine t different rtes (3.30 nd 3.36 g) led to TC increses of bout 0.13 nd 0.17%, respectively. Tble 3 Function Log (body weight) = log (3.30 g methionine) log (3.36 g methionine) T (26.88)* (16.08)* (21.15)* F (85.62)* R

5 Conclusion Supplementry feeding of methionine (3.30 g/kg concentrte feed mixture) ws significntly correlted with incresed body weight gin, nd it exerted positive effect on the overll performnce of Rhmni lmbs. Economiclly, it incresed the net profit. Moreover, the economic efficiency (verge feed cost/kg body weight gin) rnge ws significntly improved. Bsed on the bovementioned dvntges, we recommend the inclusion of methionine t 3.30 g of methionine/kg concentrte mixture in the dietry feed of growing Rhmni lmbs. Tble 1. Chemicl composition nd cell wll constituents of feed concentrte mixture nd whet strw Items Chemicl composition Feed concentrte mixture Whet strw DM OM CP CF EE NFE ASH Methionine (mg/kg) Cell wll constituents NDF ADF Hemi cellulose NFC * *NFC: Non fibrous crbohydrtes = % (CP+ NDF + EE + ASH) ccording to Clsmigli et l. (1995) DM: Dry mtter OM: Orgnic mtter CP: crude protein CF: crude fiber EE: Ether Extrct NFE: Nitrogen free extrct NDf: neutrl detergent fiber ACD: Acid detergent fiber s 1 (C) 2 (T1) 3 (T2) Tble 2.Effect of methionine feeding on the body weights of Rhmni wened lmbs Initil body weight (kg) Body weight t 65 dy (kg) Finl weight t 120 dys (kg) Totl gin of the entire period (120 dys) (kg) ± ± ± ± 0.52b ± ± ± ± ± ± ± ± 0.40b Dt re expressed s men ± stndrd error (SE). Mens within the sme column crrying the sme letters ( or b) re not significntly different (P > 0.05). 1: control group; group 2: supplemented with 3.30 g of methionine/kg concentrte feed mixture; group 3: supplemented with 3.63 g of methionine/kg concentrte feed mixture. Tble 3. Body weight chnges of Rhmni wened lmbs (g/lmb/dy) throughout the experiment Period dys (g) ± 0.004b ± ±0.009b dys (g) ± 0.008b ± ± 0.01b Entire period (0-120 dys) (g) ± 0.004c ± ± 0.003b Dt re expressed s men ± stndrd error (SE). Mens within the sme row crrying the sme letters ( or b) re not significntly different (P > 0.05). 1: control group; group 2: supplemented with 3.30 g of methionine/kg concentrte feed mixture; group 3: supplemented with 3.63 g of methionine/kg concentrte feed mixture. 11

6 Tble 4.Feed consumption (g/lmb/d) nd feed conversion throughout the experimentl period of the wened Rhmni lmbs Feed consumption Period (g/dy) Feed conversion dys (g) ± ± ± 6.01 ± 5.39 ± 5.88± 19.65b 20.79b dys (g) ± ± ± 7.07 ± 6.97 ± 7.09 ± Entire period ( ± ± 1120 ± 6.54 ± 6.13 ± 6.44 ± dys) (g) Dt re expressed s men ± stndrd error (SE). Mens within the sme row crrying the sme letters ( or b) re not significntly different (P > 0.05). Tble 5. Dry mtter intke nd pprent digestibility nd nutritive vlue of different experimentl tretments Items Dry mtter intke GROUP1 GROUP2 GROUP3 Concentrte ± ±39.23 b ± b Roughge ± ±9.17 b ± b Totl ± ±46.95 b ± b %Concentrte 81.93± ± ± 2.58 % Roughge Digestibility coefficients 18.06± ± ± 2.58 DM ±1.29 b ± ± 1.46 OM ±1.07 b ± ± 0.99 CP ±0.54 b ± ± 0.50 CF ± ± ± 1.41 EE ±1.31 b ± ± 0.93 NFE ± 0.73 b ± ± 0.63 Nutritive vlues TDN ± 0.46 b ± ± 0.40 DCP 9.25 ± 0.20 b ± ± 0.19 Mens within the sme row crrying different letters re significntly different (P<0.05) DCP: Digestible crude protein TDN: totl digestible nutrient Tble 6.Vrible nd totl costs (EGP/lmb/120 dys) throughout the experimentl period. Feed nd feed dditive costs Purchsed lmbs TVC TC ± 3.66b ± ± ± ± ± ± ± ± ± ± ± Mens within the sme column crrying different letters re significntly different (P<0.05) TC: Totl costs TVC: Totl vrible costs EGP: Egyptin pounds Tble 7.Totl returns prmeters (EGP/lmb/120 dys) throughout the experimentl period. Fertilizer sles Lmb sles TR NP ± ± 6.92c ± 6.85c ± 8.13b ± ± ± ± ± ± 7.23b ± 5.25b ± 6.88b Mens within the sme column crrying different letters re significntly different (P<0.05) TR: Totl returns NP: Net profit 12

7 1 2 3 Tble 8.Collective efficiency mesures. NP/Totl costs NP/Vrible costs Totl return/totl costs Totl return /vrible costs ± 0.25b ± 0.23b ± 0.26b ± 0.31b ± ± ± ± ± 0.21b ± 0.24b ± 0.29b ± 0.38b Mens within the sme column crrying different letters re significntly different (P<0.05) NP: Net profit Feed cost/totl costs Tble 9.Prtil efficiency mesures. Feed cost/vrible costs Feed returns cost/totl Veterinry mngement/totl costs Feed cost /totl gin ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± 0.32 Mens within the sme column crrying the sme letters re not significntly different (P>0.05) Tble 10.Correltion coefficients (r) between growth performnce nd economic prmeters of the Rhmni lmbs. Initil W.T Finl W.T W.G Feed consumption FC TVC TR Initil W.T Finl W.T * W.G * ** Feed consumption FC * ** ** TVC ** * * * * TR ** ** ** ** * TC ** ** * * * ** * **Correltion is significnt t the 0.01 level (2-tiled). *Correltion is significnt t the 0.05 level (2-tiled) W.G: weight gin FC: feed conversion TVC: totl vrible costs TR: totl returns TC: totl costs References Abdelrhmn M.M. nd Huniti D.A (2008). The effect of dietry yest nd protected methionine on performnce nd trce minerls sttus of growing Awssi lmbs. Lives. Sci. 115: Adrin F., Mendoz G., Pinos J.M., Plt F., Veg S. nd Brcen R. (2009). Effects of rumen-protected methionine on milk production of diry gots. Itl. J. Anim. Sci. 8: AOAC (1995). Officil method of nlysis. 15 th ed. Assocition of Officil Anlyticl Chemists, Arlington, Virgini, USA. AOAC (2005). Officil method of nlysis. 18 th ed. AOAC Int. Githersburg, MD. Brkt M.A. nd Sddick I.K. (1998). Effect of feeding methinonine-supplementted rtion to sheep: 1- Digestibility, nitrogen, nd sulfur blnces, body weight performnce nd wool chrcteristics. Minufiy. J. Agric.Res. 13 :(1). Clsmigli S., Stern M.D. nd Frinkins J.L. (1995). Effects of protein source on nitrogen metbolism in continuous culture nd intestinl digestion in vitro. J. Anim. Sci., 73: Cecv M.J., Merchen N.R., Berger L.L., Mckie R.I. nd Fhey G.C. (1991). Effects of dietry energy level nd protein source on nutrient digesion nd ruminl nitrogen metbolism in steers. J. Anim. Sci. 69:2230. El-Thwy A.S. (2010). The prevlence of selected diseses nd syndromes ffecting Brki sheep with specil emphsis on their economic impct. Smll. Rumin. Res. 90:

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