Effect of L-Carnitine and Amino Acids on Growth and Feed Utilization of Nile Tilapia, Oreochromis niloticus

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1 Glol Veterinri 7 (6): , 206 ISSN IDOSI Pulictions, 206 DOI: /idosi.gv Effect of L-Crnitine nd Amino Acids on Growth nd Feed Utiliztion of Nile Tilpi, Oreochromis niloticus 2 3 M.A. Soltn, Aml Elfeky nd I.M. Foud Deprtment of Animl production, Fculty of Agriculture, Benh University, Egypt 2 Deprtment of Animl production, Fculty of Agriculture, Suez Cnl University, Egypt 3 Centrl Lortory for Aquculture Reserch t Ass, Fish Technology, Egypt Astrct: This experiment imed to evlute the effect of dietry supplementtion of L-crnitine nd mino cids (methionine+lysine) for Nile tilpi (Oreochromis niloticus), the sl diet (300 g protein nd 9 MJ Gross energy kg dry mtter) ws formulted nd served s control (D). The sed diet ws supplemented with 300 mg L-crnitine (D2), 5g methionine+0g lysine (D3), 7g methionine+5g lysine (D4), 5g methionine+0g lysine+300 mg L-crnitine (D5), or 7g methionine+5g lysine+300 mg L-crnitine (D6). A totl numer of 300 pprent helthy Nile tilpi fry (.63±0.07g) were rndomly distriuted into 8 rectngulr quri (60 liter for ech) nd ech qurium holding 25 fry ws then rndomly ssigned to one of three replictes of six diets. Fish group fed D6 retined the highest significnt ody weight (BW), ody length (BL), weight gin (WG), specific growth rte (SGR) nd significntly (P<0.05) improved feed intke, feed conversion rtio (FCR) while protein efficiency rtio ws not significntly ffected. Also, fish group fed D6 gined the highest significnt (P<0.05) protein nd lowest insignificnt (P>0.05) dry mtter, ft nd sh while fish fed the control diet (D) relesed the lowest significnt protein nd the highest insignificnt ft content. All tretments significntly ltered protein content while dry mtter, ft nd sh content of fish flesh ws not significntly ffected. It is concluded tht, dietry supplementtion of O. niloticus with 7g methionine+5 g lysine+300 mg L-crnitine kg significntly improved growth nd feed utiliztion, increses tissue protein nd decrese tissue ft of Nile tilpi flesh. Key words: L-crnitine Oreochromis niloticus Growth performnce Feed utiliztion INTRODUCTION dimethylminoutyrte) is converted to crnitine. It ws lso shown tht lysine is converted to crnitine with 6-N- As the lrgest quculture industry of finfish in trimethyllysine s n intermedite [9]. The endogenous Egypt, the improvement of growth performnce for Nile formtion of crnitine in vertertes occurs primrily in tilpi (Oreochromis niloticus) is highly concerned y the the liver, s well s in the kidneys nd the rin, s feed compnies nd nutritionl scientists [-4]. Tilpi result of the occurrence of the required enzyme 4- culture hs ecome more populr ecuse of the reltive utyroetine hydroxylse. The process requires two ese of culture in vriety of quculture systems nd 2+ essentil mino cids (lysine nd methionine), iron (Fe ), ecuse of fvorle ttriutes s food fishes [5, 6]. vitmin C, vitmin B 6 nd nicin in the form of Tilpi hs ecome one of the most importnt fish species nicotinmide denine dinucleotide (NAD). One of the for fresh wter culture [7]. L-Crnitine is synthesized from erliest symptoms of vitmin C deficiency is ftigue, the essentil mino cids lysine nd methionine with the thought to e relted to decresed synthesis of L- ssistnce of vitmin C nd other secondry compounds crnitine [0]. produced in the ody [8]. As for crnitine iosynthesis, The growth-promoting effects of dietry L-crnitine it ws shown tht the methyl groups of crnitine come hve generlly een explined y incresing utiliztion from methionine (ut not from choline) nd tht g- of dietry energy resulting from incresed oxidtion utyroetine (ut not g-minoutyric cid or g- of ftty cids []. The improved energy production in Corresponding Author: M.A. Soltn, Deprtment of Animl Production, Fculty of Agriculture, Benh University, Egypt. Tel: , E-mil: mgdy.soltn@fgr.u.edu.eg. 487

2 Glol Veterinri, 7 (6): , 206 mitochondri through -oxidtion of ftty cids my e D5: sl diet supplemented with 5 g methionine+0 g suggest tht exogenous dministrtion of L-crnitine lysine+300 mg L-crnitine kg diet. could enhnce the performnce of fish y improving D6: sl diet supplemented with 7 g methionine+5 g energy utiliztion efficiency from lipid oxidtion [2]. The lysine+300 mg L-crnitine kg diet. ility of L-crnitine to increse growth rte nd reduce tissue lipid concentrtions hs een evluted in severl All dry ingredients of the fish mel, soyen mel, fish species with conflicting results. Dietry L-crnitine yellow corn, whet rn, scoric cid nd vitmin nd supplementtion showed improved growth performnces minerl mixture were lended for 5 min nd thoroughly nd feed utiliztion in red se rem, Pgrus mjor [3]; mixed with corn oil. The ingredients were mixed well nd common crp, Cyprinus crpio [4]; hyrid striped ss, mde into dry pellets using lortory pellet mill Morone sxtilis Morone chrysops [5], Nile tilpi [6]; (Cliforni Pellet Mill, Sn Frncisco, CA, USA). The elug, Huso huso [7]. It hs lso een found tht there pellets (-mm die) were dried for 4 h t 60 C nd stored t is n incresed tolernce of mmoni tht cnnot e -20 C until use. directly explined y the effect of L-crnitine [8]. It lso increses the rte of protein synthesis nd enhncing the Experimentl Fish nd Fcilities: Nile tilpi, genertion of metolic energy [9]. This could stimulte Oreochromis niloticus fry were otined from Ass some specific cell functions nd my influence severl htchery, Shrki Governorte, Egypt. Fingerlings were iochemicl nd physiologicl process, i.e., cell protection trnsferred in 50-liter plstic gs filled with wter nd ginst xenoiotics [2]. Also, supplementtion of dietry oxygen to Fish L. Prior to the eginning of the l-crnitine significntly improved survivl of Nile tilpi experiment, fish were cclimtized to the experimentl during overwintering [20]. conditions nd fed commercil diet (300 g protein kg ) The ojective of this experiment ws to evlute the twice dily to pprent stition y hnd for 5 dys. effects of dietry L-crnitine or its precursor After cclimtiztion, fry (.63±0.07g) were stocked into (methionine+lysine) or the comintion of L-crnitine nd eighteen glss quri (60 L). Three replicte quri its precursors on growth performnce, feed utiliztion nd were rndomly ssigned to ech tretment nd ech proximte composition of Nile tilpi, O. niloticus. qurium ws stocked with 25 fish. The glss quri were supplied with de-chlorinted tp wter nd were MATERIALS AND METHODS continuously supplied with compressed ir. Aout one-third of wter volume in ech qurium ws dily Experimentl Diets: This study ws crried out t Fish replced y new erted fresh wter fter clening nd Nutrition L, Fculty of Agriculture, Benh University, removing the ccumulted excret. A photoperiod of 2 h Egypt. The sl diet (300 g protein nd 9.5 MJ gross light, 2h drk (08.00 to h) ws used. Fluorescent energy kg dry mtter) ws formulted nd divided into ceiling lights hs supplied the illumintion. Fish were fed 6 prts (diets). L-crnitine nd mino cids (L-lysine their respective diets y hnd one of six experimentl diets sulphte nd methionine hydroxy nlog-c (MHA-C) for 84 dys. Fish were given the diets t dily rte 5% of were otined from Ar Compny For Phrmceuticl & totl iomss. The dily rtion ws divided into two equl Medicl Plnts - MEPACO Egypt, L-lysine sulphte nd mounts nd offered two times dy (9:30 nd 4.00). All MHA-C with mrkedly lower wter soluility thn their fish in ech qurium were weighed iweekly nd the trditionl products were selected, which in some extent mount of dily llownce feed ws djusted ccordingly. diminished the influence of mino cid leching on fish Wter temperture, dissolved oxygen, ph nd totl growth nd chieved significnt difference in results [2]. mmoni were monitored during the study, to mintin L-crnitine nd mino cids were supplemented to the wter qulity t optiml rnge for common crp. Wter sl diets s follows: temperture ws recorded dily t 3.00 using mercuric thermometer suspended t 30 cm depth. Dissolved oxygen D: sl diet (kept s control group). (DO) ws mesured dily t using YSI model 56 D2: sl diet supplemented with 300 mg L-crnitine kg oxygen meter (YSI Compny, Yellow Springs Instrument, diet. Yellow Springs, Ohio, USA) nd ph ws recorded dily t D3: sl diet incorported with 5 g methionine+0 g h using ph meter (Orion ph meter, Ailene, Texs, lysine kg diet. USA). Totl mmoni ws mesured two times week D4: sl diet supplemented with 7 g methionine+5 g ccording to APHA [22]. During the period of the feeding lysine kg diet. tril, the wter-qulity prmeters were verged (±SD): 488

3 Glol Veterinri, 7 (6): , 206 Tle : Formultion nd proximte composition of the experiment diets Experimentl diets Ingredients D D2 D3 D4 D5 D6 Fish mel Soyen mel Yellow corn Whet rn Corn oil Vitmin &Minerls Ascoric cid L-crnitine (g kg-) lysine methionine Proximte nlysis (% Dry mtter sis) Dry mtter Crude protein Ether extrct Ash Totl crohydrte Gross energy (Mj kg ) Vitmin nd minerl mixture kg of mixture contins: 4800 I.U. Vit A, 2400 IU choleclciferol (vit. D), 40 g Vit E, 8 g Vit K, 4.0 g Vit B 2, 4.0 g Vit B2, 6 g Vit B6, 4.0 g Pntothenic cid, 8.0 g Nicotinic cid, 400 mg Folic cid, 20 mg Biotin, 200 gm Choline, 4 g Copper, 0.4 g Iodine, 2 g Iron, 22 g Mngnese, 22 g Zinc, 0.04 g Selenium. folic cid,.2 mg; nicin, 2 mg; d-clcium pntothente, 26 mg; pyridoxine. HCl, 6 mg; rioflvin, 7.2 mg; thimin. HCl,.2 mg; sodium chloride (NCl, 39% N, 6% Cl), 3077 mg; ferrous sulfte (FeSO 4.7H2O, 20% Fe), 65mg; mngnese sulfte (MnSO 4, 36% Mn), 89 mg; zinc sulfte (ZnSO 4.7H2O, 40% Zn), 50 mg; copper sulfte (CuSO 4.5H2O, 25% Cu), 28 mg; potssium iodide (KI, 24% K, 76% I), 2 Totl crohydrte =00-(CP + EE+ Ash). 3 Gross energy clculted using gross clorific vlues of , nd 0.75 MJ/g for protein, ft nd crohydrte, respectively ccording to Brett [28]. Wter temperture ws 28.23±0.7 C: dissolved oxygen, nlysis. Dry mtter ws determined fter drying the 6.3±0.5 mg/l: ph 8.35±0.2 nd totl mmoni, 0.7±0.0 smples in n oven (05 C) for 24 h. Ash y incinertion mg/l. All tested wter qulity criteri were suitle nd t 550 C for 2 h. Crude protein ws determined y microwithin the cceptle limits for rering O. niloticus [23]. Kjeldhl method, N 6.25 (using Kjeltech uto nlyzer, Model 030, Tector, Högnäs, Sweden) nd crude ft y Growth Indices: Records of ll fish ody weight length Soxhlet extrction with diethyl ether (40 60 C). Crude fier individully mesured for ech qurium t the initition content of diets ws determined using the method of Vn nd the termintion of the feeding tril. Weight gin (WG), Soest et l., [25]. Nitrogen-free extrct ws computed y specific growth rte (SGR), feed conversion rtio (FCR) tking the sum of vlues for crude protein, crude lipid, nd protein efficiency rtio (PER) were clculted using crude fier nd sh then sutrcting this sum from 00. the following equtions: Sttisticl Anlysis: Sttisticl nlysis of the otined WG (g/fish)=fbw IBW; SGR% = [lnfbw - ln IBW]/t 00, dt ws nlyzed ccording to SAS [26]. Differences where FBW is finl ody weight (g); IBW is initil ody etween mens were tested for significnce ccording to weight (g); ln= nturl logrithmic; t=time in dys. FCR=FI Duncn's multiple rng test s descried y Duncn [27]. /WG, where FI is feed intke (g); PER=WG/protein intke (g). RESULTS Proximte Anlysis of Fish nd Experimentl Diets: At the experiment termintion, five fish were rndomly smpled from ech qurium nd exposed to the proximte nlysis of whole fish ody ccording to the methods of AOAC [24]. Fish nd diet smples were oven-dried 05 C for 24 h, ground nd stored t -20 C for susequent Biologicl Performnce of Fish: The growth performnce of Nile tilpi fed the experimentl diets were presented in Tle 2. The finl men weight, finl length, WG nd SGR of the fish fed diet with supplementl L-crnitine or methionine+lysine were significntly higher in comprison with the reference group. Averge initil ody 489

4 Glol Veterinri, 7 (6): , 206 Tle 2: Growth indices of O. niloticus fed diets supplemented with L-crnitine nd mino cids BW (g) BL(cm) Diets Initil Finl Initil Finl WG (g/fish) SGR(%) D.63 c c D c D c D D D Stndrd error Mens followed y the different letters in ech column re significntly (P<0.05) different. Tle 3: Feed Intke (FI) Feed conversion rtio (FCR) nd protein efficiency rtio (PER) of O. niloticus fed diets supplemented with L-crnitine nd mino cids Diets FI FCR PER D 47.5 d D c D c.62.7 D D D Stndrd error Mens followed y the different letters in ech column re significntly (P<0.05) different Tle 4: Proximte nlysis of O. niloticus fed diets supplemented with L-crnitine nd mino cids Diets Dry mtter % Protein % Ft % Ash % D D D D D D Stndrd error Mens with the sme letters in ech column re not significntly different weight (IBW) nd initil ody length (IBL) of Nile tilpi Feed intke (FI) for the different fish groups rnged O. niloticus rnged from.60 to.66 g for BW nd 4.40 to from 47.5 to 5.5 g nd lie in two clusters. The first one 4.49 cm for BL nd the differences mong fish groups for included D, D2, D3 nd D4 nd the second cluster IBW nd IBL were insignificnt (Tle 2). After 84 dys included D5 nd D6. The differences mong the two from the experiment strt, BW rnged etween 9.28 nd clusters ws significnt (Tle 3) while the differences nd BL rnged etween 0.24 to.54 cm. Weight mong mens within ech cluster were insignificnt. gin (WG) vlues rnged from 8.05 g to g/fish nd Compred to control group ll tretments significntly specific growth rte rnged etween 2.76 nd 3.2% dy (P<0.05) improved feed conversion rtio (FCR) nd fish nd the differences in BW, BL, WG nd SGR mong the group fed D6 showed the est FCR. The otined results different tretments were significnt (P<0.05). Compred (Tle 3) lso showed tht L-crnitine or its precursor did to control group (D), ll tretments showed significnt not significntly ltered PER. improvement of growth indices nd fish group fed D6(7 g methionine+5 g lysine+300 mg L-crnitine kg Proximte Composition of Fish: Dry mtter, protein, ft dry mtter) resulted the highest BW (27.94 g), BL (.54 nd sh content of whole ody rnged etween 3.0- cm), WG (26.28 g/fish) nd SGR 3.2%) while fish group for dry mtter, for protein, % fed the control diet (D) showed the significnt (P<0.05) for ft nd % for sh (Tle 4). The otined lowest BW (9.28 g), BL (0.24 cm), WG (9.28 g) nd SGR results showed tht, the comintion of L-crnitine nd (2.76%). mino cids (methionine+lysine) in low or high levels 490

5 Glol Veterinri, 7 (6): , 206 (D5 nd D6) relesed the highest significnt protein The otined results re in greement with the content of whole ody while dry mtter, ft nd sh finding of Soltn et l. [40] who found tht, L-crnitine content did not significntly ffected y dietry L- levels 300 to 500 mg/kg diet incresed feed intke nd crnitine or mino cids (methionine+lysine). improved FCR ut hd no significnt effect on PER of O. niloticus. Similrly, severl reserchers hve DISCUSSION speculted tht incresing growth rtes of fish fed supplementl L-crnitine my due to its role in Biologicl Performnce of Fish: Dietry supplementtion improving FCR vi incresing ftty cid oxidtion nd of L-crnitine or its precursors (methionine+lysine) in incresing utiliztion of dietry energy s oserved y low or high levels significntly improved growth indices Az et l. [6], Hmckov et l. [4] in common crp, (BW, BL, WG nd SGR) specilly fish group fed D6 Ozorio et l. [36] in ctfish, Schuhmcher nd Gropp [30] indicting tht the dietry methionine nd lysine used in in trout nd finlly [2] in red se rem. In this respect, vivo to synthenyze L-crnitine, therefore, the dietry nd Ozorio et l. [42] with Africn ctfish suggest tht dietry synthenized L-crnitine in fish group fed D6 significntly L-crnitine supplementtion my increse ftty cid incresed growth indices of O. niloticus in comprison to oxidtion nd possily decrese mino cid consumption the other diets. A growth-promoting effect of for energy. supplementl dietry L-crnitine hs een reported in ll L-crnitine sources or levels. Such dvnces were lso Proximte Anlysis of Fish: Our results show tht, ll oserved i y [2, 29, 30] whom reported tht tretments hd no significnt effect on dry mtter, ft supplementing growing Nile tilpi diets with oth nd sh content of whole fish odies. On the other hnd, methionine nd lysine to rech 30% over the L-crnitine (D2) or its precursor (methionine+lysine) in recommended levels significntly improved finl weights, low (D3) or high (D4) levels did not significntly lter weight gin protein. On the other hnd, Chtzifotis et l. protein content while the comintions of L-crnitine nd [3] found tht crnitine supplementtion t level of 2 g methionine+lysine in low (D5) or high (D6) levels kg diet incresed red se rem growth fed 4 g lysine significntly (P<0.05) incresed protein content of whole kg diet ut did not cuse ny effect on growth in fish fish ody. Yng et l. [2] demonstrted tht whole ody fed the diet contining 0 g lysine kg diet. Severl moisture nd muscle protein of grss crp were studies reported tht L-crnitine could induce n significntly incresed, while lipid level of whole ody improved growth performnce, proly cused y ws significntly decresed (P<0.05) with the incresed lipid oxidtion in severl mrine nd freshwter supplementtion of lysine nd methionine. species [-3, 6, 7, 3, 32]. In contrst, dietry crnitine The ility of L-crnitine to increse protein nd did not ffect growth of chnnel ctfish [33], rinow reduce tissue lipid content hs een illustrted in severl trout [34], Atlntic slmon [35], Africn ctfish [36], fish species with conflicting results. Az et l. [6] Europen sess, Dicentrrchus lrx [37], or tilpi reveled tht, L-crnitine in concentrtion of 600 or 900 [38]. mg kg diet t 5% dietry lipid increse tissue protein The otined results showed tht dietry nd did not lter ft content of Nile tilpi, O. niloticus. supplementtion of methionine nd lysine hve the sme On the other hnd, ft content of severl tissues, such s effect of dietry L-crnitine on improving feed utiliztion liver, muscle nd viscer, were reduced s the L-crnitine of O. niloticus nd this effect ws clerly noticed when supplemented to the diets of chnnel ctfish [33], tilpi dietry L-crnitine comined with dietry mino cids [3], Atlntic slmon [35], rohu [43], juvenile lck se (methionine+lysine). The results of the present study rem [32] nd elug, Huso huso [7]. In contrst, the showed tht the importnt role of L-crnitine on metolic sence of lipotropic ction of crnitine feeding hd rte is derived oth from endogenous synthesis nd diet een previously reported in red serem, rinow trout, s crnitine is synthesized from lysine nd methionine hyrid tilpi, hyrid striped ss nd Europen sess, [39]. Yng et l. [2] demonstrted tht, protein retention Dicentrrchus lrx [5, 37]. Whether such vriility (PR) of grss crp, Ctenophryngodon idell fed diet in terms of the ody lipid lowering effect of supplementl with supplementl lysine nd methionine were L-crnitine is ssocited with dietry lipid level (nd significntly higher, while the feed conversion rtio (FCR) indirectly to the energy density of the diet) remins were significntly lower in comprison with the reference uncler. Wheres Rodehutscord [34] reported tht group. supplementl dietry L-crnitine ws ineffective for 49

6 Glol Veterinri, 7 (6): , 206 reducing ody ft in rinow trout fed high-ft diets 7. Yi, Y., Lin, C.K. nd J.S. Din, 996. Influence of (26%), Ji et l. [35], in Atlntic slmon fed 0% lipid diet, Nile tilpi (Oreochromis niloticus) stocking found tht crnitine-fed fish exhiited decrese in the density in cges on their growth nd yield in conges lipid content in white muscle nd viscer y s much s nd in ponds contining the cges. Aquculture, 73 nd 43%, respectively. L-Crnitine plys n importnt 46: role in promoting the trnsport of long-chin ftty cids 8. Hrpz, S., L-Crnitine nd its ttriuted cross the inner mitochondril memrne, resulting in functions in fish culture nd nutrition- review. extr energy from -oxidtion. Therefore, dietry L- Aquculture, 249: 3-2. crnitine supplements should enhnce the oxidtion of 9. Bremer, J., 983. Crnitine-metolism nd functions. these ftty cids, therey decresing their vilility or Physiol. Rev., 63: esterifiction to tricylglycerols nd deposition in the 0. Lohninger, A., E. Kiser, E. Legenstein nd H. vrious lipid storge tissues [37]. Stniek, 987. Crnitine, metolism nd function. In: Kiser, E., Lohninger, A. (Eds.), Crnitine. Its Role REFERENCES in Lung nd Hert Disorders. Krger Press, Bsel, pp: Hssn, M.S. nd M.A. Soltn, 206. Evlution of. Becker, K., S. Scheier, C. Angoni nd R. Blum, 999. Essentil Oil of Fennel nd Grlic Seprtely or Growth performnce nd feed utiliztion responded Comined with Bcillus licheniformis on the Growth, of Oreochromis niloticus O. ureus hyrids to L- Feeding Behviour, Hemto-iochemicl Indices of crnitine mesured over full fttening cycle under Oreochromis niloticus (L.) Fry. Journl of commercil conditions. Aquculture, 74: Aquculture, Reserch & Development, 7: Chtzifotis, S., T. Tkeuchi nd T. Seiki, 995. The effect of dietry L-crnitine on growth performnce 2. Hssn, M.S., M.A. Soltn nd M.M.R. Ghonemy, nd lipid composition in red se rem fingerlings Effect of syniotics etween Bcillus Fish. Sci., 6: licheniformis nd yest extrct on growth, 3. Chtzifotis, S., T. Tkeuchi nd T. Seiki, 996. The hemtologicl nd iochemicl indices of the Nile effect of dietry crnitine supplementtion on growth tilpi Oreochromis niloticus. The Egyptin Journl of red se rem (Pgrus mjor) fingerlings t low of Aqutic Reserch, 40: levels of dietry lysine. Aquculture, 47: Hssn, M.S., M.A. Wf, M.A. Soltn, A.S. God 4. Focken, U., K. Becker nd P. Lwrence, 997. A note nd N.M.A. Mogheeth, 204. Effect of Dietry on the effect of L-crnitine on the energy metolism Orgnic Slts on Growth, Nutrient Digestiility, of individully rered crp, Cyprinus crpio L. Minerl Asorption nd Some Biochemicl Indices of Aquculture Nutrition, 3: Nile Tilpi; Oreochromis niloticus L. Fingerlings. 5. Twiell, R.G. nd P.B. Brown, Effect of dietry World Applied Science Journl, 29(): crnitine on growth rtes nd ody composition of 4. Soltn, M.A. nd S.M.M. El-Lithy, Effect of hyrid striped ss (Morone sxtilis mle proiotics nd some spices s feed dditives on the M.Chrysops femle). Aquculture, 87: performnce nd ehviour of the Nile tilpi, 6. Az, M.E., S.I. Fthll nd M.A. Soltn, Oreochromis niloticus. Egypt. J. Aqut. Biol. & Effect of feed supplementtion with L-crnitine on Fish., 2(2): growth performnce nd ody composition of Nile 5. Adel-Hkim, N.F., M.S. Hussein, M.N. Bkeer nd tilpi (Oreochromis niloticus). Suez Cnl Vet. Med. M.A. Soltn, 200. Effect of protein level nd J., 5(): stocking density on growth performnce of Nile 7. Mohseni, M. nd R.O.A. Ozorio, 204. Effects of tilpi (Oreochromis niloticus) cultured in tnks. dietry L-crnitine level on growth nd ody Egyptin J. Nutrition nd Feeds, 4: composition nd ntioxidnt sttus in in elug 6. Irhim, M.K., Ftm, A. Hfez nd M.A. Soltn, (Huso huso L. 758). A quculture Nutrition, Effect of orgnic fertiliztion, supplementry 20: feeding nd stocking rte on growth performnce of 8. Tremly, G.C. nd T.M. Brdley, 992. L-crnitine Nile tilpi nd silver crp. Egypt. J. Agric., Res., protect fish ginst cute mmoni toxicity. Comp. 78(4): Biochem. Physiol., 0C:

7 Glol Veterinri, 7 (6): , Sntulli. A., E. Pucci nd V. D Amelio, M, J.J., Z.R. Xu, Q.J. Sho, J.Z. Xu, S.S.O. Hung, Preliminry study on the effect of short-term crnitine W.L. Hu nd L.Y. Zhuo, Effect of dietry tretment on nucleic cid nd protein metolism in supplementl L-crnitine on growth performnce, se ss (Dicentrchus lrx) fry. Aquculture, ody composition nd ntioxidnt sttus in juvenile 87: lck se rem, Sprus mcrocephlus. 20. Soltn, M.A., M.M. Adell, G.A. El- Syd nd Aquculture Nutrition, 4: M.H. Au-El Wf, 205. Effect of some over- 33. Burtle, G.J. nd O.H. Liu, 994. Dietry crnitine nd wintering regimes on survivl nd growth lysine ffect on chnnel ctfish lipid nd protein performnce of Nile tilpi Oreochromis niloticus. composition. Journl of the world Aquculture Biologicl nd Chemicl Reserch, 2: Society, 25(2): Yng, H.J., Y.J. Liu, L.X. Tin, G.Y. Ling nd 34. Rodehutscord, M., 995. Effects of supplementl H.R.L. Provincil, 200. Effects of Supplementl dietry L-crnitine on the growth nd ody Lysine nd Methionine on Growth Performnce nd composition of rinow trout (Oncorhynckus Body Composition for Grss Crp mykiss) fed high-ft diets. J. Anim. Physiol. Anim. (Ctenophryngodon idell). Americn Journl of Nutr., 73: Agriculturl nd Biologicl Sciences, 5(2): Ji, H., T.M. Brdiley nd G.C. Tremly, APHA, 992. Stndrd Methods for the Exmintion Atlntic slmon (Slmo slr) fed L-crnitine exhiit th of Wter nd Wste Wters, 8 ed. Americn Pulic ltered intermediry metolism nd reduced tissue Helth Assocition, Wshington, DC, pp: 268. lipid, ut no chnge in growth rte. J. Nutr., 23. Boyd, C.E., 990. Wter Qulity in Ponds for 26: Aquculture. Auurn University Agriculture 36. Ozorio, R.A., T.B. Vn-Erkeren, E.A. Huismn nd Experimentl Sttion, Auurn, Alm, USA. J.J. Verreth, 200. Effect of dietry crnitine nd 24. AOAC, 995. In: Cunni, P.A. (Ed.), Officil Methods protein energy: non protein energy rtios on growth, of Anlysis of the Assocition Officil Anlyticl mmoni excertion nd respirtory qutient in Chemists, vol., 6th ed. AOAC Interntionl, Africn crfish, Clris griepinus (Burche LL) Arlington, USA, pp: 298. Juveniles. Aquculture Reserch, 32: Vn Soest, P.J., J.B. Roertson nd B.A. Lewis, Dis, J., J. Arzel, G. Corrze nd J. Kushik, 200. Methods for Dietry Fier, Neutrl Detergent Fier Effect of dietry L-crnitine supplementtion on nd Nonstrch Polyscchrides in Reltion to Animl growth nd lipid metolism in Europen sess Nutrition. J. Diry Sci., 74: (Dicentrrchus lrx). Aquculture Reserch, 26. SAS, 996. SAS Procedure Guide version 6.2 Ed. 32: SAS Institute Inc., Cry, NC, USA. 38. Schlechtriem, C., V. Bresler, L. Fishelson, M. 27. Duncn, D.B., 955. Multiple rnge nd Multiple test. Rosenfeld nd K. Becker, Protective effects of Biometerics, : -42. dietry L-Crnitine on tilpi hyrids (Oreochromis 28. Brett, J.R., 973. Energy expenditure of Sockeye niloticus Oreochromis ureus) rered under slmon Oncorhynchus nerk during sustined intensive pond-culture conditions. Aquculture performnce. J. Fish. Res. Bord Cn., 30: Nutrition, 0: Adel-Hkim, N.F., K.H. El-Kholy, A.A. Az nd 39. Tnphichitr, V., D.W. Horne nd H. Broquist, 97. A.A. Adel-Writh, Effect of dietry high Lysine precursor of crnitine in the rt. J. Biol. lysine nd methionine levels on growth performnce Chem., 246: of Nile Tilpi (O. niloticus) fed on diet t different 40. Soltn, M.A., H.M. Agouz, A.I. El-Syed nd A.A. Elfrequencies. Egyptin J. Nutrition nd Feeds., Qotti, 206. Effect of feed supplementtion with 9(): L-crnitine on growth nd cold tolernce of Nile 30. Schuhmcher, A. nd J.P. Gropp, 998. Crnitine tilpi, Oreochromis niloticus. Egypt. J. Aqut., vitmin for rinow trout. Journl of Applied Biol., & Fish. (In press). Ichthyology, 4: -2, Hmckov, J., P. Kozk, J. Kouril nd Z. Admek, 3. Jyprks, V., C. Smhu nd S.S. Kumr, The effect of L-crnitine supplementtion into Effect of dietry L-crnitine on growth nd feed mixtures upon production nd over wintering reproductive performnce of mle Oreochromis results in common crp (Cyprinus cprio) culture. mossmicus (peters). Fish. Techonol., 33: Krmiv. 998, 40: 4, 75-8; 9 ref. 493

8 Glol Veterinri, 7 (6): , Ozorio, R.A., G.R. Booms, E.A. Huismn nd J.J. 43. Keshvnth, P. nd P. Renuk, 998. Effect of Verreth, Chnges in mino cid composition in dietry L-crnitine supplements on growth nd ody the tissues of Africn ctfish (Clris griepinus), composition of fingerlings rohu, leeo rohit s consequence of dietry L-crnitine supplements. (Hmiltoin). Aquculture Nutrition, 4: J. Appl. Ichthyol; Z-Angew-Ichthyol, 8: