Lipid Composition of Egg Yolk and Serum in Laying Hens Fed Diets Containing Black Cumin (Nigella sativa)

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1 Interntionl Journl of Poultry Siene 5 (6): , 2006 ISSN Asin Network for Sientifi Informtion, 2006 Lipid Composition of Egg Yolk nd Serum in Lying Hens Fed Diets Contining Blk Cumin (Nigell stiv), 2 Niel M. El Bgir*, Aziz Y. Hm, Rni M. Hmed, Ahmed G. Ad El Rhim nd Anton C. Beynen Deprtment of Biohemistry, Fulty of Veterinry Mediine, University of Khrtoum, Khrtoum North, Sudn 2 Deprtment of Nutrition, Fulty of Veterinry Mediine, Utreht University, Utreht, The Netherlnds Astrt: Lying hens were fed diets without or with 0 or 30 g of the whole seed of lk umin (Nigell stiv)/kg. The onentrtions of totl lipids, totl holesterol, phospholipids nd triylglyerols in serum nd egg yolk were mesured. Feeding of the diets with nd 3% lk umin seeds for period of three months redued egg yolk totl holesterol y 34 nd 42%, respetively. Serum holesterol onentrtions verged for the whole feeding period were lowered y 5 nd 23% fter feeding the diets with nd 3% lk umin seeds, respetively. Blk umin seeds in the diet of lying hens lso used lowering of serum nd egg-yolk onentrtions of triylglyerols nd phospholipids. Inlusion of lk umin seeds in the diet used signifint redution in egg prodution, without ny effet on egg width nd length, while there ws signifint inrese in hen s ody weight. The inrese in ody weight in the hens fed lk umin seeds is explined y the ingested feed energy not used for egg prodution. It is onluded tht lk umin seeds nd/or the tive priniple re of interest s potentil egg-yolk holesterol-lowering gents. Key words: Lying hens, lipids, egg yolk, serum holesterol Introdution Egg lipids re onfined to the yolk nd ount for out 30% of the fresh weight of yolk nd for 60% of the yolk dry mtter (Lesknish nd Nole, 997). The ftty id omposition of egg lipids in lying hens n e influened preditly y the ftty id omposition of the diet (Bvelr nd Beynen, 2004; Beynen, 2005). In ontrst, ttempts to mnipulte the totl mount of ft or the holesterol ontent of eggs through diet hnge hve een only mrginlly suessful (Sott nd Leo, 993; Vn Elswyk et l., 992; Frrn et l., 995, Stewrt, 998). In review of the literture, Stewrt (988) stted tht reeding seletion my redue egg yolk holesterol y up to 5% nd tht the possile rnge of redution y diet hnge nd drugs is in the order of 5-0%. In lter work, the feeding of syntheti HMG-CoA redutse inhiitor to lying hens hs een demonstrted to lower egg-yolk holesterol ontent y Mterils nd Methods up to 30% (Elkin et l., 993). High levels of serum Sixty-three single-om White Leghorn hens ged 68 holesterol in mn re ssoited with inresed risk of weeks were used. They were kept in rised wire ges oronry hert disese. It is lso known tht the intke (30 x 46 m). There were three irds per ge. The of egg holesterol ontriutes to n elevtion of the level ges were pled in n open-sided house. Additionl of serum holesterol (Beynen nd Ktn, 989). Thus, it lighting ws provided to otin photoperiod of out 6 is onsidered relevnt to find wys to produe eggs low hours light nd 8 hours drk. The irds were llotted to in holesterol (Stewrt, 988). one of three dietry tretments for period of three The liver of the lyer hen produes most of the lipids months. Tle shows the ingredient omposition of found in egg yolk, the lipids eing trnsported to the the ontrol diet, whih lso hd served s preovry y serum lipoproteins (Elkin, 997). Thus, experimentl feed. The experimentl diets were derese in serum lipid onentrtions might led to otined y mixing the ontrol diet with intt lk derese in egg-yolk lipids. The oil omponent of lk umin seeds in either 99: or 97:3 (w/w) rtio. The 574 umin (Nigell stiv) seeds, when dministered orlly to rts, hs een shown to lower serum holesterol nd triylglyerol onentrtions (El-Dkhkhny et l., 2000). The feeding of powdered lk umin seeds to lying hens hs een shown to lower serum holesterol nd triylglyerol onentrtions, whih indeed ws ssoited with derese in egg yolk holesterol ontents (Akhtr et l., 2003). As fr s we know, the pulition of Akhtr et l. (2003) provides the only informtion in the literture on the effet of lk umin seeds on serum nd egg-yolk lipids in lying hens. This prompted us to perform the present study on the effet of feeding diets either without or with full lk umin seeds on the onentrtions totl lipids, holesterol, triylglyerols nd phospholipids in serum nd egg yolk otined from lying hens.

2 El Bgir et l.: Lipid Composition of Egg Yolk nd Serum in Lying Hens Fed Diets Contining Blk Cumin Tle : Ingredient omposition of the ontrol diet Ingredient Sorghum (g/kg) 50 Groundnut onentrte (g/kg) 240 Whet rn (g/kg) 05 Oyster shell (g/kg) 90 Sodium hloride (g/kg) 5 Conentrte (g/kg) 50 Composition: rude protein, 560 g/kg; rude ft, 80 g/kg; rude fire, 30 g/kg; sh, 60 g/kg. Tle 2: Clulted omposition of the ontrol diet without lk umin nd tht of the experimentl diets Blk umin (g/kg diet) Mronutrient Dry mtter (g/kg) Crude protein (g/kg) Crude ft (g/kg) Crude fier (g/kg) Ash (g/kg) The omposition of the diets ontining dded lk umin ws lulted using the ingredient omposition of the ontrol diet nd the reported omposition of lk umin seeds. The omposition of the seeds is s follows (g/kg): dry mtter, 945; rude protein, 23; rude ft, 355; rude fier, 55; sh, 38 (Byn et l., 978). seeds were ought on lol mrket nd their viility ws onfirmed. The diets were provided on restrited sis, eh ge eing supplied with 300 g/dy, i.e. on verge 00 g/ird/dy. Wter ws provided d liitum. Eggs were olleted eh dy t 5.00 hours during the entire experimentl period. For hemil nlysis, 0 eggs were rndomly seleted per tretment group t the eginning nd t the end of the experiment. Blood smples were tken every two weeks, the first smples eing olleted t two weeks fter the eginning of the experiment. On the dys of smpling, 0 hikens per tretment group were rndomly seleted nd led from the wing vein. The lood ws llowed to lot t room temperture for one hour nd ws then entrifuged t 2700xg for 5 minutes fter whih the serum ws olleted. Totl lipids in egg yolk nd serum were determined ording to Frings et l. (972). Totl holesterol ws mesured y the method of Kim nd Golderg (969). The weight of holesterol ws tken to e 387 g/mol. Phospholipids were determined s desried y Connerty et l. (96). To lulte the molr onentrtion of phospholipids in serum, the weight ws ssumed to e 775 g/mol. Triylglyerols were nlyzed with the use of test omintion (Biosystem Regents nd Instruments, Brelon, Spin) sed on the enzymti method desried y Fossti nd Prenips (982). The weight of triylglyerols ws tken to e 850 g/mol. Egg length nd width were mesured with liper. For sttistil evlution, the dt were nlyzed y the Generl Liner Models (GLM) proedure using softwre of the SAS Institute In. (982). P < 0.05 ws pre-set riterion of sttistil signifine. Results Tle 2 shows the mronutrient omposition of the diets. The ddition of lk umin to the diet hd no mjor impt on dietry omposition exept tht the highest inlusion level mrkedly rised the ft ontent. Finl ody weights of the hens fed lk umin were out 0% higher thn those of their ounterprts fed the ontrol diet (Tle 3). The feeding of lk umin seeds used dose-dependent drop of egg prodution (Tle 4). The length nd width of the eggs were not ffeted y lk umin (Tle 4). The time ourses of the onentrtions of the vrious serum lipids were irregulr, ut the generl piture ws tht dietry lk umin seeds produed derese in serum lipids. To enhne lrity, the men vlues for eh time point per tretment group were verged. Tle 5 shows tht inlusion of lk umin seeds in the diet used derese in ll lipid lsses, the derese eing dose-dependent for holesterol nd phospholipids. The dietry onentrtion of 3% lk umin lowered serum holesterol y on verge 23% nd serum phospholipids y 30%. Initil egg-yolk lipid onentrtions were similr for the three tretment groups (Tle 6). At the end of the experimentl period, the feeding of lk umin seeds hd produed dose-dependent dereses in egg-yolk onentrtions of totl lipids, holesterol nd triylglyerols. The diet with 3% lk umin seeds hd indued dereses in egg-yolk totl lipids, holesterol, phospholipids nd triylglyerols y 34, 45, nd 20%, respetively. Disussion Totl lipids ontent of egg yolk in the ontrol group ws found to e 30% of the totl egg yolk weight. This vlue orresponds with tht reported y others (Ternes nd Sholtyssek, 994; Cunninghm nd Lee, 978). Inlusion of lk umin in the diet t levels of 0 nd 30 g/kg signifintly redued the ontent of egg yolk totl lipids y 9 nd 34%, respetively. Cholesterol onentrtion of egg yolk in the ontrol group ws similr to vlues reported y Vn Elswyk et l. (99) nd Pnd nd Singh (990), ut lower vlues were found y Sott nd Leo (989) nd Mrks nd Wshurn (977). Generlly, with the Lieermnn-Burhrd method s used in this study, higher vlues re mesured thn with nlysis sed on gs-liquid hromtogrphy (Sott nd Leo, 989). In the hens given the diets with 0 nd 30 g lk umin seeds/kg for three months, holesterol ontents of egg yolk were lowered y 34 nd 45%, respetively. Thus, the feeding of lk umin seeds to lying hens 575

3 El Bgir et l.: Lipid Composition of Egg Yolk nd Serum in Lying Hens Fed Diets Contining Blk Cumin Tle 3: Body weight of lying hens fed the experimentl diets Blk umin (g/kg diet) Initil (g) 286±4 300±7 270±30 Finl (g) 260 ±3 384 ±7 376 ±9 Mens ± SEM; n = 2 hens. Vlues within line with different supersript letter re signifintly different (P<0.0) Tle 4: Effet of feeding lk umin on egg prodution during the entire three-month experimentl period Blk umin (g/kg diet) Egg hrteristi Hen-dy egg prodution (%) 67 ±.9 6 ±.6 56 ±.0 Egg length (mm) 56.9± ± ±0.6 Egg width (mm) 43.3± ± ±0.4 Mens ± SEM, n = 7 ges (egg prodution) or n = 0 eggs (egg length nd width). Vlues with different supersript letter re signifintly different (P<0.0). ws found to lower egg yolk holesterol y out 35%. Would the use of low-holesterol eggs s produed y hens fed lk umin hve ny impt on humn helth? The verge dily holesterol intke y dults is out 300 mg. When whole egg onsumption equls three eggs/week nd when norml egg provides 250 mg of holesterol, then the ontriution of eggs to holesterol intke is 07 mg/dy. When low-holesterol eggs providing 63 mg of holesterol re onsumed, dily holesterol intke would e 263 mg. The expeted derese in serum holesterol is 0.05 mmol/l whih equls 0.83% lowering t n initil serum holesterol onentrtion of 6 mmol/l. As rule of thum, % lowering in serum holesterol my use 2% derese in oronry hert disese in middle-ged men. Thus, 0.83% lowering of serum holesterol will derese the risk of oronry hert disese in middleged men y.66% whih, on popultion level, hs onsiderle impt in westernized ountries. As to the mehnism y whih lk umin seeds my lower egg yolk holesterol, we n only speulte. Feeding the seeds to the lying hens redued serum holesterol onentrtions y out 20%. It is resonle to suggest tht the derese in egg yolk holesterol is seondry to the derese in serum holesterol whih is the preursor for egg yolk holesterol. Why does lk umin seed lower serum holesterol? The seeds my either inhiit de novo holesterol synthesis or stimulte ile id exretion. It is well-known tht oth effets would led to derese in serum holesterol (Beynen et l., 987). Further reserh is neessry to identify the mode of tion of lk umin seeds. The mount of triylglyerols nd phospholipids omprised out 55 nd 30% of the egg yolk totl lipid ontents, whih is similr to the vlues reported y Lesknish nd Nole (997). Feeding lk umin seeds used signifint redutions in the onentrtions of egg yolk triylglyerols nd phospholipids. The seeds were lso found to lower the serum onentrtions of triylglyerols nd phospholipids. It ould thus e suggested tht the derese in serum lipids hd used derese in egg yolk lipids. It is not known how lk umin seeds lower the ontents of triylglyerols nd phospholipids in serum, ut it is tempting to speulte tht omponent of the seeds inhiits in the liver the flux of etyl-coa into the lipogeni pthwy. Suh n effet would lso dmpen holesterol synthesis. Akhtr et l. (2003) reported tht inlusion of lk umin seeds in the diet to level of.5% rised hen-dy egg prodution from 59 to 77%. In ontrst, in this study tretment with lk umin deresed the rte of egg prodution y up to 6%. The disrepny my e explined y the ft tht the lowering of egg-yolk holesterol fter feeding lk umin seeds ws muh greter in this study thn in tht reported erlier y Akhtr et l. (2003). After dministrtion of syntheti HMG-CoA redutse inhiitor to lying hens egg-yolk holesterol ws redued y 30% nd egg prodution y 20% without ffeting egg weight (Elkin et l., 993). It is resonle to suggest tht holesterol is needed y the hen for the mintenne of egg prodution. Possily, there is mximum redution of the holesterol ontent of egg yolk t whih eggs re no longer produed. It would pper tht the lower onentrtions of serum holesterol seen in this study were still suffiiently high to sustin egg formtion leit tht totl egg prodution hd dropped. Unfortuntely, the eggs were not weighed, ut egg weight my not hve een hnged s ws oserved in the study of Elkin et l. (993). In ny event, there ws no effet on the width nd length of the eggs, inditing tht egg shell formtion ws unffeted. There ws signifint inrese in hen ody weight fter feeding the diets ontining lk umin seeds. It my e onluded tht lk umin seeds my not hve toxi effets, t lest not t the inlusion level fed in this study. The inrese in ody weight seen fter feeding lk umin seeds my e explined y storge of feed energy not used for egg prodution. For the irds fed the highest level of lk umin seeds versus the ontrol hens, the expeted inrese in ody weight would e 9 g s sed on the following lultions. The mount of metolizle energy not used for egg prodution equls 5544 kj. This vlue is sed on lesser egg prodution of 594 g/90 dys while ssuming tht egg weight is 60 g, the energy vlue of n egg is 420 kj nd the effiieny of metolizle energy onversion into egg is 75%. The extr energy requirement for mintenne due to the inrese in ody weight is estimted s 367 kj. This vlue is sed on n inrese in ody weight y 06 g for n verge period 576

4 El Bgir et l.: Lipid Composition of Egg Yolk nd Serum in Lying Hens Fed Diets Contining Blk Cumin Tle 5: Effet of dietry lk umin seeds on serum lipid onentrtions in lying hens Blk umin (g/kg diet) Serum lipid Totl lipids (mg/dl serum.) 53±2 236±7 225±2 Cholesterol (mmol/l serum.) 4.06± ± ±0.44 Phospholipids (mmol/l serum) 5.5± ± ±0.55 Triylglyerols (mmol/l serum) 7.92± ± ±0.2 Mens ± SEM, n = 6 time points with verge vlues for 0 hens eh Vlues within line with different supersript letter re signifintly different (P<0.05) Tle 6: Effet of dietry lk umin seeds on egg-yolk lipid onentrtions Blk umin (g/kg) Egg yolk lipid Totl lipids (mg/g egg yolk) Initil 327± 309 ± 0 302±3 Finl 303 ±0 246 ± 200 ±3 Cholesterol (mg/g egg yolk) Initil 7±0.7 8±0.4 7±0.3 Finl 20 ±0.5 3 ±0.2 ±0.3 Phospholipids (mg/g egg yolk) Initil 06± 07±2 06± Finl 89 ±2 68 ±3 79 ±3 Triylglyerols (mg/g egg yolk) Initil 82±22 92±3 8±7 Finl 73 ± 3 50 ±4 38 ±5 Mens ± SEM, n = 0 eggs Vlues in the sme line with different supersript letter re signifintly different (P<0.0) of 45 dys nd energy requirement for mintenne of 380 kj/kg metoli weight. Beuse feed intke ws identil for the ontrol hens nd their ounterprts fed the highest mount of lk umin, the ltter nimls hd n exess of 2377 kj whih is equivlent to 782 kj in the form of extr weight, when ssuming 75% effiieny of energy inorportion. When the energy ontent of the weight gin is 5 kj/g, then 9 g would e gined. This vlue orresponds well with the mesured inrese in ody weight of 06 g. In ontrst to this study, Akhtr et l. (2003) found tht the feeding of lk umin seeds lowered ody weight of the hens, whih ws ssoited with n inrese in egg prodution. In onlusion, this study shows tht lk umin seeds effetively lowered egg yolk lipids, onfirming the dt pulished y Akhtr et l. (2003). Further reserh my 794S. fous on the identifition of the tive priniple in lk umin. Knowledge of the hemil struture of the tive priniple ould e importnt for the development of new hypoholesterolemi drugs nd for studies on the mehnisms ontrolling holesterol metolism. Referenes Akhtr, M.S., Z. Nsir nd A.R. Aid, Effet of feeding powdered Nigell stiv L. on poultry egg prodution nd their suitility for humn onsumption. Veterinrski Arhiv, 73: Byn, V.K., D. Koottugl nd G.A. Hly, 978. Proximte nlysis, ftty id nd mino id omposition of Nigell stiv seeds. J. Food Si.,43: Bvelr, F.J. nd A.C. Beynen, Reltionships etween the intke of n-3 polyunsturted ftty ids y hens nd the ftty id omposition of their eggs. Int. J. Poult. Si., 3: Beynen, A.C., Ftty id omposition of eggs produed y hens fed diets ontining groundnut, soy en or linseed. NJAS Wgeningen J. Life Si., 52: 3-0. Beynen, A.C., M.B. Ktn nd L.F.M. Vn Zutphen, 987. Hypo- nd hyperresponders: individul differenes in the response of serum holesterol onentrtion to hnges in diet. Adv. Lipid Res., 22: 5-7. Beynen, A.C. nd M.B. Ktn, 989. Impt of dietry holesterol nd ftty ids on serum lipids nd lipoproteins in mn. In: Vergroesen, A.J., Crwford, M.A. (Eds.) The Role of Fts in Humn Nutrition. Ademi Press Ltd., London, pp: Connerty, H.V., R.A. Brings nd E.H. Eston, 96. Clin. Chem., 37: 589. Cunninghm, F.E. nd H.W. Lee, 978. A study of turkey egg yolk omposition nd eletrophoreti seprtion of omponents. J. Food Biohem., 2: El-Dkhkhny, M., N.I. Mhdy nd M.A. Hlim, Nigell stiv L. oil protets ginst indued heptotoxiity nd improves serum lipid profile in rts. Arzneimittel Forshung, 50: Elkin, R.G., 997. An overview of reent developments in vin lipoprotein metolism. J. Nutr., 27: 793S- Elkin, R.G., M.B. Freed, K.A. Kieft nd R.S. Newton, 993. Altertion of egg yolk holesterol ontent nd plsm lipoprotein profiles following dministrtion of totlly syntheti HMG-CoA redutse inhiitor to lying hens. J. Agri. Food Chem., 4: Frrn, M.T., M.G. Uwnyjn, A.M.A. Miski, F.T. Slemn, F.A. Add nd V.M. Ashkrin, 995. Effet of feeding rw nd treted ommon veth seed (Vii stiv) on the performne nd egg qulity prmeters of lying hens. Poult. Si., 74:

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