The effects of sources of supplemental fat on performance,egg quality,and fatty acid composition of egg yolk in laying hens

BACKGROUND: The objective of this study was to determine the effects of sources of supplemental fat on laying performance, egg quality, and fatty acid composition of egg yolk. RESULTS: Two hundreds Isa Brown layers were assigned randomly to be fed ad libitum a standard commercial layer feed (BD), basal diet plus 2% tallow (T), basal diet plus a mixture of 1% tallow and 1% flaxseed oil (MTFO), basal diet plus 2% sunflower oil (SO), or basal diet plus 2% flaxseed oil (FO), which were offered for 8 weeks. Each diet was given to five groups, each containing 10 hens. The feed efficiency and egg production were 2.78 and 53.51% for BD; 2.30 and 63.47% for T; 2.45 and 60.14% for MTFO; 2.29 and 64.30% for SO, and 2.62 and 61.18% for FO groups, respectively. Dietary fat supplementation affected the laying performance but had no significant effects on egg quality parameters. The fatty acid composition of egg yolk lipids were significantly affected by dietary fatty acid composition. The supplemental tallow increased palmitic fatty acid. The proportions of linoleic and arachidonic fatty acids in egg yolks for layers fed the SO diet were higher than in the BD group and those on diets containing other fats. Concentrations of oleic and omega‐3 fatty acids were the highest in layers fed the FO diet during the laying period. CONCLUSION: The results indicated that dietary animal and plant fats changed the fatty acid composition of egg yolk. Copyright © 2008 Society of Chemical Industry     

Chemical Compositions of Egg Yolks and Egg Quality of Laying Hens Fed Prebiotic,Probiotic, and Synbiotic Diets

A 16‐wk feeding experiment was conducted to investigate the effects of a prebiotic, isomaltooligosaccharide (IMO), a probiotic, PrimaLac®, and their combination as a synbiotic on the chemical compositions of egg yolks and the egg quality of laying hens. One hundred and sixty 16‐wk‐old Hisex Brown pullets were randomly assigned to 4 dietary treatments: (i) basal diet (control), (ii) basal diet + 1% IMO (PRE), (iii) basal diet + 0.1% PrimaLac® (PRO), and (iv) basal diet + 1% IMO + 0.1% PrimaLac® (SYN). PRE, PRO, or SYN supplementation not only significantly (P < 0.05) decreased the egg yolk cholesterol (24‐ and 28‐wk‐old) and total saturated fatty acids (SFA; 28‐, 32‐, and 36‐wk‐old), but also significantly (P < 0.05) increased total unsaturated fatty acids (UFA; 28‐, 32‐, and 36‐wk‐old), total omega 6 and polyunsaturated fatty acids (PUFA), including linoleic and alpha‐linolenic acid levels in the eggs (28‐wk‐old). However, the total lipids, carotenoids, and tocopherols in the egg yolks were similar among all dietary treatments in the 24‐, 28‐, 32‐, and 36‐wk‐old hens. Egg quality (Haugh unit, relative weights of the albumen and yolk, specific gravity, shell thickness, and yolk color) was not affected by PRE, PRO, or SYN supplementation. The results indicate that supplementations with IMO and PrimaLac® alone or in combination as a synbiotic might be useful for improving the cholesterol content and modifying the fatty acid compositions of egg yolk without affecting the quality of eggs from laying hens between 24 and 36 wk of age.     

Effects of dietary microalgae,other lipid sources,inorganic selenium and iodine on yolk n‐3 fatty acid composition,selenium content and quality of eggs in laying hens

BACKGROUND: This aim of this study was to investigate the effects of supplementing laying hen diets with different n‐3 fatty acid sources (linseed oil, fish oil and microalgae) on egg quality and fatty acid profile. The addition of inorganic selenium (Se) and iodine (I) and their effects on egg characteristics and Se concentration were also evaluated. RESULTS: A significantly lower egg weight was found in the control group and in groups fed a diet containing fish oil or a diet containing microalgae plus Se and I. Yolks from all supplemented diet groups exhibited a significant reduction in n‐6 fatty acid content compared with the control group. The docosahexaenoic acid (DHA) content of yolks was higher (P < 0.01) in all supplemented diet groups. Selenium supplementation increased the Se concentration (P < 0.001) in eggs. CONCLUSION: The results of this study provide evidence that an improvement in egg weight and in the DHA content of yolks can be achieved by feeding hens a microalgae‐rich diet, which avoids the unpleasant flavours associated with fish oil supplementation. Dietary inorganic Se, especially in combination with I, can enhance the concentration of Se in eggs. Copyright © 2009 Society of Chemical Industry     

Fatty acid profile and cholesterol content of egg yolk from chickens fed diets supplemented with purslane (Portulaca oleracea L.)

BACKGROUND: The aim of the present study was to evaluate the effects of purslane on egg production, egg weight, feed efficiency, yolk fatty acid composition, and egg cholesterol content in laying hens. MATERIAL AND METHODS: Sixty 80‐week‐old layers were allocated randomly to receive diets supplemented with 0 (control), 10 g kg^?1 or 20 g kg^?1 dried purslane for 84 days. Egg weights and egg production in the groups were recorded daily, whereas feed intake was measured weekly. RESULTS: Diet supplemented with 20 g kg^?1 purslane significantly decreased body weight of the chickens compared to the control. Inclusion of purslane at the level of 10 g kg^?1 or 20 g kg^?1 into the diet significantly (P < 0.05) improved egg weight compared to the control. Chickens fed the diet including 20 g kg^?1 purslane had a significantly (P < 0.05) higher egg production and improved feed efficiency compared to the control. Cholesterol content of eggs from the hens fed 0, 10 or 20 g kg^?1 did not differ and was 10.45, 9.51 or 9.51 mg g^?1 dried egg yolk, respectively. Inclusion of purslane at the level of 20 g kg^?1 into the diet significantly (P < 0.05) increased ω‐3 fatty acids such as C18:3(ω‐3) and C22:6(ω‐3). The ratio of ω‐6 to ω‐3 also was significantly (P < 0.05) lower in the eggs from chickens fed 10 g kg^?1 or 20 g kg^?1 purslane supplemented diets compared to the control. CONCLUSION: This study showed that adding dried purslane to the diet of laying hens significantly increased egg production and egg weights although there was no reduction in the egg cholesterol concentration. This study also showed that inclusion of purslane into diet enriched eggs with ω‐3 fatty acids and decreased the ratio of ω‐6/ω‐3 in the yolk. Copyright © 2010 Society of Chemical Industry     

GROWTH, SURVIVAL AND HEAT RESISTANCE OF SALMONELLA TYPHIMURIUM AND ESCHERICHIA COLI IN REGULAR AND OMEGA-3 HENS EGG PRODUCTS

Omega‐3 enriched eggs are currently produced by hens fed a flax diet. Since omega‐3 polyunsaturatedfatty acids are prone to oxidation, the addition of vitamin E is supplemented into the hen's diet as an antioxidant. Typically these eggs contain about 2 and 4 times more omega‐3 fatty acids and vitamin E, respectively compared to regular eggs. Since table eggs have a long history of association with foodborne salmonellosis, it was of interest to compare the growth and/or survival of several bacterial pathogens in omega‐3 and regular eggs. In this respect nalidixic‐resistant Escherichia coli and Salmonella Typhimurium were inoculated into regular and omega‐3 hen's egg products (whole eggs, albumen, yolk) and incubated at 22, 8 and ?20C. Time‐course studies indicated that by 72 h both Salmonella and E. coli levels increased by 7 logs at 22C in both types of whole egg. At 8C population levels for these bacteria both increased by approximately 3 logs at 6 weeks. In regular and omega‐3 yolks, salmonellae maintained at 22 and 8C for 48 h and 6 weeks increased by approximately 6 and 1.5 logs, respectively. E. coli levels were higher in egg yolk compared to Salmonella at both temperatures. Regardless of the yolk source, however, no significant (P > 0.05) differences in population levels were observed. Survival patterns of E. coli at ?20C were not significantly (P > 0.05) different between whole egg sources. This trend was also observed in the yolks. For Salmonella no significant (P > 0.05) differences in survival were observed between yolk preparations maintained at ?20C. Increasing the level of α‐tocopherol from c. 63 to 240 ppm in regular egg yolk, resulted in no significant (P > 0.05) differences in the growth of Salmonella at 22C. In addition, when the bacterium was heated in regular egg yolk amended with vitamin E at 56.5C, no significant (P > 0.05) difference was observed in resistance regardless of α‐tocopherol (55‐713 ppm) or total tochopherol (92–1238 ppm) level.     

Egg yolk fatty acid profile in relation to dietary fatty acid concentrations

BACKGROUND: The health benefits of n‐3 fatty acids have led to much research on manipulating the fatty acid composition of animal‐derived foods. In this study, two experiments were conducted to investigate the interaction of dietary fatty acids on egg yolk fatty acid concentrations. In experiment I, 32 dietary treatments with three replicates of three birds each were fed for 35 days. Diets were prepared by mixing one type of fish oil with four vegetable oils in different proportions. In experiment II, three different types and two levels of fish oil in combination with two vegetable oils were tested under the same conditions as in experiment I. RESULTS: In experiment I the results showed that the egg yolk saturated (SFA) and monounsaturated (MUFA) fatty acid concentration was determined by the dietary SFA, MUFA and 18:2n‐6 content. The egg 18:2n‐6 concentration was mainly explained by the dietary inclusion of 18:2n‐6 and negatively by the dietary MUFA content. The egg C18:3n‐3, C20:5n‐3 and C22:6n‐3 concentration is almost exclusively determined by their direct supply from the diet. The egg 20:4n‐6 concentration was inversely proportional to the long‐chain n‐3 polyunsaturated fatty acid content of the diet. The results of experiment II showed that the egg yolk C20:5n‐3 and C22:6n‐3 concentration was determined by both the level of dietary fish oil (1 or 2%) and the C20:5n‐3/C22:6n‐3 ratio in the fish oil. CONCLUSION: The results of this study demonstrated that the direct dietary supply of fatty acids is the most important factor determining the egg yolk fatty acid composition, in particular for the n‐3 fatty acids. The interaction effect from other dietary fatty acids was in general small. Copyright © 2011 Society of Chemical Industry     

Fatty acid profile and sensory characteristics of table eggs from laying hens fed hempseed and hempseed oil

Hempseed (HS) is rich in omega-3 polyunsaturated fatty acids, with approximately 17% of total fatty acids as alpha-linolenic acid. As such, HS and its oil may be used in hen diet formulations to produce eggs enriched in essential fatty acids. Because omega-3 eggs have the potential for unpleasant aromas and flavors, the current study was designed to assess the fatty acid profile and sensory attributes of eggs procured from hens consuming diets containing hempseed oil (HO) or HS. A total of 48 individually caged White Bovan hens received 1 of 6 diets containing 4%, 8%, 12% HO, 10%, 20% HS or 0% hemp (w/w) for 12 wk. Total omega-3 polyunsaturated fatty acid content was highest in the 12% HO group (15.3 mg/g of yolk) compared to the control (2.4 mg/g of yolk). Trained panellists (n= 8) found no significant differences (P≥ 0.05) in aroma or flavor between cooked eggs from different dietary treatments, with the exception of sweet flavor. The 4% HO group yielded the least sweet eggs compared to the 20% HS group, which was highest. For yolk color, L*, a*, and b* values (Mean ± SEM) for control eggs were 61.2 ± 0.10, 1.1 ± 0.05, and 43.0 ± 0.22, respectively. Addition of hemp led to significant (P < 0.001) reductions in L*, and significant increases in a* and b*, with the largest changes observed in the 20% HS treatment (L*= 58.7 ± 0.10; a*= 5.8 ± 0.05; b*= 60.5 ± 0.22). The results show that hemp use in hen diets leads to increased omega-3 polyunsaturated fatty acid content and color intensity of egg yolks, but does not have adverse effects on the sensory profiles of the cooked eggs. PRACTICAL APPLICATION: This study provides evidence that HS and hempseed oil (HO) can safely be utilized as feed ingredients for laying hens to produce table eggs that are enriched in essential fatty acids. Additionally, the eggs procured from these hens had similar aroma and flavor compared to eggs from hens not fed any hemp. The greater the dietary hemp inclusion, the more pigmented the resulting yolks became in terms of darkness, redness, and yellowness.     

Composition, Functionality, and Sensory Evaluation of Eggs from Hens Fed Dietary Menhaden Oil

Enrichment of omega-3 fatty acid content of egg yolk may increase consumer acceptance of egg products if eggs maintain characteristic functionality, exhibit compositional stability, and are sensorially acceptable. The diet of laying hens was enriched with 3% menhaden oil. Arachidonic acid (20:4n-6) was decreased 70.2%, and linolenic (18:3n-3) and docosahexaenoic acid (22:6n-3) were increased 78.5% and 356%, respectively, in egg yolk. Eicosapentaenoic acid (20:5n-3) was also incorporated into test egg yolk as compared to nondetectable levels in control eggs. Cooking did not alter the fatty acid composition of eggs nor were functional properties of test eggs affected. Panelists differentiated n-3 enriched eggs from controls (P ≤ 0.01) when scrambled but not when hard cooked.     

Enrichment of eggs in n-3 polyunsaturated fatty acids by feeding hens with different amount of linseed oil in diet

The production of n-3 polyunsaturated fatty acid enriched eggs by addition of linseed oil to the laying hens' diet has been evaluated in terms of production parameters and n-6/n-3 ratio. A total of 150 18weeks old Lohmann Brown laying hens were housed in cages and fed with basal diet and four experimental diets containing 1%, 2%, 3% or 4% of linseed oil added to the basal diet. The effect of the altered level of linseed oil on hens laying performance, fatty acid content and composition and cholesterol content in egg yolk has been evaluated during 13weeks of experiment. Egg weight, yolk fat content, yolk weight, yolk percentage and shape index were not influenced by dietary treatment. The ratio between n-6 and n-3 polyunsaturated fatty acids in eggs decreased in first 5weeks and then remained stable until the end of the experiment for all experimental groups. Different contents of linseed oil in feed highly influenced the n-6/n-3 ratio (P<0.0001). Addition of linseed oil did not influence the cholesterol content in yolks (P=0.5200) while the only factor affecting the cholesterol content was the hens age (P<0.0001).     

Effects of L‐carnitine supplementation to diets with different fat sources and energy levels on fatty acid composition of egg yolk of laying hens

BACKGROUND: The present study was carried out to determine the effects of feeding diets with two different levels of metabolisable energy (ME) (11.51 or 10.88 MJ ME kg^?1 diet) and three different sources of fat (palm oil, sunflower oil or fish oil) with or without supplemental L ‐carnitine (0 or 500 mg kg^?1 diet) on the fatty acid (FA) composition of egg yolk and the passage of n3 polyunsaturated FAs to egg yolk in laying hens. RESULTS: The ∑n3, particularly C22:6n‐3, FA contents of egg yolk were significantly reduced by adding of L ‐carnitine (C2) to different fat sources (P < 0.01). The ratio of n6/n3 was reduced from 53.77 to 17.72 in eggs yolks when ME was lowered in the diet with C2‐sunflower oil (SFO) whereas it was enhanced from 2.19 to 9.31 in C2‐E2 (low energy) diet with fish oil (FO) (P < 0.001). The diet with E2 or C2 containing FO resulted in a decrease of the C22:5n‐3, C22:6n‐3 and ∑n3 FA contents of egg yolk (P < 0.001). On the other hand, supplementation of C2 to diets with SFO or palm oil (PO) caused to a decrease in the C22:6n‐3 and ∑n3 FA contents of egg yolk (P < 0.01). A significant increase of the ratio of n6/n3 in egg yolk can be seen by feeding with E2 diet by adding of C2 to all fat sources like in E1 (normal energy) diet (P < 0.001). CONCLUSION: Dietary treatments resulted in major changes in FA composition of egg yolk. The supplemental C2 in diet decreased the C22:5n‐3, C22:6n‐3 and ∑n3FA contents in egg yolk. The use of FO in diets with E2 significantly reduced the passage rate of C22:6n‐3 FA to egg yolk. Copyright © 2008 Society of Chemical Industry     

Influence of rapeseed cake, linseed cake and hemp seed cake on laying performance of hens and fatty acid composition of egg yolk

In hens the effects of expeller/cakes from rapeseed, linseed, and hemp seed were investigated on feed intake, laying performance and fatty acid composition of egg yolk. A total of 216 individually caged laying hens were allocated to nine dietary treatments (5, 10, 15 % cake) and fed for six laying months. For feed intake, egg mass production and feed-to-egg mass ratio at 15 % dietary cake level a significant lower performance was shown compared with the 5 and 10 % cake level groups. Also interaction was significant for all these parameters, indicating that the cake level acted differently for the three cakes. The egg mass production was lower in the linseed cake than in the hempseed groups and the hens fed the linseed cake needed significantly more feed per kg egg mass compared with both the other cakes tested. Increasing dietary level of all oil seed cakes lowered the yolk percentage and increased the egg white percentage. Increased dietary levels of all three oil seed cakes lowered the percentages of most saturated fatty acids and also the percentages of the monounsaturated fatty acids. The linoleic acid and the linolenic acid as polyunsaturated fatty acids were heightened by increasing the cake levels from 5 to 10 and 15 % in the diet. The results allow the conclusion that compound feeds with up to 10 % of cakes does not negatively influence the laying performance of hens and provides the possibility of the enrichment of yolk fat with polyunsaturated fatty acids.     

Stability,sensory quality,texture properties and nutritional value of fish oil‐enriched spreadable fat

A Correction has been published for this article in Journal of the Science of Food and Agriculture 84(15):2142 (2004). The intake of omega‐3 long‐chain polyunsaturated fatty acids (PUFAs) in the typical Western diet is usually below the recommended level. Without radical changes of eating patterns the diet may be enhanced by enrichment of foods with unhydrogenated fish oil, which is the richest source of the long‐chain omega‐3s, eicosapentaenoicacid (EPA) and docosahexaenoicacid (DHA). The aims of the study were to establish the sensorily acceptable fish oil enrichment level of a reduced‐fat spread, to enhance the omega‐3 long‐chain PUFA content and to evaluate the enriched spread's stability during 3 months of storage (6°C, limited exposure to light and air). Samples were prepared in an industrial pilot plant. Overall sensory quality, intensity of fishy flavour, texture properties (sensory and instrumental), peroxide value, acid number and fatty acids composition were measured. A spread enriched by addition of 30.0 g kg^?1 of unhydrogenated fish oil could be stored for up to 3 months without significant decrease of the measured stability indicators. A daily portion of this enriched spread (30 g) would provide 0.25 g of EPA and DHA, significantly increasing long‐chain omega‐3 levels in the average diet. Copyright © 2004 Society of Chemical Industry     

INFLUENCE OF DIETARY MENHADEN FISH OIL ON FATTY ACID COMPOSITION OF THE EGG

The influence of menhaden fish oil and other oils on the fatty acid composition of the egg was studied. Diets containing 1.5% menhaden oil, 1.5% corn oil and no oil added were fed to 50 hens. The menhaden oil diet increased the composition of C_14:0, C_16:1, C_18:1, C_18:3w3, C_20:5w3 and C_22:6w3 in the eggs but decreased C_18:2w6 and C_20:4w6 compared with the corn oil diet. The concentration of C_20:5w3 was greater than C_22:6w3 in menhaden oil, but more C_22:6w3 was found in eggs than C_22:6w3. A significant increase in total w-3 PUFAs (polyunsaturated fatty acids) occurred in the eggs after feeding the menhaden oil diet for 5 days and the concentration continued to increase through day 15. Dietary fats tend to produce a fatty acid pattern in eggs similar to that of the diet and varies with the oil source concentration. Most fatty acid profiles in egg yolks were altered within 15 days after hens began to consume test diets.     

Change in α‐tocopherol contents,lipid oxidation and fatty acid profile in eggs enriched with linolenic acid or very long‐chain ω3 polyunsaturated fatty acids after different processing methods

The influences of dietary supplementation with α‐tocopheryl acetate (α‐TA) and of processing (by hard‐boiling and scrambling) of eggs enriched with ω3 fatty acids, either very long‐chain ω3 polyunsaturated fatty acids (VLC ω3 PUFAs) or linolenic acid (LNA), on fatty acid composition, α‐tocopherol content and lipid oxidation (thiobarbituric acid (TBA) values) were studied. Four dietary treatments were formulated from a basal diet containing 40 g kg^?1 linseed oil (LO) or fish oil (FO) combined with either 0 or 100 mg α‐TA kg^?1 of feed. Eggs from LO treatments were enriched with LNA and those from FO treatments were rich in VLC ω3 PUFAs. Neither processing nor dietary supplementation with α‐TA modified greatly the fatty acid profile of eggs. Dietary supplementation with α‐TA increased the α‐tocopherol content of eggs (187.2 versus 407.9 µg g^?1 dry matter). Eggs from FO treatments showed lower α‐tocopherol content than those from LO treatments (273.5 versus 321.6 µg g^?1 dry matter), and processing of eggs enriched with VLC ω3 PUFA reduced the α‐tocopherol content by a significant 16%. Moreover, processing of eggs increased lipid oxidation two‐ to nine‐fold. Oxidation levels of hard‐boiled eggs were 30.4% higher than those of scrambled eggs. TBA values in hard‐boiled and scrambled eggs were significantly reduced when 100 mg α‐TA kg^?1 of feed supplemented the diet only in those eggs enriched with VLC ω3 PUFA (from FO treatments). Copyright © 2003 Society of Chemical Industry     

Positional analysis of egg triacylglycerols and phospholipids from hens fed diets enriched with refined seal blubber oil

The effect of feeding laying hens with refined seal blubber oil (SBO, containing 22.2% ω3 polyunsaturated fatty acids) on the fatty acids composition and regiospecific distribution of fatty acids in triacylglycerols (TAG) and phospholipids (PL) of egg produced was investigated. The hens were fed four diets containing 0 (control), 1.25, 2.5 or 5% SBO for 5 and 9 weeks. Comparison of the total fatty acids composition indicated that a 5 week feeding period was sufficient to obtain the highest amount of total polyunsaturated fatty acids in the eggs. The fatty acids composition of the egg lipids reflected the fatty acids composition of the diet. The substantial reduction in the ω6/ω3 ratio (ie 8.5 to 2.6) is of interest, and is in line with the recommendations of health authorities in several countries, where it has been suggested that the human diet should contain a ω6/ω3 ratio of 3–4. The greatest reduction of the ω6/ω3 ratio occurred for diet A (control) and diet B (1.25% SBO). Principal component analysis analysis of the fatty acids composition of egg lipid showed four clusters representing: (i) the control diet; (ii) the diet containing 1.25% SBO as well as samples obtained from feeding 2.5% SBO for 9 weeks; (iii) the diet with 5% SBO; and (iv) samples obtained from hens fed 2.5% SBO for 5 weeks. More ω‐3 polyunsaturated fatty acids (ω3 PUFA) were incorporated in phosphatidylethanolamine and phosphatidylcholine than in TAG. Although ω3 were predominantly linked in the position Sn‐1,3 of TAG in SBO, they were esterified in the Sn‐2 position of the TAG and PL of eggs obtained after feeding laying hens with enriched diets. Copyright © 2005 Society of Chemical Industry     

Effects of Lactobacillus cultures on performance of laying hens,and total cholesterol,lipid and fatty acid composition of egg yolk

BACKGROUND: The use of antibiotic growth promoters in animal feeds is not approved for laying hens in many countries, and economically feasible biological measures which include probiotics are developed to improve hen performance. The present study investigated the effects of probiotics on hen performance for a 48‐week period and the cholesterol, total lipid and fatty acid composition of egg yolk at 24, 28 and 32 weeks of age. RESULTS: Egg weight of Lactobacillus culture (LC)‐fed hens was significantly (P < 0.05) greater than that of control hens throughout the laying period. From 20 to 44 weeks of age, LC‐fed hens produced a significantly (P < 0.05) lower percentage of small eggs and a higher percentage of large eggs, and from 45 to 68 weeks of age a significantly (P < 0.05) lower percentage of medium eggs and a higher percentage of large and extra‐large eggs than control hens. Significantly (P < 0.05) less cholesterol was found in egg yolks of hens fed LC at 24 and 28 weeks of age, but not at 32 weeks of age. The total lipid content and the fatty acid composition of egg yolks were similar between the treatments at 24, 28 and 32 weeks of age, except for stearic acid (C_{18 : 0}), which was significantly reduced in the egg yolk of LC‐fed hens at 28–32 weeks of age. CONCLUSION: The greatest benefit of LC was in increasing egg weight and improving egg size by influencing a shift from small and medium to large and extra‐large eggs. Copyright © 2008 Society of Chemical Industry     

Influence of dietary linoleic acid on egg fatty acid composition in hens deficient in essential fatty acids

The effect on egg yolk lipids of adding linoleic acid in the form of corn oil to the diet of hens depleted of essential fatty acids over a prolonged period was examined. There was an immediate increase in the amount of linoleate deposited in all yolk lipid fractions. The addition of 8% corn oil resulted in a maximum value of about 20% lineoleic acid in the egg yolk fatty acids being attained over a period of 14 days. This increase in lineoleate deposition was accompanied by a reduction in the level of oleic acid. Minor adjustments in the other egg fatty acids accompanied these major changes.     

Enriching the egg yolk in n − 3 fatty acids by feeding hens with diets containing horse fat produced in Uruguay

The present study was conducted to evaluate the ability of horse fat produced in Uruguay, compared with other lipid sources supplemented in the diet of laying hens, to modify the lipid composition and the n − 6/n − 3 fatty acid ratio of the produced eggs. For this purpose, 60 laying hens (Gallus domesticus) were fed for 30 days with five experimental diets (12 hens/diet) containing 3% sunflower oil (SO), rice oil (RO), beef tallow (BT), pressed-fat (PF), obtained by pressing fat from bovine viscera, and horse fat (HF) obtained from horse bone medulla. Throughout the trial, feeding rate, shell index, weight and total lipid contents of eggs, were not affected by the different diets. Feeding on the SO and RO diets significantly increased the amount of linoleic acid of the egg, although it was lower in the RO than in the SO eggs. Diet BT did not affect the saturated fatty acid content of the yolks. The diets with animal fats containing 18:3n − 3 (diets PF and HF), resulted in a significant increase in the n − 3 fatty acid contents of the eggs, through an increase of linolenic (18:3n − 3) and docosahexaenoic acid (DHA, 22:6n − 3) contents. Eggs from hens fed the HF diet showed increased linolenic acid (46 mg/yolk) and DHA (71 mg/yolk, 1.7% of total fatty acids) contents. These levels were obtained after two weeks of feeding. Moreover, the fatty acid profiles of eggs from treatment HF were not significantly affected by thermal treatment of the yolks. In conclusion, the fat from horse bone medulla, as produced in Uruguay, can be considered as a suitable lipid source for diets of laying hens, to modify the nutritional composition of the eggs in n − 3 PUFA content, especially DHA, and consequently, the n − 6/n − 3 fatty acid ratio.     

Effects of dietary black cumin seed (Nigella sativa L.) on performance,egg traits,egg cholesterol content and egg yolk fatty acid composition in laying hens

BACKGROUND: The objective of this study was to determine the effects of dietary black cumin seed on performance, egg traits, egg cholesterol content and egg yolk fatty acid composition in laying hens during a 12 week period. For this purpose a total of 160 Lohmann Brown laying hens 36 weeks of age were allocated to four dietary treatments with one control group and three treatment groups. Black cumin seed (Nigella sativa L.) was used at the level of 5, 10 and 15 g kg^?1 in the diets of the first, second and third treatment groups, respectively. RESULTS: Dietary treatments did not significantly affect body weight, feed intake, egg production, egg quality characteristics and blood parameters. Diets containing 10 and 15 g kg^?1 black cumin seed increased egg weight (P < 0.01), improved feed efficiency (P < 0.01) and decreased egg yolk cholesterol, saturated fatty acids (% of total fatty acid methyl esters) and the ratio of saturated to unsaturated fatty acids (P < 0.05) compared to the diet of control group. CONCLUSION: Dietary black cumin seed at the level of 10 and 15 g kg^?1 had beneficial effects on egg weight, feed efficiency, egg cholesterol content and egg yolk fatty acid composition. Therefore it can be used at the level of 10 and 15 g kg^?1 in the diets of laying hens. Copyright © 2009 Society of Chemical Industry     

Lipid oxidation of stored eggs enriched with very long chain n−3 fatty acids,as affected by dietary olive leaves (Olea europea L.) or α-tocopheryl acetate supplementation

The antioxidant potential of dietary olive leaves or α-tocopheryl acetate supplementation on lipid oxidation of refrigerated stored hen eggs enriched with very long-chain n−3 fatty acids, was investigated. Ninety-six brown Lohmann laying hens, were equally assigned into three groups. Hens within the control group were given a typical diet containing 3% fish oil, whereas other groups were given the same diet further supplemented with 10 g ground olive leaves/kg feed or 200 mg α-tocopheryl acetate/kg feed. Results showed that α-tocopheryl acetate or olive leaves supplementation had no significant effect on the fatty acid composition and malondialdehyde (MDA) levels of fresh eggs but reduced their lipid hydroperoxide levels compared to controls. Storage for 60 d decreased the proportions of polyunsaturated fatty acids (PUFAs) but increased those of monounsaturated fatty acids (MUFAs) in eggs from the control group, while had no effect on the fatty acid composition of the eggs from the other two groups, which showed decreased levels of lipid hydroperoxides and MDA. Therefore, the very long chain n−3 PUFAs in eggs were protected from undergoing deterioration partly by olive leaves supplementation and totally by α-tocopheryl acetate supplementation. In addition, incorporating tocopherols into eggs might also provide a source of tocopherols for the human diet.