• Korean journal of food and cookery science
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• v.13 no.2
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• pp.87-91
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• 1997

Egg yolk oil was obtained by roasting and Pressing egg yolks of hen's egg breeding on the open bin system and the cage system, respectively. Lipids in egg yolk oil were extracted with a mixture of chloroform and methanol (2 : 1, V/V), and fractionated into neutral lipid, glycolipid, and phospholipid by silicic aicd column chromatography. Fatty acid composition of each fraction was determined by gas chromatography. The major fatty acids of total lipids and neutral lipids are in sequence of oleic acid, palmitic acid, and linoleic acid. The major fatty acids of the glycolipids are palmitic acid, oleic acid, stearic acid, and lauric acid successively. The major fatty acids of phospholipids are oleic acid, lauric acid, and Palmitic acid consecutively. About the fatty acids composition of egg yolk oil in the open barn system, the contents of saturated fatty acid are lower and the contents of unsaturated fatty acid are higher than that of the case system. The contents of unsaturated fatty acid in egg yolk oil is higher than that of saturated fatty acid in total lipids and nutral lipids. Unsaturated fatty acid/saturated fatty acid of e99 yolk oil in the open barn system is higher than that of the cage system in glycolipids and phospholipids.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.831-836
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• 2001

Little information on the cholesterol content and the fatty acid composition of avian species other than chicken is available. This study was conducted to compare the yolk cholesterol content and the fatty acid profiles of some wild birds maintained in captivity on commercial grain-based chicken diets. The concentration of cholesterol/g of yolk as well as the total yolk cholesterol per egg varied among species. Yolk cholesterol concentration, expressed as mg/g of yolk, was highest in chukar, followed by pheasant, guinea fowl and quail, while total yolk cholesterol in an egg was highest in guinea fowl, followed by pheasant, chuckar and quail. An inverse relationship between yolk cholesterol concentration and egg weight was observed among species with an exception of quail. Although major fatty acids of egg yolk were oleic acid, palmitic acid, linoleic acid and stearic acid in all birds, the composition varied among species. Chukar and quail showed higher oleic acid content than pheasant and guinea fowl, while showing lower linoleic acid. Fatty acids of chukar and guinea fowl eggs were more saturated than those of pheasant and quail. Chukar and especially quail had higher monounsaturated fatty acids (MUFA) than pheasant and guinea fowl; in quail egg 51.6% of total fatty acids were MUFA. Polyunsaturated fatty acids (PUFA), essential fatty acids (EFA) and the ratio of PUFA to saturated fatty acid (P/S ratio) were higher in pheasant and guinea fowl than in chukar and quail. Differences in fatty acid profile of triglyceride (TG) among birds were largely similar to those of total lipid. In comparison to TG, phosphatidyl choline (PC) was low in MUFA while high in saturated fatty acids (SFA), PUFA, P/S ratio and EFA. PC was most saturated in guinea fowl egg yolk, followed by chukar, quail and pheasant. PUFA, P/S ratio and EFA in PC were highest in pheasant followed by chukar, guinea fowl and quail. PE was distinguished from PC by its high contents of stearic acid, eicosapentenoic acid (EPA) and docosahexenoic acid (DHA) while low in palmitic, oleic and linoleic acids. In egg yolk of all birds MUFA was significantly lower in PE than in PC except in quail. Compared to other species, quail had a considerably higher content of MUFA in PE at the expense of SFA and PUFA.

• Korean Journal of Poultry Science
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• v.21 no.2
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• pp.139-150
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• 1994

Egg cholesterol has been a hot issue in respect of it's effect on health and diseases in human. There is a general recognition that the cholesterol from eggs is similar to that from the other dietary sources in its biochemical functions. Many evidences show that egg yolk increased plasma cholesterol levels at an average rate of 2.3 mg /100 rnL plasma for every 100 mg cholesterol consumed. The elevation of plasma cholesterol could, however, be altered by various dietary factors such as ratios of polyunsaturated fatty acids and saturated fatty acids. Blood cholesterol levels of Korean adults have been raised up to, on the average, 193 and 187 mg /100 mL plasma for men and women, respectively, from 167/5 mg /100 mL in 1980. Furthermore, proportion of hypercholesterolemics(> 210 mg /dL) has been increased up to 23% of the population. These changes in blood cholesterol levels are attributed to the changes of dietary patterns, suggesting the arguement that Koreans are insensitive to changes of blood cholesterol is not right. Egg cholesterol levels have never been successfully reduced to any significant levels even with tremendous amounts of efforts made during last decades. The alternative and the best way to control blood cholesterol level originating from egg consumption appeares to enrich egg fat with omega-3 series fatty acids. Ingestion of the fatty acid group has specific functions to reduce hypertension and prevent various types of cancer as well as to reduce blood cholesterol. Another way to reduce egg cholesterol directly is to produce smaller egg yolk without reducing whole egg size since cholesterol is located only in the yolk. It is important to keep faith with consumers by providing correct informations on eggs, meanwhile efforts need to focus on to improve the quality of eggs as one of the best protein food items.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.444-449
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• 2006

This study investigated the effects of dietary supplementation of cheese byproduct on performance, egg quality and fatty acid profile of egg yolk lipids from laying hens. One hundred five 30-wk-old White leghorn laying hens were randomly distributed into five groups of twenty one hens each and maintained in individual laying cages for 4 weeks. The hens were assigned to five treatments that consisted of corn-soybean meal based diets containing 0, 1, 3, 5 or 10% of cheese byproduct. Feed intake and rate of egg production of hens were not significantly different across the treatments during the whole experiment (p>0.05). Similarly, egg yolk cholesterol level, egg weight, Haugh's unit, eggshell thickness, color, and strength were not significantly different across the treatments (p>0.05). The amount of C16:0 in egg yolk was not significantly different across the treatments, but that of C18:0 decreased with increased cheese byproduct (p<0.01). Monounsaturated fatty acid (C16:1 and C18:1) content in egg yolk was similar across the treatments. Total CLA and cis-9, trans-11 CLA content increased linearly with increased cheese byproduct (p<0.001), while trans-10, cis-12 CLA amount was not significantly different across the treatments (p>0.05). Total saturated fatty acid (SFA) in the egg yolk was decreased as the level of cheese byproduct including CLA increased (p<0.01). However, the amount of unsaturated fatty acids (UFA) such as monounsaturated fatty acids (MUFA), n-3 polyunsaturated fatty acids (PUFA), n-6 PUFA, and total PUFAs in the egg yolk were not significantly different across the treatments (p>0.05). Therefore, the present results showed that cheese byproduct beneficially improved the fatty acid composition of concern to human health in the egg yolk without adverse effects on egg quality.

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.145-151
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• 1997

This study was conducted to investigate the influence of dietary olive oil, canola oil, or sardine oil on the fatty acids composition and cholesterol contents in eggs The experimental layers, 62~65 weeks of age, were randomly allotted to one of the four treatments; a) Control (commercial feed), b) T1 (commercial feed plus 10% olive oil), c) T2 (commercial feed plus 10% sardine oil), d) m (commercial feed plus 10% sardine oil) for 3 weeks. The egg samples were stored at 4${\pm}$1˚C for a certain period (1, 3, 5, 7, and 9 days) and analyzed for the fatty acids composition and cholesterol contents. The unsaturated fatty acid contents in the egg yolk were slightly decreased as the storage periods extended. The oleic acid content in T1 was the highest in all treatments. The linoleic and linolenic acid contents in T2 were higher than in the other treatments. The eicosahexaenoic acid (EPA), docosapentaenoic acid (DPA), and docosasahexaenoic acid ( DH A) contents in eggs from m were higher than the other treatments. The ratio of egg yolk n-6 /n-3 fatty acids contents in all treatments were slightly increased as the storage periods extended. The n-3 fatty acid contents of the egg yolk from T3 was the highest in all treatments. The cholesterol contents of the eggs were significantly decreased as the storage period extended(P<0.05). There was no significant difference in egg cholesterol content among all treatments.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.184-188
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• 2002

The fatty acid contents of egg yolk from various chicken eggs such as general egg, ginseng egg, gamgoal egg and docosahexaenoic acid (DHA) egg were analysed during storage at 4$^{\circ}C$ for 3 weeks. The major fatty acids of all egg yolk oils were oleic acid (18 : 1) and palmitic acid (16 : 0). The contents of both fatty acids reached maximum at the first or second week and decreased at the third week. DHA was detected from 4 kinds of eggs stored for 2 or 3 weeks. The n-6/n-3 ratio was obtained under recommended intake range in fresh gamgoal egg and in general and DHA eggs stored far 0~3 weeks. For 3 weeks, polyunsaturated fatty acid / monounsaturated fatty acid/ saturated fatty acid (P/M/S) ratio of DHA e99 did not chance, but that of ginseng e99 gradually increased. The P/M/S ratio was generally maintained under recommended intake range in general egg stored for 3 weeks, in ginseng egg stored for 2 weeks and in DHA egg during all the storage period.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.14-19
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• 2001

This study was designed to compare content and composition of fatty acid in egg yolk oil among general eggs from chicken, quail, duck. We also compared those of general and functional chicken egg. Fatty acids were determined by GC method and the results were as follows: Palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid and timnodonic acid were identified in egg of chicken, quail and duck. The major fatty acid was oleic acid and palmitic acid in three kinds of eggs. Arachidonic acid and docosahexaenoic acid (DHA) were analyzed in egg of quail , but no in chicken. Monounsaturaterd fatty acid (MUFA) was higher in egg yolk oil of chicken and quail. Polyunsaturated fatty acid (PUFA) was higher in duck egg. Ginseng egg had significantly higher palmitic acid and oleic acid lower than general chicken egg. Gamgoal egg had lower palmitic acid and oleic acid, and higher palmitoleic acid and stearic acid than general chiekcn egg. The content of oleic acid was lower in DHA egg than in general chiecken egg, but arachidonic acid was detected only in DHA egg. Ginseng egg had the highest content of saturated fatty acid among chicken eggs. The content of MUFA acid was the highest in gamgoal egg and general chicken egg. DHA egg had the most amount of PUFA among all chicken egg.

• Animal Bioscience
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• v.34 no.1
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• pp.119-126
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• 2021

Objective: This study aims to evaluate the effects of dietary supplement of rubber seed oil on production performance, egg quality, and yolk fatty acid composition in laying hens during a 16-week feeding trial period. Methods: Forty-eight 25-week-old laying hens of Hy-Line Brown were randomly divided into three groups. Each group comprised four replicates and each replicate had four birds. Rubber seed oil was incorporated into a corn-soybean meal basal diet by 3.5% (group I), 4.5% (group II), or 0 (control group) and equivalent nutrition was supplied for the test groups and the control group. The performance related values were determined using standard or well established methods. Results: No significant difference was found in the production performance, the egg quality, the composition of saturated fatty acids, and the content of cholesterol and monounsaturated fatty acids in the yolk within the three groups. Interestingly, both test groups achieved a significantly higher content of linoleic acid, α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid and a significantly lower content of arachidonic acid (p<0.05) compared with the control group. With the increased level of dietary rubber seed oil, there was an increasing trend in the content of n-6 polyunsaturated fatty acids (PUFA), n-3 PUFA and total PUFA, but a declining trend in the n-6/n-3 ratio. Conclusion: These results demonstrate that the rubber seed oil supplemented diet effectively improved the total PUFA content in eggs without impairing the layers' production performance and the egg quality.

• Korean Journal of Poultry Science
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• v.39 no.4
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• pp.261-267
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• 2012

Different housing systems have considerable influence on performance in poultry production. Therefore, the present study was undertaken to investigate the impact of different housing systems on the performance, bone mineral density and egg yolk fatty acid composition in laying hen. Hy-line brown pullets (n=450) of 12 weeks age were randomly divided into 3 housing systems with 6 replicates of 25 birds in each room. A diet with 2,750 kcal/kg ME and 16.5% CP was assigned to all birds. The pullets provided free access to feed and water. Significantly (P<0.05) higher values for egg production, egg mass and feed conversion efficiency were found in battery cages, however egg weight, egg shell color and breaking strength was remarkably (P<0.05) higher in floor system. The albumin height and Haugh unit were significantly higher (P<0.05) in battery cages which was statistically similar to aviary housing system. The egg yolk fatty acids concentration of linoleic acid and linolenic acids were significantly higher in aviary and in floor system, respectively, however both values were lower in battery cages. Saturated and unsaturated fatty acid content (%) in egg yolk did not influence by any housing systems. Bone mineral density was significantly higher (P<0.05) in floor and aviary housing system than that of battery cage system. It was concluded that in battery cages the egg production and composition maximized, however higher bone mineral density and yolk fatty acids content can be improved in the laying hen reared on floor and aviary housing systems.

• Korean Journal of Organic Agriculture
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• v.12 no.2
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• pp.171-181
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• 2004

A study was conducted to investigate the effect of supplementing earthworm meal (EWM) on the performance of spent laying hens after induced molting, and fatty acid composition in egg yolks. A total of 90 laying hens at 73 weeks of age were fed the experimental diets containing 0.0% (Control) and 0.2% of EWM for 4 weeks. Eggs were collected and weighted every day and Egg production and feed conversion were recorded every week during the experimental period. However fatty acid composition of egg yolk were measured at last week of experimental period. An amount of feed intake increased by supplemental with EMW except for Erst week experimental period (P<0.05). When 76 and 77 week of age, egg production and daily egg mass were improved by the supplemented with EWM (P<0.01), but average egg weight was not different when fed a EWM, therefore feed/egg mass was significantly decreased when fed a EWM. The ratio of egg yolk n-6/n-3 fatty acids contents was significantly improved fed a EMW (P<0.05). It is concluded that supplementing 0.2% of earthworm meal in the spent laying hens after induced molting was fast in recover of physical strength, therefore improves laying performance.