Combined Effect of Feed and Housing System Affects Free Amino Acid Content of Egg Yolk and Albumen in Brown Layer Chickens
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In recent years, the market share for cage-free eggs has gradually increased. Because commercially available cage-free eggs are often produced not only by several housing systems but also with different feed crude protein (CP) levels, there are combined effects of feed and housing systems between cage-free and cage eggs. Therefore, using field data, this study aimed to determine the combined effects of feed and housing systems on egg traits and yolk and albumen amino acids in table eggs. Brown layers (n = 40) at the middle laying stage under two feed and housing systems (cage, CP 15.5% diet; barn, CP 17.0% diet) were used. One-way analysis of variance and Pearson's correlation analysis were used to evaluate 10 egg traits, 19 yolk amino acid traits, and 20 albumen amino acid traits. We observed significant effects of feed and housing on two egg traits (yolk weight and eggshell color redness), 16 yolk amino acids (Asp, Glu, Asn, Ser, Gln, His, Arg, Thr, Ala, Tyr, Met, Cys, Ile, Leu, Phe, and Lys), and 14 albumen amino acids (Asp, Asn, Ser, Gln, Gly, His, Arg, Thr, Ala, Val, Met, Cys, Ile, and Leu). This study revealed that eggs from the barn system (CP 17.0%) contained higher levels of free amino acids in 15 yolk and nine albumen amino acid traits. Phenotypic correlations among the 49 egg traits indicated similar correlation patterns in both systems, which implies that the balance of free amino acid content in yolk and albumen is similar in each system. Although some potential confounding factors may be present for comparing egg content between cage (CP 15.5%) and barn (CP 17.0%) systems, this study suggests that commercially available cage-free eggs may be different from cage eggs not only in external egg traits but also yolk and albumen amino acid traits.Keywords:
Yolk
Egg albumen
The purpose of this investigation was to test the influence of increasing amounts of albumen and selected additives on selected characteristics of liquid egg yolk. Yolks were blended with albumen at levels of 0, 5, 10, 15, 20 and 25% and tested for emulsifying capacity, viscosity, pH and solids content. The emulsifying properties decreased significantly with increased amounts of albumen. At 20% albumen, emulsifying power of yolk was reduced by 50%. Viscosity of liquid egg yolk decreased nearly 80% when diluted with only 10% albumen. There was only a slight increase in pH with addition of up to 25% albumen. The percent solids decreased linearly from 53.2% to 42.4%, as the albumen level increased from 0 to 25%. Since 20% albumen dilution reduces egg yolk emulsifying capacity by nearly 50%, it is suggested that for commercial operations, where emulsifying properties are important, that every effort be made to limit the level of albumen contamination to below 20% and, preferably, to 15%. Addition of sodium stearoyl-2-lactylate at 0.05% significantly (P < 0.01) increased the emulsifying capacity of yolk; however, lecithin at 0.05% significantly reduced emulsifying ability.
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Egg albumen
Dilution
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As an excellent foaming agent, egg white protein (EWP) is always contaminated by egg yolk in the industrial processing, therefore, decreasing its foaming properties. The aim of this study was to simulate the industrial EWP (egg white protein with 0.5% w/w of egg yolk) and characterize their foaming and structural properties when hydrolyzed by two types of esterase (lipase and phospholipase A2). Results showed that egg yolk plasma might have been the main fraction, which led to the poor foaming properties of the contaminated egg white protein compared with egg yolk granules. After hydrolyzation, both foamability and foam stability of investigated systems thereof (egg white protein with egg yolk, egg white protein with egg yolk plasma, and egg white protein with egg yolk granules) increased significantly compared with unhydrolyzed ones. However, phospholipids A2 (PLP) seemed to be more effective on increasing their foaming properties as compared to those systems hydrolyzed by lipase (LP). The schematic diagrams of yolk fractions were proposed to explain the aggregation and dispersed behavior exposed in their changes of structures after hydrolysis, suggesting the aggregated effects of LP on yolk plasma and destructive effects of PLP on yolk granules, which may directly influence their foaming properties.
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Egg albumen
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Egg albumen
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Ovomucoid is a egg white protein which has a strong allergenicity with a unique characteristic in heat-noncoagulable one contrast to heat-coagulable other major egg white proteins. By ELISA and immunoblots analysis, ovomucoid was detected in heat-coagulated egg yolk after immediate boiling of hen's egg for 15 min (boiled egg) at the concentration of 4.8 +/- 0.8 micrograms/g egg yolk, but not detected in raw egg yolk collected by insertion of a needle into the egg yolk cavity. Ovomucoid in heat-coagulated egg yolk was increased by standing the boiled eggs at room temperature for 10, 30, 60 and 120 min at the concentration of 7.5 +/- 3.4, 17.2 +/- 15.1, 28.1 +/- 5.9 and 78.8 +/- 31.3 micrograms/g egg yolk, respectively. The soluble fraction prepared from heat-coagulated egg white of boiled egg contained 37.7 +/- 3.2 mg/ml of proteins including 14.2 +/- 11.9 mg/ml of ovomucoid as a major and miners of detectable ovalbumin and ovotransfferin. These results suggested that the appearance of ovomucoid in coagulated egg yolk of boiled egg was due to passing the soluble fraction rich in ovomucoid in heat-coagulated egg white through into the coagulated egg yolk, which may have notable consequences for the present of ovomucoid as a major egg white allergen in yolk egg of boiled egg.
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Egg albumen
Egg allergy
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Experiments were conducted to evaluate the effect of albumen pH on the incidence and degree of yolk mottling. Eggs stored for 5 days at 24° C. in a high CO2 or HCl environment, oiled on the top half or completely oiled had lower albumen pH and less yolk mottling than untreated control eggs. Eggs with higher albumen pH had the greatest degree of yolk mottling and lowest vitelline membrane weight. Washed eggs had higher albumen pH and more yolk mottling after 5 days of storage at 24° C. than unwashed eggs. Albumen pH and yolk mottling increased during storage. Oiling the eggs reduced the increase in albumen pH and yolk mottling during storage. Vitelline membrane weight decreased during storage, but was retarded in oiled eggs. Membranes retained in buffers of pH 7.6, 8.0, 8.4, 8.8, or 9.2 for 15 or 24 hours decreased in weight as the pH increased and a significant decrease was obtained at the two higher pH’s. These experiments support the idea that increasing albumen pH causes increased yolk mottling, probably by altering the vitelline membrane.
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Acetylsalicylic acid (ASA), the active ingredient of aspirin, has been evaluated as a potential feed ingredient in laying hen rations because of its antipyretic and antiprostaglandin properties. Therefore, the present study was designed to determine whether dietary ASA or its metabolites are transferred to the egg. A single oral dose of 14 C-carboxyl-labeled ASA administered to White Leghorn hens resulted in eggs containing approximately .02% of the administered dose. More 14 C-label was found in the first egg laid than in subsequent eggs laid, and more 14 C-label was detected in the albumen than in the yolk when eggs were analyzed on an entire egg component basis. The distribution of the 14 C-label changed markedly with each egg laid, as 96.5, 33.5, and 12.0% of the radioactivity was present in the albumen in the first three eggs laid following dosing. Conversely, 3.5, 66.5, and 88.0% of the egg radioactivity was present in the yolk of the first three eggs laid postdosing. White Leghorn breeder hens fed .100, .200, and .400% ASA for an entire (13 mo) production cycle laid eggs containing measurable amounts of salicylic acid (SA, the major metabolite of ASA) in the albumen and yolk, with no detectable levels found in eggs of hens fed 0, .025, and .050% ASA. Again, more SA was detected in the albumen than in the yolk, when expressed either on a per gram or entire egg component basis, from hens fed .200 and .400% ASA. Thus, it appears that ASA can be fed to hens at dietary levels of .05% or lower for an entire production cycle without detectable accumulation (<5 ppm) of SA in the egg yolk or albumen.
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Egg albumen
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Egg weight, component weights, yolk and albumen indices and Haugh units of a sample of 84 eggs of Isa-Brown (IB) and Nigerian Local Chicken (NLC) respectively were studied. 18 and NLC hens were raised under the intensive system and fed oommen:ial layer mash (15.6 C.P, 3.6% Ca. aad 2850 Kcal ME/Kg). Hens of the two genotypes (IB and NLC) were in their 48th week in lay at the st.art of the study. Mean egg panameters of IB were 59.18, 15.57, 37, 13 and 6.33 for egg, yolk, albumen and shell weights respectively. Corresponding me:.n values for NLC egg were 40.6Sg (egg wt.), 14.97g (yolk weight), 21.37g (albumen wt.) and 4.18g (sheU wt.). Egg shell thickness for IB and NLC were 0.35 and 0.30mm respectively. However, peReat yolk ia NLC was 10.53% higher than for m. Baugh unit, JOlk and albumen iadices were significantly higher for IB than for NLC eggs. Moderate to strong relationships were obtained between egg weight and component weights in both genotypes. Percent yolk showed some decrease w•ile albumen weight increased with egg size ia botll groups. Keywords : Egg quality parameters, Isa- Brown, Local Chicken
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Haugh unit
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To compare the egg nutrition in different culture models,the egg quality and nutrition of coop-reared and free-reared hen's were determined.The results showed that egg weight,the ratio of albumen/yolk,albumen or yolk/the whole egg were significant(p0.05) between coop-reared and free-reared hens.The content of water in whole fresh eggs,the ashes,fat and cholesterol in yolk were significant in difference.But the protein,carbohydrate and lecithin were not significant in difference.
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Egg albumen
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A kit, FASTKIT ELISA version II (Egg) (Nippon Meat Packers) is an enzyme-linked immunosorbent assay kit for detecting hen's egg proteins in foodstuffs. This kit is an enhanced version of FASTKIT ELISA (Egg) with a greater efficiency in terms of extraction of egg proteins from heated foodstuffs. However, the property of this kit remains to be fully elucidated.Using this new kit, we measured the amount of egg proteins in unheated or heated (140 degrees C or 180 degrees C, 20 min) homemade cookies containing whole egg, egg white or egg yolk.The capability for detection of unheated or heated (140 degrees C or 180 degrees C) whole egg proteins was similar. In addition, there was no significant difference in the detectability between heated (140 degrees C) whole egg and egg white proteins. However, unheated or heated (140 degrees C or 180 degrees C) egg yolk proteins were not sufficiently measured by this kit.Our data suggest that this new kit is significantly improved for detection of heated egg white proteins as compared to that of old version, but not sufficient for detection of egg yolk proteins.
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Abstract The composition of the yolk and albumen content in the egg was 60 and 30%, respectively. The purpose of this paper is to examine the fatty acid profile (FA) of egg yolk and albumen in cemani and white leghorn chickens. Cemani and white leghorn chickens were given a commercial feed of 110 g/head/day, and drinking water was given ad libitum. Two fresh eggs from each hen were used in this study to examine egg yolk and albumen fatty acids by gas chromatography. The data obtained were analyzed statistically with an independent sample T-test. The results showed that the FA profiles of egg yolk and albumen were not significantly different (P>0.05) for the parameters of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) from chicken. Cemani and white leghorn chickens, monounsaturated fatty acids (MUFA) are found in more amounts than SFA and PUFA in egg yolks and albumen. It can be concluded that the FA profiles of cemani and white leghorn chickens are almost the same.
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