Yolk Fractions Research Articles

Research Note: Comprehensive proteomic, phosphoproteomic, and N-glycoproteomic analysis of chicken egg yolk plasma

Chicken egg yolk plasma (EYP), the supernatant fraction of egg yolk obtained by water dilution and centrifugation, is a rich source of various bioactive substances and a significant bearer of yolk-emulsifying properties. This study utilized proteomics to conduct a comprehensive and in-depth analysis of both common and modified EYP proteins (phosphorylated proteins and N-glycosylated proteins). Total of 208 proteins were identified in EYP, including 42 phosphorylated proteins with 137 phosphorylation sites and 150 N-glycoproteins with 332 N-glycosylation sites. Among the phosphorylation sites, tyrosine accounted for 80.6%, while the N-glycosylation sites predominantly featured "N-X-T" motifs, accounting for 58.7%. Functional enrichment analysis revealed that most proteins were involved in regulating enzyme activity and inhibition with a particular focus on modulating peptidase activity. Notably, vitellogenins-2 (30 phosphorylation sites, 9 N-glycosylation sites) and apolipoprotein B (10 phosphorylation sites, 56 N-glycosylation sites) were the 2 proteins with the most modification sites. Additionally, EYP was found to contain the highly N-glycosylated complement proteins C3 and C4. These findings provide new insights into the protein composition of EYP and its roles in chicken embryo development and immune defense, offering a theoretical foundation for the application of EYP in various fields.

Albumen and Yolk Plasma Peptidomics for the Identification and Quantitation of Bioactive Molecules and the Quality Control of Hen Egg Products.

Hen eggs and the correspondingfood products are essential components of human diet. In addition to supplying basic nutrients, they contain functional peptides that are released in vivo within the intact raw material following physiological proteolytic events affecting specific proteins or derive from technological processing of albumen and yolk fractions as a result of the dedicated use of proteases from plant and microbial sources. Besides their potential importance for functional applications, peptides released under physiological conditions in intact egg can be used as markers of product storage and deterioration. Therefore, characterization and quantitation of peptides in egg and egg-derived products can be used to implement evaluation of potential bioactivities as well as to assess food product qualitative characteristics. Here, we provide dedicated information on extraction, identification, and quantitative analysis of peptides from albumen and yolk plasma; nano-liquid chromatography-mass spectrometry combined with bioinformatic analysis of resulting raw data by different software tools allowed to assign molecules based on database searching and to evaluate their relative quantity in different samples.

New Processes to Extract and Purify Phosvitin by Using Aqueous Salt Solutions, Precipitation and Ultrafiltration Techniques

Phosvitin is the most phosphorylated naturally occurring protein and it is concentrated in the granular fraction of egg yolk. It has interesting antioxidant and cation chelating properties that can be used to preserve food and cosmetics, but its industrial application is limited as its separation relies on the use of organic solvents and chromatographic techniques, which are expensive and difficult to assimilate in a continuous procedure. In this study, we propose a new phosvitin separation process using substances legally accepted for use in the food industry (NaCl and HCl), employing egg yolk granules as raw material. In this case, the NaCl concentration and the pH of the solution of granules were screened in order to obtain a phosvitin-rich supernatant after centrifugation. Additionally, two new processes were proposed to purify this phosvitin-rich solution. The first was the precipitation of impurities during the desalting stage at optimized pH values. The second was ultrafiltration under selected pH value conditions. A low nitrogen/phosphorous (N/P) atomic ratio is considered a quality parameter, with 3.6 ± 0.2 being the value of the phosvitin-rich supernatant. The two purification processes provided highly purified phosvitin with a similar N/P value of 2.5 ± 0.1. The high level of purification of the phosvitin was confirmed using electrophoresis and ion-exchange chromatography. In particular, the purified phosvitin obtained via ultrafiltration is already desalted and membrane technology is more easily scalable than that based on chromatography, thus facilitating the industrial separation and commercialization of the phosvitin.

Identification of potent antioxidant bioactive peptides from the soluble proteins of chicken egg yolk

Background: Eggs are an excellent nutrient-dense food containing proteins, fats, carbohydrates, minerals, and vitamins. While many proteins are present in egg yolk, there arefew studies on their health benefits. Objective: The aim of this study was to explore the antioxidant peptides derived from the soluble protein fractions of egg yolk. Lipids and lipoproteins were removed with activated carbon and centrifugation after water dilution at acidic pH. Materials and Methods: Compared with 3.6 grams of protein in egg white, egg yolk contains 2.7 grams of protein in a single large egg. The egg yolk soluble protein (EYsP) was digested with pepsin for 2h at pH 3.0 (P-EYsP), followed by digestion with trypsin (P-EYsP-T), α-chymotrypsin (P-EYsP-α), or both enzymes (P-EYsP-T/α). The most active digest was fractionated using sephacryl S-100 gel filtration, followed by reversed phase-HPLC of the most active fraction. The antioxidant activities were evaluated using a superoxide anion-generating system of xanthine oxidase, DPPH-scavenging assay, and yeast cells as an oxidative-stress tolerance cellular model. Results: The intact proteins (EYsP) showed antioxidant activity, but pepsin hydrolysate (P-EYsP) exhibited greater superoxide-scavenging activities than EYsP, while P-EYsP-T, P-EYsP-α and P-EYsP-T/α lacked activities. The P-EYsP and its subsequent proteases (P-EYsP-T, P-EYsP-α and P-EYsP-T/α) exhibited significant DPPH reduction, but P-EYsP-T, P-EYsP-α and P-EYsP-T/α exhibited the strongest DPPH reduction activities. MALDI-TOF-MS analysis revealed five major antioxidant peptides, two derived from yolk glycoprotein 40 (859 Da, 883Da), two from lipovitelline (901Da, 945 Da), and one from livetin (1089 Da). The peptides exhibited potent superoxide anion as well as DPPH scavenging activities and markedly enhanced the tolerance of yeast cells against peroxide-induced oxidative stress.Conclusion: The results show that these bioactive peptides hold a fascinating opportunity for their potential as nutraceuticals in prevention and combating oxidative stress-associated diseases.Keywords: Egg yolk proteins; bioactive peptides; antioxidant; superoxide-scavenging; DPPH-reduction; yeast tolerance

Towards the purification of IgY from egg yolk by centrifugal partition chromatography

Although their high potential as alternative biopharmaceuticals, less than 2% of the total polyclonal antibodies produced worldwide correspond to immunoglobulin Y (IgY) due to the difficulties in isolating them from egg yolk (complex biological matrix). In this work, the water-soluble proteins fraction (WSPF) of egg yolk was first obtained and the proteins present identified by one-dimensional gel electrophoresis (SDS-PAGE) and label-free quantitative nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS). The egg yolk WSPF was then applied to create aqueous biphasic systems (ABS) composed of polyethylene glycol 1000 g·mol−1 (PEG 1000) and K2HPO4/ KH2PO4 buffer, followed by centrifugal partition chromatography (CPC) to purify IgY. The characterization of the WSPF showed the presence of six major proteins: the target antibody IgY, serum albumin (α-livetin), ovalbumin, ovotransferrin, vitellogenin 1 and vitellogenin 2. The results obtained by ABS revealed a high affinity of all proteins to the polymer-rich phase. However, by changing the PEG and salt concentrations, a higher selectivity was observed for IgY, with the remaining proteins partitioning between the two phases. The best ABS were applied in CPC, finally allowing a multi-stage partition and to the technology scale-up. The CPC operating conditions were optimized, allowing to obtain IgY with 50.6% of purity.

A comparative study of unpasteurized and pasteurized frozen whole hen eggs using size-exclusion chromatography and small-angle X-ray scattering

Hen eggs are rich in proteins and are an important source of protein for humans. Pasteurized frozen whole hen eggs are widely used in cooking and confectionery and can be stored for long periods. However, processed eggs differ from raw eggs in properties such as viscosity, foaming ability, and thermal aggregation. To develop pasteurized frozen whole egg products with properties similar to those of unpasteurized whole eggs, it is necessary to establish a method that can differentiate between the two egg types with respect to the structures of their proteins. In this study, size-exclusion chromatography (SEC) and SEC coupled with small-angle X-ray scattering (SEC-SAXS) were successfully used to differentiate between the proteins in unpasteurized and pasteurized frozen whole eggs. We found that proteins in the plasma fraction of egg yolk, especially apovitellenins I and II, formed large aggregates in the pasteurized eggs, indicating that their structures are sensitive to temperature changes during pasteurization, freezing, and thawing. The results suggest that SEC and SEC-SAXS can be used to differentiate between unpasteurized and pasteurized frozen whole eggs. Additionally, they may be useful in determining molecular sizes and shapes of multiple components in various complex biological systems such as whole eggs.

Caracterização reológica de ovos rhea (Rhea americana) submetidos a diferentes períodos de armazenamento

Abstract Eggs are used as food industry ingredients due to their functional properties. Eggs from different bird species are used in industrial processing; therefore, rheological experiments were carried out at steady state to obtain the flow curves and also at a dynamic state to study the rheological properties of greater rhea eggs. The viscoelastic behavior of the fluids as a function of the coagulation temperatures for albumen and yolk and of the oscillatory shear frequency was studied. Fifteen rhea eggs stored for up to 28 days at 10 °C were analyzed at 1, 7, 14, 21, and 28 days. The albumen and yolk fractions showed pseudoplastic rheological behavior with small initial flow shear and dependence on shear time, with albumen demonstrating thixotropy and the yolk showing rheopexy. In low shear rheological tests, thermal gelation of albumen was observed, presenting a first change in the elastic modulus around 56 °C, and a second from 78 °C. In the yolk, a change was observed from 66 °C, with more structural variations in the development of the gel at higher temperatures. For rhea eggs, the gel structuring (gelation) temperature of albumen (80 °C) and egg yolk (69 °C) did not undergo variations during the storage periods. Compared to commercial eggs, the higher viscosity and gelation temperatures presented by the rhea eggs can help determine the size of the industrial processing system as they can be submitted to higher temperatures without modifying protein structures and hindering the process.

Comparative study of herbal and non-herbal egg protein profile using High Performance Liquid Chromatography (HPLC)

The purpose of this research is to compare the protein profile of herbals egg and non herbal egg using High Performance Liquid Chromatography (HPLC). This research used HPLC Shimadzu 6.1 with column C18, flow rate mobile phase 1 ml/min, wavelenght detector UV Vis 220 nm and temperature 50o C. Mobile fase that used in this research was 10 and 60 % acetonitril (CH3CN) in water containing 0,05% triflouroacetic acid. Supplementation of herb containing bioactive antioxidant compounds affect the formation of egg yolk protein containing immunoglobulin. In this study, herbal eggs and non-herbal eggs were seen from their protein profile using the high performance liquid chromatography (HPLC) method and then analyzed using descriptive qualitative analysis. The result show that herbal egg yolk sample has a dominant protein with a molecular weight of 50.41 kDa. Herbal egg yolk protein appears at a retention time (RT) of 56.87 minutes, an area of 3303488 units of area, and the peak height of the graph / peak at 50,974 µAU. Meanwhile, non-herbal egg yolk sample has a dominant protein with a molecular weight of 49.94 kDa. This protein appears at a retention time of 1.307 minutes, an area of 149445550 units of area, and the peak height of the graph / peak at 402.6026 µAU. The results showed that the the peak of HPLC indicated an antioxidants were bound to the bioactive protein fractions of egg yolk. It could be concluded that bioactive herbal bound to egg yolk igY, but the bioactive compounds have not been identified yet.

In vitro digestion of folate in yolk and granule fraction as tested in a dynamic, computer-controlled model of stomach and small intestine

In our previous studies, we showed that egg yolk fractionation by centrifugation can lead to complete separation of folate in granule fraction of egg yolk which has two folds more protein than egg yolk. Folate in egg yolk presents in the form of 5-methyltetrahydrofolate (5MTHF), a predominant type of highly available form of folate. However, evidence is lacking as to the bioaccessibility of the 5MTHF in granule fraction separated through water-based fractionation technique. Thereby, a dynamic and computer-controlled gastro-small intestinal system was used to study and compare the distribution of 5MTHF throughout intestinal compartments during digestion of egg yolk and granule fraction in their native form. As granule fraction of yolk composed of higher protein content compare to egg yolk, the dialysis profile of protein change during the process for yolk and granule was determined. The 5MTHF was stable during digestion with average recoveries of 58% and 42% in granule and yolk, respectively. The present work is the first to present data on the bioaccessibility of natural folate from egg yolk granule and shows the potential of egg yolk granules as «natural» delivery system of 5MTHF.

Comparative Study on Foaming Properties of Egg White with Yolk Fractions and Their Hydrolysates.

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.

Freeze-thaw stability of emulsions made with native and enzymatically modified egg yolk fractions

Frozen storage of food emulsions can increase their tenability and create possible applications in frozen food products. However, coalescence and phase separation can occur during freezing/thawing. In order to assess options for mitigating freeze/thaw-destabilization, egg yolk's emulsifying functionality in the form of whole egg yolk and its granula and plasma fractions was investigated. The fractions were enzymatically pretreated (phospholipase A2) and their emulsifying functionalities were assessed in dependence of pH, salinity, freezing velocity and frozen storage time with oil droplet size and phase separation as measures. Mayonnaise-type oil in water emulsions of sunflower oil were prepared at pH 3, 4 and 6.5 with a salt content of 0.15 and 0.55 M NaCl with a colloid mill. The emulsions were frozen to −20 °C with varying freezing rates and stored up to 24 h. Egg yolk and plasma stabilized emulsions showed higher freeze/thaw stabilities than granule stabilized emulsions. Enzymatic treatment increased the stability of emulsions prepared with egg yolk and granula, but decreased the stability for plasma stabilized emulsions. The destabilization increased with longer frozen storage time. Very slow or fast freezing velocity resulted in higher destabilization effects than an intermediate freezing rate at low salt content. Increasing salinity from 0.15 to 0.55 M NaCl as well as increasing pH from 3 to 6.5 resulted in more stable emulsions and highest destabilization at the highest freezing rate.

Emulsifying properties of plasma fractionated from egg yolk using low centrifugal forces—Mayonnaise preparation

Egg yolk can be fractionated into two fractions, plasma and granule, at high centrifugation force. This work was designed to study the influence of using low centrifugal forces (2000 to 6,000 ×g) for a short time (5 min) on the fractionation efficiency. The chemical composition and emulsifying properties (oil droplet size and stability against creaming) of fractionated plasmas were also investigated. The results showed that the separation efficiency of granules was significantly increased with increasing centrifugal force. No significant difference was found in emulsifying properties of plasmas fractionated at all centrifugal forces compared to whole egg yolk. Plasma fractionated at 5,000 and 6,000 ×g was further applied for mayonnaise preparation. Mayonnaises prepared from plasmas showed no significant difference in the rheological and colorimetric properties compared to whole egg yolk. Plasma prepared from low centrifugal force, compatible to industrial setting, maintains its original emulsifying properties and is applicable for mayonnaise preparation. Novelty impact statement Although many years of research on fractionation of egg yolk fractions, industrial application of egg yolk fractions is rare. Literature information on this field was relied on high centrifugal forces of fractionation. The conditions we applied using low centrifugation forces are thus significant to help the industry realize the potential of value-addition to egg yolk component such as phosvitin in the granule while using the plasma fraction for its emulsifying property. The obtained results suggested that plasma prepared using low centrifugal forces showed comparable rheological properties and was applicable for preparing mayonnaise, which indicates its potential in future industry application.

Water dynamics in eggs by means of Nuclear Magnetic Resonance relaxometry

1H Nuclear Magnetic Resonance relaxometry has been applied to reveal dynamical properties of water molecules embedded into egg yolk and white of three species: turkey, chicken and quail. Two fractions of water molecules, referred to as confined-water and free-water fractions, have been revealed. It has been demonstrated that translation diffusion of the confined-water fraction is three-dimensional. The dynamics of the confined-water has been quantitatively described in terms of diffusion coefficients and rotational correlation times. The parameters have been compared for egg yolk and white for all the species. In addition to these quantities, the number of the confined-water molecules per unit volume has been provided for all cases. The obtained parameters provide insight into the dynamics of water in eggs of different origin and allow to identify similarities and differences between them in connection to the structure of the network formed by the macromolecular fraction of egg yolk and white.

Monitoring UV-accelerated alteration processes of paintings by means of hyperspectral micro-FTIR imaging and chemometrics

We explored the potential of infrared hyperspectral microimages to investigate the alteration of organic binders in pictorial layers after artificial UV light ageing. A set of paint mockups was prepared considering three different binders, namely, rabbit glue (a collagen-based proteinaceous binder), linseed oil (representative of drying oils) and egg tempera (a mixture of egg yolk and linseed oil). Four pigments (vermilion, orpiment, azurite and lead white) were considered in order to investigate the influence of pigment-binder interaction, following color changes by means of fiber optic reflectance spectroscopy (FORS). FTIR micro-images provided a representative picture of the complex and heterogeneous structure of paintings since each pixel contained the whole spectrum of the sample area from it was recorded. Principal component analysis (PCA) was used to analyze the FTIR images data in order to extract useful information about spectral changes taking place during UV induced ageing.Significant trends were observed, mainly depending on the binders and their degradation as a consequence of UV exposition in this pilot study on model samples. Several processes, such as the oxidation of proteins with the formation of carbonyl moieties and changes in amide band positions have been detected in the case of rabbit skin glue. The evaporation of linseed oil, probably due to the breakdown of the triacylglycerols, has been noticed for the binder alone but not when it was mixed with the pigments. In these cases, other spectral features depending on the pigment have been observed in the loading plots upon oxidation, namely the broadening of the carbonyl band, the appearance of carboxylic and dicarboxylic acids and the formation of metal carboxylates. For egg tempera, the main changes detected were related to the oxidation of lipidic components present in egg yolk fraction. Furthermore, in this case, the trend observed in the score graphs suggested that the presence of lead white accelerates its oxidation. It is interesting to note the major stability of the colored pigments when using this binder.

3D Cell Culture of Human Salivary Glands Using Nature-Inspired Functional Biomaterials: The Egg Yolk Plasma and Egg White

The egg yolk plasma (EYP)—a translucent fraction of the egg yolk (EY) obtained by centrifugation—was tested as a developmentally encouraging, cost-effective, biomaterial for salivary gland (SG) tissue engineering. To find optimal incubating conditions for both the human NS-SV-AC SG acinar cell line and SG fibroblasts, cells were stained with Live/Dead®. The cellular contents of 96-well plates were analyzed by high content screening image analysis. Characteristically, the EYP biomaterial had lipid and protein content resembling the EY. On its own, the EYP was non-conducive to cell survival. EYP’s pH of 6 mainly contributed to cell death. This was demonstrated by titrating EYP’s pH with different concentrations of either commercial cell culture media, NaOH, or egg white (EW). These additives improved SG mesenchymal and epithelial cell survival. The best combinations were EYP diluted with (1) 70% commercial medium, (2) 0.02 M NaOH, or (3) 50% EW. Importantly, commercial medium-free growth was obtained with EYP + NaOH or EYP + EW. Furthermore, 3D cultures were obtained as a result of EW’s gelatinous properties. Here, the isolation, characterization, and optimization of three EYP-based biomaterial combinations are shown; two were free of commercial medium or supplements and supported both SG cells’ survival.

The effect of capsulated and noncapsulated egg-yolk–specific antibody to reduce colonization in the intestine of Salmonella enterica ssp. enterica serovar Infantis–challenged broiler chickens

The antibacterial properties of egg yolk antibodies have been known for many years. Enhanced antibiotic resistance has resulted in increased need for using these antibodies as an alternative. In the present study, generation, capsulation, and inhibition growth properties of IgY directed against Salmonella enterica subsp. enterica serovar Infantis (SI) were evaluated. White Leghorn layer hens were immunized using whole cell of inactivated SI. Salmonella Infantis–specific antibody activities in sera and egg yolk were determined by ELISA. A total of 480 one-day-old male “Cobb 500” chicks were randomly divided into 8 groups, with 6 replications of 10 birds kept for 21 D. All birds from 7 challenged groups were orally inoculated with 1 mL of SI suspension (1 × 107 CFU/mL) at 3 and 4 D of age. Two groups were dietary supplemented with 5 g/kg immune powdered yolk or nonimmune powdered yolk. One group was dietary supplemented with 12.8 g/kg capsulated immune yolk (CIY). Two groups were given 8.3 mL/L of immune water-soluble yolk or nonimmune water-soluble yolk fraction in drinking water. In the antibiotic group, 1 mL/L Enrofloxacin 10% was added to drinking water. All supplements except for the antibiotic (on Day 4 for 10 D) were added on day one and continued during the experiment. Negative and positive control groups received no supplements. During the experiment, among the challenged groups, the minimum SI cecal colonization and the lowest isolation of SI from the liver (P < 0.01) was observed in the antibiotic group. Following antibiotic group, in the group receiving CIY, colonization of bacteria in ceca and liver was significantly reduced during the second and third weeks of the experiment (P < 0.01). According to the results, capsulated specific IgY has a beneficial effect in reducing the colonization of Salmonella under the conditions of this study in comparison with other forms of IgY antibody.

Dietary levels of methionine plus cystine and chelated copper on the chemical composition of eggs and yolk cholesterol of 49-week-old brown laying hens

The present study aims to evaluate the possible interactions of dietary levels of methionine plus cystine (Met + Cys) and organic copper (Cu) on the chemical composition of eggs, using 320 Hy-Line Brown hens at 49 weeks of age. Composition and deposition variables were evaluated in a 4 × 5 factorial arrangement, with total analysed levels of 18, 44, 71, and 99 mg kg-1 of Cu and 0.613, 0.631, 0.816, 0.918, and 0.955% Met + Cys. We allocated four replicate cages (four hens/cage) to each treatment group. Two eggs per plot were sampled to determine the chemical composition of albumen and yolk, based on natural and dry matter and on daily rates of deposition. An interaction effect of Met + Cys and Cu levels was observed for deposition rates of ash and Cu in the yolk, and the chemical composition of Ethereal Extract (EE) and ash in eggs, EE in albumen and Nitrogen, EE, and ash in the yolk. An isolated effect was observed for Met + Cys on egg chemical composition and on shell and yolk fractions, as well as on deposition rates of albumen N, EE, and ash, and yolk EE. The yolk cholesterol content increased by 18.17% with increasing Met + Cys in diets. In conclusion, the chemical composition of eggs varied with dietary Met + Cys and organic Cu concentrations. Dietary levels of Met + Cys determined the yolk cholesterol concentration in laying hens.

Dietary levels of methionine plus cystine and chelated copper on the chemical composition of eggs and yolk cholesterol of 49-week-old brown laying hens

The present study aims to evaluate the possible interactions of dietary levels of methionine plus cystine (Met + Cys) and organic copper (Cu) on the chemical composition of eggs, using 320 Hy-Line Brown hens at 49 weeks of age. Composition and deposition variables were evaluated in a 4 × 5 factorial arrangement, with total analysed levels of 18, 44, 71, and 99 mg kg-1 of Cu and 0.613, 0.631, 0.816, 0.918, and 0.955% Met + Cys. We allocated four replicate cages (four hens/cage) to each treatment group. Two eggs per plot were sampled to determine the chemical composition of albumen and yolk, based on natural and dry matter and on daily rates of deposition. An interaction effect of Met + Cys and Cu levels was observed for deposition rates of ash and Cu in the yolk, and the chemical composition of Ethereal Extract (EE) and ash in eggs, EE in albumen and Nitrogen, EE, and ash in the yolk. An isolated effect was observed for Met + Cys on egg chemical composition and on shell and yolk fractions, as well as on deposition rates of albumen N, EE, and ash, and yolk EE. The yolk cholesterol content increased by 18.17% with increasing Met + Cys in diets. In conclusion, the chemical composition of eggs varied with dietary Met + Cys and organic Cu concentrations. Dietary levels of Met + Cys determined the yolk cholesterol concentration in laying hens.

Dietary levels of methionine plus cystine and chelated copper on the chemical composition of eggs and yolk cholesterol of 49-week-old brown laying hens

The present study aims to evaluate the possible interactions of dietary levels of methionine plus cystine (Met + Cys) and organic copper (Cu) on the chemical composition of eggs, using 320 Hy-Line Brown hens at 49 weeks of age. Composition and deposition variables were evaluated in a 4 × 5 factorial arrangement, with total analysed levels of 18, 44, 71, and 99 mg kg-1 of Cu and 0.613, 0.631, 0.816, 0.918, and 0.955% Met + Cys. We allocated four replicate cages (four hens/cage) to each treatment group. Two eggs per plot were sampled to determine the chemical composition of albumen and yolk, based on natural and dry matter and on daily rates of deposition. An interaction effect of Met + Cys and Cu levels was observed for deposition rates of ash and Cu in the yolk, and the chemical composition of Ethereal Extract (EE) and ash in eggs, EE in albumen and Nitrogen, EE, and ash in the yolk. An isolated effect was observed for Met + Cys on egg chemical composition and on shell and yolk fractions, as well as on deposition rates of albumen N, EE, and ash, and yolk EE. The yolk cholesterol content increased by 18.17% with increasing Met + Cys in diets. In conclusion, the chemical composition of eggs varied with dietary Met + Cys and organic Cu concentrations. Dietary levels of Met + Cys determined the yolk cholesterol concentration in laying hens.

Enriching ISA brown and Shaver white breeder diets with sources of n−3 polyunsaturated fatty acids increased embryonic utilization of docosahexaenoic acid

There is limited information on feeding egg-type chick breeders n−3 polyunsaturated fatty acids (PUFA) and its impact on hatching egg quality and embryonic fatty acid (FA) utilization. We investigated the effects of feeding brown and white egg-type chick breeders diets containing sources of n−3 PUFA on egg composition, apparent embryonic FA utilization, and intestinal FA transporter in hatchlings. Twenty-six-week-old ISA brown and Shaver white breeders were fed either 1) control (CON); 2) CON + 1% of microalgae (DMA, Aurantiochytrium limacinum) fermentation product, as a source of docosahexaenoic acid (DHA); or 3) CON + 2.60% of coextruded full-fat flaxseed and pulse mixture (FFF, 1:1 wt/wt) as a source of α-linolenic acid (ALA). Test diets had similar total n−3 and n−6:n−3 ratio. Eggs were hatched, and residual yolk (RY) samples taken for FA analyses. Apparent embryonic FA utilization was calculated by subtracting concentration of FA in RY from concentration of FA in yolk before incubation. There was an interaction between strains and diets (P < 0.05) on DHA in phospholipid and triglyceride fractions of yolk. Both n−3 PUFA sources increased DHA to a greater extent in Shaver white than in ISA brown. The interactive effect of strains and diets (P = 0.019) on embryonic utilization of ALA was such that DMA and FFF reduced ALA utilization, and this pattern was more prevalent in Shaver white birds than in ISA brown birds. There was no interaction between strains and diets on DHA utilization (P > 0.05). Embryos from hens fed n−3 PUFA sources used less total FA in phospholipid fraction (P < 0.001), and they preferentially used more DHA than CON embryos. Shaver white embryos used more (P < 0.05) ALA and DHA than ISA brown embryos. Although data suggested Shaver white had higher propensity of depositing DHA than ISA brown, irrespective of strain, feeding n−3 PUFA modified embryonic pattern of FA utilization toward utilization of DHA.