Biological Activities of Egg Yolk Lipids: A Review

Monitoring the aging process in egg-tempera paint films

Tempera painting, a predominant pictorial technique during the Middle Ages, used a variety of aqueous binders, egg yolk being the main one for easel paintings. In an effort to replicate the aging process, multiple mockup paints based on egg yolk tempera, incorporating selected pigments such as lead tin yellow, azurite, and Sienna, were exposed to visible or UVA light for up to 130 days. The chemical transformations within the lipoprotein functional groups of yolk were closely monitored using FTIR spectroscopy throughout the aging process in order to study the reactions leading to the spectra recorded on naturally aged films and historical samples. Lipids and proteins undergo oxidation under complex pathways illustrated by the absorption band evolutions (especially CH2 and Amide I elongations). Notably, in the presence of pigments, the observed chemical changes display a comparable but accelerated pattern. Decomposition of the amide I band of both unpigmented and pigmented tempera paints IR spectra revealed conformational changes in proteins during the aging process. In addition, thermal analysis suggested chain shortening revealed by lower degradation temperatures. This investigation sheds light on the intricate evolution of tempera binder and its components over time.

The Beneficial Dietary Effect of Dried Olive Pulp on Some Nutritional Characteristics of Eggs Produced by Mid- and Late-Laying Hens

This research evaluated the impact of incorporating dried olive pulp (OP) into the feed of laying hens on the fatty acid profile, cholesterol, triglyceride, total phenolic, oleuropein and hydroxytyrosol content, and health lipid indices of eggs produced by mid- (39 weeks) and late-laying (59 weeks) birds. Over a 36-week trial, 300 eggs from 180 Isa-Brown hens, assigned to three dietary groups with different OP levels (CON, OP4 and OP6), were analyzed. OP reduced egg cholesterol, with significant effects in late-age eggs (p < 0.05). In mid-age hens, the OP6 eggs had higher total phenolics than the controls (p < 0.05) and more PUFAs than the other groups (p < 0.05). The concentration of total phenolics, cholesterol, n3 PUFAs and % fat increased with hen age (p < 0.05), while triglycerides and oleuropein decreased (p < 0.05). With increasing hen age, the SFAs in the OP eggs decreased (p < 0.05) and the MUFAs increased (p < 0.05). Eggs from older hens had higher nutritional value, as indicated by the lower n6/n3 PUFA ratio, lower AI and TI indices, and higher h/H ratio (p < 0.05). Overall, dietary OP supplementation improved the nutritional quality of eggs, suggesting potential health benefits. Our results also highlighted eggs from older hens as a valuable source of high-quality fats.

Extraction of egg yolk lipids via salt-induced synergistic heat treatment: Fabrication, characterization and flavor analysis

In this study, the oxidation of egg yolk lipids (EYL) by salt-induced heat and non-heat treatments was investigated for quality and flavor. The correlation between physicochemical properties, lipid oxidation and antioxidant activity was modeled using partial least squares discriminant analysis (PLS-DA). The results indicated that the prolonged salt-induced synergistic heat treatment produced the highest level of lipid oxidation, antioxidant activity and oil exudation, along with the lowest level of polyunsaturated fatty acid content. In addition, higher contents of pyrazines and fewer acid species were detected, which was not the case with the salt-free heat treatment. In total, 14 identical volatile organic compounds (VOCs) were produced, yet their overall flavor profiles determined by the electronic nose would remain dramatically distinguished. Therefore, heat treatment was particularly critical for lipid oxidation and the generation of aromatic compounds, implying that heat-treated EYL induced by salt is a flavor component with good antioxidant potential.

Effects supplementation of novel multi-enzyme on laying performance, egg quality, and intestinal health and digestive function of laying hens

This study investigated the effects of multi-enzyme supplementation on various aspects of laying hens, including laying performance, egg quality, intestinal health and digestive function. In total, 384 Jingfen No.6 laying hens at 65-week-age were randomly assigned to four distinct dietary treatments: a basal diet (CON), CON supplemented with 150 g/t multi-enzyme (T1), CON with 300 g/t multi-enzyme (T2), and 600 g/t multi-enzyme (T3). A significant linear (P = 0.044) and quadratic (P = 0.014) increase was observed in the laying rate, while the feed/egg ratio exhibited a linear (P = 0.001) and quadratic (P < 0.001) decrease with increasing multi-enzyme supplementation. Additionally, linear (P < 0.05) and quadratic (P < 0.05) increases were observed in yolk rate and haugh unit with increasing levels of multi-enzyme supplementation. The trypsin activity in the duodenum and crude protein digestibility showed linear (P < 0.05) and quadratic (P < 0.05) increase with the addition of multi-enzyme. Furthermore, lipase and amylase activities in the duodenum increased quadratically (P = 0.041) and linearly (P = 0.040), respectively. Both jejunal and ileal digesta viscosities showed linear (P < 0.05) and quadratic (P < 0.05) decrease with the increasing addition of multi-enzyme. Moreover, multi-enzyme supplementation significantly increased (P < 0.05) the number of goblet cells in the intestinal of the treatment groups. The mRNA expression of Occludin-1, mucin 2 (MUC-2), large neutral amino acids transporter small subunit 1 (LAT-1) in the jejunum were significantly increased (P < 0.05) in the treatment groups (T1, T2 and T3) compared to the CON group. Additionally, the mRNA expression of solute carrier family 6-member 19 (B0AT-1) and large neutral amino acids transporter small subunit 4 (LAT-4) were significantly evaluated (P < 0.05) in the T2 and T3 groups, respectively. In conclusion, multi-enzyme supplementation enhanced digestive enzyme activities and intestinal barrier function, reduced intestinal digesta viscosity, and regulated mRNA expression of intestinal amino acid and lipid transporter genes, thereby improving crude protein digestibility and positively affecting laying performance and egg quality in hens.

Alahmari A, A. Alqabbani A, Aldayel AM. Exploring the landscape of Lipid Nanoparticles (LNPs): A comprehensive review of LNPs types and biological sources of lipids

Lipid nanoparticles (LNPs) have emerged as promising carriers for delivering therapeutic agents, including mRNA-based immunotherapies, in various biomedical applications. The use of LNPs allows for efficient delivery of drugs, resulting in enhanced targeted delivery to specific tissues or cells. These LNPs can be categorized into several types, including liposomes, solid lipid nanoparticles, nanostructured lipid carriers, and lipid-polymer hybrid nanoparticles. The preparation of LNPs involves the manipulation of their structural, dimensional, compositional, and physical characteristics via the use of different methods in the industry. Lipids used to construct LNPs can also be derived from various biological sources, such as natural lipids extracted from plants, animals, or microorganisms. This review dives into the different types of LNPs and their preparation methods. More importantly, it discusses all possible biological sources that are known to supply lipids for the creation of LNPs. Natural lipid reservoirs have surfaced as promising sources for generating LNPs. The use of LNPs in drug delivery is expected to increase significantly in the coming years. Herein, we suggest some environmentally friendly and biocompatible sources that can produce lipids for future LNPs production.

Analysis of bioactive compounds of hen egg components at the first half of incubation

A comparative analysis of mass-volume characteristics of structural and morphological components of hen eggs before incubation and on the fifth (HH25-HH27) and 10th (HH36) days of incubation was carried out. During incubation, egg weight decreased by 9.25% (10 days), mainly due to a decrease in albumen weight (35.8%). The ratio of lipid-soluble fraction (LSF) and water-soluble fraction (WSF) in the mixed components and yolk did not change significantly. The total amount of solids in the mixed substances practically does not change during incubation. Antiradical activity of substances increased significantly by more than three times on the fifth day and additionally by 38.6% at the 10th day in relation to the fifth day. Total antioxidant activity increased by 18.9% on the fifth day and by 24.3% on the 10th day, compared to eggs before incubation. Transformation of the main components of WSF and LSF of albumin, yolk, and chicken embryo (CE) was studied using high-performance liquid chromatography and gas chromatography with mass spectrometry. On the 10th day, an increase in the number of high-molecular proteins is recorded, which indicates the activation of enzymatic processes of transformation of the main albumen proteins into proteins of organs and tissues of CE. This may cause an increase in the biological activity of substances. It was found that in conditions of in vitro digestion, antiradical activity increases by two times, anti-inflammatory activity increases by 2.4 times, and an angiotensin-converting enzyme inhibitory effect occurs in the mixed components of a 10-day incubation egg.

Different effects of low- and high-density lipoproteins in egg yolk on lipid metabolism of mouse: Role of phospholipids-to-cholesterol intake ratio

Recent evidence increasingly indicates that moderate egg consumption (up to one egg per day) poses no significant risk of cardiovascular diseases in healthy individuals, leading researchers to speculate whether other lipids in eggs affect lipid metabolism. In this research, C57BL/6J mice were given chow diets containing egg yolk low-density lipoprotein (LDL) and high-density lipoprotein (HDL), two natural components with different proportions of phospholipids and cholesterol, to explore the effects of the phospholipids-to-cholesterol intake ratio on lipid metabolism. Increases in liver weight and liver index were observed following LDL intake, while body weight and epididymal fat decreased after HDL intake in a dose-dependent manner. The food efficiency of chow diets decreased with increasing phospholipids content. Lipid biomarkers indicated that LDL intake significantly increased plasma LDL cholesterol and liver cholesterol levels. At equivalent cholesterol doses, the cholesterol-raising effects of HDL were weaker than those of LDL. Higher protein expression of cytochrome P450 family 7 subfamily A member 1 in the HDL groups suggested increased bile acid excretion at higher phospholipids-to-cholesterol intake ratios. Fecal metabolite analysis revealed significant changes in lipid composition, primarily involving glycerophospholipids, sphingolipids, and sterol lipids, consistent with the lipid profiles of LDL and HDL. The upregulation of cholic acid and deoxycholic acid in feces further confirmed increased bile acid excretion. This study highlights the differences in lipid metabolism in mice under varying phospholipids-to-cholesterol intake ratios, which may be associated with changes in dietary energy supply and bile excretion following phospholipids involvement.

Redistribution and fusion of protein-lipid assemblies within the egg yolk sphere under slight non-destructive deformation causing a change in thermal gel properties

Egg yolk production processed after separating egg white is a common method to shorten cycle, but its taste quality will change even the vitelline membrane is intact. This might be related to the slight non-destructive deformation causing redistribution and fusion of protein-lipid assemblies within the egg yolk spheres. We investigated the mechanism of the change in thermal gel properties under slight deformation. The results of microscopic structural morphology revealed that the whole boiled egg yolk (WEY) underwent a transition in protein-lipid assembly morphology within yolk spheres, which changed from local aggregation to disordered fusion in shaken boiled egg yolks (SEYs). The spectroscopic and physicochemical properties analysis demonstrated that the redistribution of protein-lipid assemblies gave rise to marked changes in water migration, texture properties, molecular interactions, and oral sensation simulation of egg yolk thermal gels. This is benefit to guide the regulation of the taste quality egg yolk products in industry.

Modification Effects of Microorganisms and Enzymes on Egg Components: A Review

In eggs, there are several components: eggshell (ES), eggshell membrane (ESM), egg white (EW), and egg yolk (EY). Many modification methods exist, such as thermal treatment, high pressure, freeze-thaw cycles, ultrasonic treatment, ozonation, phosphorylation, and acylation, all aimed at improving the functional properties of EW and EY. Additionally, microorganism and enzyme modifications have proven effective in enhancing the functional properties of EW and EY. ES and ESM are unique components of eggs. The eggshell is rich in calcium carbonate, while the eggshell membrane is rich in protein. The effective utilization of ES and ESM can help promote economic income in the poultry industry and benefit the environment. Research on the modification of ES and ESM has shown that microorganisms and enzymes have the potential to improve their functional properties. After modification, egg components can be utilized in the production of egg-based and other food products for improved performance. Furthermore, enzyme modification of egg components can produce bioactive peptides, which have the potential to treat specific diseases and may even be used in the biomedical field. This review primarily focuses on the effects of microorganisms and enzymes on the modification of egg components and summarizes the roles of microbial and enzymatic modifications in this context.

Comparative analysis on the properties of egg yolk lipids extracted by different extraction methods

Egg yolk lipids are important components in egg yolk. Compared with proteins, minerals, vitamins and pigments in egg yolk, there is a lack of systematic research on extraction methods and characteristics of yolk lipid. Therefore, in this study, the extraction of egg yolk lipids by supercritical CO2 fluid extraction (SFE), subcritical propane extraction (SPE) and ethanol solvent extraction (SE) was studied, and the differences in composition and physicochemical properties of the three yolk lipids were analyzed. The egg yolk lipids extracted by SFE had the advantages of high unsaturated fatty acid content, low saponification value, acid value, peroxide value, and high content of neutral lipids such as triglyceride and cholesterol, but the polar phospholipids were completely retained in the yolk powder. The efficiency of lipid extraction of SPE was the highest among all the three methods, but the extraction capacity to the polar phospholipid was in the middle of the three methods. The efficiency of lipid extraction of SE was low, but the extraction capacity to the polar phospholipid was the highest. Suitable extraction methods could be selected based on the specific application requirements of egg yolk lipids and low-fat egg yolk powders.

Effects of Chicken Egg Powder, Bovine Colostrum, and Combination Therapy for the Treatment of Gastrointestinal Disorders

Natural-based products are of interest to the pharmaceutical industry as potential sources of novel medicinal compounds. They are also used by consumers/patients as standalone therapies or as an adjunct to Western medicines. Two natural-based products of interest are chicken egg and bovine colostrum (the milk produced in the first few days following calving). Both products are rich in immunoglobulins, antimicrobial peptides, growth factors, and macro- and micro-nutrients. In vitro, in vivo, and a limited number of clinical studies suggest therapeutic benefits of both components given alone and together. Combination therapy is of particular interest, as preclinical studies suggest synergistic effects on growth, repair, and gut protection, including microbiome-induced damage. This article describes the main constituents of egg and bovine colostrum, studies of their use alone and together for a wide range of conditions, highlights areas requiring further research, and describes novel indications such as GLP-1-associated gut symptoms. While well placed in the food supplement arena, additional high-quality clinical trials are required to establish their benefits in clinical practice.

Mass spectrometry unveils heat-induced changes in yolk oxylipins and key lipid molecules during home cooking

INTRODUCTION

Oxylipins, as a widespread class of metabolic markers following oxidative stress, and several studies have reported dietary regulation of lipid metabolism. However, there is a lack of investigation of dietary oxylipins, especially cooking-induced changes in food lipid oxidation.

OBJECTIVES

Investigated the effects of cooking methods and lipid profiles on polyunsaturated fatty acids derived oxylipins generation within egg yolks.

METHODS

The lipid profile of egg yolk was determined by UPLC-QTOF-MS/MS, oxylipins were detected by HPLC-QTRAP-MS/MS, while the total fatty acid content was quantified by GC-FID. Random Forest (RF) and Partial Least Squares (PLS) regression models were employed to explore the association between oxidized lipids and key lipid species.

RESULTS

Heating reduced egg yolk docosahexaenoic acid (DHA) content, and no consistent trends for arachidonic acid (AA), linoleic acid (LA), and linolenic acid (ALA). Yolk lipid composition affected triacylglycerol (TG), phosphatidylethanolamine (PE), and LA-monoepoxide contents after cooking. 9- and 13-HODE (hydroxyoctadecadienoic acid), 9,10,13-TriHOME (trihydroxyoctadecenoic acid), 9,10- and 12,13-EpOME (epoxyoctadecenoic acid), 9,10- and 12,13-DiHOME (dihydroxyoctadecenoic acid), 5-HETE (hydroxyeicosatetraenoic acid), and 4-HDHA (hydroxydocosahexaenoic acid) were the prevalent oxylipins with high concentrations, accounting for 1.08 %-29.58 % of the total content of 29 oxylipins. Steaming resulted in a 1.9-fold increase in oxylipin concentrations in yolks compared to raw yolks, and boiling with or without shells (poaching) resulted in a 1.30- to 1.76-fold increase in oxylipin concentrations. In contrast, pan-fried yolks exhibited the lowest and least variable levels of total oxylipins, while still retaining some epoxides, including epoxyeicosatrienoic acid (EET) and EpOME. Utilizing big data analysis, we mapped the oxylipin network in both ordinary and DHA-enriched egg yolks, revealing a strong correlation between cooking-induced oxylipin production and variations in 24 lipid species.

CONCLUSION

Revealed the potential mechanisms and key lipid molecules for heating-induced oxylipin production of yolk through lipidomics and big data analysis.

Metabolome analysis of egg yolk and white following dietary supplementation with Ampelopsis grossedentata extract

Eggs are recognized for their rich nutrient profile, providing essential proteins and lipids with notable functional properties. This study examines the effects of incorporating Water Extract of Ampelopsis grossedentata (WEA) into poultry feed on egg quality, focusing on lipid content, choline, L-carnitine levels, and flavonoid compound deposition. Our results show significant increases in essential amino acids, flavonoids, and other bioactive compounds in eggs from WEA-treated hens, suggesting enhanced cardiovascular, antioxidant, and anti-inflammatory benefits. Additionally, we observed elevated levels of choline and betaine in egg yolks, alongside increased L-carnitine content, which may contribute to improved lipid metabolism and reduced cardiovascular disease risk. KEGG pathway analysis revealed upregulation of metabolites involved in critical metabolic pathways, enhancing the nutritional profile of eggs. Flavonoid compounds, traditionally associated with plant-based foods, were also significantly increased, with notable levels of 7, 4'-dihydroxyflavone, daidzein, and glycitein identified in WEA-treated eggs, indicating potential health benefits. These findings suggest that WEA supplementation can produce functional eggs with improved nutritional quality, offering a novel approach to enhancing egg production and meeting the growing demand for functional foods. Further research is needed to fully understand the bioavailability and health impacts of these enriched compounds.

Natural Food Components as Biocompatible Carriers: A Novel Approach to Glioblastoma Drug Delivery

Efficient drug delivery methods are crucial in modern pharmacotherapy to enhance treatment efficacy, minimize adverse effects, and improve patient compliance. Particularly in the context of glioblastoma treatment, there has been a recent surge in interest in using natural dietary components as innovative carriers for drug delivery. These food-derived carriers, known for their safety, biocompatibility, and multifunctional properties, offer significant potential in overcoming the limitations of conventional drug delivery systems. This article thoroughly overviews numerous natural dietary components, such as polysaccharides, proteins, and lipids, used as drug carriers. Their mechanisms of action, applications in different drug delivery systems, and specific benefits in targeting glioblastoma are examined. Additionally, the safety, biocompatibility, and regulatory considerations of employing food components in drug formulations are discussed, highlighting their viability and future prospects in the pharmaceutical field.

Lipid discovered in American ginseng alleviates doxorubicin-induced cardiotoxicity by inhibiting cardiomyocyte ferroptosis

Doxorubicin (Dox)-induced cardiotoxicity (DIC) has limited its clinical application. It is crucial to discover more effective substances to treat DIC. In this study, a zebrafish model is used to evaluate the inhibition of DIC in the lipids in American ginseng (AGL) compared with the lipids in soybeans (SOL) and in egg yolks (YOL). A lipidomics approach based on Q Exactive LC-MS/MS is employed to monitor, identify, and analyze the lipid composition of three lipid samples. The H9c2 cell was used to investigate the key lipid in AGL for its effect mechanism in alleviating DIC. The results showed that AGL alleviated DIC on zebrafish by increasing the stroke volume, heart rate, and fractional shortening compared to SOL and YOL. A total of 216 differential lipids were identified among the three types of lipids using lipidomics. Besides, a fatty acid with 18 carbons and four double bonds, FA (18:4) was the dominant proportion in AGL and possessed the highest variable importance of projection (VIP) value. FA (18:4) also showed significant bioactivity to alleviate DIC in zebrafish. Furthermore, FA (18:4) reduced the ferric ions and reactive oxygen species (ROS) accumulation, increased GPX4 expression, and relieved mitochondrial damage to inhibit Dox-induced ferroptosis in H9c2 cells. Therefore, the composition characteristic and anti-DIC effect of AGL were revealed; FA (18,4) was identified for the first time to be a novel active component of AGL against DIC by inhibiting ferroptosis. These results provide a new understanding of AG-derived bioactive lipids and their potential benefits for heart health.

Protective Effect of Egg Yolk Lipids against Dextran Sulfate Sodium-Induced Colitis: The Key Role of Gut Microbiota and Short-Chain Fatty Acids

Egg yolk lipids significantly alleviate dextran sulfate sodium (DSS)-induced colitis by inhibiting NLRP3 inflammasome, reversing gut microbiota dysbiosis, and increasing short chain fatty acids (SCFAs) concentrations. However, the role of gut microbiota and the relationship between SCFAs and NLRP3 inflammasome are still unknown. Here, this study confirms that antibiotic treatment abolishes the protective effect of egg yolk lipids on DSS-induced colonic inflammation, intestinal barrier damage, and lipopolysaccharide translocation. Fecal microbiota transplantation also supports that egg yolk lipids alleviate colitis in a gut microbiota-dependent manner. Then, the study investigates the relationship between SCFAs and NLRP3 inflammasome, and finds that SCFAs significantly suppress colitis via inhibiting colonic NLRP3 inflammasome activation and proinflammatory cytokines secretions (interleukin, IL)-1β and IL-18, and combined treatment of SCFAs and MCC950 (NLRP3 inhibitor) shows a better activity against colitis and NLRP3 inflammasome activation. Together, these findings provide positive evidence for gut microbiorta-SCFAs-NLRP3 axis as a novel target involving in the therapy of inflammatory bowel disease.

Protocol for evaluating the effects of the Reducing Cardiometabolic Diseases Risk dietary pattern in the Chinese population with dyslipidaemia: a single-centre, open-label, dietary intervention study

INTRODUCTION

Cardiometabolic disease (CMD) is the leading cause of mortality in China. A healthy diet plays an essential role in the occurrence and development of CMD. Although the Chinese heart-healthy diet is the first diet with cardiovascular benefits, a healthy dietary pattern that fits Chinese food culture that can effectively reduce the risk of CMD has not been found.

METHODS/DESIGN

The study is a single-centre, open-label, randomised controlled trial aimed at evaluating the effect of the Reducing Cardiometabolic Diseases Risk (RCMDR) dietary pattern in reducing the risk of CMDs in people with dyslipidaemia and providing a reference basis for constructing a dietary pattern suitable for the prevention of CMDs in the Chinese population. Participants are men and women aged 35-45 years with dyslipidaemia in Tianjin. The target sample size is 100. After the run-in period, the participants will be randomised to the RCMDR dietary pattern intervention group or the general health education control group with a 1:1 ratio. The intervention phases will last 12 weeks, with a dietary intervention of 5 working days per week for participants in the intervention group. The primary outcome variable is the cardiometabolic risk score. The secondary outcome variables are blood lipid, blood pressure, blood glucose, body composition indices, insulin resistance and 10-year risk of cardiovascular diseases.

ETHICS AND DISSEMINATION

The study complies with the Measures for Ethical Review of Life Sciences and Medical Research Involving Human Beings and the Declaration of Helsinki. Signed informed consent will be obtained from all participants. The study has been approved by the Medical Ethics Committee of the Second Hospital of Tianjin Medical University (approval number: KY2023020). The results from the study will be disseminated through publications in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR2300072472).

Comparison of Fatty Acid Profile in Egg Yolk from Late-Age Hens Housed in Enriched Cages and in a Free Range System

In recent years, the free-range system for laying hens has increased, driven by societal sensitivity to animal welfare. This study aimed to comparatively analyze the total lipid, cholesterol, and fatty acid composition of egg yolks of late-age laying hens reared in enriched cages (C) and the free-range system (FR). Eggs were collected from Lohmann Brown Classic hens at the 68th, 70th, 72nd, and 74th week of age. The concentrations of total lipids and cholesterol were not affected (p > 0.05) by either factor. Egg yolk from the FR group showed lower (p < 0.01) monounsaturated fatty acids and higher (p < 0.01) polyunsaturated fatty acid (PUFA) compared with that of the C group. From a nutritional point of view, the PUFA n-6/n-3 and the PUFA/SFA ratios of egg yolk from the FR group were favorably lower and higher (p < 0.01) compared with the C one. Conversely, hen age did not affect (p > 0.05) the fatty acid composition of yolks. Interactions between factors were found for total n-3 and n-6 PUFA and the n-6/n-3 ratio (p < 0.01), as well as the thrombogenic index (p < 0.05). In conclusion, the results confirmed that the free-range system may improve the nutritional yolk fatty acid profile and its positive impact on human health.

The Chicken Egg: An Advanced Material for Tissue Engineering

The chicken egg, an excellent natural source of proteins, has been an overlooked native biomaterial with remarkable physicochemical, structural, and biological properties. Recently, with significant advances in biomedical engineering, particularly in the development of 3D in vitro platforms, chicken egg materials have increasingly been investigated as biomaterials due to their distinct advantages such as their low cost, availability, easy handling, gelling ability, bioactivity, and provision of a developmentally stimulating environment for cells. In addition, the chicken egg and its by-products can improve tissue engraftment and stimulate angiogenesis, making it particularly attractive for wound healing and tissue engineering applications. Evidence suggests that the egg white (EW), egg yolk (EY), and eggshell membrane (ESM) are great biomaterial candidates for tissue engineering, as their protein composition resembles mammalian extracellular matrix proteins, ideal for cellular attachment, cellular differentiation, proliferation, and survivability. Moreover, eggshell (ES) is considered an excellent calcium resource for generating hydroxyapatite (HA), making it a promising biomaterial for bone regeneration. This review will provide researchers with a concise yet comprehensive understanding of the chicken egg structure, composition, and associated bioactive molecules in each component and introduce up-to-date tissue engineering applications of chicken eggs as biomaterials.

Eggs - a scoping review for Nordic Nutrition Recommendations 2023

Cardiovascular diseases (CVD), type 2 diabetes (T2D), and cancer are a significant public health burden in the Nordic and Baltic countries. High intake of eggs, mainly due to its high cholesterol content, has been suggested to have adverse health effects. The purpose of this scoping review is to describe the evidence related to the impact of egg intake on health. A literature search identified 38 systematic reviews and meta-analyses on egg consumption in relation to health outcomes published between 2011 and 30 April 2022. Overall, current evidence from systematic reviews of randomized clinical trials indicates that higher egg intake may increase serum total cholesterol concentration and the ratio of low-density lipoprotein to high-density lipoprotein cholesterol, but with substantial heterogeneity in the response. However, recent evidence from observational studies does not provide strong support for a detrimental role of moderate egg consumption (up to one egg/day) on the risk of CVD, especially in the European studies. The overall evidence from observational studies indicates that egg consumption is not associated with increased risk of mortality or T2D in European study populations. There is also little support for a role of egg consumption in cancer development, although a weak association with higher risk of certain cancers has been found in some studies, mainly case-control studies. Again, no associations with cancer risk have been observed in European studies. Systematic reviews and meta-analyses of egg consumption in relation to other health-related outcomes are scarce. There are also limited data available on the associations between the consumption of more than one egg/day and risk of diseases. Based on the available evidence, one egg/day is unlikely to adversely affect overall disease risk.

Egg Yolk Lipids Alleviated Dextran Sulfate Sodium-Induced Colitis by Inhibiting NLRP3 Inflammasome and Regulating Gut Microbiota

The increasing incidence of inflammatory bowel disease (IBD) has become a global phenomenon. Egg yolk lipids are one of the essential dietary foods, but its effects on intestinal immunity remain unclear. Here, egg yolk lipids are obtained using ethanol extraction and a total of 601 kinds of lipids are detected via lipidomics, including 251 kinds of triglycerides, 133 kinds of phosphatidylcholines, 44 kinds of phosphatidylethanolamines. Then, the study finds that egg yolk lipids significantly alleviate dextran sulfate sodium-induced colitis and reduce the production of inflammatory factors. Meanwhile, egg yolk lipids also maintain intestinal barrier integrity and decrease lipopolysaccharide translocation by alleviating intestinal structure damage and increasing the numbers of goblet cells and mucin 2. Mechanistically, egg yolk lipids attenuate colitis by inhibiting the assembly and activation of NLRP3 inflammasome. Moreover, the study also finds that egg yolk lipids reverse gut microbiota dysbiosis referring to increased relative abundance of Bacteroides acidifaciens and decrease relative abundance of Akkermansia muciniphila, as well as increased short chain fatty acids concentration in the gut. Together, the study elucidates the anti-colitis effect of egg yolk lipids and provides positive evidences for egg yolk lipids involving in dietary strategy and IBD therapy.

The effect of lutein on the oxidation of egg yolk phospholipids in a liposome model

Egg yolk phospholipids (PLs) extracted by organic solvent are prone to oxidation, while they are quite stable in egg yolk. This study was to verify the decisive role of lutein (naturally present in egg yolk) on the oxidative stability of PLs by constructing liposome. The liposome samples were heated at 100 °C for 10 min, and then the oxidation products of the liposome samples were analyzed by 1H NMR and GC-MS. The results showed that the concentrations of most of the oxidation products in the PLs-liposomes sample were significantly higher than those in the PLs&lutein-liposomes sample. Therefore, lutein could protect egg yolk PLs from oxidation, thus inhibiting the formation of lipid-derived volatile compounds. As those lipid-derived volatile compounds are the key fatty note odorants, this study has confirmed that the removal of lutein is the determining factor in using egg yolk PLs as an ideal precursor of fatty note odorants.

Effects of dietary Chinese herbal mixtures on productive performance, egg quality, immune status, caecal and offspring meconial microbiota of Wenchang breeder hens

This study aimed to evaluate the effects of Chinese herbal mixtures (CHMs) on productive performance, egg quality, immune status, anti-apoptosis ability, caecal microbiota, and offspring meconial microbiota in hens. A total of 168 thirty-week-old Wenchang breeder hens were randomly divided into two groups, with each group comprising six replicate pens of fourteen hens. The groups were fed a basal diet (CON group) and a basal diet with 1,000 mg/kg CHMs (CHMs group) for 10 weeks. Our results showed that dietary supplementation with CHMs increased the laying rate, average egg weight, hatch of fertile, and offspring chicks' weight while concurrently reducing the feed conversion ratio (FCR) and embryo mortality (p < 0.05). The addition of CHMs resulted in significant improvements in various egg quality parameters, including eggshell strength, albumen height, haugh unit, and the content of docosatetraenoic acid (C20:4n-6) in egg yolk (p < 0.05). The supplementation of CHMs had a greater concentration of IgA and IgG while decreasing the content of IL-6 in serum compared with the CON group (p < 0.05). Addition of CHMs to the diet increased the expression of Bcl-2 and IL-4 in liver and ovary, decreased the expression of IL-1β, Bax, and Caspase-8 in jejunum and ovary, and decreased the expression of NF-κB in liver, jejunum, and ovary (p < 0.05). Moreover, dietary CHMs reduced the abundance of Desulfovibrio in caecal microbiota as well as decreased the abundance of Staphylococcaceae_Staphylococcus and Pseudomonadaceae_Pseudomonas in the offspring meconial microbiota (p < 0.05). In conclusion, the CHMs could improve productive parameters by enhancing immune status, anti-apoptosis capacity, and modulating the caecal microbiota of Wenchang breeder hens, as well as maintaining the intestinal health of the offspring chicks.

Egg yolk phosphatidylcholine alleviates DSS-induced colitis in BALB/c mice

Ulcerative colitis (UC) is a common inflammatory bowel disease, whose incidence is on the rise worldwide. The drugs commonly used for UC are often associated with a number of side effects. Therefore, the development of effective, food-borne substances for UC is in line with the current needs. Egg yolk phosphatidylcholine (EYPC) is one of the abundant lipids in egg yolk and possesses various biological activities. However, its protective effect against UC has not been clarified. In this study, the anti-UC activity of EYPC was investigated using a dextran sodium sulfate (DSS)-induced colitis model of BALB/c mice. The results showed that EYPC supplementation inhibited DSS-induced colon shortening, the spleen index and disease activity index increase and intestinal structural damage. EYPC could down-regulate the levels of TNF-α, IL-1β, IL-6 and MPO in the colon and restore the number of goblet cells and the level of tight junction (TJ) proteins. Besides, EYPC modulated the composition of the gut microbiota, lowered the relative abundance of the pathogenic bacterium Parabacteroides and upregulated the abundance of the beneficial bacteria Alistipes and Lachnospiraceae_NK4A136_group. These results evidenced that EYPC could attenuate DSS-induced colitis in mice and had the potential to prevent and treat UC.

Comparative characterization of flavor precursors and volatiles of Taihe black-boned silky fowl and Hy-line Brown yolks using multiomics and GC-O-MS-based volatilomics

Eggs are nutritious and highly valued by consumers. However, egg flavor varies greatly among different hen breeds. The present study used gas chromatography-olfactometry-mass spectrometry-based volatilomics to identify and compare volatile compounds in Taihe black-boned silky fowl (TS) and Hy-line Brown (HL) egg yolks. In addition, the relationships between the levels of different metabolites and lipids and flavor-associated differences were investigated using multiomics. Twenty-eight odorants in total were identified; among them, the levels of 3-methyl-butanal, 1-octen-3-ol, 2-pentylfuran, and (E, E)-2,4-decadienal differed significantly (P < 0.05) between TS and HL egg yolks. The difference in flavor compounds results in TS egg yolks having a stronger overall odor and flavor and a higher acceptance level than HL egg yolks. Metabolomic analysis revealed that 112 metabolites in the egg yolks were significantly different between the two breeds. Furthermore, these different metabolites in the egg yolks of both breeds were significantly enriched in phenylalanine, tyrosine, and tryptophan biosynthesis pathways and phenylalanine metabolism, alanine, aspartate, and glutamate metabolism pathways (P < 0.05), as identified by both metabolite set enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses. Lipidomic analysis revealed significant differences in the lipid subclasses, lipid molecules, and fatty acid profiles between the egg yolks from the two breeds. As a result, 48 lipid molecules had variable influence in projection values > 1 based on the partial least squares regression model, which may play a role in the differences in aroma characteristics between the two breeds through oxidative degradation of fatty acids. Our study revealed the metabolite, lipid, and volatility profiles of TS and HL egg yolks and may provide an important basis for improving egg flavor to satisfy various consumer preferences.

Effects of konjac glucomannan on physicochemical and rheological properties of whole egg liquid and in vitro fermentation of egg curd

The mixture of proteins, polysaccharides, and other nutrients not only safeguards the nutritional value of the food but also demonstrates superior performance compared to these nutrients when used individually. This study aimed to investigate the effects of konjac glucomannan (KGM) on the properties of whole egg liquid (WEL) and the in vitro fermentation of egg curd (made by the mixture of WEL/KGM). The results revealed that the foaming ability (FA) of the mixture decreased, while the foam stability (FS), emulsifying activity (EA), and emulsion stability (ES) of the mixture increased with increasing concentrations of KGM. The concentration of KGM had a significant effect on the sol-gel transition temperature of WEL. Compared to the fermentation broth of E group (without KGM), KGM decreased the pH from 6.65 to 6.16, free ammonia content from 87.53 μg/g to 72.21 μg/g, and sulfide concentration from 580 μg/L to 470 μg/L in the WEL/KGM mixture (EK group). Moreover, KGM slowed down the gas production of intestinal protein fermentation within 10 h, without affecting the final total gas yield. These findings suggest that adding KGM can be an effective strategy to modify the properties of WEL and improve the intestinal fermentation performance of protein-rich foods.

Effects of different protectants on the IgY content and physico-chemical properties of spray-dried egg yolk powder

BACKGROUND

Egg yolk powder (EYP) with high immunoglobulin of yolk (IgY) content and good solubility is in great demand in the market of functional foods. In this article, the properties of spray-dried EYP with the addition of five protectants (maltodextrin, trehalose, mannitol, maltitol and sucrose) were investigated.

RESULTS

All the protectants increased IgY activity and solubility of EYP. Among them, EYP with maltodextrin displayed the highest activity of IgY (27.11 mg/g), the highest solubility (66.39%) and the lowest surface hydrophobicity. Moreover, the average particle size of EYP with maltodextrin was the smallest (9.78 μm). The egg yolk particles obtained by adding the protectants are more uniformly distributed and have smaller particle size. Fourier-transform infrared spectroscopy confirmed the structural integrity of the proteins, indicating that the protectants addition enhanced the hydrogen bonding forces between the EYP protein molecules.

CONCLUSION

The addition of protectants can significantly improve the IgY content, solubility and structural stability of EYP. © 2023 Society of Chemical Industry.

A study of the lipid profile of Coix seeds from four areas based on untargeted lipidomics combined with multivariate algorithms to enable tracing of their origin

The geographical traceability of food products is seen as a distinctive feature of the future of food which is increasingly becoming a concern for consumers. In this research, differences in the lipid composition of Coix seed samples from four major Chinese origins were investigated using non-targeted lipidomics. By multivariate statistical analysis, unsupervised PCA and OPLS-DA based differentiation between the four origins of Coix seed samples could be achieved. The OPLS-DA VIP > 1 screened 72 lipids out of 1211 lipids as potential markers to distinguish Coix seeds from different origins. In addition, the potential markers (SPH(d16:0), Cer(d18:2/20:0 + O) and PC(8:0e/8:0) were combined with statistical analysis algorithms to construct a discriminant function for rapid differentiation of Coix seed samples from different origins and a specific function for different origins with 100% discrimination accuracy. In general, a rapid and accurate method combining multivariate chemometrics and algorithms was developed based on untargeted lipidomics to determine the geographical origin of Coix seed samples, which can also be applied to other agricultural products.

Characterization and Mechanism of Gel Deterioration of Egg Yolk Powder during Storage

Egg yolk forms have several health and industrial applications, but their storage characteristics and gel mechanisms have not been thoroughly studied. In order to investigate the relationship between the changes in structure and properties of egg yolk gel and egg yolk powder during storage, in this paper, egg yolk powder was stored at 37 °C for 0, 1, 3, and 6 months in an accelerated storage experiment, and the influence of storage time on the gel properties of egg yolk powder was analyzed. The results showed that the contents of protein carbonylation and sulfhydryl in the yolk decreased gradually with the extension of storage time. Circular dichroism and fluorescence spectra showed that the ordered structure and structural stability of egg yolk proteins decreased gradually. Oxidation led to the formation of intermolecular crosslinking in the egg yolk proteins and oxidized aggregates, resulting in a decrease in surface hydrophobicity, which affected the gel properties of the egg yolk powder after rehydration, resulting in the phenomenon of lipid migration and gel degradation. The results provide a theoretical basis for improving egg yolk powder's overall quality and storage stability.

Quantitative Lipidome Analysis of Boiled Chicken Egg Yolk under Different Heating Intensities

The effects of the four heating intensities (hot-spring egg yolk, HEY; soft-boiled egg yolk, SEY; normal-boiled egg yolk, NEY; and over-boiled egg yolk, OEY) on lipidomes of boiled egg yolks were investigated. The results indicated that four heating intensities had no significant effect on the total abundance of lipids and lipid categories except for bile acids, lysophosphatidylinositol, and lysophosphatidylcholine. However, of all the 767 lipids quantified, the differential abundance of 190 lipids was screened among the egg yolk samples at four heating intensities. Soft-boiling and over-boiling altered the assembly structure of the lipoproteins through thermal denaturation and affected the binding of lipids and apoproteins, resulting in an increase in low-to-medium-abundance triglycerides. The decreased phospholipid and increased lysophospholipid and free fatty acid in HEY and SEY suggests potential hydrolysis of phospholipids under relatively low-intensity heating. Results provide new insights into the effect of heating on the lipid profiles of egg yolk and would support the public's choice of cooking method for egg yolks.

Changes in physicochemical properties and lipid oxidation lead to the formation of mud on salted egg yolks during storage

Salted egg yolk (SEY) becomes easily "muddy" during storage, leading to a decrease in the quality of salted eggs. The mechanism of SEY mudding was studied in this paper. The results showed that SEY hydrogen proton binding decreased, and SEY water and lipid fluidity increased during storage. In addition, the degree of lipid oxidation and monounsaturated fatty acids in salted egg yolk lipids (SEYL) increased, and primary oxidation products and secondary oxidation products were formed. Moreover, the structure of SEY was degraded to release lipids and proteins, and these proteins and lipids were re-emulsified to form new aggregates. Finally, by PLS-DA modeling analysis, it was found that the content of ω-3 polyunsaturated fatty acids and phospholipids changed significantly after SEY became muddy. These results suggest that the muddiness of SEY can primarily be attributed to higher fluidity and protein-lipid re-emulsification, and secondarily to the oxidation of SEYL.

Effect of yolk spheres as a key histological structure on the morphology, character, and oral sensation of boiled egg yolk gel

This study explored the effect of yolk sphere on gel state and taste differences between whole boiled egg yolk (WBEY) and stirred boiled egg yolks (SBEYs). Optical microscopy, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM) indicated that the WBEY was formed via the accumulation of yolk spheres, whereas the SBEY was a gel with a tight and ordered microstructure. The stirring disrupted the yolk sphere structure, leading to a homogeneous distribution of proteins and lipids in SBEYs, and a cross-linked network in gel was established with higher hardness and springiness. In the oral sensation simulation, WBEY had a higher saliva adsorption capacity and frictional force to oral soft tissue during swallowing than SBEY. This work contributes to a deeper understanding of the gel structure and taste of egg yolk, and provides a theoretical basis for the research on the formation of the gritty taste of egg yolks.

Egg yolk phospholipids as an ideal precursor of fatty note odorants for chicken meat and fried foods: A review

Egg yolk phospholipids (PLs) have been demonstrated to generate large quantities of lipid-derived odorants, especially the fatty note odorants. Recently, egg yolk PLs have been successfully used in chicken meat and fried foods to improve aroma. This review comprehensively summarizes the properties of egg yolk PLs as precursors of fatty note odorants, including their classes, extraction, identification, oxidation, decomposition and odorant formation, applications, considerations and future prospects in the food industry. Most likely, phosphatidylcholine (PC) is the most abundant class in egg yolk PLs, and PC is more efficient than phosphatidylethanolamine in generating fatty note odorants; moreover, the predominant polyunsaturated fatty acid is linoleic acid, and its corresponding predominant hydroperoxide is 9-hydroperoxy-10,12-octadecadienoic acid during autoxidation, which is the precursor of 2,4-decadienals and 2,4-nonadienals, the key fatty note odorants. Therefore, egg yolk PLs could be an ideal precursor of fatty note odorants for chicken meat and fried foods.

Effects of Partial Replacement of Soybean Meal with Defatted Hermetia illucens Meal in the Diet of Laying Hens on Performance, Dietary Egg Quality, and Serum Biochemical and Redox Indices

This study was carried out on 96 caged Bovans Brown laying hens at an initial age of 25 weeks, which were randomly assigned to four experimental groups of 12 replicates (cages) of two hens per cage. The control group hens received a diet containing 20% soybean meal (SBM), without Hermetia illucens larvae meal (HIM) content. The hens in the experimental groups received a diet containing defatted HIM at levels of 5, 10, and 15% (HIM 5%, HIM 10%, and HIM 15%, respectively), at the expense of a proportionally decreasing content of SBM. During the 12-week experiment, the laying performance, biochemical and redox blood indices, and liver condition were examined. The cholesterol level, fatty acid profile, and malondialdehyde content in egg yolks were also evaluated to determine the dietary quality of the eggs. The inclusion of HIM at any level in the diet did not affect the laying performance parameters (p > 0.05). Increased serum Ca and uric acid contents were observed. There was no effect on the redox indices in plasma. The number of hepatocytes was decreased in the HIM-fed groups. The level of cholesterol in yolks was reduced, and the fatty acid profile showed significant changes. Despite the high lauric acid content in the H. illucens meal, it was present in trace amounts in yolks. In the HIM-fed groups, the levels of saturated fatty acids increased significantly, whereas those of unsaturated fatty acids decreased in the yolks in the same groups.

Effect of β - hydroxy - γ -aminophosphonate (β - HPC) on the hydrolytic activity of Nocardia brasiliensis as determined by FT-IR spectrometry

The use of immunomodulatory and metabolic modulating drugs has been considered a better strategy to improve the efficacy of conventional treatments against pathogens and metabolic diseases. L-carnitine is relevant in fatty acid metabolism and energy production by β-oxidation, but it also has a beneficial therapeutic immunomodulatory effect. The β-hydroxy-γ-aminophosphonate (β-HPC) was developed, synthesized and studied in different pathologies as a more soluble and stable analog than L-carnitine, which has been studied in bacterial physiology and metabolism; therefore, we set out to investigate the direct effect of β-HPC on the metabolism of N. brasiliensis, which causes actinomycetoma in Mexico and is underdiagnosed. To analyze the effect of β-HPC on the metabolic capacity of the bacterium for the hydrolysis of substrate casein, L-tyrosine, egg yolk, and tween 80, Fourier transform infrared spectroscopy (FT-IR) was employed. It was found that β-HPC increases the metabolic activity of N. brasiliensis associated with increased growth and increased hydrolysis of the substrates tested. By the effect of β-HPC, it was observed that, in the hydrolysis of L-tyrosine, the aromatic ring and functional groups were degraded. At 1515 cm^-1, any distinctive signal or peak for this amino acid was missing, almost disappearing at 839, 720, 647, and 550 cm^-1. In casein, hydrolysis is enhanced in the substrate, which is evident by the presence of NH, OH, amide, and CO. In casein, hydrolysis is enhanced in the substrate, which is evident by the presence of NH, OH, amide, COO, and P = O signals, characteristic of amino acids, in addition to the increase of the amide I and II bands. In Tween 80 the H-C = and C = C signals disappear and the ether signals are concentrated, it was distinguished by the intense band at 1100 cm^-1. Egg yolk showed a large accumulation of phosphate groups at 1071 cm^-1, where phosvitin is located. FT-IR has served to demonstrate that β-HPC is a hydrolysis enhancer. Furthermore, by obtaining the spectrum of N. brasiliensis, we intend to use it as a quick comparison tool with other spectra related to actinobacteria. Eventually, FT-IR may serve as a species identification option.

Preclinical evaluation of the polycaprolactone-polyethylene glycol electrospun nanofibers containing egg-yolk oil for acceleration of full thickness burns healing

Considering the great potential of egg yolk oil (EYO) in management of burn wounds and superb biological properties of polycaprolactone (PCL) and polyethylene glycol (PEG), hereby, a PCL-PEG-EYO scaffold was developed by electrospinning method for burn healing. The physico-chemical characterizations were performed using SEM, FTIR and contact angle tests. The biological properties of the fabricated scaffolds were evaluated by antibacterial test, in vitro cell culturing, MTT assay and in vivo experiments. The SEM images of PCL-PEG-EYO nanofibers demonstrated a uniform bead-free morphology with 191 ± 61 nm diameter. The fabricated scaffold revealed hydrophilicity with the water contact angel of 77°. No cytotoxicity was observed up to 7 days after cell culturing onto the PCL-PEG-EYO nanofibrous surface. The presence of EYO in the PCL-PEG-EYO scaffold meaningfully improved the cell viability, proliferation and attachment compared to PCL-PEG scaffold. Moreover, the PCL-PEG-EYO scaffolds demonstrated antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa bacteria strain. Finally, a statistically significant enhancement in wound closure, re-epithelialization, angiogenesis and collagen synthesis was observed at the end of 21-day treatment period using PCL-PEG-EYO nanofibrous scaffold. Overall, the PCL-PEG-EYO nanofibrous scaffolds demonstrated a great potential in management of full thickness burn wounds in vivo.

Evaluation of the Role of Soybean Lecithin, Egg Yolk Lecithin, and Krill Oil in Promoting Ovarian Development in the Female Redclaw Crayfish Cherax quadricarinatus

The optimal supplementation of lipid nutrients in the diet showed crucial physiological functions in gonadal development and maturation in adult female aquatic animals. Four isonitrogenous and isolipidic diets with no extra lecithin supplementation (control), 2% soybean lecithin (SL), egg yolk lecithin (EL), or krill oil (KO) supplementation were formulated for Cherax quadricarinatus (72.32 ± 3.58 g). Ovary development and physiological characteristics of crayfish were evaluated after a 10-week feeding trial. The results indicated that SL, EL, or KO supplementation all significantly increased the gonadosomatic index, especially in the KO group. Crayfish fed the diet with SL showed the highest hepatosomatic index compared with those fed the other experimental diets. KO was more efficient than SL and EL in promoting triacylglycerol and cholesterol deposition in the ovary and hepatopancreas but also showed the lowest concentration of low-density lipoprotein cholesterol in the serum. KO significantly increased yolk granule deposition and accelerated oocyte maturation than other experimental groups. Furthermore, dietary phospholipids significantly enhanced the gonad-stimulating hormone concentration in the ovary and reduced the secretion of gonad-inhibiting hormones in the eyestalk. KO supplementation also significantly improved organic antioxidant capacity. From the ovarian lipidomics results, phosphatidylcholine and phosphatidylethanolamine are two main glycerophospholipids that respond to different dietary phospholipids. Polyunsaturated fatty acids (especially C18:2n-6, C18:3n-3, C20:4n-6, C20:5n-3, and C22:6n-3) were pivotal participants during ovarian development of crayfish regardless of lipid type. Combined with the ovarian transcriptome, the best positive function of KO was due to activated steroid hormone biosynthesis, sphingolipid signaling, retinol metabolism, lipolysis, starch and sucrose metabolism, vitamin digestion and absorption, and pancreatic secretion. As a consequence, dietary supplementation with SL, EL, or KO all improved the ovarian development quality of C. quadricarinatus, especially KO, which was the optimum choice for promoting ovary development in adult female C. quadricarinatus.

Feeding Laying Ducks Eucommia ulmoides oliv. Leaves Increases the n-3 Fatty Acids Content and Decreases the n-6: n-3 PUFA Ratio in Egg Yolk without Affecting Laying Performance or Egg Quality

The objective was to determine the effects of supplementing duck diets with Eucommia ulmoides oliv. leaf powder (EUL). Laying ducks (n = 480) were randomly allocated into 4 experimental treatments and fed diets containing 0, 1, 2, or 4% EUL. Dietary inclusion of EUL had no effect (p > 0.05) on laying performance or egg quality, but linearly increased (p < 0.05) total plasma protein, globulin, and HDL-C concentrations with concurrent reductions (p < 0.05) in plasma concentrations of cholesterol and LDL-C. Eggs laid by ducks receiving EUL had yolks with linearly higher phenolic concentrations (p < 0.05) but lower cholesterol concentrations (p < 0.05). EUL supplementation in duck diets significantly reduced n-6: n-3 PUFA ratio by enriching n-3 fatty acids in yolks (p < 0.05) with no changes in n-6 PUFA (p >0.05).

Effect of Four Extraction Processes with Acetone-Ethanol Protocols on the Properties of Egg Yolk Phosphatidylcholine and the Structure of Residual Protein

In this study, four acetone-ethanol protocols were employed to investigate the effect of extraction processes on the yield and purity of phosphatidylcholine (PC) from dried egg yolk powder and fresh liquid egg yolk, as well as the cholesterol distribution between the oil and PC fraction. Furthermore, the physicochemical (thermo-stability, fatty acid composition, and molecular structure) and emulsifying (zeta potential, particle size, EAI, ESI, and creaming index) properties of the final PC product were also examined. In addition, the structural characteristics of the egg yolk residual protein were highlighted to promote its application in food industries. The results showed that de-oiling with acetone prior to ethanol extraction can achieve high yield (19.92%) and purity (68.62%) of the PC product with low cholesterol content (< 0.12%). The extraction processes exhibited a significant impact on the emulsifying properties of the PC product. The creaming index of PC emulsions was higher than that of egg yolk powder emulsions with high protein concentration, suggesting that PC plays a critical role in the emulsifying stability of egg yolk protein dispersion. The structural characteristics of residual protein, including free sulfhydryl groups and primary, secondary, and ternary structures, showed considerable differentiation related to extraction processes. These findings provide a powerful tool for the dietary utilization of egg yolk PC and protein in future.

Quantitative lipidomics analysis of changes in egg yolk lipids during spray-drying and subsequent accelerated storage

Egg yolks are rich in lipids that are easily altered during processing and storage. In this study, a liquid chromatography-tandem mass spectrometry strategy was used for quantitative lipidomics analysis of egg yolk after spray-drying processing and accelerated storage. Spray-drying treatment caused lipid oxidation (especially the oxidation of free fatty acids), potential hydrolysis of phospholipids, and alteration of the form of certain polyunsaturated fatty acids (docosahexaenoic acid, eicosapentaenoic acid, linolenic acid, and eicosatetraenoic acid) in egg yolk. These lipid alterations caused by the spray-drying process were further aggravated by the accelerated storage process. In detail, following storage, the abundance of free fatty acids, phosphatidic acid and phosphatidylethanolamine decreased further; and the abundance of polyunsaturated fatty acids in the form of triglycerides increased significantly. These results provide new insight into the mechanism underlying egg yolk property changes during spray-drying and storage, and offer valuable reference data for egg yolk powder promotion and application in food processing.

Characterization and Comparison of Lipid Profiles of Selected Chicken Eggs Based on Lipidomics Approach

The present study aimed to analyze the lipid profiles of three selected chicken eggs (Nixi, silky fowl, and ordinary eggs) from the market of China by an UPLC-Q-Exactive-MS based untargeted lipidomics approach. In total, 11 classes and 285 lipid molecular species were identified from the egg yolks. Glycerophospholipids (GPLs, 6 classes, 168 lipid species) are the most abundant lipids groups, followed by sphingolipids (3 classes, 50 lipid species), and two neutral lipid classes (TG and DG). Notably, two ethersubclass of GPLs (PC-e and PE-p) and 12 species of cerebrosides were firstly detected from the chicken eggs. Furthermore, multivariate statistical analysis was performed and the lipids profiles of the three types of eggs were well discriminated from each other by 30 predominant lipids species. The characteristic lipid molecules of the different kind of eggs were also screened out. This study provides a novel insight for better understanding the lipid profiles and nutritional values of different chicken eggs.

Quantitative metabolome analysis of boiled chicken egg yolk

Boiling has important effects on the texture of chicken eggs, but its effects on egg nutrients have not been systematically investigated. In this study, changes in the metabolites of egg yolks boiled under different heating intensities were quantified and compared by metabolomic analysis. A total of 797 metabolites were identified, and the abundance of 162 metabolites changed significantly after boiling. The significant reduction of L-lysine and D-fructose suggested that Maillard reactions occurred in over-boiled egg yolks. Egg yolk endogenous enzymes might induce a partial hydrolysis of proteins and phospholipids during the warm-up period of boiling, as the abundance of dipeptides, lysophospholipids, and free fatty acids was significantly increased in boiled egg yolks. Boiling increased the detectable abundance of fat-soluble vitamins, riboflavin, and biotin, possibly by altering the complex structure of protein-lipid-lipophilic compounds or denaturing vitamin-binding proteins. The results of metabolomic analyses provide important information for understanding the nutritional changes of egg yolk boiled under different heating intensities.

Identification of candidate genomic regions for thermogelled egg yolk traits based on a genome-wide association study

Egg yolk texture is an important indicator for evaluating egg yolk quality. Genetic markers associated with economic traits predict genomes and facilitate mining for potential genes. Numerous genome-wide association studies have been conducted on egg traits. However, studies on the genetic basis of thermogelled yolk texture are still lacking. The aim of the present study was to find significant single nucleotide polymorphism (SNP) sites and candidate genes related to thermogelled yolk texture in Hetian Dahei chicken (HTHD) flocks that can be used as genetic markers. Five traits, including hardness, cohesiveness, gumminess, chewiness, and resilience, had low heritability (0.044-0.078). Ten genes, including U6, FSHR, PKDCC, SLC7A11, TIMM9, ARID4A, PSMA3, ACTR10, EML4, and SLC35F4 may control the hardness of the thermogelled egg yolks. In addition, 12 SNPs associated with cohesiveness were identified. RELCH located on GGA2 participates in cholesterol transport. The candidate gene LRRK2, which is associated with gumminess, influences the concentrations of very low-density lipoprotein in blood. Eight SNPs associated with resilience were identified, mainly on GGA3 and GCA28. In total, 208 SNPs associated with chewiness were identified, and 159 candidate genes, which were mainly involved in proteasome-mediated ubiquitin-dependent protein catabolic process, negative regulation of transport, lipid droplet organization, and vehicle docking involved in exocytosis, were found near these regions. Thermogel egg yolk texture is a complex phenotype controlled by multiple genes. Based on heritability assays and GWAS results, there is a genetic basis for the texture of thermogelled egg yolks. We identified a series of SNPs associated with yolk texture and candidate genes. Our result provides a theoretical basis for breeding high-quality egg yolk using molecular marker-assisted selection and could facilitate the development of novel traits.

The Association of Dietary Cholesterol from Egg Consumption on Cardiovascular Diseases Risk Varies from Person to Person

The public and scientists remain skeptical about egg consumption, given that cardiovascular diseases (CVDs) are the leading causes of death in worldwide. This review mainly explained the recurrence of contradictory conclusions about relationships between egg consumption and CVD risk and discussed effects of egg cholesterol intake on cholesterol homeostasis. Factors including individual health status and cholesterol sensitivity, dietary pattern, region, and race should be distinguished when understanding generalized conclusions. Identified compensatory mechanisms in response to dietary cholesterol and the resulting balance in cholesterol biosynthesis, absorption, and efflux supported the view that moderate egg consumption had no substantial overall impacts on cholesterol homeostasis in healthy people. Excessive cholesterol intake is not recommended in individuals with distempered metabolism. More than cholesterol metabolism, impacts of egg consumption as a part of overall diet on CVD risk should be considered from aspects of nutrient intake, lipid metabolism, and energy supply in the future.

Developmental changes in lipid and fatty acid metabolism and the inhibition by in ovo feeding oleic acid in Muscovy duck embryogenesis

Hepatic lipid and fatty acid (FA) metabolism are critical for regulating energetic homeostasis during embryogenesis. At present, it remains unclear how an exogenous FA intervention affects embryonic development in an avian embryo model. In Exp. 1, 30 fertilized eggs were sampled on embryonic days (E) 16, 19, 22, 25, 28, 31 and the day of hatch (DOH) to determine the critical period of lipid metabolism. In Exp. 2, a total of 120 fertilized eggs were divided into two groups (60 eggs/group) for in ovo feeding (IOF) procedures on E25. Eggs were injected into the yolk sac with PBS as the control group and with oleic acid (OA) as the IOF-OA treatment group. Samples were collected on E28 and E31. In Exp. 1, hepatic triacylglycerol (TG) and cholesterol (CHO) contents increased while serum TG content decreased from E16 to DOH (P < 0.05). Both serum and liver displayed an increase in unsaturated FA and a decrease in saturated FA (P < 0.05). There was a quadratic increase in the target gene and protein expression related to hepatic FA de novo synthesis and oxidation (P < 0.05), whose inflection period was between E22 and E28. In Exp. 2, compared with the control embryos, IOF-OA embryos had an increased yolk sac TG content on E28 and E31, and a decreased serum TG and CHO content on E28 (P < 0.05). The IOF-OA embryos had less OA in the yolk sac and liver on E28, and less unsaturated FA in the serum and liver on E31 than did the control embryos (P < 0.05). Hepatic gene mRNA expression related to FA uptake, synthesis, and oxidation on E28 was lower in IOF-OA than in control embryos (P < 0.05), not on E31 (P > 0.05). Maximal metabolic changes in lipid and FA metabolism occurred on E22-E28 in Muscovy duck embryogenesis, along with the altered target gene and protein expression related to lipogenesis and lipolysis. IOF-OA intervention on E25 could inhibit the target gene expression related to FA uptake, synthesis, and oxidation, which may influence the normal FA metabolism on E28 during embryogenesis.