Yolk Samples Research Articles

Research note: Changes in chicken egg yolk metabolome during its spray drying and storage.

The differences in metabolites between fresh egg yolk (FEY), spray-dried egg yolk powder (SEY), and stored egg yolk powder (S-SEY) were quantitatively compared through metabolomic analysis. Total of 1004 metabolites were identified in the three groups of egg yolk samples. In pairwise group analysis, 242 differential metabolites were identified in FEY and SEY, 311 differential metabolites were identified in FEY and S-SEY, and 157 differential metabolites were identified in SEY and S-SEY. The analysis of differential metabolites with the highest abundance showed that amino acids, carbohydrates and lipids in FEY would undergo oxidation reactions after spray drying and storage and thus led to significant changes in the type and abundance of metabolites. The representative differential metabolites were then screened out for judging the freshness of egg yolk powder. Therefore, the results are highly important for evaluating the quality of egg yolk powder and provide important information for understanding the nutritional changes of egg yolk after spray drying and storage.

Multivariate Modelling Based on Isotopic, Elemental, and Fatty Acid Profiles to Distinguish the Backyard and Barn Eggs.

The ability to trace the origin of eggs from backyard-raised hens is important due to their higher market value compared to barn-raised eggs. This study aimed to differentiate eggs from these two rearing systems using isotopic, elemental, and fatty acid profiles of egg yolks. A total of 90 egg yolk samples were analyzed, analytical results being followed by statistical tests (Student's t-test) showing significant differences in δ18O, several elements (Mg, K, Sc, Mn, Fe, Ni, Cu, Zn, As, Cd, Ba, Pb), and fatty acids compositions (C23:0, C17:0, C18:0, C16:1n7, C18:1n9, C18:2n6, C20:1n7, C20:4n6, C20:5n3, C22:6n3), as well as in the ratios of SFA, PUFA, and UFA. The results indicated a nutritional advantage in backyard eggs due to their lower n-6 polyunsaturated fatty acid content and a more favorable n-6 to n-3 ratio, linked to differences in the hens' diet and rearing systems. To classify the production system (backyard vs. barn), three pattern recognition methods were applied: linear discriminant analysis (LDA), k-nearest neighbor (k-NN), and multilayer perceptron artificial neural networks (MLP-ANN). LDA provided perfect initial separation, achieving 98.9% accuracy in cross-validation. k-NN yielded classification rates of 98.4% for the training set and 85.7% for the test set, while MLP-ANN achieved 100% accuracy in training and 92.3% in testing, with minor misclassification. These results demonstrate the effectiveness of fusion among isotopic, elemental, and fatty acid profiles in distinguishing backyard eggs from barn eggs and highlight the nutritional benefits of the backyard-rearing system.

Metal accumulation in female green sea turtles (Chelonia mydas) from Eastern Atlantic affects their egg quality with potential implications for embryonic development

Sea turtles, with their global distribution and complex life cycle, often accumulate pollutants such as metals and metalloids due to their extended lifespan and feeding habits. However, there are limited studies exploring the impact of metal pollution on the reproductive health of female sea turtles, specifically focusing on the quality of their eggs, which has significant implications for the future generations of these charismatic animals. São Tomé Island, a crucial nesting and feeding habitat for green sea turtles, underscores the urgent need for comprehensive research in this ecologically significant area. This study aimed to investigate whether metals and metalloids in the blood of nesting female green sea turtles induce genotoxic effects in their erythrocytes and affect their egg morphometric characteristics and the composition of related compartments. Additionally, this study aimed to evaluate whether the quality of energetic reserves for embryo development (fatty acids in yolk's polar and neutral lipids) is influenced by the contamination status of their predecessors. Results revealed correlations between Cu and Hg levels and increased “lobed” erythrocytes, while As and Cu negatively influenced shell thickness. In terms of energy reserves, both polar and neutral lipid fractions contained primarily saturated and monounsaturated fatty acids, with prevalent 18:1n-9, 18:0, 16:0, 14:0, and 12:0 fatty acids in yolk samples. The yolk polar fraction was more susceptible to contaminant levels in female sea turtles, showing consistent negative correlations between pollution load index and essential n3 fatty acids, including linolenic, eicosatrienoic, eicosapentaenoic, and docosapentaenoic acids, crucial for embryonic development. These metals accumulation, coupled with the reduced availability of these key fatty acids, may disrupt the eicosanoid and other important pathways, affecting reproductive development. This study reveals a negative correlation between metal contamination in female sea turtles' blood and egg lipid reserves, raising concerns about embryonic development and the species' future generations.

Viable Campylobacter jejuni on Eggshells and Its Potential to Cross-contaminate Egg White and Yolk When Using a Manual Separation Technique, Determined by Culture and Propidium Monoazide (PMA) qPCR

Manual separation of egg yolk from egg white using the eggshell is common practice in private households. For this, the egg is cracked and both components are separated by passing the egg yolk back and forth between the two halves of the eggshell, allowing the egg white to drip down while the egg yolk remains in the shell. During this process, the egg content naturally gets in contact with the outside of the eggshell, which might lead to a cross-contamination with its microorganisms, thus was correspondingly assessed in this study. Campylobacter jejuni is one of the most important zoonotic pathogens that can be found on eggshells. Therefore, this bacterium was used to artificially contaminate the eggshells (n = 22) with concentrations of 3.1 ± 0.6 log10 cfu/g. After separating the egg yolk from the egg white, cross-contamination was determined using culture and qPCR. Altogether, cross-contaminations with C. jejuni were found in 15 egg white (68%) and in three egg yolk (14%) samples. Afterward, 90 eggs from 30 egg packs from different producers in and around Munich (Germany) were obtained for field study purposes. To address the problem of culturing due to a possible viable but nonculturable (VBNC) status of C. jejuni, a method to differentiate viable and dead C. jejuni on eggshell using 10 µM propidium monoazide (PMA) and qPCR was developed. As a result, seven egg packs (23%) were positive for C. jejuni. Of these, only one (3%) was contaminated with viable cells, but still in a concentration of 3.3 log10 cells/g shell. According to these results and considering that eggshells might also be naturally contaminated with other pathogens, the authors recommend avoiding the manual separation technique of egg white and yolk by the eggshell. Especially if raw egg white or yolk is used for preparation of not sufficiently heated foods, where contaminating pathogens are not inactivated during processing, this technique might be a safety hazard for the consumer.

Egg Quality, Yolk Fatty Acid Profiles from Laying Hens Housed in Conventional Cage and Cage-Free Production Systems in the Andean Tropics.

Egg consumers worldwide have increased their concerns about laying hens' welfare and its impact on final egg product quality. This study compared the egg quality parameters under the conventional cage (CC) and cage-free (CF) egg production systems in the tropics. The study was conducted on a commercial farm in Colombia using Hy-Line Brown pullets, reared under the same conditions for the first 15 wks. At 16 wks, the hens were distributed into two housing systems, CC and CF, on the same farm. The hens were fed the same diet for each phase in both systems and feed intake varied slightly. Egg samples were collected every six wks, from 22 to 82 wks of age. A total of 3960 eggs were analyzed at 11 sampling times. Parameters such as albumen height, egg weight, yolk color, eggshell thickness, eggshell strength, and Haugh units were determined using a DET-6000 machine. At 22 and 82 wks, screening for Salmonella spp. status was conducted using environmental and egg samples. Additionally, at 34, 64, and 82 wks, yolk samples were obtained for fatty acid profiles and crude protein (CP) analysis. The data were analyzed in a completely randomized block design with repeated measures (11 times): mean separation by Student's t-test yolk pigmentation, Haugh Units, and albumen height (p < 0.001) were higher in the CF compared with the CC between 38 and 69 wks of age, and eggs at 63 and 82 wks (p < 0.05) were heavier in the CF compared to the CC. Likewise, eggs from the CC had better eggshell strength from 57 to 82 wks. In the egg yolk fatty acid profile at the 34th wk, the pentadecanoic, palmitic, and heptadecanoic acids had higher concentrations in the CF systems than the CC. At the 64th wk, the egg yolk fatty acids-lauric, myristic, and heptadecanoic-had higher concentrations in the CF; likewise, at the 82nd wk, egg yolks from the CC had higher concentrations of lauric, heptadecanoic, and nervonic fatty acids than the CF. The eggs and environmental samples were negative for Salmonella spp. throughout the whole production phase. These results indicated that the production system might impact internal and external egg quality measures, potentially due to various stressors, including environmental factors or behavior restrictions.

The effect of maltodextrin on properties of sated egg yolk

Salted eggs are mainly produced through salting treatments that taste salty. However, high sodium intake is part of the pathophysiology of hypertension. Thus, this study aimed to develop low-sodium egg yolks with salting treatment using sodium chloride (NaCl) and maltodextrin to reduce salt content in the salting process. Salted egg yolks were produced using methods in the salting process using maltodextrin (10% and 20% supplement) and were compared to salted eggs brined with 20 and 26% sodium chloride (NaCl) solutions. The moisture content, salt content, color, and texture properties of salted egg yolks during salting for up to 35 days were determined. Nevertheless, salted egg yolks produced with the salting solution using maltodextrin supplement had a significant salt content (0.21-3.30 mg/g) that was lower than the amount discovered in commercial salted yolks (2.84-4.15 mg/g). The results revealed that the maltodextrin substitution affected the salted yolks' properties. The salt contents of all salted egg yolk samples gradually increased during the salting process, along with slight decreases in moisture content as salting time and salt solution concentration increased. The lightness (L*) and the yellowness (b*) decreased while the redness (a*) increased. The hardness, adhesiveness, cohesiveness, gumminess, and chewiness of salted egg yolks increased rapidly over the time of salting, while springiness decreased during the initial stages of salting and reached almost constant levels at the end of salting. As the salting time increased to 35 days, the salted yolk gradually became dark reddish. The maximum denaturation temperature (Tmax) and denaturation enthalpy (DH) of egg proteins increased with increasing salting time. These effects were most pronounced due to the high maltodextrin content of the salting solution. This study suggests that this approach with maltodextrin substitution using the shell egg salting protocol can produce low-sodium salted eggs.

Mesoporous Silica-stabilized Magnetite Nanoparticles with Peroxidase-like Activities for Sensitively Detecting Cholesterol in Animal-derived Foods

Sensitive detection of cholesterol in animal-derived foods is crucial for maintaining human healthy diets. In this study, an elegant approach utilizing inorganic nanozyme-based magnetic mesoporous silica nanoparticles (MMSNs) for the highly sensitive detection of cholesterol in animal-derived food products was reported. The results revealed the fabricated MMSNs exhibited remarkably intrinsic Peroxidase (POD)-like catalytic activities with improved affinity, and the catalytic behavior aligned well with Michaelis–Menten equation. In addition, the data indicated that the MMSNs enabled visual colorimetric detection of cholesterol with a remarkably low detection limit of 7.12μM by combining catalytic oxidation with cholesterol oxidase (ChOx). Furthermore, the prepared MMSNs were successfully employed for assessing cholesterol content in milk and egg yolk samples, indicating potential applications for cholesterol detection in animal-derived foods in future.

Effects of High-Biotin Sample Interference on Antibody Concentrations in Sandwich Immunoassays.

The use of antimicrobial growth promoters (AGPs) is banned because of problems associated with drug residues in animal products and increased bacterial resistance. The immunization of chickens with specific antigens is a promising strategy for generating specific antibodies that can target a wide range of antibiotic-resistant bacteria and can be used as an alternative to antibiotics. Immunoglobulin Y (IgY) antibodies in a polyclonal antibody (pAb) format, when administered orally, modulate the ruminal microbiome and maintain animal health and performance; however, there are concerns pertaining to protein impurities and biotin concentrations in the samples. Signal amplification strategies involving the noncovalent interaction of biotin with streptavidin is extensively used in diagnosis and scientific research, particularly in enzyme-linked immunosorbent assays (ELISAs). However, the high concentrations of biotin in samples, especially in those derived from rich sources such as egg yolk, can pose challenges and potentially harm the accuracy of diagnostic tests and protein concentration measurements. This study aimed to evaluate the influence of biotin on the measurement of IgY in freeze-dried egg yolk samples obtained from immunized laying hens using immunoassays with biotin-avidin/streptavidin. The detection of IgY in yolk samples using ELISA with streptavidin-biotin binding could lead to misdiagnosis due to biotin interference; the level of interference varies with the specific assay conditions and the concentration of biotin in the yolk samples. An ELISA without streptavidin-biotin binding is advisable to avoid interactions between biotin and target proteins, prevent biotin interference with the results, and achieve more reliable and accurate results.

Supplementation of Japanese Quail (Coturnix coturnix japonica) Breeders with Tagetes erecta Flower Extract and Vitamin E Improves the Oxidative Status of Embryos and Chicks

The effects of Tagetes erecta flower extract (TFE) and increasing levels of vitamin E (VE) in the diet of Japanese quail breeders on progeny performance and oxidative status were studied. Methods: 480 Japanese quail breeders were distributed in a completely randomized design with five treatments and twelve replications of six females and two males each. A control diet (25 mg/kg VE) and four diets supplemented with TFE (3 g/kg) and VE (25, 100, 175, or 250 mg/kg) were used. Fresh yolk samples and the yolk sac and liver from embryos (11 and 15 days) and chicks (hatch and 3 days) were analysed. Data were subjected to ANOVA, a regression linear model, and contrast tests and the level of significance was set at p &lt; 0.05. Results: TF and VE in the maternal diet improved the amount of alfa-tocopherol and total carotenoid content in the yolk. TFE + VE reduced lipid peroxidation and improved the oxidative status in the fresh yolk, in the embryo and chick yolk, and in the liver. Liver superoxide dismutase activity in hatched chicks increased linearly with the VE level and was not altered by TFE. Maternal diets did not influence progeny performance (1 to 28 days) or the relative expression of superoxide dismutase or glutathione peroxidase genes in the liver of chicks. Conclusions: TFE is an effective antioxidant in fresh eggs and supplementation of 3 g/kg TFE and high levels of VE in quail breeders improves the oxidative status of embryos and newly hatched chicks.

Microplastics evidence in yolk and liver of loggerhead sea turtles (Caretta caretta), a pilot study.

The potential toxicity of microplastics is a growing concern for the scientific community. The loggerhead sea turtle (Caretta caretta) is particularly inclined to accidently ingest plastic and microplastic due to its long-life cycle features. The possible transfer of microplastics from the female to the eggs should be investigated.The present study investigated the presence of microplastics in yolk and liver samples evaluating the number of melanomacrophages in the hepatic tissue as a possible biomarker of microplastics impact on the embryonic health status. The biometric parameters and liver histological analysis of 27 and 48 embryos (from two different nests respectively) at the 30 stage of development were analyzed. Raman Microspectroscopy was performed to identify the microplastics after alkaline digestion (10% KOH) of yolk and portion of liver from 5 embryos at the 30 developmental stage per nest. Microplastics were found in yolk and liver of loggerhead sea turtles at late embryonic stage for the first time. All microplastics were smaller than 5 μm and were made of polymers and colors suggesting their diverse origins. A total number of 21 microplastics, with dimensions lower than 5 μm, were found between the two nests (11 and 10 microplastics respectively). Only two shape categories were identified: spheres and fragments. The most frequent polymers observed were polyethylene, polyvinyl chloride and acrylonitrile butadiene styrene (31.5%, 21.1% and 15.8% respectively). Despite the eggs showing a higher number of microplastics in yolk samples than liver (15 and 6 microplastics in yolk and liver respectively), a positive correlation was observed only between the number of melanomacrophages (r = 0.863 p < 0.001) and microplastics in the liver. This result may suggest that microplastics could exert some effects on the hepatic tissues. Future studies should investigate this aspect and the possible relation between microplastics and other stress biomarkers.

Variation in element contents among free-range turkey egg yolks and albumens analyzed by inductively coupled plasma optical emission spectrometry

Poultry eggs are not only a source of nutrients for embryonic development, but also one of the main sources of food for humans. The demand for turkey eggs is increasing day by day due to their functional properties such as supporting muscle and cell formation and being beneficial to the immune and digestive systems. In addition, it contains essential elements such as iron at a reasonable level, which is among the reasons for the consumer's preference. The data on the element content of free-range turkey eggs, which is such an ancient food, is very scarce. This study focused on determining various element content of freerange turkey egg yolk and albumen by inductively coupled plasma optical emission spectrometry (ICP-OES). Within the scope of the research, sodium (Na), potassium (K), calcium (Ca), phosphorus (P), iron (Fe), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), chromium (Cr), boron (B), aluminum (Al), and lead (Pb) levels were determined in turkey egg yolk (n=52) and albumen (n=52) samples. Phosphorus was the most concentrated element in both egg yolk and albumen. Element contents in yolks were higher than those in albumen, except Na, K, B, Al, and Pb. The element with the lowest concentration was Al in turkey egg yolks, while Mg was the lowest analyzed element in albumens. This study separately exhibited the element content of turkey egg consumers in their preference for egg yolk or albumen

Sea turtle egg yolk and albumen as biomonitoring matrices for maternal burdens of organic pollutants

To establish the use of eggs as biomonitoring tools for maternal body burdens, we investigated the mother-to-egg ratio of 56 PCB, 12 OCP and 34 PBDE unique compounds from maternal plasma into replicate egg yolk and albumen samples in the loggerhead turtle (Caretta caretta) as a case study of a threatened migratory marine species. We applied robust Regression on Order Statistics to fully account for the information in both censored and uncensored data. Our results added new insights into the use of yolk as a suitable biomonitoring matrix; the difference between yolk and albumen which were previously analysed as a homogeneous mixture; and the value of accounting for censored data. Overall, compound-specific mother-to-egg ratios need to be considered when translating yolk levels back to maternal pollution burdens, and when assessing the risk to the subsequent generations of turtle embryos.

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.

Pattern and repeatability of ascarid-specific antigen excretion through chicken faeces, and the diagnostic accuracy of coproantigen measurements as compared with McMaster egg counts and plasma and egg yolk antibody measurements in laying hens

BackgroundA coproantigen enzyme-linked immunosorbent assay (ELISA) has recently been proposed for detecting ascarid infections in chickens. The excretion pattern of ascarid antigens through chicken faeces and the consistency of measurements over the course of infections are currently unknown. This study evaluates the pattern and repeatability of worm antigen per gram of faeces (APG) and compares the diagnostic performance of the coproantigen ELISA with a plasma and egg yolk antibody ELISA and McMaster faecal egg counts (M-FEC) at different weeks post-infection (wpi).MethodsFaecal, blood and egg yolk samples were collected from laying hens that were orally infected with a mix of Ascaridia galli and Heterakis gallinarum eggs (N = 108) or kept as uninfected controls (N = 71). Measurements including (a) APG using a coproantigen ELISA, (b) eggs per gram of faeces (EPG) using the McMaster technique and (c) ascarid-specific IgY in plasma and in egg yolks using an ascarid-specific antibody ELISA) were performed between wpi 2 and 18.ResultsTime-dependent significant differences in APG between infected and non-infected laying hens were quantified. At wpi 2 (t(164) = 0.66, P = 1.00) and 4 (t(164) = −3.09, P = 0.094) no significant differences were observed between the groups, whereas infected hens had significantly higher levels of APG than controls by wpi 6 (t(164) = −6.74, P < 0.001). As indicated by a high overall repeatability estimate of 0.91 (CI = 0.89–0.93), APG could be measured consistently from the same individual. Compared to McMaster and antibody ELISA, coproantigen ELISA showed the highest overall diagnostic performance (area under curve, AUC = 0.93), although the differences were time-dependent. From wpi 6 to 18 coproantigen ELISA had an AUC > 0.95, while plasma IgY ELISA showed the highest diagnostic performance in wpi 2 (AUC = 0.95). M-FEC had the highest correlation with total worm burden, while APG had highest correlations with weights and lengths of A. galli.ConclusionAscarid antigen excretion through chicken faeces can be measured with high accuracy and repeatability using a coproantigen ELISA. The antigen excretion increases over time, and is associated with worm maturation, particularly with the size of A. galli. Our results suggest the necessity of complementary use of different diagnostic tools for a more accurate diagnosis of infections.Graphical

Effects of dietary protein levels on performance, nitrogen excretion, and odor emission of growing pullets and laying hens

The objective of this study was to determine the effects of dietary crude protein (CP) levels on production performance, nitrogen balance, and odor emission of excreta in growing pullets and laying hens from 13 to 32 wk of age. Two hundred and forty pullets (Hy-Line Brown) were randomly assigned to 1 of 4 dietary groups with 10 replicates per group, and 6 birds per replicate. Experimental diets were formulated to contain 4 graded CP levels in the diets of pullets ranging from 180, 160, 140, and 120 g/kg of diet during 13 to 18 wk (phase 1) and in the diets of laying hens from 190, 170, 150, and 130 g/kg of diet during 19 to 32 wk (phase 2). The limiting amino acids including lysine, methionine, and threonine were supplemented to maintain constant equal amino acid concentrations in all experiment diets. In phase 1, decreasing dietary CP levels did not affect growth performance but increased (linear and quadratic effect, P < 0.05) the relative abdominal fat contents and triglyceride concentration in serum samples. High-density lipoprotein cholesterol in serum samples decreased as the CP levels decreased in the diets of pullets. Dietary CP levels quadratically increased (P < 0.05) the villus height and the villus height to crypt depth ratio but did not affect tibia traits and relative organ weights in pullets at 18 wk. Apparent digestibility of dry matter and ether extract increased with decreasing dietary CP levels in pullets. Graded CP levels linearly increased the digestibility of dry matter, CP, and ether extracts but lowered that of crude ash in laying hens. Nitrogen excretion was linearly decreased (P < 0.05) as the dietary CP levels decreased in both pullets and laying hens. Dietary CP levels only affected carbon dioxide emission in pullets. In phase 2, dietary CP levels did not affect growth performance and the ages at first egg laying and to reach 50% egg production in laying hens. However, egg weights were decreased (linear and quadratic effect, P < 0.05) as the dietary CP level decreased in laying hens. Increasing dietary CP levels increased Haugh unit at 26 wk but lowered corticosterone concentrations in yolk samples at 22 wk. Collectively, this study shows that dietary CP levels could be decreased to reduce nitrogen excretion without adverse effects on performance and egg quality of growing pullets and laying hens.

The Effect of Increasing Concentrations of Omega-3 Fatty Acids from either Flaxseed Oil or Preformed Docosahexaenoic Acid on Fatty Acid Composition, Plasma Oxylipin, and Immune Response of Laying Hens

BackgroundThere is a lack of nutrition guidelines for the feeding of omega-3 polyunsaturated fatty acids (PUFA) to laying hens. Knowledge as to whether the type and concentrations of α-linolenic acid (ALA) and/or docosahexaenoic acid (DHA) in the diet can make a difference to the birds’ immune responses when subjected to a lipopolysaccharide (LPS) challenge is limited. ObjectivesThe study was designed to determine the potential nutritional and health benefits to laying hens when receiving dietary omega-3 PUFA from either ALA or DHA. MethodsA total of 80 Lohmann LSL-Classic (white egg layer, 20 wk old) were randomly assigned to 1 of 8 treatment diets (10 hens/treatment), provided 0.2%, 0.4%, 0.6%, or 0.8% of total dietary omega-3 PUFA, provided as either ALA-rich flaxseed oil or DHA-enriched algal biomass. After an 8-wk feeding period, the birds were challenged with Escherichia coli-derived LPS (8 mg/kg; i.v. injection), with terminal sample collection 4 h after challenge. Egg yolk, plasma, liver, and spleen samples were collected for subsequent analyses. ResultsIncreasing dietary omega-3 supplementation yielded predictable responses in egg yolk, plasma, and liver fatty acid concentrations. Dietary intake of ALA contributed mainly to ALA-derived oxylipins. Meanwhile, eicosapentaenoic acid- and DHA-derived oxylipins were primarily influenced by DHA dietary intake. LPS increased the concentrations of almost all the omega-6 PUFA-, ALA-, and DHA-derived oxylipins in plasma and decreased hepatic mRNA expression of COX-2 and 5-LOX (P < 0.001) involved in the biosynthesis of oxylipins. LPS also increased mRNA expression of proinflammatory cytokine IFN-γ and receptor TLR-4 (P < 0.001) in the spleen. ConclusionsThese results revealed that dietary intake of ALA and DHA had unique impacts on fatty acid deposition and their derived oxylipins and inflammatory responses under the administration of LPS in laying hens.

In ovo corticosterone exposure does not influence yolk steroid hormone relative abundance or skeletal muscle development in the embryonic chicken

In ovo corticosterone (CORT) exposure reportedly reduces growth and alters body composition traits in meat-type chickens. However, the mechanisms governing alterations in growth and body composition remain unclear but could involve myogenic stem cell commitment, and/or the presence of yolk steroid hormones. This study investigated whether in ovo CORT exposure influenced yolk steroid hormone content, as well as embryonic myogenic development in meat-type chickens. Fertile eggs were randomly divided at embryonic day (ED) 11 and administered either a control (CON; 100 µL of 10 mM PBS) or CORT solution (100 µL of 10 mM PBS containing 1 µg CORT) into the chorioallantoic membrane. Yolk samples were collected at ED 0 and ED 5. At ED 15 and hatch, embryos were humanely killed, and yolk and breast muscle (BM) samples were collected. The relative abundance of 15 steroid hormones, along with total lipid content was measured in yolk samples collected at ED 0, ED 5, ED 15, and ED 21. Muscle fiber number, cross-sectional area, and fascicle area occupied by muscle fibers were measured in BM samples collected at hatch. Relative expression of MyoD, MyoG, Pax7, PPARγ, and CEBP/β, and the sex steroid receptors were measured in BM samples collected at hatch. The administration of CORT had a limited effect on yolk steroid hormones. In ovo CORT significantly reduced fascicle area occupied by muscle fibers and CEBP/β expression was increased in CORT exposed birds at hatch. In addition, the quantity of yolk lipid was significantly reduced in CORT-treated birds. In conclusion, in ovo exposure to CORT does not appear to influence early muscle development through yolk steroid hormones in embryonic meat-type chickens however, the results provide a comprehensive analysis of the composition of yolk steroid hormones in ovo at different developmental time points. The findings may suggest increased mesenchymal stem cell commitment to the adipogenic lineage during differentiation and requires further investigation.

Comprehensive lipidomics and volatile compounds profiling reveals correlation of lipids and flavors in DHA-enriched egg yolk

DHA-enriched eggs have gained popularity due to their unique nutritional value, but their flavor can be challenging for some consumers to accept. The study analyzed the correlation of lipids and flavors in DHA-enriched egg yolks using comprehensive lipidomics and volatile compound analysis. The results showed that 411 lipids were detected in two egg yolk samples. Among them, 148 lipid species, including 48 DHA-containing lipids, were significantly higher in DHA-enriched egg yolks than in Common ones (P ​< ​0.05). Furthermore, of the 24 volatile compounds detected, the contents of benzaldehyde, heptanal, hexanal, decanal and 2-nonanone in DHA-enriched egg yolks were significantly higher than in Common egg yolks (P ​< ​0.05). The “fishy” smell characteristic of DHA-enriched egg yolks was mainly caused by volatile aldehydes, which may be produced through the hydrolysis of lipids in the egg yolk to free fatty acids and further oxidation. Analysis of the correlation network diagram revealed that phospholipids containing docosahexaenoic acid (DHA), linoleic acid, or oleic acid chains were the main contributors to the characteristic flavor of DHA-enriched egg yolks. Overall, this study explored the effect of different lipids on the flavor of DHA-enriched egg yolks and provided a theoretical basis for the production and improvement of DHA-enriched eggs.

A consortium of detoxifying bacteria mitigates the aflatoxin B1 toxicosis on performance, health, and blood constituents of laying hens

Detoxification approaches are evolving from physical to biological to eliminate the toxins altogether. The current study was conducted to compare the impact of 2 newly developed toxin deactivators, Magnotox-alphaA (MTA) and Magnotox-alphaB (MTB) with a commercially available toxin binder, Mycofix PlusMTV INSIDE (MF) in alleviating the pernicious effects of aflatoxin B1 (AFB1) in laying hens. The treatments were: 1) negative control (NC; without AFB1), 2) positive control (PC; contaminated with 500 ppb AFB1), 3) MF (PC+2 kg MF/ton feed), 4) MTA (PC+2 kg MTA/ton feed), and 5) MTB (PC+2 kg MTB/ton feed). Detoxifying bacteria revealed a substantial reduction of different toxins in vitro, in which 98.8, 94.5, and 73.3% degradation rates were achieved, respectively, for zearalenone (ZEN), patulin, and AFB1 in the first 1 h of exposure. The PC group had a sharp decline in egg production (EP; 68.83%) while MTB showed the superior EP (95.74%) followed by NC (90.66%), MF (86.57%), and MTA (82.08%; P ≤ 0.05). Egg weight (EW) was also observed to be inferior in PC group (53.80 g; P ≤ 0.05). Egg mass (EM) was higher in MTB (57.55 g) and NC (54.33 g) groups while PC produced the lowest (39.64 g; P ≤ 0.05). MTB and NC groups also demonstrated the best FCR, 1.62 and 1.68, respectively, and PC manifested the poorest FCR (1.98) with higher ADFI (P ≤ 0.05). MTB also produced a superior moisture content (MC; 82.11%) with inferior DM (17.89%) in ileum content (P ≤ 0.05). The greatest liver fat content was found in MF group (48.19%) and MTA yielded the superior serum β-carotene and Vit A. MDA level in yolk samples was influenced by treatments, rendering the highest level in PC group (P ≤ 0.05). Ileum microbiota and blood characteristics were also affected by treatments. In general, MTB proves to be a toxin-deactivator candidate with comparable results to that of commercially available toxin-binders.

Characterization of four thermogelled egg yolk varieties based on moisture and protein content

There are obvious differences between egg yolks of different varieties. Additionally, boiled eggs, which are widely liked and consumed globally, are nutrient rich. However, they absorb water in the esophagus during swallowing, and this result in an uncomfortable sensation. Here, we determined the moisture content and distribution as well as the protein contents and properties of 4 varieties of thermogelled egg yolks. Among the varieties, Green Shelled thermogelled egg yolk showed the highest protein content and solubility. Additionally, the ionic, hydrogen, and disulfide bonds corresponding to Rhode Island Red thermogelled egg yolk samples were the weakest, while the hydrophobic interaction force corresponding to the Hetian Dahei (HD) egg yolk samples was the weakest. Further, the distribution of the moisture contents of the 4 varieties was significantly different (P < 0.05). HD egg yolk showed the highest moisture content, and its bound and immobile moisture contents were significantly higher than those of the other 3 varieties. Egg yolk moisture content also affected free amino acid content, which was the highest for HD egg yolk. Therefore, owing to its high moisture content, HD egg yolk was conducive for chewing and swallowing and given its high free amino acid content, it also had a more suitable taste and flavor. The results of this study provide a theoretical basis for the application of egg yolks in food processing.