Tandem mass tag-based quantitative proteomics analysis and gelling properties in egg albumen of laying hens feeding tea polyphenols

Effects of dietary protein-oxidized soybean meal and quercetin on gel properties, microstructure, molecular structure and proteomics of egg white in laying hens

This study investigated the effects of dietary protein-oxidized soybean meal (SBM) and quercetin on gel properties, microstructure, molecular structure and proteomics of egg white in laying hens. A total of 288 Hy-Line Gray laying hens (500 days) were assigned to three groups, basal diets, protein-oxidized SBM diet, and protein-oxidized SBM diet supplemented with 300 mg/kg quercetin. The results showed that dietary protein-oxidized SBM decreased egg albumen height, gel hardness, gumminess and chewiness, and free sulfhydryl levels, although differences were not significant (P > 0.05). Quercetin supplementation reversed above mentioned indicators (P < 0.05). Dietary protein-oxidized SBM significantly increased the protein secondary structure α-helix content, reduced β-turn content, and reduced foam capacity of egg white (P < 0.05), while dietary quercetin alleviated the corresponding index (P < 0.05). Quercetin improved the egg Haugh unit, potentially due to its ability to increase the levels of microfilament proteins.

Proteomic Analysis of the Differences in Heat-Induced Gel Properties of Egg White between Two Chinese Indigenous Duck Breeds

The gel properties of egg white are important functional traits of poultry eggs, yet limited research exists on the utilization of egg whites from local Chinese duck breeds. This study systematically investigated gel properties, ultrastructure, and proteomics of Putian Black Duck (PTEW) and Liancheng White Duck egg whites (LCEW). Results showed that PTEW gels exhibited superior texture properties (hardness, 20.6% higher than LCEW; gumminess, 11.3% higher; chewiness, 11.1% higher; cohesiveness, 7.1% higher) and water holding capacity (7.7% higher). In contrast, LCEW gels were lighter (9.6% higher than PTEW) and whiter (7.3% higher than PTEW). Moreover, LCEW (78 °C) gelation occurred at a higher temperature than PTEW (74 °C). PTEW gels demonstrated a higher relative content of ordered secondary structures (α-helix, 8.6%; β-sheet, 77.3%; 3.7% and 6.2% higher than those of LCEW, respectively) and hydrophobic interactions (56.8%, 9.4% higher than LCEW), enhancing hardness and stability. SEM imaging revealed a denser, more uniform protein network in PTEW. Proteomic analysis identified key proteins, including ovalbumin, ovomucoid, ovalbumin-related protein Y, and ovostatin, as primary contributors to gelation differences. This study offers a comprehensive "properties-structure-substance" understanding of thermal gelation differences between PTEW and LCEW, providing a theoretical basis for utilizing Chinese native duck eggs.

The effect of theabrownins on the amino acid composition and antioxidant properties of hen eggs

Pu-erh tea theabrownins (TBs) exert beneficial effect on egg quality and antioxidant properties of eggs, but the underlying mechanisms behind this response are unclear. In this study, we investigate the effect of TBs on egg antioxidative activity, amino acid and fatty acid profiles, and the underlying relationship between the TBs and oxidant-sensitive Nrf2 signaling pathway in laying hens. Eighty layers were fed a basal diet (control) and 400 mg/kg of TBs supplemented diet for 12 wk. TBs led to an increase in albumen height and Haugh unit (P < 0.05). The albumen lysine, valine, and tryptophan were higher in layers fed TBs, whereas yolk tryptophan, methionine, vitamin A, and α-tocopherol content were enhanced by TBs (P < 0.05). Eggs albumen and yolk showed higher total antioxidant capacity (T-AOC), reducing power (RP), and the scavenging rate of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH), and lower MDA content than those of eggs from the control group (P < 0.05). Also, magnum Nrf2, hemeoxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and Bcl2 expression were up-regulated by TBs, whereas magnum proapoptotic gene (Bax, caspase 3, Cyt C) were down-regulated by TBs (P < 0.05). Our findings suggest that TBs improved egg albumen quality and antioxidant activity, and the Nrf2-ARE pathway were found to be involved in this process.

Effects of garcinol supplementation on the performance, egg quality, and intestinal health of laying hens in the late laying period

The problem of rapid decline in egg production performance and poor egg quality is a key obstacle to improving the economic benefits of laying hens. Garcinol is an antioxidant polyphenol plant extract that has multiple physiological functions. Diets with the appropriate amount of garcinol might be able to improve the performance traits and health of late laying hens. Therefore, this study was conducted to evaluate the utilization of garcinol in late laying hens. A total of 400 healthy 59-wk-old Tingfen No. 6 hens were randomly allocated into 4 dietary treatment groups and fed a basal diet supplemented with 0, 100, 300, and 500 mg/kg garcinol for 12 wk, denoted the Con, LG, MG, and HG groups, respectively. The results showed that the addition of garcinol in the diet tended to increase the egg production rate compared with that of the control group (P = 0.080), while the average egg weight was significantly lower (P < 0.05) during the whole period of the experiment. The results showed that MG group hens had higher egg quality and strengthened antioxidant capacity in their serum (P < 0.05). Moreover, the laying hens in the MG group had significantly decreased crypt depth (CD) and increased villus height (VH) in the jejunum and ileum (P < 0.05), as well as an increased ratio of VH to CD (P < 0.05) and increased expression levels of Occludin (P < 0.05) and Claudin-2 (P < 0.05) in the jejunum to improve intestinal barrier function. In addition, dietary supplementation with garcinol influenced the cecal microbiota of laying hens, which was characterized by changes in the microbial community composition, including increased abundances of Firmicutes, Romboutsia, and Ruminococcus torques. In conclusion, dietary 300 mg/kg garcinol supplementation could increase the egg production and egg quality of late laying hens, which may be attributed to the antioxidant effects of garcinol and the improvement of intestinal morphology and epithelial barrier function as well as the regulation of mucosal immune status by altering microbial composition.

Quantitative proteomics study on the changes of egg white of yellow preserved primary chicken eggs soaked in alkali solution

In order to investigate the changes of egg white of primary chicken eggs after being soaked in alkali solution, the tandem mass tags (TMT)-labeled quantitative proteomic technology combined with bioinformatics was conducted in this study. The results indicated that 100 differentially expressed proteins (DEPs) in yellow preserved primary egg white (YPPEW), 75 of which were highly and significantly correlated with the quality traits of YPPEW (| r | ≥ 0.9000, P < 0.01). Most of DEPs were involved in cellular processes by binding in extracellular space. Six pathways revealed the potential anti-inflammatory, anti-virus, anti-cancer and neuromodulatory mechanism of YPPEW. The current research provided a theoretical basis for the further study on YPPEW.

Natural Products of Plants and Animal Origin Improve Albumen Quality of Chicken Eggs

Albumen quality is recognized as one of the major yardsticks in measuring egg quality. The elasticity of thick albumen, a strong bond in the ovomucin-lysozyme complex, and excellent biological properties are indicators of high-quality albumen. The albumen quality prior to egg storage contribute to enhance egg’s shelf life and economic value. Evidence suggests that albumen quality can deteriorate due to changes in albumen structure, such as the degradation of β-ovomucin subunit and O-glyosidic bonds, the collapse of the ovomucin-lysozyme complex, and a decrease in albumen protein-protein interaction. Using organic minerals, natural plants and animal products with antioxidant and antimicrobial properties, high biological value, no residue effect and toxicity risk could improve albumen quality. These natural products (e.g., tea polyphenols, marigold extract, magnolol, essential oils, Upro (small peptide), yeast cell wall, Bacillus species, a purified amino acid from animal blood, and pumpkin seed meal) are bio-fortified into eggs, thus enhancing the biological and technological function of the albumen. Multiple strategies to meeting laying hens’ metabolic requirements and improvement in albumen quality are described in this review, including the use of amino acids, vitamins, minerals, essential oils, prebiotics, probiotics, organic trace elements, and phytogenic as feed additives. From this analysis, natural products can improve animal health and consequently albumen quality. Future research should focus on effects of these natural products in extending shelf life of the albumen during storage and at different storage conditions. Research in that direction may provide insight into albumen quality and its biological value in fresh and stored eggs.

Potential Implications of Natural Antioxidants of Plant Origin on Oxidative Stability of Chicken Albumen during Storage: A Review

Enhanced albumen quality is reflected in increased thick albumen height, albumen weight, and Haugh unit value, while the antimicrobial, antioxidant, foaming, gelling, viscosity, and elasticity attributes are retained. Improved albumen quality is of benefit to consumers and to the food and health industries. Egg quality often declines during storage because eggs are highly perishable products and are most often not consumed immediately after oviposition. This review provides insights into albumen quality in terms of changes in albumen structure during storage, the influence of storage time and temperature, and the mitigation effects of natural dietary antioxidants of plant origin. During storage, albumen undergoes various physiochemical changes: loss of moisture and gaseous products through the shell pores and breakdown of carbonic acid, which induces albumen pH increases. High albumen pH acts as a catalyst for structural changes in albumen, including degradation of the β-ovomucin subunit and O-glycosidic bonds, collapse of the ovomucin-lysozyme complex, and decline in albumen protein–protein interactions. These culminate in declined albumen quality, characterized by the loss of albumen proteins, such as ovomucin, destabilized foaming and gelling capacity, decreased antimicrobial activity, albumen liquefaction, and reduced viscosity and elasticity. These changes and rates of albumen decline are more conspicuous at ambient temperature compared to low temperatures. Thus, albumen of poor quality due to the loss of functional and biological properties cannot be harnessed as a functional food, as an ingredient in food processing industries, and for its active compounds for drug creation in the health industry. The use of refrigerators, coatings, and thermal and non-thermal treatments to preserve albumen quality during storage are limited by huge financial costs, the skilled operations required, environmental pollution, and residue and toxicity effects. Nutritional interventions, including supplementation with natural antioxidants of plant origin in the diets of laying hens, have a promising potential as natural shelf-life extenders. Since they are safe, without residue effects, the bioactive compounds could be transferred to the egg. Natural antioxidants of plant origin have been found to increase albumen radical scavenging activity, increase the total antioxidant capacity of albumen, reduce the protein carbonyl and malondialdehyde (MDA) content of albumen, and prevent oxidative damage to the magnum, thereby eliminating the transfer of toxins to the egg. These products are targeted towards attenuating oxidative species and inhibiting or slowing down the rates of lipid and protein peroxidation, thereby enhancing egg quality and extending the shelf life of albumen.

The pros and cons of cytokines for fowl adenovirus serotype 4 infection

Hepatitis-hydropericardium syndrome (HHS), caused by fowl adenovirus serotype 4 (FAdV-4), has spread on chicken farms worldwide, causing huge economic losses. Currently, the exact mechanism of pathogenesis of FAdV-4 remains unknown. Despite the severe inflammatory damage observed in chickens infected with pathogenic FAdV-4, few studies have focused on the host immune system-virus interactions and cytokine secretion. Host immunity acts as one of the most robust defense mechanisms against infection by pathogens, and cytokines are important in their elimination. However, excessive inflammatory cytokine secretion could contribute to the pathogenesis of FAdV-4. Understanding of the roles of cytokines produced during FAdV-4 infection is important for the study of pathogenicity and for developing strategies to control FAdV-4. Several previous studies have addressed the immune responses to FAdV-4 infection, but there has not been a systematic review of this work. The present review provides a detailed summary of the current findings on cytokine production induced by FAdV-4 infection to accelerate our understanding of FAdV-4 pathogenesis.

Potential role of tea extract in oocyte development

Tea is the second most popular beverage in the world and beneficial to health. It has been demonstrated that tea polyphenols can reduce the risk of diseases, such as cancers, diabetes, obesity, Alzheimer's disease, etc. But the knowledge of tea extract on the female germline is limited. Folliculogenesis is a complicated process and prone to be affected by ROS. Tea polyphenols can reduce the accumulation of ROS in folliculogenesis and affect oocyte maturation. Tea extract also influences granulosa cell proliferation and expansion during oocyte growth and maturation. However, the studies about the benefits of tea extract on female germline are few, and the underlying mechanisms are obscure. In the present study, we will mainly discuss the effects of tea extract on ovarian function, oocyte maturation, and the underlying possible mechanisms, and according to the discussion, we suggest that tea extract may have benefits for oocytes at an appropriate dose.