Alterations in lycopene concentration and Z ‐isomer content in egg yolk of hens fed all‐ E ‐isomer‐rich and Z ‐isomer‐rich lycopene

Deposition and enrichment of carotenoids in livestock products: An overview

A wide range of research has illustrated that carotenoids play a key role in human health through their versatile beneficial biological functions. Traditionally, the majority dietary sources of carotenoids for humans are obtained from vegetables and fruits, however, the contribution of animal-derived foods has attracted more interest in recent years. Livestock products such as eggs, meat, and milk have been considered as the appropriate and unique carriers for the deposition of carotenoids. In addition, with the enrichment of carotenoids, the nutritional quality of these animal-origin foods would be improved as well as the economic value. Here, we offer an overview covering aspects including the physicochemical properties of carotenoids, the situation of carotenoids fortified in livestock products, and the pathways that lead to the deposition of carotenoids in livestock products. The summary of these important nutrients in livestock products will provide references for animal husbandry and human health.

Effects of Astaxanthin Preparation Form on the Efficiency of Egg Yolk Pigmentation in Laying Hens

This study investigated the effects of the preparation form of astaxanthin on egg yolk pigmentation and egg quality in laying hens. The following four astaxanthin sources were prepared in this study: (1) dried cell powder of Paracoccus carotinifaciens (Panaferd-AX), (2) fine cell powder of P. carotinifaciens (Panaferd-P), (3) astaxanthin oil suspension, and (4) water-soluble astaxanthin powder. These astaxanthin preparations were added to the basal diet at a final concentration of 2 mg/kg and fed to White Leghorn laying hens for 14 days. Although the administration of these astaxanthin preparations did not largely affect egg quality (i.e., egg weight, yolk weight, albumen height, and Haugh unit), feeding significantly improved astaxanthin concentration and yolk color fan score. When water-soluble astaxanthin powder was fed, the yolk astaxanthin concentration and color fan score were most improved, followed by Panaferd-P. These results indicated that astaxanthin pulverization and water solubilization significantly improved its bioavailability in laying hens. Furthermore, although diets rich in (all-E)-astaxanthin were fed to the hens, approximately 30% of astaxanthin was present as the Z-isomers in the egg yolk. These findings may contribute to improving not only the egg quality but the nutritional value of hen eggs.

Astaxanthin Isomers: A Comprehensive Review of Isomerization Methods and Analytic Techniques

The presence of multiple conjugated double bonds and chiral carbon atoms endows astaxanthin with geometric and optical isomers, and these isomers widely exist in biological sources, food processing, and in vivo absorption. However, there remains no systematic summary of astaxanthin isomers regarding isomerization methods and analytic techniques. To address this need, this Review focuses on a comprehensive analysis of Z-isomerization methods of astaxanthin, including solvent system, catalyst, and heat treatment. Comparatively, high-efficiency and health-friendly methods are more conducive to put into practical use, such as food-grade solvents and food-component catalysts. In addition, we outline the recent advances in analysis techniques of astaxanthin isomers, as well as the structural characteristics reflected by various methods (e.g., HPLC, NMR, FTIR, and RS). Furthermore, we summarized the related research on the safety evaluation of astaxanthin isomers. Finally, future trends and barriers in Z-transformation and analysis of astaxanthin isomers are also discussed.

Carotenoid enrichment in eggs: From biochemistry perspective

The emergence of safe and functional eggs for consumer acceptance has gained focus. The production of carotenoid-enriched eggs has received attention due to its multifunctional biological properties. Nutritional modification of laying hens' diet can be a strategy to produce such eggs. This review presents the chemistry of carotenoids in nature and eggs, the accumulation process of carotenoids into eggs, and the functions of carotenoids in eggs. Our findings showed that carotenoids can be deposited into the egg and contribute to improving its nutritive value. The biosynthesis, chemical structure, and metabolism pathways of carotenoids lead to the deposition of carotenoids into eggs in their original or metabolized forms. Also, some factors modulate the efficiency of carotenoids in fowls before accumulation into eggs. Carotenoid-enriched eggs may be promising, ensuring the availability of highly nutritive eggs. However, further studies are still needed to comprehend the full metabolism process and the extensive functions of carotenoids in eggs.

Development and application of a SFC-DAD-MS/MS method to determine carotenoids and vitamin A in egg yolks from laying hens supplemented with β-carotene

β-Carotene, a provitamin A carotenoid, can be converted into vitamin A in animals' bodies, and can also be accumulated intactly in many animal products. In this study, supercritical fluid chromatography-tandem mass spectrometry was utilized to determine β-carotene and different forms of vitamin A in eggs simultaneously. According to the results, β-carotene contained in yolk reached a plateau after about 2 weeks of supplementation. With an increase in dietary supplement level, the amount of β-carotene gradually increased, as well as slightly changing the yolk color. Moreover, the contents of retinoids including retinol, retinyl propionate, retinyl palmitate and retinyl stearate were also elevated in yolks with the β-carotene additive levels; meanwhile, the lutein and zeaxanthin decreased. On the whole, β-carotene in the diet of laying hens could be partially deposited in egg yolk, and the contents of vitamin A in yolk could be increased due to β-carotene bioconversion.

Application of E/Z-Isomerization Technology for Enhancing Processing Efficiency, Health-Promoting Effects, and Usability of Carotenoids: A Review and Future Perspectives

Carotenoids are naturally occurring pigments whose presence in the diet is beneficial to human health. Moreover, they have a wide range of applications in the food, cosmetic, and animal feed industries. As carotenoids contain multiple conjugated double bonds in the molecule, a large number of geometric (E/Z, trans/cis) isomers are theoretically possible. In general, (all-E)-carotenoids are the most predominant geometric isomer in nature, and they have high crystallinity and low solubility in various mediums, resulting in their low processing efficiency and bioavailability. Technological developments for improving the processing efficiency and bioavailability of carotenoids utilizing the Z-isomerization have recently been gaining traction. Namely, Z-isomerization of carotenoids induces a significant change in their physicochemical properties (e.g., solubility and crystallinity), leading to improved processing efficiency and bioavailability as well as several biological activities. For the practical use of isomerization technology for carotenoids, the development of efficient isomerization methods and an acute understanding of the changes in biological activity are required. This review highlights the recent advancements in various conventional and unconventional methods for carotenoid isomerization, such as thermal treatment, light irradiation, microwave irradiation, and catalytic treatment, as well as environment-friendly isomerization methods. Current progress in the improvement of processing efficiency and biological activity utilizing isomerization technology and an application development of carotenoid Z-isomers for the feed industry are also described. In addition, future research challenges in the context of carotenoid isomerization have been elaborated upon.

Astaxanthin Z-isomer-rich diets enhance egg yolk pigmentation in laying hens compared to that in all-E-isomer-rich diets

The effects of feeding diets containing astaxanthin with different Z-isomer ratios to laying hens on egg qualities, such as astaxanthin concentration in egg yolk and yolk color, were investigated. As the astaxanthin source, a natural microorganism Paracoccus carotinifaciens was used. Astaxanthin with different Z-isomer ratios was prepared by thermal treatment with different conditions and then added to the basal diet at a final astaxanthin concentration of 8 mg/kg. We found that, as the Z-isomer ratios of astaxanthin in the diet increased, the astaxanthin concentration in egg yolk and the yolk color fan score also increased significantly. Importantly, feeding a 50.6% Z-isomer ratio diet increased astaxanthin concentration in egg yolk by approximately fivefold and the color fan score by approximately 2 compared to that in hens fed an all-E-isomer-rich diet. Moreover, we showed that feeding Z-isomer-rich astaxanthin to laying hens increased plasma astaxanthin concentration by more than five times in comparison to that in hens fed an all-E-isomer-rich diet. These results indicate that Z-isomers of astaxanthin have higher bioavailability than that of the all-E-isomer and thus they exhibit greater egg yolk-accumulation efficiency.

Enrichment of chicken table eggs with lycopene and astaxanthin

Ensuring an attractive commercial appearance of egg yolks involves the introduction to the feed of laying hens of the dyes of various origins. Recently, egg producers have preferred natural dyes, which include carotenoids: lycopene and astaxanthin, which can be deposited in chicken egg yolks. The aim of this study was to determine the quality of egg yolks, colour intensity and carotenoid composition of yolks when oil extracts of lycopene (20, 40 and 60 mg/kg feed) or astaxanthin (10, 20 and 30 mg/kg feed) are included in the chickens’ diet. 45 High Line W36 chickens at the age of 24 weeks were used for the experiment. Feeding laying hens with supplements of lycopene oil extracts at doses of 30, 40 and 60 mg/kg and astaxanthin at doses of 10, 20 and 30 mg/kg of feed for 30 days in increasing concentrations did not affect egg weight, albumen height, Haugh unit, strength and the thickness of the shell. The addition of lycopene to the diet of chickens at doses of 20 mg/kg of feed increased the content of lycopene, unidentified carotenoids and the total content of carotenoids in the yolks, but did not change the intensity of their colour. Increasing the dose of lycopene in the diet of chickens to 40 and 60 mg/kg of feed increased the content of lycopene in yolks and the intensity of their colour to 7.4 and 8.0 points against 5.6–6.1 points in the control, but did not affect the content of β-carotene and total carotenoids in the yolks. The addition of astaxanthin oil extract at doses of 10, 20 and 30 mg/kg of feed increased the content of astaxanthin, β-carotene and total carotenoids in chicken egg yolks and increased the intensity of their colour to 12.8, 14.8 and 14.4 points on a 16-point colour scale YolkFanTM. To obtain chicken table eggs with a given colour of the yolks, it is advisable to use the addition of astaxanthin oil extract in doses from 10 to 20 mg/kg of feed for 30 days. The results of the research can be used to develop a technology for the production of functional table eggs enriched with carotenoids of natural origin with an attractive colour for consumers.

Lycopene supplementation does not change productive performance but lowers egg yolk cholesterol and gene expression of some cholesterol-related proteins in laying hens

1. This work examined the effects of purified lycopene (LYC) supplementation or a source of LYC as tomato powder (TP) on productive performance, egg yolk cholesterol levels as well as gene expression related to mechanism and regulation of cholesterol.2. One hundred and fifty laying hens (Lohman LSL, hybrid) were randomly divided into one of three treatments, with 10 replicates of five hens per cage, totalling 50 hens per treatment. The hens were fed either a standard diet (control) or a standard diet supplemented with 20 mg purified lycopene/kg diet (LYC) or an equal amount of lycopene-containing tomato powder (TP) for 12 weeks.3. Feed consumption, egg production, and feed efficiency remained similar among treatments (P ≥ 0.27). Supplementing lycopene, either as a purified form or in TP, increased the levels of serum and egg yolk lycopene and reduced serum and egg yolk cholesterol concentrations (P < 0.001). Supplementation in either form decreased gene expression for intestinal NPC1L1, MTP, ACAT2, hepatic SREBP1c, ACLY, and LXRα but increased hepatic ABCG5 and ABCG8 (P < 0.001).4. The results of the present work revealed that egg yolk cholesterol metabolism is regulated by the modulation of a group of genes, particularly with LYC supplementation.

Possibility of Using Astaxanthin-Rich Dried Cell Powder from Paracoccus carotinifaciens to Improve Egg Yolk Pigmentation of Laying Hens

The study investigated egg quality aspects such as astaxanthin concentration, E/Z-isomer ratio, and yolk color in laying hens fed with astaxanthin-containing diets. Dried Paracoccus carotinifaciens cell powder (Panaferd-AX) and fine cell powder (Panaferd-P) were used as sources of astaxanthin, with average particle diameters of approximately 100 μm and 10 μm, respectively. Paracoccus carotinifaciens contains valuable rare carotenoids such as adonirubin and adonixanthin, and thus the concentrations of these carotenoids in egg yolk were also evaluated. The E/Z-isomer ratios of the egg yolk carotenoids were determined by normal-phase high-performance liquid chromatography (HPLC) with an improved solvent system. Feeding diets containing P. carotinifaciens resulted in increased concentrations of astaxanthin, adonirubin, and adonixanthin in egg yolk, as well as a marked increase in the yolk color fan score; values associated with the Panaferd-P-containing diet were higher than those associated with the Panaferd-AX-containing diet. For example, the astaxanthin concentration in egg yolks of hens fed with the Panaferd-AX- and Panaferd-P-containing diets for 21 days were 1.21 μg/g and 1.85 μg/g, respectively. This indicates that the pulverization treatment of the P. carotinifaciens powder increased the efficiency of carotenoid accumulation in the egg yolk. Moreover, more than 95% of astaxanthin in P. carotinifaciens was present as the all-E-isomer. However, approximately 25% of astaxanthin in egg yolk was present as the Z-isomers. In recent years, astaxanthin Z-isomers have attracted substantial attention as they exhibit a greater bioavailability and bioactivity than the all-E-isomer. These data are important not only for understanding egg yolk pigmentation but also for improving the nutritional value of hens’ egg yolk through the addition of P. carotinifaciens to their diet.