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

Abstract

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.

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

“…For example, feeding a Z-isomer-rich astaxanthin diet (total Z-isomer ratio＝50.6％) increased astaxanthin concentration in egg yolk by approximately five-fold and improved the color fan score by approximately two folds compared to that in hens fed an all-E-isomerrich diet (total Z-isomer ratio＝3.9％ ) ( Fig. 6) 35) . In this study, we also confirmed that when Z-isomer-rich astaxanthin (total Z-isomer ratio＝82.4％) was fed to the hens, plasma astaxanthin concentration increased by more than five times compared to that in hens fed an all-E-isomer-rich astaxanthin (total Z-isomer ratio＝1.2％) 35) .…”

“…Naturally predominant (all-E) -carotenoids have high crystallinity and low solubility in media, resulting in low carotenoid processing efficiency 14,26,30,31) , and have low bioavailability, resulting in low pigmentation efficiency of flesh and egg yolk in seafood and laying hens, respectively 7,34,35) ; these are often major problems for the industrial use of carotenoids. Carotenoid isomerization induces significant changes in physicochemical properties, bioavailability, and biological activities 14,26) .…”

“…Carotenoid isomerization induces significant changes in physicochemical properties, bioavailability, and biological activities 14,26) . We recently found that these changes can utilize the improvements in carotenoid processing efficiency (e.g., extraction and micronization) 32,33,41) and hen s egg yolk pigmentation efficiency 34,35) . In this section, changes in the basic characteristics of carotenoids (i.e., physicochemical properties, bioavailability, and bio-logical activities) with E/Z-isomerization have been outlined, along with the potential industrial applications of the isomerization technology.…”

“…Therefore, we investigated the possibility of improving the pigmentation efficiency of hen egg yolk by utilizing the high bioavailability of carotenoid Z-isomers. Specifically, the effects of the Z-isomer ratio of lycopene and astaxanthin on their concentration and color fan score in egg yolk were examined 34,35) . In both carotenoids, as the Z-isomer ratios in the diet increased, their concentrations in egg yolk and yolk color fan score increased significantly.…”

“…For example, as the Z-isomerization of carotenoids results in a significant change in their physicochemical properties (e.g., solubility and crystallinity) 30,31) , their processing efficiency (e.g., extraction and micronization) can be improved by utilizing this effect 26,32,33) . In addition, the feeding of a carotenoid Z-isomer-rich diet to laying hens improves egg yolk pigmentation compared to that of an all-E-isomer-rich one 34,35) , thereby indicating the potential of Z-isomer-rich carotenoid materials in the feed industry. From the above, it evident that a comprehensive understanding of the isomerization technology, including Z-isomerization methods and differences in physicochemical characteristics and biological activities between the E/Z-isomers, should facilitate a more effective utilization of these valuable compounds across various industrial fields.…”