Evaluation and improvement of storage stability of astaxanthin isomers in oils and fats.

Astaxanthin Z-isomers potentially have greater bioavailability and biological activity than (all-E)-astaxanthin. However, the stability of the Z-isomers is lower than the all-E-isomer, which is a serious problem affecting its practical use. In this study, we investigated the impacts of different suspension media (oils and fats) and additives on astaxanthin isomer stability and identified suitable ones for astaxanthin stabilization. The evaluations showed that several vegetable oils and antioxidants significantly improved astaxanthin isomer stability, e.g., when soybean and sunflower oils were used as the suspension medium, astaxanthin isomers were hardly degraded; however the total Z-isomer ratio decreased from ~80% to ~50% during 6-week storage at 30 °C. Moreover, it was revealed that (9Z)-astaxanthin showed higher stability than the 13Z- and 15Z-isomers. Hence, to maintain astaxanthin concentration and the Z-isomer ratio over long periods, it is important to use suitable suspension mediums and antioxidants, and select a Z-isomerization method that increases (9Z)-astaxanthin ratio.

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.

Effect of astaxanthin-rich extract derived from Paracoccus carotinifaciens on the status of stress and sleep in adults.

This study investigated the effect of a dietary supplement containing astaxanthin-rich extract derived from Paracoccus carotinifaciens (astaxanthin supplement) on the status of stress and sleep in individuals aged 20-64 years. Twenty-five subjects orally administered 12 mg astaxanthin/day of astaxanthin supplement for 8 weeks (astaxanthin group) and 29 subjects given a placebo (placebo group) were evaluated with Profile of Mood States 2nd Edition for stress and Oguri-Shirakawa-Azumi Sleep Inventory for Middle-aged and Aged version for sleep. We did not observe any significant intergroup differences in the stress and sleep. A subgroup analysis was performed after dividing the subjects into two groups: those who scored >65 and those who scored ≤65 in the "Depression-Dejection" dimension of Profile of Mood States 2nd Edition. The sleep of subjects who scored >65 ("Depression-Dejection") showed significant improvement in the astaxanthin group compared with the placebo group, whereas no significant improvement was observed in stress and the other subjects. Our results indicate that people who tend to be strongly depressed may experience improved sleep after ingesting astaxanthin supplement. On the basis of the parameters tested, administration of astaxanthin supplement was not associated with any problems related to safety. Clinical registration: This study has been registered at the University Hospital Medical Information Network (https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000038619) on August 24, 2018 as "A study to evaluate the effect of intake of astaxanthin on the status of stress and sleep in adults," Identification No. UMIN000033863.

Effects of astaxanthin-rich dried cell powder from Paracoccus carotinifaciens on carotenoid composition and lipid peroxidation in skeletal muscle of broiler chickens under thermo-neutral or realistic high temperature conditions.

Thirty-two 15-day old broiler chicks (Chunky strain ROSS 308) were randomly divided into four treatments in a 2 × 2 factorial design. The main factors were diet (basal diet or basal diet supplemented with 0.15% astaxanthin-rich dried cell powder (Panaferd-P [astaxanthin 30 ppm]) and ambient temperature (thermo-neutral [25 ± 1°C] or high [35 ± 1°C for 6 hr]). Dietary supplementation with Panaferd-P did not affect growth performance, though high ambient temperature decreased feed intake and the weight of breast tender muscle, liver, and heart. High ambient temperature also decreased redness in both breast and leg muscles of chickens, while Panaferd-P increased redness and yellowness of breast and leg muscles of chickens. Panaferd-P increased Paracoccus carotinifaciens-derived pigments (i.e., adonixanthin, astaxanthin, adonirubin, and cantaxanthin) as well as corn-derived pigments such as zeaxanthin and lutein in breast and leg muscles. High ambient temperature increased the malondialdehyde (MDA) concentration in breast muscle, while Panaferd-P decreased the MDA concentration in breast muscle under both temperature conditions. Our results suggest that dietary supplementation with Panaferd-P increases muscle carotenoid content, the redness and yellowness of meat and decreases the muscle MDA concentration in broiler chickens kept under thermo-neutral or high ambient temperature conditions.