In this study, vitamin D ₃ (VD ₃ ) enriched diets were fed to breeding quails and the feeding effects on their chicks were investigated.
The content of VD ₃ in a diet was enhanced to 1800 IU/kg VD ₃ and eggs and chicks resulting from breeding quails fed the VD ₃ -enriched diet were analyzed. Eggs were analyzed for VD ₃ and 25-hydroxy-VD ₃ concentrations in the yolk and for Ca concentrations in the eggshell and eggshell membrane. Chicks were dissected within 24 hours of hatching and then body and liver weights were determined. Livers were sampled and the expression levels of genes involved in the metabolism of VD ₃ were measured in the livers.
Feeding breeding quails with the VD ₃ -enriched diet tended to decrease the VD ₃ concentration in the egg yolk, but the feeding tended to increase the weight of the eggshell and eggshell membrane. This suggests that enriching VD ₃ intake in breeding quails may promote eggshell formation. Furthermore, although no difference was observed in the growth of day-old chicks between the test and control groups, the expression level of CYP2R1, an enzyme that hydroxylates VD ₃ at position 25, in the liver of the test group was higher than that of the control group, suggesting that feeding breeding quails with a VD ₃ -enriched diet may enhance VD ₃ metabolism in chicks. However, the mechanism by which VD ₃ fortification for breeding quails increases CYP2R1 expression in chicks is unknown, and further studies, including the measurement of blood 25-hydroxyvitamin D ₃ levels in chicks, are needed.

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Polyphenols and carotenoids are pigments that are widely present in plant foods and are also biofactors with antioxidant and anti-inflammatory activities. In order to determine the contribution of polyphenols and carotenoids to human health, it is necessary to estimate the amount of intake from an individual's daily diet. Our research group has developed an original database on the total polyphenol and carotenoid content of selected foods and has assessed the daily intakes in several Japanese populations. These studies showed that beverages, especially coffee and green tea, were the main sources of total polyphenol intake in Japanese adults. Furthermore, cross-sectional studies and a prospective cohort study clarified that polyphenol intake was negatively associated with oxidative stress markers and the risk of coronary artery disease. Green and yellow vegetables (such as carrots, tomatoes, and spinach), mandarin oranges, and eggs were important sources of carotenoids. These findings may contribute to the elucidation of the effects of polyphenols and carotenoids in the prevention of atherosclerosis and provide important data on the diet and health of the Japanese.

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Folate, a water-soluble vitamin belonging to the B group, is abundantly found in green and yellow vegetables. Adequate intake of folate helps reduce the risk of megaloblastic anemia and neural tube defects in fetuses. In Japan, the evaluation of nutrient intake in humans is generally estimated based on consumed foods and the nutrient content listed in the Standard Tables of Food Composition in Japan. Folate naturally exists in various molecular forms and is present in foods in a bound state with proteins or starch. Due to this complexity, the extraction and quantification of folate compounds in foods have posed significant challenges, and various analytical methods have been developed. This paper introduces methods for the extraction and enzymatic treatment of folate in foods, a microbiological assay for measuring total folate content, and quantification techniques of folate using high-performance liquid chromatography. Furthermore, the current status and challenges of folate quantification methods in Japan are discussed.

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Niacin is involved in many biological reactions related to energy metabolism, redox reactions, DNA repair, and longevity, and a decrease in NAD level with aging and intake of high fat diets causes and advances age-related diseases. Recent findings suggest that further development of niacin research requires niacin-insufficient animal models. However, no appropriate animal models have been established yet because niacin is biosynthesized from tryptophan via the tryptophan-nicotinamide pathway. In this review, we introduce the niacin-insufficient model mouse established in kynurenine 3-monooxygenase knock out (KMO-KO) mice given a niacin-limited diet. Niacin nutritional status can be reflected by niacin nutritional markers, such as liver and blood NAD. The niacin requirement for the maximum growth of this model mouse is 4 mg of nicotinic acid per kg diet. In addition, we have shown that chronic ethanol intake and chronic endurance exercise impair niacin nutritional status in the KMO-KO mouse and that enough niacin intake can prevent this impairment. We have also suggested that these factors impair niacin nutritional status via an increase of NAD consumption.

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