Effect of Short-Term UVB Exposure on Vitamin D Concentration of Eggs and Vitamin D Status of Laying Hens

Abstract

Vitamin D deficiency in humans is widespread, and only a few food items are important natural sources of vitamin D. This study investigated the effect of UVB exposure of laying hens on the vitamin D content in egg yolk. In a two-factorial design, hens fed a vitamin D-deficient (-D) or -adequate (+D) diet were nonexposed or exposed to UVB light over a period of 4 weeks. UVB exposure of the -D group caused nearly normal egg production rate and egg shell quality; exposure of the +D group did not further improve these parameters. UVB exposure tended to improve the concentration of plasma 25-hydroxycholecalciferol (25(OH)D(3)), but had no effect on 1,25-dihydroxycholecalciferol in plasma or on cholecalciferol and 25(OH)D(3) in egg yolk. The present study shows that a short-term exposure of laying hens to UVB light is not an appropriate way to improve the vitamin D content of egg yolk.

UV‐light and dietary vitamin D and their effects on ionized calcium and 25‐OH‐D plasma concentrations in captive gentoo penguins (Pygoscelis papua)

“…As the synthesis of 25‐OH‐D is rarely regulated, its blood concentrations correlate well with dietary vitamin D intake (Stanford, ). This has also been shown in different studies in poultry (Jiang et al., ; Lietzow et al., ; Tsang & Grunder, ). In contrast, an increase of 1,25‐(OH) 2 ‐D, which has a slow and well‐regulated synthesis, could only be observed in white Leghorn hens when supplementing 1,100 IU vitamin D/kg (27.5 μg/kg) to a vitamin D free diet, whereas doubling the vitamin D supplementation did not further increase the plasma concentrations (Tsang & Grunder, ).…”

“…This method was found to be reliable to detect 25‐OH‐D in different species such as cattle, pigs, poultry, mink, horse and humans (Hymoller & Jensen, ). Plasma concentrations of 1,25‐(OH) 2 ‐D were analysed by radioimmunoassay (RIA), a method already used in chickens (Lietzow et al., ; Sedrani, ) or African grey parrots ( Psittacus e erithacus ; Stanford, ).…”

“…The animals were manually restrained in ventral recumbency and blood was taken from the dorsal coccygeal vein (V. coccygealis dorsalis) using a 3 ml blood gas analysis syringe (BD A-Line TM , syringe con- (Hymoller & Jensen, 2011). Plasma concentrations of 1,25-(OH) 2 -D were analysed by radioimmunoassay (RIA), a method already used in chickens (Lietzow et al, 2012;Sedrani, 1984) or African grey parrots (Psittacus e erithacus; Stanford, 2007).…”

Maternal and newborn vitamin D status and its impact on food allergy development in the German LINA cohort study

“…), serum 25 hydroxy‐vitamin D (25(OH)D) levels were measured. Cord and maternal vitamin D concentrations were determined by liquid chromatography tandem mass spectroscopy (HPLC‐MS/MS) by the laboratory of the Institute of Agricultural and Nutrition Science, Martin‐Luther‐University Halle/Wittenberg (Halle/Saale, Germany) as previously described (, ). Briefly, 25(OH)D 3 and 25(OH)D 2 were obtained from standards, cord and maternal serum via protein precipitation using the HPLC‐MS/MS MassChrom Reagent Kit (Chromsystems, Munich, Germany).…”

UVB Exposure of Farm Animals: Study on a Food-Based Strategy to Bridge the Gap between Current Vitamin D Intakes and Dietary Targets

“…We therefore came up with the idea that UVB exposure of farm animals such as laying hens might become a promising option to further improve the vitamin D content of foods from animal origin. In an initial experiment we could show that chickens whose upper part of their body was exposed to UVB did not produce vitamin D-enriched eggs [16]. Current analysis from our research group showed that most of the 7-dehydrocholesterol (7-DHC), the pre-cursor and limiting factor for vitamin D 3 synthesis, was located in the unfeathered skin of the chicken legs.…”