Genotype-dependent impact of dietary vitamin D3 on laying hens.

Vitamin D3 has an integral part in calcium and phosphorus homoeostasis, which in turn plays a key role in egg production of hens. The present study aimed to investigate whether an additional vitamin D3 supplementation improves the laying performance and egg quality of hens according to their genetic potential. For this purpose, four layer lines (low performing: R11 and L68; high performing: WLA and BLA) supplemented either with 300 or 3000 IU vitamin D3 per kg feed were compared concerning serum 25-hydroxyvitamin D3 (25-OHD3), calcium, phosphorus and alkaline phosphatase (ALP), laying performance and egg quality. The higher supplementation of vitamin D3 increased 25-OHD3 serum concentrations in all genotypes, except for R11 and WLA hens in week 49, and also elevated vitamin D3 and 25-OHD3 content in the egg yolk (p < 0.05). In week 29, 3000 IU vitamin D3 decreased pooled least squares means (LSMeans) of serum calcium concentrations considering all genotypes and increased the ALP concentrations in BLA hens (p < 0.05). Considering the whole experimental period daily egg mass of R11 hens was increased by an additional vitamin D3 supplementation (p < 0.001). Regarding all genotypes and the whole experimental period the pooled LSMeans of breaking strength of eggs from hens fed 3000 IU vitamin D3 were higher than those of hens fed 300 IU (p = 0.044). In conclusion, present results give evidence that the higher vitamin D3 supplementation might have genotype-dependently beneficial effects on calcium and phosphorus homoeostasis of hens, which might improve feed efficiency in the early laying period and promote the persistence of the laying period irrespectively of genotype. The increase of serum 25-OHD3 by the higher vitamin D supplementation supported the higher transfer of vitamin D in the egg yolk and improved genotype-dependently the breaking strength of the eggshell.

Impact of Regular Intake of Microalgae on Nutrient Supply and Cardiovascular Risk Factors: Results from the NovAL Intervention Study.

A 14-day randomized controlled study with a parallel design was conducted with 80 healthy participants. Intervention groups I (IG1) and II (IG2) received a defined background diet and consumed a smoothie enriched with either 15 g of Chlorella dry weight (d.w.) or 15 g of Microchloropsis d.w. daily. Control group II (CG2) received a defined background diet without the smoothie. Control group I (CG1) received neither. Blood samples and 24-h urine were collected at the beginning and the end of the study. Serum concentrations of 25-hydroxyvitamin D3, vitamin D3, selenium, iron, ferritin, transferrin saturation, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, non-HDL cholesterol and the LDL-cholesterol/HDL cholesterol ratio decreased in IG1 (p < 0.05), while 25-hydroxyvitamin D2 increased (p < 0.05). In IG2, vitamin D3, 25-hydroxyvitamins D2 and D3 decreased (p < 0.05), while concentrations of fatty acids C20:5n3 and C22:5n3 increased. Serum and urine uric acid increased in IG1 and IG2 (p < 0.05). Microchloropsis is a valuable source of n3 fatty acids, as is Chlorella of vitamin D2. Regular consumption of Chlorella may affect the iron and selenium status negatively but may impact blood lipids positively. An elevated uric acid concentration in blood and urine following the regular consumption of microalgae poses potential risks for human health.

Oral Intake of Lumisterol Affects the Metabolism of Vitamin D.

SCOPE: The treatment of food with ultraviolet-B (UV-B) light to increase the vitamin D content is accompanied by the formation of photoisomers, such as lumisterol2 . The physiological impact of photoisomers is largely unknown. METHODS AND RESULTS: Three groups of C57Bl/6 mice are fed diets containing 50 µg kg-1 deuterated vitamin D3 with 0, 50 (moderate-dose) or 2000 µg kg-1 (high-dose) lumisterol2 for four weeks. Considerable quantities of lumisterol2 and vitamin D2 are found in the plasma and tissues of mice fed with 2000 µg kg-1 lumisterol2 but not in those fed 0 or 50 µg kg-1 lumisterol2 . Mice fed with 2000 µg kg-1 lumisterol2 showed strongly reduced deuterated 25-hydroxyvitamin D3 (-50%) and calcitriol (-80%) levels in plasma, accompanied by downregulated mRNA abundance of cytochrom P450 (Cyp)27b1 and upregulated Cyp24a1 in the kidneys. Increased tissue levels of vitamin D2 were also seen in mice in a second study that are kept on a diet with 0.2% UV-B exposed yeast versus those fed 0.2% untreated yeast containing iso-amounts of vitamin D2 . CONCLUSION: High doses of lumisterol2 can enter the body, induce the formation of vitamin D2 , reduce the levels of 25(OH)D3 and calcitriol and strongly impact the expression of genes involved in the degradation and synthesis of bioactive vitamin D.

Prevalence of vitamin D insufficiency and evidence for disease prevention in the older population.

The prevalence of vitamin D insufficiency, usually assessed by the analysis of circulating 25-hydroxyvitamin D (25[OH])D), is very high in the aging German population. An important factor that reduces endogenous vitamin D synthesis in older persons is physical inactivity or care-dependency that limits the time spent outside. Additionally, it has been suggested that the age-dependent decline in the glomerular filtration rate is associated with a reduced production of bioactive calcitriol. As this phenomenon is not detectable by the assessment of 25(OH)D, it is necessary to analyze the level of parathyroid hormone as a marker of calcitriol function. Because 25(OH)D levels are highly correlated with an active and healthy life style, data from epidemiological studies are not necessarily suitable to elucidate the role of vitamin D in disease prevention. Recently published meta-analyses of randomized controlled trials (RCTs) showed moderate effects of vitamin D supplementation on fracture risk and found that vitamin D was more effective when administered in combination with calcium. The role of vitamin D in the prevention of falls and frailty remains unclear. Much evidence has demonstrated the beneficial effects of vitamin D on respiratory tract infections and asthma, which are very relevant health issues in the older population. To conclude, vitamin D, particularly combined with calcium, has moderately beneficial effects on the skeletal system and is useful for the prevention of respiratory tract infections.

Primary Afferent-Derived BDNF Contributes Minimally to the Processing of Pain and Itch.

BDNF is a critical contributor to neuronal growth, development, learning, and memory. Although extensively studied in the brain, BDNF is also expressed by primary afferent sensory neurons in the peripheral nervous system. Unfortunately, anatomical and functional studies of primary afferent-derived BDNF have been limited by the availability of appropriate molecular tools. Here, we used targeted, inducible molecular approaches to characterize the expression pattern of primary afferent BDNF and the extent to which it contributes to a variety of pain and itch behaviors. Using a BDNF-LacZ reporter mouse, we found that BDNF is expressed primarily by myelinated primary afferents and has limited overlap with the major peptidergic and non-peptidergic subclasses of nociceptors and pruritoceptors. We also observed extensive neuronal, but not glial, expression in the spinal cord dorsal horn. In addition, because BDNF null mice are not viable and even Cre-mediated deletion of BDNF from sensory neurons could have developmental consequences, here we deleted BDNF selectively from sensory neurons, in the adult, using an advillin-Cre-ER line crossed to floxed BDNF mice. We found that BDNF deletion in the adult altered few itch or acute and chronic pain behaviors, beyond sexually dimorphic phenotypes in the tail immersion, histamine, and formalin tests. Based on the anatomical distribution of sensory neuron-derived BDNF and its limited contribution to pain and itch processing, we suggest that future studies of primary afferent-derived BDNF should examine behaviors evoked by activation of myelinated primary afferents.

Neuronal aromatase expression in pain processing regions of the medullary and spinal cord dorsal horn.

In both acute and chronic pain conditions, women tend to be more sensitive than men. This sex difference may be regulated by estrogens, such as estradiol, that are synthesized in the spinal cord and brainstem and act locally to influence pain processing. To identify a potential cellular source of local estrogen, here we examined the expression of aromatase, the enzyme that catalyzes the conversion of testosterone to estradiol. Our studies focused on primary afferent neurons and on their central targets in the spinal cord and medulla as well as in the nucleus of the solitary tract, the target of nodose ganglion-derived visceral afferents. Immunohistochemical staining in an aromatase reporter mouse revealed that many neurons in laminae I and V of the spinal cord dorsal horn and caudal spinal trigeminal nucleus and in the nucleus of the solitary tract express aromatase. The great majority of these cells also express inhibitory interneuron markers. We did not find sex differences in aromatase expression and neither the pattern nor the number of neurons changed in a sciatic nerve transection model of neuropathic pain or in the Complete Freund's adjuvant model of inflammatory pain. A few aromatase neurons express Fos after cheek injection of capsaicin, formalin, or chloroquine. In total, given their location, these aromatase neurons are poised to engage nociceptive circuits, whether it is through local estrogen synthesis or inhibitory neurotransmitter release.

Oral intake of 7-dehydrocholesterol increases vitamin D3 concentrations in the liver and kidney.

INTRODUCTION: Due to the high prevalence of vitamin D deficiency, strategies are needed to improve vitamin D status. Food components can affect vitamin D metabolism and have to be considered when estimating the efficacy of vitamin D supplements. 7-dehydrocholesterol (7-DHC) occurs naturally in food, but its impact on vitamin D metabolism has not yet been examined. METHODS: Three groups of male C57BL/6 mice (n=12 per group) were placed on a diet that contained 0, 2.5 or 5mg 7-DHC per kg diet over a period of 6 weeks. Vitamin D and other sterols in the serum, skin, liver and kidney were quantified by LC-MS/MS. The relative mRNA abundance of hepatic genes encoding vitamin D hydroxylation enzymes and transporters was analyzed by real-time RT-PCR. RESULTS: We found a substantial dose-dependent increase of non-hydroxylated vitamin D3 in the liver and kidney of mice fed a diet containing 7-DHC. The vitamin D3 content in the liver was 2.80±0.61pmol/g, 7.34±4.28pmol/g and 12.9±3.58pmol/g in groups that received 0, 2.5 and 5mg/kg 7-DHC, respectively. In the kidney, the vitamin D3 content of these groups was 1.78±1.17pmol/g, 3.55±1.06 and 6.36±2.29pmol/g, respectively. The serum and tissue concentrations of 25-hydroxyvitamin D3 (25(OH)D3) remained unaffected by 7-DHC. The relative mRNA data provided no plausible mechanism for the observed effects of 7-DHC on vitamin D3. All groups of mice had similar concentrations of cholesterol, desmosterol and 7-DHC in their serum and tissues. CONCLUSION: The current findings provide the first evidence that dietary 7-DHC seems to affect vitamin D metabolism. The underlying mechanism remains elusive and needs further investigation.