Dietary Vitamin D3 Research Articles

Dietary Vitamin D3 Deficiency Increases Resistance to Leishmania (Leishmania) amazonensis Infection in Mice.

The leishmaniases are a group of diseases caused by Leishmania parasites, which have different clinical manifestations. Leishmania (Leishmania) amazonensis is endemic in South America and causes cutaneous leishmaniasis (CL), which can evolve into a diffuse form, characterized by an anergic immune response. Since the leishmaniases mainly affect poor populations, it is important to understand the involvement of immunonutrition, how the immune system is modulated by dietary nutrients and the effect this has on Leishmania infection. Vitamin D3 (VitD) is an immunonutrient obtained from diet or endogenously synthesized, which suppresses Th1 and Th17 responses by favoring T helper (Th) 2 and regulatory T cell (Treg) generation. Based on these findings, this study aims to evaluate dietary VitD influence on L. (L.) amazonensis experimental infection in C57BL/6 and BALB/c mice. Thus, C57BL/6 and BALB/c VitD deficient (VDD) mice were generated through dietary VitD restriction 45 days prior to infection. Both strains of VDD mice showed a more controlled lesion development compared to mice on a regular diet (Ctrl). There were no differences in serum levels of anti-Leishmania IgG1 and IgG2a, but there was a decrease in IgE levels in BALB/c VDD mice. Although CD4+ T cell number was not changed, the CD4+ IFN-y+ T cell population was increased in both absolute number and percentage in C57BL/6 and BALB/c VDD mice compared to Ctrl mice. There was also no difference in IL-4 and IL-17 production, however, there was reduction of IL-10 production in VDD mice. Together, our data indicate that VitD contributes to murine cutaneous leishmaniasis susceptibility and that the Th1 cell population may be related to the resistance of VDD mice to L. (L.) amazonensis infection.

Influence of different levels of calcium and vitamin D3 in cassava-based diet on the performance of laying hens

This study was conducted to determine the influence of different levels of calcium and vitamin D3 in a cassava-based diet on performance of laying hens. One hundred and eight Isa Brown hens which were 34 weeks' old were used in a three by two factorial arrangement in a complete randomized design. Birds were fed diets containing different levels of calcium (A= 2.5%, B= 3.5%, and C= 4.5%), with each calcium level also containing vitamin D3 at levels of 2000, 4000 and 6000 IU. All birds were raised under the same management condition within the nine treatment combinations which had three replicates of four (4) birds each. Records of the feed intake, egg lay, cost of feed ingredients and mortality were documented. The records were used to calculate the hen-day production (HDP), feed intake, number of eggs laid per hen, dozens of eggs laid per hen, feed consumed per dozen egg, feed cost per dozen egg produced and mortality. The result obtained showed that diets B (3.5%), C (4.5%), the 2000 IU vitamin D3 level and diet C (4.5% calcium) containing 2000 IU vitamin D3 were better in terms of the number of eggs laid per egg, hen day production, and dozen egg per hen. Thus, farmers can use 3.5%, 4.5% calcium levels or 2000 IU vitamin D3 levels singly/individually in diet for laying hens and obtain better result. However, the C diet (4.5% calcium) containing 2000 IU vitamin D3 which had the highest number of eggs, HDP, dozen egg per hen, best feed conversion to eggs as well as the least cost of production is recommended for laying hens in the humid tropics, when calcium and vitamin D3 are used together in a cassava-based diet to feed hens

Vitamin D supplementation alters the expression of genes associated with hypertension and did not induce DNA damage in rats

ABSTRACTVitamin D3 deficiency has been correlated with altered expression of genes associated with increased blood pressure (BP); however, the role of vitamin D3 supplementation in the genetic mechanisms underlying hypertension remains unclear. Thus, the aim of this study was investigate the consequences of vitamin D3 supplemented (10,000 IU/kg) or deficient (0 IU/kg) diets on regulation of expression of genes related to hypertension pathways in heart cells of spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) controls. An additional aim was to assess the impact of vitamin D3 on DNA damage and oxidative stress markers. The gene expression profiles were determined by PCR array, DNA damage was assessed by an alkaline comet assay, and oxidative stress markers by measurement of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels. In SHR rats data showed that the groups of genes most differentially affected by supplemented and deficient diets were involved in BP regulation and renin-angiotensin system. In normotensive WKY controls, the profile of gene expression was similar between the two diets. SHR rats were more sensitive to changes in gene expression induced by dietary vitamin D3 than normotensive WKY animals. In addition to gene expression profile, vitamin D3 supplemented diet did not markedly affect DNA or levels of TBARS and GSH levels in both experimental groups. Vitamin D3 deficient diet produced lipid peroxidation in SHR rats. The results of this study contribute to a better understanding of the role of vitamin D3 in the genetic mechanisms underlying hypertension.Abbreviations: AIN, American Institute of Nutrition; EDTA, disodium ethylenediaminetetraacetic acid; GSH, glutathione; PBS, phosphate buffer solution; SHR, spontaneously hypertensive rats; TBARS, thiobarbituric acid reactive substances; WKY, Wistar Kyoto.

Dietary Formic Acid and Vitamin D3 as Growth Effective Supplement for Grass Carp Fingerlings

Dietary Formic Acid and Vitamin D3 as Growth Effective Supplement for Grass Carp Fingerlings

Pulmonary activation of vitamin D3 and preventive effect against interstitial pneumonia.

Calcitriol [1,25(OH)2D3] is usually investigated in studies on the preventive effect of activated vitamin D against interstitial pneumonia. Although cholecalciferol (vitamin D3) can be easily obtained in the diet and has a longer half-life than calcitriol, there have been few investigations of its effect on interstitial pneumonia. We used human pulmonary fibroblast cell lines (HPFCs) and a mouse model of bleomycin-induced pulmonary fibrosis to evaluate whether vitamin D3 was activated in the lungs and had a preventive effect against interstitial pneumonia. Expression of the vitamin D receptor gene and genes for enzymes metabolizing vitamin D was evaluated in two HPFCs, and the suppressive effect of vitamin D3 on induction of inflammatory cytokines was also assessed. Gene expression of the vitamin D receptor and vitamin D-metabolizing enzymes was observed in both human pulmonary fibroblast cell lines. Vitamin D3 suppressed bleomycin-induced expression of inflammatory cytokines and fibrosis markers by the HPFCs. In mice, symptoms of bleomycin-induced pulmonary fibrosis were improved and expression of fibrosis markers/fibrosis inducers was decreased by a high vitamin D3 diet. Vitamin D3 is activated locally in lung tissues, suggesting that high dietary intake of vitamin D3 may have a preventive effect against interstitial pneumonia.

Anti-inflammatory effects of dietary vitamin D3 in patients with multiple sclerosis.

ObjectiveTo assess the effects of dietary vitamin D3 on proinflammatory (interleukin-17A [IL-17A] and IL-6) and anti-inflammatory (IL-10) cytokines.MethodsOur study was conducted on 75 participants who were divided into 3 groups: multiple sclerosis participants (MSPs, n = 25), first-degree relative participants (FDRPs, n = 25), and healthy participants (HPs, n = 25). All groups received 50,000 IU vitamin D3/wk for 8 weeks. Serum 25-(OH) vitamin D3 levels and messenger RNA (mRNA) expression levels of ILs were determined using electrochemiluminescence assay and real-time PCR, respectively.ResultsVitamin D3 affected the levels of IL-17A, IL-10, and IL-6 among the 3 groups (p < 0.001 for all). Levels of IL-17A (MSPs: fold change [FC] = 5.9, p = 0.014; FDRPs: FC = 5.2, p = 0.006; HPs: FC = 4.2, p = 0.012) and IL-6 (MSPs: FC = 5.6, p = 0.003; FDRPs: FC = 5.5, p = 0.002; HPs: FC = 5.1, p < 0.001) were downregulated after vitamin D3 treatment. In addition, levels of IL-10 (MSPs: FC = 6.2, p = 0.005; FDRPs: FC = 4.6, p < 0.001; HPs: FC = 5.2, p < 0.001) were upregulated after 8 weeks.ConclusionsAlthough supplementation with vitamin D3 reduced the mRNA expression levels of IL-17A and IL-6, it increased the mRNA expression level of IL-10 in all groups. However, these effects were more considerable in the MSP group than in the other groups. Of interest, in a deficiency state of serum vitamin D3, IL-17A expression had a positive feedback effect on the expression of IL-6. Conversely, in the sufficient state, IL-10 expression had a negative feedback effect on the expression of IL-17A and IL-6.

Dietary supplemental vitamin D3 enhances phosphorus absorption and utilisation by regulating gene expression of related phosphate transporters in the small intestine of broilers.

The present study was carried out to evaluate the effect of dietary supplemental vitamin D3 (VD3) on P absorption and utilisation as well as its related mechanisms in the small intestine of broilers. A total of 384 1-d-old Arbor Acres male broilers were assigned randomly into four treatments following a completely randomised design with a 2 (dietary non-phytate P (NPP) contents: 0·43 and 0·22 %)×2 (dietary VD3 supplemental levels: 0 and 87·5 μg/kg) factorial arrangement. The experiment lasted for 22 d. The results showed that P contents in serum from the hepatic portal vein and tibia ash of broilers were higher (P&lt;0·05) for 0·43 % NPP than for 0·22 % NPP. The type IIb Na-dependent phosphate cotransporter (NaP-IIb) protein expressions in the duodenum and ileum were higher (P&lt;0·05) also for 0·43 % NPP than 0·22 % NPP. Supplementation of VD3 enhanced (P&lt;0·05) tibia P retention rate and type III Na-dependent phosphate cotransporter (PiT)-1 protein expression in the duodenum of all broilers. Moreover, VD3 supplementation decreased (P&lt;0·002) mortality and increased (P&lt;0·02) serum P content from the hepatic portal vein after 4 h of feeding, tibia ash content, tibia ash P content and protein expressions of NaP-IIb and PiT-1 in the jejunum of broilers fed diet with 0·22 % NPP. Thus, dietary supplemental VD3 promoted intestinal P absorption and bone P utilisation, and this effect might be associated with enhanced PiT-1 levels in the duodenum and PiT-1 and NaP-IIb levels in the jejunum respectively when dietary NPP is limiting.

To assess the role of VIT. D3 in proximal femur Fracture in elderly patients

Background: The purpose of the present study was to assess the role of vitamin D3 in proximal femur fracture in elderly patients. Methods: This is a retrospective study of 120 elderly patient presenting with lower limb fracture who were evaluated clinically and radiologically. Serum vitamin D3 level assessment done in all patient. Results: In my study, I have studied 120 patients of aged more than 60 years, presented to our hospital with lower limb trauma, 62.5% had proximal femoral fractures and 38.5% had other fractures of lower limb. Out of those patients 43% patients were male and 57% were female, which comes to 1:1.3 of male to female ratio. Previous history of fall is very common factor associated with proximal femoral fractures, in my study history of fall was associated with 42% of patients. Distribution of fractures was equal 1: 1 in patients not having history of fall. Proximal femoral fractures was four times more common in patients with previous history of fall, recurrent fall is due to proximal muscle weakness, imbalance, poor eye sight, loss of protective mechanism. In my study 43% of patients have serum d3 level 30 ng/dl. Grading of the osteoporosis with singh index was noted in my study 60% of patients have singh osteoporotic index 3 or less than 3, and most of them had proximal femoral fractures. Patients having fractures of lower limb other than proximal femur have singh osteoporotic index 4 or more than 4.in patients of proximal femoral fractures most of them have singh osteoporotic index 3 or less than 3 and also most of them have serum vitamin d3 level 750 mg per day. same type of finding was found by feskanschi et al. in patients taking high dietary calcium and vitamin d3 intake have less chance of hip fractures.

Dietary vitamin D3 supplementation protects laying hens against lipopolysaccharide-induced immunological stress

BackgroundThe effects of vitamin D on the immune function of laying hens are not well understood. This study investigated the effects of vitamin D3 (VD3) on laying performance and immunological functions in laying hens under Escherichia coli lipopolysaccharide (LPS) challenge.MethodsIn experiment one, 360 Jinghong-1 strain layers (32 weeks) were randomly divided into four groups with six replicates per group and 15 hens per replicate. Hens were fed a basal diet supplemented with different levels of VD3 (0; 500; 1500; or 3000 IU VD3/kg of diet) for 10 weeks to determine laying performance, egg quality, and other parameters. In experiment two, 24 Jinghong laying hens (32 weeks) were fed basal diets with either 0 or 3000 IU VD3/kg of diet. After 10 weeks of feeding, six hens from each treatment were injected intravenously with 8 mg/kg of body weight of either LPS or saline. Blood and spleen samples were obtained for immune parameter analysis 4 h after injection.ResultsVD3 deficiency reduced egg production and egg quality; in addition, feed intake and feed-to-egg ratio increased. No significant differences were observed in these parameters except eggshell strength between dietary VD3 supplemental levels at 500; 1500; and 3000 IU VD3/kg of diet. VD3 deficiency increased serum hormone (calcitonin, parathyroid hormone, estradiol, and progesterone) and cytokine (IL-6, IL-10) levels, the ratio of IFN-γ to IL-4, myeloperoxidase activity and total IgG content in the serum, and upregulated the blood CD3+ T cell population. Splenic retinoid X receptor (RXR), nuclear factor-κB (NF-κB), inducible nitric oxide synthase (iNOS), and polymeric immunoglobulin receptor (pIgR) gene mRNA levels were upregulated in VD3-deficienct hens. VD3 deficiency significantly reduced serum Follicle stimulating hormone (FSH) and Luteinizing hormone (LH) concentrations and the number of CD4+CD25+ T cells in the blood. These changes were completely normalized by VD3 sufficiency. LPS reduced serum LH concentration, splenic lysozyme, and pIgR gene mRNA levels. LPS induced an increase in total serum IgM levels and the percentage of CD8+ T cells in the blood. The changes were completely reversed by VD3 addition.ConclusionVD3 supplementation could protect laying hens not only from VD3 deficiency but also from immunological stress.

Growth performance and carcass quality of broilers as affected by light flashes program in relation to dietary vitamin d3 levels (Abstract)

Growth performance and carcass quality of broilers as affected by light flashes program in relation to dietary vitamin d3 levels (Abstract)

Effect of dietary vitamin D3 and 25-hydroxyvitamin D3 supplementation on plasma and milk 25-hydroxyvitamin D3 concentration in dairy cows

Milk enriched with vitamin D by supplementing dairy cow diets could provide a valuable dietary source of vitamin D, but information on the feasibility of this approach is limited. In the current study, the effects of supplementing dairy cows with either vitamin D3 or 25(OH)D3 over the transition/early lactation period on plasma and milk vitamin D concentrations were compared. Sixty dairy cows were randomly allocated to 1 of 4 dietary treatments from 14 d precalving to 56 d postcalving. Treatments were a control diet (control) for both precalving and postcalving periods containing 0.625 mg/d of vitamin D3; a precalving diet supplemented with 6 mg of 25(OH)D3/d, but with a postcalving diet matching that of the control diet [25(OH)D3 precalving]; the control diet precalving but with the postcalving diet supplemented with 2 mg of vitamin D3/d (D3max), and the control diet precalving but with the postcalving diet supplemented with 1.5 mg of 25(OH)D3/d [25(OH)D3 postcalving]. No treatment effect on milk yield, composition or 25(OH)D3 concentration was observed. However, an interaction was observed of treatment and time for plasma 25(OH)D3 concentration; this increased within 2 wk of supplementation for the 25(OH)D3 precalving treatment (peaking just after calving, 202 ng/mL), whereas that of the 25(OH)D3 postcalving group had a slower response following supplementation, continuing to increase at 56 d. Correlations were observed between plasma and milk 25(OH)D3 concentrations at d 4 and 14 of lactation, but not at later sampling times. The D3max treatment did not increase 25(OH)D3 concentration in plasma or milk. Overall, results from this study indicate that supplemental 25(OH)D3 is an effective means of enhancing dairy cow plasma 25(OH)D3 concentrations compared with vitamin D3 supplementation, but not necessarily milk concentrations.

Skin-Derived Vitamin D3 Protects against Basal Cell Carcinoma

UVR in sunlight causes mutations that drive basal cell carcinomas. However, the incidence of these tumors plateaus with prolonged exposure, but the incidence of other skin cancers increases. Makarova etal. now show that vitamin D3 produced in the skin by UVR protects against its oncogenic effects by inhibiting Hedgehog signaling, whereas dietary vitamin D3 does not.

Vitamin D prevents lipid accumulation in murine muscle through regulation of PPARγ and perilipin-2 expression

Vitamin D plays an important role in regulation of skeletal muscle tone and contraction. Serum vitamin D status is linked to muscle power and force in adolescent girls, and vitamin D deficiency is associated with myopathies in children and poorer physical performance in the elderly. We previously reported that vitamin D deficiency is linked to a significant increase in muscle fatty infiltration in healthy young women, and studies in patients with neuromuscular disorders also associate muscle weakening and lipid content. In order to better understand the link between vitamin D status and skeletal muscle lipid metabolism, we compared the effect of a low (25 IU/kg) or normal (1000 IU/kg) vitamin D3 diet on muscle fat in female FVB mice maintained in a room without UVB lighting to minimize endogenous vitamin D production. Animals on low vitamin D diet displayed lower circulating 25(OH)D levels and a dramatic increase (287 ± 52% compared to normal diet, p < 0.0001) in lipid deposition in skeletal muscle accompanied by muscle fiber disorganization. Lipid droplet staining increased by 242 ± 23% (p < 0.0001) in low vitamin D diet, and lipid droplet coat protein perilipin-2 and nuclear receptor transcription factor PPARγ expression levels were increased compared to mice fed the normal vitamin D diet: average staining for PLIN2: 0.22 ± 0.08 (25 IU/kg diet) vs 0.10 ± 0.02 (1000 IU/kg). Average staining for PPARγ: 0.24 ± 0.06 (25 IU/kg diet) vs 0.07 ± 0.04 (1000 IU/kg) p < 0.0001. Tissue mass spectrometry imaging revealed major differences in muscle phospholipids profile depending on diet. In vitro, 1,25(OH)2D3 treatment of 3T3-L1 pre-adipocytes inhibited appearance of lipid droplets by 79 ± 9.3%, and caused a 80 ± 10% and 25 ± 8% (p = 0.001) reduction in PPARγ and perilipin-2 mRNA levels (by qPCR) compared to control cells. In summary, we report here the first in vivo model illustrating the important structural muscle fiber disorganization and fat accumulation inside and outside muscle fibers that accompany vitamin D deficiency. Furthermore, we show that the underlying mechanisms involve PPARγ and perilipin-2.

E-cadherin Mediates the Preventive Effect of Vitamin D3 in Colitis-associated Carcinogenesis.

Vitamin D3 is beneficial in ameliorating or preventing inflammation and carcinogenesis. Here, we evaluated if vitamin D3 has a preventive effect on colitis-associated carcinogenesis. Administration of azoxymethane (AOM), followed with dextran sulfate sodium (DSS), was used to simulate colitis-associated colon cancer in mice. The supplement of vitamin D3 at different dosages (15, 30, 60 IU·g·w), started before AOM or immediately after DSS treatment (post 60), was sustained to the end of the experiment. Dietary vitamin D3 significantly reduced the number of tumors and tumor burden in a dose-dependent manner. Of note, vitamin D3 in high doses showed significant preventive effects on carcinogenesis regardless of administration before or after AOM-DSS treatment. Cell proliferation decreased in vitamin D3 groups compared with the control group after inhibition of expression of β-catenin and its downstream target gene cyclin D1 in the colon. In vitro, vitamin D3 reduced the transcriptional activity and nuclear level of β-catenin, and it also increased E-cadherin expression and its binding affinity for β-catenin. Moreover, repression of E-cadherin was rescued by supplemental vitamin D3 in mouse colons. Taken together, our results indicate that vitamin D3 effectively suppressed colonic carcinogenesis in the AOM-DSS mouse model. Our findings further suggest that upregulation of E-cadherin contributes to the preventive effect of vitamin D3 on β-catenin activity.

25-Hydroxyvitamin D3 and its C-3 epimer are elevated in the skin and serum of Skh-1 mice supplemented with dietary vitamin D3.

UV exposure is a risk factor for keratinocyte carcinoma (KC) while critical for endogenous vitamin D production. We investigated dietary modulation of skin and serum 25-hydroxyvitamin D3 (25OHD3 ) and its C-3 epimer (C3epi) in a mouse model of KC. C3epi is an under-investigated metabolite of vitamin D with respect to its biological implications. Male and female Skh-1 mice were supplemented with 25, 150 or 1000 IU/kg diet vitamin D3 for 25 weeks, with some exposed to UV light. Skin and serum vitamin D metabolites were quantitated using HPLC-MS/MS (n = 3 per dose/sex/UV treatment). Serum and skin 25OHD3 and C3epi significantly increased with dose (P<0.0001), but with different response patterns. UV exposure significantly attenuated serum, but not skin, levels of both metabolites (P<0.001, P = 0.0287), while up-regulating expression of renal Cyp24a1 (P < 0.01). A dose by sex interaction trended toward significance with serum and skin levels of C3epi, wherein male mice attained higher levels of C3epi with higher dietary vitamin D3 . This reflected a similar, but non-significant pattern in average tumor size. The complex relationship between vitamin D and KC requires further investigation. This study provides insight into modulation of local and systemic vitamin D status with dietary supplementation.

Effects of the different levels of dietary vitamin D on boar performance and semen quality

Vitamin D plays a major role primarily in bone mineral homeostasis; however, the action of vitamin D on male reproduction of boars remains unknown. This study was conducted to evaluate the effects of dietary vitamin D3 supplementation on reproductive performance of boars. Twenty-four Yorkshire boars with eighteen months were randomly allocated to one of three vitamin D3 levels diets: 200 IU/kg (C), 2000 IU/kg (T1) and 4000 IU/kg (T2) of vitamin D3 for a 16-week period. Results showed that sperm motility, effective sperm number per ejaculate, acrosome intactness ratio, and membrane intactness ratio in T1 group were significantly higher than those in C group. The sperm membrane intactness ratio was higher in T1 group than in T2 group, whereas the deformity ratio was significantly lower in T1 than in C and T2 groups. Dietary supplementation with vitamin D3 significantly increased 25-OHD3 concentration in the blood and seminal plasma, but there was no significant difference in its concentration in the seminal plasma between T1 and T2 groups. The concentrations of blood testosterone and aromatase activity increased following vitamin D supplementation. Seminal plasma Ca2+, fructose concentration, and acid phosphatase activity were higher in T1 group than in C group, but not significantly different from the corresponding values in T2 group. Furthermore, expression of CYP19, CYP24A1, and VDR mRNAs in sperm was up-regulated in T1 group compared to that in C group. In conclusion, supplementation of boar diets with 2000 IU/kg vitamin D3 increased the sperm motility and effective sperm number, which was in line with the elevated concentrations of vitamin D, hormone secretion and gene expression.

Vitamin D3 supplementation attenuates the early stage of mouse hepatocarcinogenesis promoted by hexachlorobenzene fungicide

Hexachlorobezene (HCB), a fungicide widely distributed in the environment, promotes the development of hepatocellular preneoplastic lesions (PNL) and tumors in rodents. In contrast, vitamin D3 (VD3) supplementation presents a potential role for the prevention/treatment of chronic liver diseases. Thus, we investigated whether VD3 supplementation attenuates the early stage of HCB-promoted hepatocarcinogenesis. Female Balb/C mice were injected a single dose of diethylnitrosamine (DEN, 50 mg/kg) at postnatal day 15. From day 40 onwards, mice were fed with a standard diet containing 0.02% HCB alone or supplemented with VD3 (10,000 or 20,000 IU/Kg diet) for 20 weeks. Untreated mice were fed just standard diet. After this period, mice were euthanized and liver and serum samples were collected. Compared to the untreated group, DEN/HCB treatment decreased total hepatic glutathione levels and glutathione peroxidase (GSH-Px) activity while increased lipid peroxidation, p65 protein expression, cell proliferation/apoptosis and the PNL development. In contrast, dietary VD3 supplementation enhanced vitamin D receptor (VDR) protein expression, total glutathione levels and GSH-Px activity while diminished lipid hydroperoxide levels. Also, VD3 supplementation decreased p65 protein expression, hepatocyte proliferation, the size and the liver area occupied by PNL. Therefore, our findings indicate that VD3 supplementation attenuates the early stage of HCB-promoted hepatocarcinogenesis.

High dose dietary vitamin D3 increases bone mass and strength in mice

Vitamin D plays a critical role in skeletal homeostasis. Vitamin D supplementation is used worldwide to maintain optimal bone health, but the most appropriate level of supplementation remains controversial. This study aimed to determine the effects of varying doses of dietary vitamin D3 on the mechanical properties and morphology of growing bone.Eight-week-old female mice were supplied with one of 3 diets, each containing a different dose of vitamin D3: 1000IU/kg (control), 8000IU/kg or 20,000IU/kg. Mice had ad libitum access to the specialty diet for 4weeks before they were culled and their tibiae collected for further analysis. The collected tibia underwent three-point bending and reference-point indentation from which their mechanical properties were determined, and cortical and trabecular morphology determined by micro computed tomography.Dietary supplementation with 20,000IU/kg vitamin D3 resulted in greater ductility (~200%) and toughness (~150%) compared to the 1000IU/kg control. The 20,000IU/kg diet was also associated with significantly greater trabecular bone volume fraction and trabecular number. The 8000IU/kg diet had no significant effect on trabecular bone mass.We conclude that vitamin D3 supplementation of 20,000IU/kg during early adulthood leads to tougher bone that is more ductile and less brittle than that of mice supplied with standard levels of dietary vitamin D3 (1000IU/kg) or 8000IU/kg. This suggests that dietary vitamin D3 supplementation may increase bone health by improving bone material strength and supports the use of vitamin D3 supplementation, during adolescence, for achieving a higher peak bone mass in adulthood and thereby preventing osteoporosis.

Effects of the supplementation of vitamin D3 on the growth and vitamin D metabolites in juvenile Siberian sturgeon (Acipenser baerii).

The objective of this study was to evaluate the effects of the supplementation of vitamin D3 on the growth, vitamin D metabolites, and osteocalcin secretion in juvenile Siberian sturgeon (Acipenser baerii). A 90-day growth trial was conducted with juvenile Siberian sturgeon (initial body weight 3.47±0.14g) fed seven isonitrogenous and isoenergetic practical diets (45% CP and 13% lipid) containing 60 (basal diet), 240, 450, 880, 1670, 3300, or 1.0×105IU/kg feed (D60~D 1.0×105) vitamin D3. The results showed that weight gain and specific growth rate increased as the dietary vitamin D3 levels increased from 450 to 3300IU/kg (P<0.05). The fish fed with D1670 and D3300 diets had higher crude lipid and ash levels than the fish fed the D60 diet (P<0.05). The fish fed D880, D1670, or D3300 diets had higher 25-OH-D3 and 1,25-(OH)2-D3 levels than the fish fed the D60 diet (P<0.05). The fish fed D880, D1670, D3300, or D1.0×105 diets had higher osteocalcin levels than the fish fed the D60 diet (P<0.05). Based on the broken line method analysis of weight gain and osteocalcin, the dietary vitamin D3 requirement of juvenile Siberian sturgeon was estimated to be 1683.30 and 1403.27IU/kg per diet, respectively.

An inhibition mechanism of dihydromyricetin on tyrosinase and the joint effects of vitamins B6, D3 or E.

Dihydromyricetin (DMY), a natural flavonoid, was found to effectively inhibit tyrosinase activity in a mixed-type manner with an IC50 value of (3.66 ± 0.14) × 10-5 mol L-1. DMY combined with the dietary vitamin D3 at lower concentrations exhibited a synergistic effect on the inhibition of tyrosinase. The formation of a DMY-tyrosinase complex led to fluorescence quenching and conformational changes of tyrosinase, which was driven mainly by hydrophobic interactions and hydrogen bonds. The molecular simulation further found that DMY inserted into the active pocket of tyrosinase interacted with amino acid residues Tyr78, His85, and Ala323, occupying the catalytic center of tyrosinase to hinder entrance of the substrate, leading to the inhibition of tyrosinase. This study may provide a scientific foundation for screening effective tyrosinase inhibitors.