Intake of ergosterol increases the vitamin D concentrations in serum and liver of mice

Effect of 2 dosages of prepartum cholecalciferol injection on blood minerals, vitamin D metabolites, and milk production in multiparous dairy cows: A randomized clinical trial

The objective of the present study was to evaluate the effect of 2 dosages of prepartum cholecalciferol injection on blood minerals, vitamin D metabolites, and milk production. Cows entering their second or greater lactation (n = 158) were randomly assigned to a control group (CON) or one of 2 treatment groups receiving either 6 × 106 IU (6VitD) or 12 × 106 IU (12VitD) cholecalciferol intramuscularly on d 275 ± 1.2 (SD) of gestation. Concentrations of serum total Ca (tCa), phosphate, and Mg were determined on 1, 2, 3, 5, 7, and 10 d in milk (DIM). For a subsample of 30 cows entering the third lactation (n = 10/group), these samples were analyzed for cholecalciferol, 25-hydroxycholecalciferol (25-OHD3), and 24,25-dihydroxycholecalciferol (24,25-[OH]2D3). In these cows, we also determined 1,25-dihydroxycholecalciferol (1,25-[OH]2D3), the biologically most active metabolite, on 1, 2, 3, and 5 DIM. Repeated measures ANOVA was performed to evaluate the effect of different dosages of cholecalciferol on blood minerals, vitamin D metabolites, and milk yield over the first 5 test days after calving. Binary outcomes such as retained placenta and metritis were analyzed using a chi-squared test. Although the 12VitD treatment increased tCa concentrations on 1, 2, and 3 DIM compared with CON, administration of 6VitD increased tCa concentrations only on 1 DIM. Compared with CON cows and 6VitD cows, 12VitD cows had greater serum phosphate concentration during the first 10 DIM. Furthermore, 6VitD cows had greater serum phosphate concentrations compared with CON cows. On the contrary, 12VitD cows had lower serum Mg concentrations during the first 10 DIM compared with CON and 6VitD cows. Cholecalciferol was increased by the treatment and decreased quickly until 10 DIM. In respect to 25-OHD3, the 6VitD treatment resulted in a 4.1-fold increase in comparison to the CON group, while a 6.5-fold increase was observed in 12VitD animals. The vitamin D metabolite 24,25-(OH)2D3 increased linearly with 25-OHD3 serum levels, resulting in the highest concentrations in the 12VitD group. An increase of 1,25-(OH)2D3 until 3 DIM was observed in all cows. However, this rise was most pronounced in the CON group. The incidence of retained placenta was 1.9%, 11.5%, and 29.6%, and that of metritis was 11.5%, 15.4%, and 31.5% for CON, 6VitD, and 12VitD cows, respectively. Although none of the treated cows exerted clinical signs of hypocalcemia, one cow in CON incurred clinical hypocalcemia. Cows of the 12VitD group had a lower milk yield over the first 5 monthly test days compared with the control and 6VitD group (42.2 ± 0.5, 42.0, ± 0.5 and 40.7 ± 0.5 kg for control cows, 6VitD cows and 12VitD cows, respectively). Although no negative side effects were observed in 6VitD cows, we do not recommend the general application of 6 × 106 IU cholecalciferol before calving as positive effects on calcium homeostasis were marginal and restricted to the first DIM. The present findings confirm that the application of 12 × 106 IU cholecalciferol negatively affected milk production on this farm.

Effects of Long-Term High-Ergosterol Intake on the Cholesterol and Vitamin D Biosynthetic Pathways of Rats Fed a High-Fat and High-Sucrose Diet

Dyslipidemia is a lifestyle-related (physical inactivity or obesity) disease; therefore, dietary foods that can easily be consumed in daily life is important to prevent dyslipidemia. Ergosterol, a precursor of vitamin D2, is a fungal sterol present in the membranes of edible mushrooms and other fungi. Ergosterol is converted to brassicasterol by 7-dehydrocholesterol reductase (DHCR7), a cholesterol biosynthesis enzyme that converts 7-dehydrocholesterol (a precursor of vitamin D3) into cholesterol. Previously, we reported that ergosterol increases 7-dehydrocholesterol, decreases cholesterol levels by competitive effect of DHCR7, and reduces DHCR7 mRNA and protein levels in human HepG2 hepatoma cells. Here, we investigated the effects of long-term high ergosterol intake on the cholesterol, vitamin D2, and D3 biosynthetic pathways of rats fed a high-fat and high-sucrose (HFHS) diet using GC-MS and LC with tandem mass spectrometry. In HFHS rats, oral ergosterol administration for 14 weeks significantly decreased plasma low-density lipoprotein cholesterol, total bile acid, and cholesterol precursor (squalene and desmosterol) levels and increased 7-dehydrocholesterol levels compared to HFHS rats without ergosterol. Ergosterol, brassicasterol, and vitamin D2 were detected, cholesterol levels were slightly decreased, and levels of vitamin D3 and its metabolites were slightly increased in rats fed HFHS with ergosterol. These results showed that ergosterol increased vitamin D2 levels, inhibited the cholesterol biosynthetic pathway, and possibly promoted vitamin D3 biosynthesis in vivo. Therefore, daily ergosterol intake may aid in the prevention of dyslipidemia.

Novel Lipids to Regulate Obesity and Brain Function: Comparing Available Evidence and Insights from QSAR In Silico Models

Lipid molecules, such as policosanol, ergosterol, sphingomyelin, omega 3 rich phosphatidylcholine, α-tocopherol, and sodium butyrate, have emerged as novel additions to the portfolio of bioactive lipids. In this state-of-the-art review, we discuss these lipids, and their activity against obesity and mental or neurological disorders, with a focus on their proposed cellular targets and the ways in which they produce their beneficial effects. Furthermore, this available information is compared with that provided by in silico Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) models in order to understand the usefulness of these tools for the discovery of new bioactive compounds. Accordingly, it was possible to highlight how these lipids interact with various cellular targets related to the molecule transportation and absorption (e.g., α-tocopherol transfer protein for α-Tocopherol, ATP-binding cassette ABC transporters or Apolipoprotein E for sphingomyelins and phospholipids) or other processes, such as the regulation of gene expression (involving Sterol Regulatory Element-Binding Proteins for ergosterol or Peroxisome Proliferator-Activated Receptors in the case of policosanol) and inflammation (the regulation of interleukins by sodium butyrate). When comparing the literature with in silico Quantitative Structure-Activity Relationship (QSAR) models, it was observed that although they are useful for selecting bioactive molecules when compared in batch, the information they provide does not coincide when assessed individually. Our review highlights the importance of considering a broad range of lipids as potential bioactives and the need for accurate prediction of ADMET parameters in the discovery of new biomolecules. The information presented here provides a useful resource for researchers interested in developing new strategies for the treatment of obesity and mental or neurological disorders.

NMR-Based Characterization of Wood Decay Fungi as Promising Novel Foods: Abortiporus biennis, Fomitopsis iberica and Stereum hirsutum Mycelia as Case Studies

Wood Decay Fungi (WDF) are fungi specialized in degrading wood. An interesting perspective is their use as a source of Novel Foods or food ingredients. Here, for the first time, the metabolite profiling of hydroalcoholic and organic extracts from A. biennis, F. iberica, S. hirsutum mycelia was investigated by NMR methodology. Amino acids (alanine, arginine, asparagine, aspartate, betaine, GABA, glutamate, glutamine, histidine, isoleucine, leucine, lysine, phenylalanine, threonine, tryptophan, tyrosine, valine), sugars (galactose, glucose, maltose, trehalose, mannitol), organic acids (acetate, citrate, formate, fumarate, lactate, malate, succinate), adenosine, choline, uracil and uridine were identified and quantified in the hydroalcoholic extracts, whereas the ¹H spectra of organic extracts showed the presence of saturated, mono-unsaturated and di-unsaturated fatty chains, ergosterol,1,2-diacyl-sn-glycero-3-phosphatidylethanolamine, and 1,2-diacyl-sasglycero-3-phosphatidylcholine. A. biennis extracts showed the highest amino acid concentration. Some compounds were detected only in specific species: betaine and mannitol in S. hirsutum, maltose in A. biennis, galactose in F. iberica, GABA in F. iberica and S. hirsutum, and acetate in A. biennis and S. hirsutum. S. hirsutum showed the highest saturated fatty chain concentration, whereas DUFA reached the highest concentration in A. biennis. A high amount of ergosterol was measured both in A. biennis and F. iberica. The reported results can be useful in the development of WDF-based products with a high nutritional and nutraceutical value.

Tachysterol2 increases the synthesis of fibroblast growth factor 23 in bone cells

Tachysterol₂ (T₂) is a photoisomer of the previtamin D₂ found in UV-B-irradiated foods such as mushrooms or baker’s yeast. Due to its structural similarity to vitamin D, we hypothesized that T₂ can affect vitamin D metabolism and in turn, fibroblast growth factor 23 (FGF23), a bone-derived phosphaturic hormone that is transcriptionally regulated by the vitamin D receptor (VDR). Initially, a mouse study was conducted to investigate the bioavailability of T₂ and its impact on vitamin D metabolism and Fgf23 expression. UMR106 and IDG-SW3 bone cell lines were used to elucidate the effect of T₂ on FGF23 synthesis and the corresponding mechanisms. LC-MS/MS analysis found high concentrations of T₂ in tissues and plasma of mice fed 4 vs. 0 mg/kg T₂ for 2 weeks, accompanied by a significant decrease in plasma 1,25(OH)₂D and increased renal Cyp24a1 mRNA abundance. The Fgf23 mRNA abundance in bones of mice fed T₂ was moderately higher than that in control mice. The expression of Fgf23 strongly increased in UMR106 cells treated with T₂. After Vdr silencing, the T₂ effect on Fgf23 diminished. This effect is presumably mediated by single-hydroxylated T₂-derivatives, since siRNA-mediated silencing of Cyp27a1, but not Cyp27b1, resulted in a marked reduction in T₂-induced Fgf23 gene expression. To conclude, T₂ is a potent regulator of Fgf23 synthesis in bone and activates Vdr. This effect depends, at least in part, on the action of Cyp27a1. The potential of oral T₂ to modulate vitamin D metabolism and FGF23 synthesis raises questions about the safety of UV-B-treated foods.

UVB-exposed wheat germ oil increases serum 25-hydroxyvitamin D2 without improving overall vitamin D status: a randomized controlled trial

Purpose

This study investigated whether UVB-exposed wheat germ oil (WGO) is capable to improving the vitamin D status in healthy volunteers.

Methods

A randomized controlled human-intervention trial in parallel design was conducted in Jena (Germany) between February and April. Ultimately, 46 healthy males and females with low mean 25-hydroxyvitamin D (25(OH)D) levels (34.9 ± 10.6 nmol/L) were randomized into three groups receiving either no WGO oil (control, n = 14), 10 g non-exposed WGO per day (– UVB WGO, n = 16) or 10 g WGO, which was exposed for 10 min to ultraviolet B-light (UVB, intensity 500–630 µW/cm²) and provided 23.7 µg vitamin D (22.9 µg vitamin D₂ and 0.89 µg vitamin D₃) (+ UVB WGO, n = 16) for 6 weeks. Blood was obtained at baseline, after 3 and 6 weeks and analyzed for serum vitamin D-metabolite concentrations via LC–MS/MS.

Results

Participants who received the UVB-exposed WGO were characterized by an increase of circulating 25(OH)D₂ after 3 and 6 weeks of intervention. However, the 25(OH)D₃ concentrations decreased in the + UVB WGO group, while they increased in the control groups. Finally, the total 25(OH)D concentration (25(OH)D₂ + 25(OH)D₃) in the + UVB WGO group was lower than that of the non-WGO receiving control group after 6 weeks of treatment. In contrast, circulating vitamin D (vitamin D₂ + vitamin D₃) was higher in the + UVB WGO group than in the control group receiving no WGO.

Conclusion

UVB-exposed WGO containing 23.7 µg vitamin D can increase 25(OH)D₂ levels but do no improve total serum levels of 25(OH)D of vitamin D-insufficient subjects.

Trial registration

ClinicalTrials.gov: NCT03499327 (registered, April 13, 2018).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02827-w.

Simulation, In Vitro, and In Vivo Cytotoxicity Assessments of Methotrexate-Loaded pH-Responsive Nanocarriers

In this study, pH-responsive niosomal methotrexate (MTX) modified with ergosterol was prepared for potential anticancer application. The prepared formulation had a size of 176.7 ± 3.4 nm, zeta potential of −31.5 ± 2.6 mV, EE% of 76.9 ± 2.5%, and a pH-responsive behavior in two different pHs (5.4 and 7.4). In-silico evaluations showed that MTX intended to make a strong hydrogen bond with Span 60 compartments involving N2 and O4 atoms in glutamic acid and N7 atom in pteridine ring moieties, respectively. The cytotoxic effects of free and pH-MTX/Nio were assessed against MCF7 and HUVECs. Compared with free MTX, we found significantly lower IC50s when MCF7 cells were treated with niosomal MTX (84.03 vs. 9.464 µg/mL after 48 h, respectively). Moreover, lower cell killing activity was observed for this formulation in normal cells. The pH-MTX/Nio exhibited a set of morphological changes in MCF7 cells observed during cell death. In-vivo results demonstrated that intraperitoneal administration of free MTX (2 mg/kg) after six weeks caused a significant increase in serum blood urea nitrogen (BUN), serum creatinine, and serum malondialdehyde (MDA) levels of rats compared to the normal control rats. Treatment with 2 and 4 mg/kg doses of pH-MTX/Nio significantly increased serum BUN, serum creatinine, and serum lipid peroxidation. Still, the safety profile of such formulations in healthy cells/tissues should be further investigated.

An LC-MS/MS Method for Analysis of Vitamin D Metabolites and C3 Epimers in Mice Serum: Oral Supplementation Compared to UV Irradiation

Introduction: The most common forms of vitamin D in human and mouse serum are vitamin D3 and vitamin D2 and their metabolites. The aim of this study is to determine whether diet and sunlight directly affect the circulating concentrations of vitamin D metabolites in a mouse model. We investigated the serum concentrations of eight vitamin D metabolites—vitamin D (vitamin D3 + vitamin D2), 25OHD (25OHD3 + 25OHD2), 1α25(OH)₂D (1α25(OH)₂D2, and 1α25(OH)₂D3)—including their epimer, 3-epi-25OHD (3-epi-25OHD3 and 3-epi-25OHD2), and a bile acid precursor 7alpha-hydroxy-4-cholesten-3-one (7αC4), which is known to cause interference in liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Method: The LC-MS/MS method was validated according to FDA-US guidelines. The validated method was used for the analysis of mouse serum samples. Forty blood samples from mice were collected and divided into three groups. The first group, the DDD mice, were fed a vitamin D-deficient diet (25 IU VD3/kg of diet) and kept in the dark; the second group, the SDD mice, were maintained on a standard-vitamin D diet (1000 IU VD3) and kept in the dark; and the third group, SDL, were fed a standard-vitamin D diet (1000 IU VD3) but kept on a normal light/dark cycle. LC-MS/MS was used for the efficient separation and quantitation of all the analytes. Results: The validated method showed good linearity and specificity. The intraday and interday precision were both <16%, and the accuracy across the assay range was within 100 ± 15%. The recoveries ranged between 75 and 95%. The stability results showed that vitamin D metabolites are not very stable when exposed to continuous freeze–thaw cycles; the variations in concentrations of vitamin D metabolites ranged between 15 and 60%. The overlapping peaks of vitamin D, its epimers, and its isobar (7αC4) were resolved using chromatographic separation. There were significant differences in the concentrations of all metabolites of vitamin D between the DDD and SDL mice. Between the groups SDD (control) and SDL, a significant difference in the concentrations of 3-epi-25OHD was noted, where C3 epimer was about 30% higher in SDL group while no significant differences were noted in the concentrations of vitamin D, 25OHD, 1α25(OH)₂D, and 7αC4 between SDD and SDL group. Conclusions: A validated method, combined with a simple extraction technique, for the sensitive LC-MS/MS determination of vitamin D metabolites is described here. The method can eliminate the interferences in LC-MS/MS analysis caused by the overlapping epimer and isobar due to them having the same molecular weights as 25OHD. The validated method was applied to mouse serum samples. It was concluded that a standard-vitamin D diet causes an increase in the proportion of all the vitamin D metabolites and C3 epimers and isobar, while UV light has no pronounced effect on the concentrations of the majority of the vitamin D metabolites except 3-epi-25OHD. Further studies are required to confirm this observation in humans and to investigate the biochemical pathways related to vitamin D’s metabolites and their epimers.

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.

Active vitamin D is cardioprotective in experimental uraemia but not in children with CKD Stages 3-5

BACKGROUND

Uraemic cardiac remodelling is associated with vitamin D and Klotho deficiency, elevated fibroblast growth factor 23 (FGF23) and activation of the renin-angiotensin system (RAS). The cardioprotective properties of active vitamin D analogues in this setting are unclear.

METHODS

In rats with 5/6 nephrectomy (5/6Nx) treated with calcitriol, the cardiac phenotype and local RAS activation were investigated compared with controls. A nested case-control study was performed within the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study, including children with chronic kidney disease (CKD) Stages 3-5 [estimated glomerular filtration rate (eGFR) 25 mL/min/1.73 m2] treated with and without active vitamin D. Echocardiograms, plasma FGF23 and soluble Klotho (sKlotho) were assessed at baseline and after 9 months.

RESULTS

In rats with 5/6Nx, left ventricular (LV) hypertrophy, LV fibrosis and upregulated cardiac RAS were dose-dependently attenuated by calcitriol. Calcitriol further stimulated FGF23 synthesis in bone but not in the heart, and normalized suppressed renal Klotho expression. In the 4C study cohort, treatment over a mean period of 9 months with active vitamin D was associated with increased FGF23 and phosphate and decreased sKlotho and eGFR compared with vitamin D naïve controls, whereas LV mass index did not differ between groups.

CONCLUSIONS

Active vitamin D ameliorates cardiac remodelling and normalizes renal Klotho expression in 5/6Nx rats but does not improve the cardiac phenotype in children with CKD Stages 3-5. This discrepancy may be due to further enhancement of circulating FGF23 and faster progression of CKD associated with reduced sKlotho and higher serum phosphate in vitamin D-treated patients.

High-phosphorus diets reduce aortic lesions and cardiomyocyte size and modify lipid metabolism in Ldl receptor knockout mice

The consumption of phosphorus in Western populations largely exceeds the recommended intake, while vitamin D supply is often insufficient. Both situations are linked to an increased cardiovascular risk. A 17-week two-factorial study with Ldl receptor^-/- mice was conducted to investigate the cardiovascular impact of dietary phosphorus [adequate (0.3%; P_0.3) vs. high (1.5%; P_1.5)] in combination with a low (50 IU/kg; D₅₀) or adequate vitamin D diet (1000 IU/kg; D₁₀₀₀). The data demonstrate that mice fed the P_1.5 vs. P_0.3 diets developed smaller vascular lesions (p = 0.013) and cardiac hypotrophy (p = 0.011), which were accompanied by diminished IGF1 and insulin signalling activity in their hearts. Vitamin D showed no independent effect on atherogenesis and heart morphology. Feeding P_1.5 vs. P_0.3 diets resulted in markedly reduced serum triacylglycerols (p < 0.0001) and cholesterol (p < 0.0001), higher faecal lipid excretion (p < 0.0001) and a reduced mRNA abundance of hepatic sterol exporters and lipoprotein receptors. Minor hypocholesterolaemic and hypotriglyceridaemic effects were also found in mice fed the D₁₀₀₀ vs. D₅₀ diets (p = 0.048, p = 0.026). To conclude, a high phosphorus intake strongly affected the formation of vascular lesions, cardiac morphology, and lipid metabolism, although these changes are not indicative of an increased cardiovascular risk.

Differential effects of vitamin D3 vs vitamin D2 on cellular uptake, tissue distribution and activation of vitamin D in mice and cells

To combat vitamin D deficiency, vitamin D₃ and vitamin D₂ are commonly used as a supplement or to fortify food sources. Human data show that the response of 25-hydroxyvitamin D (25(OH)D) to supplementation with vitamin D₃ is higher than to vitamin D₂. To elucidate the metabolic route of both vitamers, we conducted a study with vitamin D-depleted mice, which were allotted into three groups (n = 12) and received equal doses of either deuterated vitamin D₃, deuterated vitamin D₂ or both for 4 weeks. To further investigate the hepatic uptake and hydroxylation of both D-vitamers to 25(OH)D, we conducted cell culture experiments with murine and human hepatoma cells (Hepa1-6 and HepG2). The vitamin D metabolite concentrations in serum, tissues and cells were analyzed by LC-MS/MS or ELISA. In mice, vitamin D₂ resulted in lower serum and tissue concentrations of vitamin D (P < 0.001) than vitamin D₃, while the group which received both D-vitamers showed values in between. Interestingly, vitamin D₂ fed mice had 1.9-times and 2.9-times higher serum concentrations of total and free 25(OH)D (P < 0.001) than mice fed vitamin D₃, while the concentration of 1,25-dihydroxyvitamin D (1,25(OH)₂D) was 1.8-times lower (P < 0.001). The gene and protein expression of enzymes, involved in the hydroxylation and renal uptake of vitamin D remained largely unaffected by the D-vitamer. In contrast to the mice data, hepatoma cells preferred vitamin D₃ for 25-hydroxylation over vitamin D₂ (P < 0.001). In general, the formation of 25(OH)D was much more pronounced in human than in murine hepatoma cells (P < 0.001). To conclude, in contrast to humans, vitamin D₂ was more efficient in increasing 25(OH)D than vitamin D₃ in mice, although this difference was not caused by a preferential hydroxylation of vitamin D₂ in the liver. The metabolic routes of D₃ and D₂ in mice differ, showing lower circulating 1,25(OH)₂D and tissue vitamin D concentrations in D₂- than in D₃-fed mice.

Diverse bioactive metabolites from Penicillium sp. MMA derived from the red sea: structure identification and biological activity studies

A soft coral-derived fungus Penicillium sp. among other isolates e high antibacterial, anti-yeast and cytotoxic activities. The fungus, Penicillium sp. MMA, isolated from Sarcphyton glaucoma, afforded nine diverse compounds (1-9). Their structures were identified by 1D and 2 D NMR and ESI-MS spectroscopic data as two alkaloids: veridicatol (1), aurantiomide C (2); one sesquiterpene, aspterric acid (3); two carboxylic acids, 3,4-dihydroxy-benzoic acid; (4) and linoleic acid (5); three steroids, ergosterol (6), β-Sitosterol (7), β-Sitosterol glucoside (8) along with the sphingolipid, cerebroside A (9). Biologically, the antimicrobial, antioxidant, in vitro cytotoxicity and antibiofilm activities were studied in comparison with the fungal extract. The in silico computational studies were implemented to predict drug and lead likeness properties for 1-4. The fungus was taxonomically characterized by morphological and molecular biology (18srRNA) approaches.

Markers Indicating Body Vitamin D Stores and Responses of Liver and Adipose Tissues to Changes in Vitamin D Intake in Male Mice

Circulating 25-hydroxyvitamin D (25(OH)D) is regarded as the most reliable biomarker of vitamin D status. However, limited data exist concerning the suitability of 25(OH)D as an indicator of body vitamin D stores and the ability of adipose tissue to mobilize vitamin D. In the first study, in which male mice received different vitamin D₃ doses for three weeks, we found strong linear response relationships between vitamin D₃ intake and levels of vitamin D₃ in the plasma (p < 0.001), liver (p < 0.001) and adipose tissues (p < 0.001), and strong positive correlations between plasma and tissue stores of vitamin D₃ (p < 0.001). Plasma levels of 25(OH)D₃ and 24,25-dihydroxyvitamin D₃ (24,25(OH)₂D₃) showed weak or no correlations with tissue vitamin D₃ stores. Data from a second study demonstrate a strong and rapid response of plasma 25(OH)D₃ in vitamin D₃-treated mice with a low vitamin D status. Additionally, mice fed a vitamin D-free diet showed a strong and rapid decline in vitamin D₃ in the liver, whereas the decline in different adipose tissues was distinctly lower than that in the liver. To conclude, tissue stores of vitamin D₃ were best reflected by plasma vitamin D₃. In contrast to the liver, adipose tissues responded less sensitively to an absence of vitamin D intake.

The Effects of Fungal Feed Additives in Animals: A Review

As probiotics, fungi enhance animal health and are suitable animal feed additives. In addition to brewing fungi, there are also edible and medicinal fungi. Common fungi utilized in feeding programs include Saccharomyces cerevisiae, Aspergillus oryzae, Pleurotus spp., Antrodia cinnamomea, and Cordyceps militaris. These fungi are rich in glucans, polysaccharides, polyphenols, triterpenes, ergosterol, adenosine, and laccases. These functional components play important roles in antioxidant, anti-inflammatory, anti-obesity, and immune system regulation. As such, fungal feed additives could be of potential use when breeding livestock. In previous studies, fungal feed additives enhanced body weight and egg production in poultry and improved the feed conversion rate. Several mycotoxins can be produced by hazardous fungi but fortunately, the cell walls constituents and enzymes of fungal probiotics can also act to decrease the toxicity of mycotoxins. Overall, fungal feed additives are of value, but their safety and usage must be studied further, including cost-benefit economic analyses.