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BACKGROUND: Iron and vitamin D (VD) is essential to health. Previous studies have shown that iron homeostasis has a potential effect on VD metabolism, but the mechanism is not fully understood. OBJECTIVES: To explore the relationship between VD metabolism and iron metabolism, as well as the regulatory mechanism of iron on VD metabolism. METHODS: 40 male rats were fed adaptively for 7 days and randomly divided into control (C, n = 6 normal diet) group and model (M, n = 24 iron deficient diet) by simple randomization, the latter was used to establish iron deficiency anemia (IDA) model. After 6 weeks of feeding, the M group was randomly divided into: iron deficiency group (DFe), low iron group (LFe), medium iron group (MFe) and high iron group (HFe) by block randomization. Different doses of iron dextran (based on iron content (100 g·bw·d)): 0, 1.1, 3.3 and 9.9 mg) were given respectively. After 4 weeks, the rats were anesthetized with 8% chloral hydrate, Blood (collected from the abdominal aorta), liver and kidney tissues were collected. The serum and tissues were separately packed and frozen at -80â for testing. RESULTS: The results showed that the levels of hemoglobin (Hb), red blood cell (RBC), serum iron (SI), liver iron, and kidney iron in DFe group were lower than those in the other four groups, while the levels of total iron-binding capacity (TIBC), transferrin (TF) and transferrin receptor (Tfr) in DFe group were higher than those in other groups; The serum levels of 25-(OH)D3 and 1,25-(OH)2D3 in DFe group were significantly lower than those in C group (P < 0.05). The correlation analysis showed that the levels of 25-(OH)D3 and 1,25-(OH)2D3 were negatively correlated with TIBC, TF and Tfr no correlation with SI. Western blotting, immunofluorescence, and q-PCR results showed that compared with C group, the protein and gene expressions of CYP2R1, CYP27A1, and CYP24A1 in DFe group were down-regulated, and the expression of CYP27B1 protein and gene was up-regulated in DFe group. CONCLUSION: Iron may be involved in the metabolism of VD3 by regulating the expression of VD3 hydroxylase, suggesting that appropriate iron supplementation might promote the activation of VD3.
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BACKGROUND: Tight junction proteins play crucial roles in maintaining the intestinal mucosal barrier. Although previous studies have shown that Notch signaling is closely related to tight junction proteins, the mechanism remains unclear. This study was performed to investigate whether vitamin C combined with vitamin D3 affects intestinal mucosal barrier stability via the Notch signaling pathway. METHODS: Intestinal epithelial barrier and notch signaling pathway were studied using guinea pig and SW480 cells. The guinea pigs were randomized into four groups (n = 6 in each group): control group (C, 200 IU/kg d VD3 + 100 mg/kg d VC), low VC group (LVC, 200 IU/kg d VD3 + 10 mg/kg d VC), medium VC group (MVC, 200 IU/kg d VD3 + 100 mg/kg d VC), and high VC group (HVC, 200 IU/kg d VD3 + 200 mg/kg d VC). Except for the control group, the other three groups were freely drinked with 2% dextran sodium sulfate solution for 4 days. And the control group was free to drink distilled water. The following cell groups were used: control group (SW480 cells without intervention); LPS group (100 ng/mL LPS); VD3 group (0.1 µmol/L VD3); VC + VD3 group (0.1, 1, 5, 10 µmol/mL VC + 0.1 µmol/L VD3). RESULTS: Electron microscopy analysis revealed that both low and high doses of vitamin C combined with vitamin D3 maintained dextran sodium sulfate-induced ulcerative colitis in the guinea pig intestinal epithelium tight junction. Compared with the control group, the expression level of ZO-1 mRNA in the colon tissue of the high-dose vitamin C group was significantly increased. In SW480 cell experiments, compared with the control group, cell migration and repair following treatment with different concentrations of vitamin C combined with vitamin D3 were significantly improved and the protein expression of Notch-1 was increased, whereas the protein expression of claudin-2 was significantly decreased. Thus, our results demonstrate that an appropriate amount of vitamin C combined with vitamin D3 can regulate the expression of claudin-2 by regulating Notch-1, relieve destruction of the intestinal mucosal barrier, and promote the repair of damage to the cell mucosal barrier. CONCLUSIONS: We found that vitamin C combined with vitamin D3 protected against dextran sodium sulfate-induced ulcerative colitis in the guinea pig intestinal mucosa.
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Efficient use of feed resources is a challenge in the pork industry because the largest variability in expenditure is attributed to the cost of fodder. Efficiency of feeding is directly related to feeding behavior. In order to identify genomic regions controlling feeding behavior and eating efficiency traits, 338 Duroc boars were used in this study. The Illumina Porcine SNP60K BeadChip was used for genotyping. Data pertaining to individual daily feed intake (DFI), total daily time spent in feeder (TPD), number of daily visits to feeder (NVD), average duration of each visit (TPV), mean feed intake per visit (FPV), mean feed intake rate (FR), and feed conversion ratio (FCR) were collected for these pigs. Despite the limited sample size, the genome-wide association study was acceptable to detect candidate regions association with feeding behavior and eating efficiency traits in pigs. We detected three genome-wide (P < 1.40E-06) and 11 suggestive (P < 2.79E-05) single nucleotide polymorphism (SNP)-trait associations. Six SNPs were located in genomic regions where quantitative trait loci (QTLs) have previously been reported for feeding behavior and eating efficiency traits in pigs. Five candidate genes (SERPINA3, MYC, LEF1, PITX2, and MAP3K14) with biochemical and physiological roles that were relevant to feeding behavior and eating efficiency were discovered proximal to significant or suggestive markers. Gene ontology analysis indicated that most of the candidate genes were involved in the development of the hypothalamus (GO:0021854, P < 0.0398). Our results provide new insights into the genetic basis of feeding behavior and eating efficiency in pigs. Furthermore, some significant SNPs identified in this study could be incorporated into artificial selection programs for Duroc-related pigs to select for increased feeding efficiency.