Department of Animal Science, College of Life Science, Shangqiu Normal University, Shangqiu 476000, Henan, China.
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, China.
Poult Sci. 2018 Apr 1;97(4):1263-1270. doi: 10.3382/ps/pex423.
1α-Hydroxycholecalciferol (1α-OH-D3) is a vitamin D derivative. The objective of this study was to evaluate the effects of 1α-OH-D3 on the growth and the mRNA expression of vitamin D receptor (VDR) in the small intestine and kidney of chickens. A total of 240 males of one-day-old Ross 308 broilers was randomly assigned to 4 treatments with 5 replicates of 12 birds per replicate. Three levels of 1α-OH-D3 (1.25, 2.5, and 5 μg/kg) were added to a basal diet containing 0.50% calcium (Ca), 0.25% non-phytate phosphorus (NPP), and without supplemental cholecalciferol (vitamin D3). The control diet contained 1.00% Ca, 0.45% NPP, and 25 μg/kg cholecalciferol. Dietary 1α-OH-D3 levels linearly improved the average daily feed intake (ADFI), average daily gain (ADG), femur and tibia mineralization, and plasma Ca concentration, and retained Ca and total phosphorus (tP) amounts in broilers from 1 to 21 d of age (P < 0.05). In addition, 1α-OH-D3 also linearly up-regulated the mRNA expression levels of VDR in the duodenum as well as those of VDR and sodium-phosphate cotransporter NaPi-IIa and NaPi-IIc in the kidney of broilers (P < 0.05). However, 1α-OH-D3 did not affect the mRNA levels of 25-hydroxylase in the liver or NaPi-IIb in the duodenum (P > 0.05). No differences were observed in the ADFI, ADG, bone length, plasma mineral concentration, retained tP amount, or the mRNA levels of the above genes (except for VDR in the kidney) between the birds fed the diet with 5 μg/kg 1α-OH-D3 and the birds fed the control diet (P > 0.05). By contrast, the weight, ash weight, ash percentage, and Ca percentage of the bone, retained Ca amount, and the mRNA level of VDR in the kidney were lower in the birds fed the diet with 5 μg/kg 1α-OH-D3 than in the birds fed the control diet (P < 0.05). These data indicate that 1α-OH-D3 up-regulates the gene expression of VDR in the small intestine and kidney at the transcriptional level, thereby improving the growth performance and bone mineralization of broiler chickens from 1 to 21 d of age.
1α-羟胆钙化醇（1α-OH-D3）是维生素 D 的一种衍生物。本研究旨在评估 1α-OH-D3 对鸡小肠和肾脏中维生素 D 受体（VDR）生长和 mRNA 表达的影响。将 240 只 1 日龄 Ross 308 肉鸡随机分为 4 个处理组，每组 5 个重复，每个重复 12 只鸡。在含有 0.50%钙（Ca）、0.25%非植酸磷（NPP）和无补充胆钙化醇（维生素 D3）的基础日粮中添加 1α-OH-D3 的 3 个水平（1.25、2.5 和 5μg/kg）。对照日粮含有 1.00% Ca、0.45% NPP 和 25μg/kg 胆钙化醇。日粮 1α-OH-D3 水平线性提高了 1 至 21 日龄肉鸡的平均日采食量（ADFI）、平均日增重（ADG）、股骨和胫骨矿化以及血浆 Ca 浓度，并保留了肉鸡的 Ca 和总磷（tP）（P <0.05）。此外，1α-OH-D3 还线性上调了肉鸡十二指肠中 VDR 的 mRNA 表达水平，以及肾脏中 VDR 和钠离子-磷酸盐共转运体 NaPi-IIa 和 NaPi-IIc 的 mRNA 表达水平（P <0.05）。然而，1α-OH-D3 对肝脏中 25-羟化酶或十二指肠中 NaPi-IIb 的 mRNA 水平没有影响（P >0.05）。在 ADFI、ADG、骨长、血浆矿物质浓度、保留 tP 量或上述基因的 mRNA 水平（肾脏中的 VDR 除外）方面，喂食 5μg/kg 1α-OH-D3 的鸡与喂食对照日粮的鸡之间没有差异（P >0.05）。相比之下，喂食 5μg/kg 1α-OH-D3 的日粮的鸡的骨骼重量、灰分重量、灰分百分比、Ca 百分比、保留的 Ca 量以及肾脏中 VDR 的 mRNA 水平低于喂食对照日粮的鸡（P <0.05）。这些数据表明，1α-OH-D3 在转录水平上上调了小肠和肾脏中 VDR 的基因表达，从而改善了 1 至 21 日龄肉鸡的生长性能和骨矿化。
