Poultry Mineral Nutrition Laboratory, College of Animal Science and Technology, Yangzhou University, Yangzhou, People's Republic of China.
Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
J Anim Sci. 2024 Jan 3;102. doi: 10.1093/jas/skae204.
Recent study showed that zinc (Zn) and amino acid transporters may be involved in enhancing Zn absorption from Zn proteinate with moderate chelation strength (Zn-Prot M) in the duodenum of broilers. However, the specific mechanisms by which Zn-Prot M promotes the above Zn absorption are unknown. Therefore, in this study, 3 experiments were conducted to investigate specific and direct effects of Zn-Prot M and Zn sulfate (ZnS) on Zn absorption and expression of related transporters in primary duodenal epithelial cells of broiler embryos so as to preliminarily address possible mechanisms. In experiment 1, cells were treated with 100 μmol Zn/L as ZnS or Zn-Prot M for 20, 40, 60, 80, 100, or 120 min. Experiment 2 consisted of 3 sub-experiments. In experiment 2A, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 100 or 200 μmol Zn/L as ZnS or Zn-Prot M for 60 min; in experiment 2B, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 200 μmol Zn/L of as the ZnS or Zn-Prot M for 120 min; in experiment 2C, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 400 or 800 μmol Zn/L as ZnS or Zn-Prot M for 120 min. In experiment 3, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 400 μmol Zn/L as ZnS or Zn-Prot M for 120 min. The results of experiment 1 indicated that the minimum incubation time for saturable Zn absorption was determined to be 50.83 min using the best fit line. The results in experiment 2 demonstrated that a Zn concentration of 400 μmol/L and an incubation time of 120 min were suitable to increase the absorption of Zn from Zn-Prot M compared to ZnS. In experiment 3, Zn absorption across cell monolayers was significantly increased by Zn addition (P < 0.05), and was significantly greater with Zn-Prot M than with ZnS (P < 0.05). Compared to the control, Zn addition significantly decreased Zn transporter 10 and peptide-transporter 1 mRNA expression levels and increased y + L-type amino transporter 2 (y + LAT2) protein abundance (P < 0.05). Moreover, protein expression levels of zrt/irt-like protein 3 (ZIP3), zrt-irt-like protein 5 (ZIP5), and y + LAT2 were significantly greater for Zn-Prot M than for ZnS (P < 0.05). These findings suggest that Zn-Prot M promote Zn absorption by increasing ZIP3, ZIP5 and y + LAT2 protein expression levels in primary duodenal epithelial cells.
最近的研究表明，锌（Zn）和氨基酸转运体可能参与增强中肠中具有适度螯合强度的蛋白锌（Zn-Prot M）对 Zn 的吸收。然而，Zn-Prot M 促进上述 Zn 吸收的确切机制尚不清楚。因此，本研究通过 3 个实验来研究 Zn-Prot M 和 Zn 硫酸盐（ZnS）对鸡胚原代十二指肠上皮细胞中 Zn 吸收和相关转运体表达的特异性和直接影响，初步探讨可能的机制。在实验 1 中，细胞用 100 μmol/L 的 ZnS 或 Zn-Prot M 处理 20、40、60、80、100 或 120 min。实验 2 包括 3 个子实验。在实验 2A 中，细胞用不含 Zn 的基础培养基（对照）或用基础培养基补充 100 或 200 μmol/L 的 ZnS 或 Zn-Prot M 处理 60 min；在实验 2B 中，细胞用不含 Zn 的基础培养基（对照）或用基础培养基补充 200 μmol/L 的 ZnS 或 Zn-Prot M 处理 120 min；在实验 2C 中，细胞用不含 Zn 的基础培养基（对照）或用基础培养基补充 400 或 800 μmol/L 的 ZnS 或 Zn-Prot M 处理 120 min。在实验 3 中，细胞用不含 Zn 的基础培养基（对照）或用基础培养基补充 400 μmol/L 的 ZnS 或 Zn-Prot M 处理 120 min。实验 1 的结果表明，使用最佳拟合线确定了 Zn 吸收的最小孵育时间为 50.83 min。实验 2 的结果表明，与 ZnS 相比，400 μmol/L 的 Zn 浓度和 120 min 的孵育时间更适合增加 Zn-Prot M 的 Zn 吸收。在实验 3 中，Zn 的添加显著增加了细胞单层的 Zn 吸收（P<0.05），并且 Zn-Prot M 处理组的 Zn 吸收显著高于 ZnS 处理组（P<0.05）。与对照组相比，Zn 的添加显著降低了 Zn 转运蛋白 10 和肽转运蛋白 1 mRNA 的表达水平，并增加了 y+L 型氨基酸转运体 2（y+LAT2）蛋白丰度（P<0.05）。此外，Zn-Prot M 处理组的 zrt/irt-like 蛋白 3（ZIP3）、zrt/irt-like 蛋白 5（ZIP5）和 y+LAT2 的蛋白表达水平显著高于 ZnS 处理组（P<0.05）。这些发现表明，Zn-Prot M 通过增加原代十二指肠上皮细胞中 ZIP3、ZIP5 和 y+LAT2 的蛋白表达水平来促进 Zn 的吸收。
