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.

中文翻译：

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具有中等螯合强度的蛋白锌通过上调肉鸡胚胎原代培养的十二指肠上皮细胞中锌和氨基酸转运蛋白的表达来增强锌的吸收


最近的研究表明，锌 （Zn） 和氨基酸转运蛋白可能参与增强肉鸡十二指肠中具有中等螯合强度 （Zn-Prot M） 的 Zn 蛋白对 Zn 的吸收。然而，Zn-Prot M 促进上述 Zn 吸收的具体机制尚不清楚。因此，本研究进行了 3 个实验，研究了 Zn-Prot M 和硫酸锌 （ZnS） 对肉鸡胚胎原代十二指肠上皮细胞中 Zn 吸收和相关转运蛋白表达的特异性和直接影响，以初步解决可能的机制。在实验 1 中，用 100 μmol Zn/L 作为 ZnS 或 Zn-Prot M 处理细胞 20、40、60、80、100 或 120 分钟。实验 2 由 3 个子实验组成。在实验 2A 中，用未补充 Zn 的基础培养基（对照）或补充 100 或 200 μmol Zn/L 作为 ZnS 或 Zn-Prot M 的基础培养基处理细胞 60 分钟;在实验 2B 中，用未补充 Zn 的基础培养基（对照）或补充 200 μmol Zn/L 的 ZnS 或 Zn-Prot M 的基础培养基处理细胞 120 分钟;在实验 2C 中，用未补充 Zn 的基础培养基（对照）或补充 400 或 800 μmol Zn/L 作为 ZnS 或 Zn-Prot M 的基础培养基处理细胞 120 分钟。在实验 3 中，用未补充 Zn 的基础培养基（对照）或补充 400 μmol Zn/L 作为 ZnS 或 Zn-Prot M 的基础培养基处理细胞 120 分钟。实验 1 的结果表明，使用最佳拟合线确定可饱和 Zn 吸收的最小孵育时间为 50.83 分钟。实验 2 的结果表明，与 ZnS 相比，Zn 浓度为 400 μmol/L 且孵育时间为 120 min 适合增加 Zn-Prot M 对 Zn 的吸收。 在实验 3 中，Zn 添加显著增加了细胞单层对 Zn 的吸收 （P < 0.05），并且 Zn-Prot M 显著大于 ZnS （P < 0.05）。与对照相比，Zn 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，增加了 y + L 型氨基转运蛋白 2 （y + LAT2） 蛋白丰度 （P < 0.05）。此外，Zn-Prot M 的 zrt/irt 样蛋白 3 （ZIP3） 、zrt-irt 样蛋白 5 （ZIP5） 和 y + LAT2 的蛋白表达水平显著高于 ZnS （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 蛋白表达水平来促进 Zn 吸收。