Copper (Cu) is an essential trace element in the production of swine. This study was conducted to investigate the effect of 3 different sources of Cu on growth performance, Cu metabolism, and intestinal microorganisms of finishing pigs, so as to estimate the bioavailability of the 3 sources for pigs. A total of 42 male finishing pigs (88.74 ± 5.74 kg) were randomly allocated to 7 treatments. The factors were 3 sources (CuSO₄, Cu-glycine, Cu-proteinate) and 2 levels (5 and 20 mg/kg) of Cu, plus one negative control treatment (0 mg/kg added Cu level) for the entire 28-d experiment. The average daily gain (ADG) and feed to gain ratio (F:G) both increased when Cu was added. The Cu level in liver, bile, kidney, serum, lung, urine and feces rose (P < 0.001) with increasing dietary Cu level regardless of the source. Meanwhile, pigs receiving organic Cu (glycinate or proteinate) retained more Cu and excreted less Cu than those receiving inorganic Cu (CuSO₄), which showed that organic forms were more bioavailable. At the transcriptional level, changes in the level and source of dietary Cu resulted in modulation of transporters. In the jejunal mucosa, import transporter high affinity copper uptake protein 1 (CTR1) and export transporter ATPase copper transporting alpha (ATP7A) in supplemental Cu treatments were down-regulated compared to the control. Also, peptide transporter 1 (PepT1) and lanine-serine-cysteine transporter, type-2 (ASCT2) were significantly (P < 0.01) up-regulated in 20 mg/kg Cu-proteinate and Cu-glycinate treatments, respectively. Microbial diversity was lowest in the 20 mg/kg CuSO₄ treatment, and the ratio of Firmicutes to Bacteroidetes was higher in added Cu treatments, especially Cu-glycinate treatment. These results indicate that uptake of different Cu forms is facilitated by different transporters and transport mechanisms, and compared with inorganic Cu, organic Cu provides benefits to intestinal microflora and reduces Cu excretion.

铜 (Cu) 是养猪生产中必需的微量元素。本研究旨在调查 3 种不同来源的铜对肥育猪生长性能、铜代谢和肠道微生物的影响，以估计 3 种来源对猪的生物利用度。共 42 头雄性育肥猪 (88.74 ± 5.74 kg) 被随机分配至 7 个处理。这些因素是 3 个来源（CuSO ₄、Cu-甘氨酸、Cu-蛋白质）和 2 个 Cu 水平（5 和 20 mg/kg），加上一个阴性对照处理（0 mg/kg 添加的 Cu 水平）用于整个 28- d 实验。添加铜后，平均日增重 (ADG) 和料重比 (F:G) 均增加。肝脏、胆汁、肾脏、血清、肺、尿液和粪便中的铜含量升高（P < 0.001) 随着日粮铜含量的增加而与来源无关。同时，接受有机铜（甘氨酸盐或蛋白质）的猪比接受无机铜（CuSO ₄）的猪保留更多的铜和排出更少的铜，这表明有机形式的生物利用度更高。在转录水平上，膳食铜水平和来源的变化导致转运蛋白的调节。在空肠粘膜中，与对照相比，补充铜处理中的输入转运蛋白高亲和力铜摄取蛋白 1 ( CTR1 ) 和输出转运蛋白 ATPase 铜转运 α ( ATP7A ) 下调。此外，肽转运蛋白 1 ( PepT1 ) 和 lanine-serine-cysteine transporter, type-2 ( ASCT2) 分别 在 20 mg/kg Cu-蛋白质和 Cu-甘氨酸处理中显着上调( P < 0.01)。20 mg/kg CuSO ₄处理的微生物多样性最低，添加Cu处理的厚壁菌门与拟杆菌门的比例较高，尤其是Cu-甘氨酸处理。这些结果表明，不同的转运蛋白和转运机制促进了不同形态铜的吸收，与无机铜相比，有机铜有利于肠道菌群并减少铜的排泄。