Department of Poultry Science, The University of Georgia, Athens, GA 30602, USA.
Department of Animal Nutrition, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China.
Poult Sci. 2019 Mar 1;98(3):1146-1152. doi: 10.3382/ps/pey484.
The objective of this experiment was to study the effects of dietary zinc (Zn) source on gene expression of Zn transporters (metallothionein [MT], ZIP 3, 5, 8, 9, 10, 11, 13, and 14, and ZnT 1, 4, 5, 6, 7, 9, and 10) in the jejunum and cecal tonsils of broilers challenged with coccidia or coccidia plus Clostridium perfringens. A 2 × 2 factorial design was used with 2 Zn sources (90 mg Zn/kg from either ZnSO4 or an organic Zn, Bioplex® Zn) and challenged with approximately 5,000 oocysts of Eimeria maxima at 14 d of age with or without C. perfringens (108 CFU/bird) at 18, 19, and 20 d of age (8 pens per treatment and 8 birds per pen) after which 1 bird/pen was sampled at 21 d of age. In the jejunum, co-infection resulted in higher ZnT 5 and 6 gene expression, while organic Zn fed birds had lower ZIP 5 and 11, and higher ZnT1. Additionally, an interaction of challenge by Zn source was noted wherein ZnT10 was unaffected by the C. perfringens in the organic Zn treatment but was 2.7-fold lower in the co-infected ZnSO4 fed birds. S100A9 gene expression, a biomarker of inflammatory response in necrotic enteritis, increased 2 and 2.8-fold in the cecal tonsils and jejunum with the co-infection, respectively. Supplementation with organic Zn lowered S100A9 by 1.9 and 4.4-fold in the cecal tonsils and jejunum, respectively, when birds were supplemented with ZnSO4. Notably, MT, ZIP 3, 8, 9, 10, 13, or 14, and ZnT 4, 7, and 9 were unaffected by Zn source and/or method of challenge. An interaction of challenge by Zn source was also noted for serum Zn concentration, which was reduced when birds were challenged with C. perfringens and fed ZnSO4 but no difference between challenge method when birds were fed organic Zn. Based on the expression of ZnT and ZIP genes, more Zn trafficking due to treatment occured in the jejunum than cecal tonsils, but further studies are needed to ascertain how Zn source regulates intracellular free Zn concentrations and whole-body Zn status during an enteric challenge.
本实验的目的是研究日粮锌源对感染球虫和/或感染球虫加产气荚膜梭菌的肉鸡空肠和盲肠扁桃体锌转运体（金属硫蛋白[MT]、ZIP3、5、8、9、10、11、13 和 14 以及 ZnT1、4、5、6、7、9 和 10）基因表达的影响。采用 2×2 因子设计，2 种锌源（90mg/kg 锌来自 ZnSO4 或有机锌 Bioplex®Zn），14 日龄时每只鸡感染约 5000 个柔嫩艾美耳球虫卵囊，18、19 和 20 日龄时感染产气荚膜梭菌（每只鸡 108 CFU），21 日龄时每栏鸡取 1 只进行采样（每处理 8 个栏，每个栏 8 只鸡）。在空肠中，混合感染导致 ZnT5 和 6 基因表达升高，而饲喂有机锌的鸡则导致 ZIP5 和 11 基因表达降低，ZnT1 基因表达升高。此外，还观察到挑战与锌源之间存在互作，即 ZnT10 不受有机 Zn 处理中产气荚膜梭菌的影响，但在混合感染的 ZnSO4 组中表达降低了 2.7 倍。S100A9 基因表达，坏死性肠炎炎症反应的生物标志物，在盲肠扁桃体和空肠中分别增加了 2 倍和 2.8 倍。当鸡只补充 ZnSO4 时，有机 Zn 分别降低了盲肠扁桃体和空肠中 S100A9 基因表达的 1.9 倍和 4.4 倍。值得注意的是，MT、ZIP3、8、9、10、13 或 14 以及 ZnT4、7 和 9 不受锌源和/或挑战方法的影响。还观察到血清 Zn 浓度因挑战与锌源之间存在互作而降低，当鸡只感染产气荚膜梭菌并饲喂 ZnSO4 时降低，但当鸡只饲喂有机 Zn 时，挑战方法之间没有差异。基于 ZnT 和 ZIP 基因的表达，处理导致空肠中 Zn 转运增加，而盲肠扁桃体中 Zn 转运增加较少，但还需要进一步研究来确定锌源如何在肠道挑战期间调节细胞内游离 Zn 浓度和全身 Zn 状态。
