Chang Yaqi, Wang Ke, Liu Guangmang, Zhao Hua, Chen Xiaoling, Cai Jingyi, Jia Gang
Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition of China, Ministry of Education, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.
J Anim Sci Biotechnol. 2024 Jan 19;15(1):5. doi: 10.1186/s40104-023-00962-w.
Zinc glycine chelate (Zn-Gly) has anti-inflammation and growth-promoting properties; however, the mechanism of Zn-Gly contribution to gut barrier function in Cherry Valley ducks during intestinal inflammation is unknown. Three-hundred 1-day-old ducks were divided into 5 groups (6 replicates and 10 ducks per replicate) in a completely randomized design: the control and dextran sulfate sodium (DSS) groups were fed a corn-soybean meal basal diet, and experimental groups received supplements of 70, 120 or 170 mg/kg Zn in form of Zn-Gly. The DSS and treatment groups were given 2 mL of 0.45 g/mL DSS daily during d 15-21, and the control group received normal saline. The experiment lasted 21 d.
Compared with DSS group, 70, 120 and 170 mg/kg Zn significantly increased body weight (BW), villus height and the ratio of villus to crypt, and significantly decreased the crypt depth of jejunum at 21 d. The number of goblet cells in jejunal villi in the Zn-Gly group was significantly increased by periodic acid-Schiff staining. Compared with control, the content of intestinal permeability marker D-lactic acid (D-LA) and fluxes of fluorescein isothiocyanate (FITC-D) in plasma of DSS group significantly increased, and 170 mg/kg Zn supplementation significantly decreased the D-LA content and FITC-D fluxes. Compared with control, contents of plasma, jejunum endotoxin and jejunum pro-inflammatory factors IL-1β, IL-6 and TNF-α were significantly increased in DSS group, and were significantly decreased by 170 mg/kg Zn supplementation. Dietary Zn significantly increased the contents of anti-inflammatory factors IL-10, IL-22 and sIgA and IgG in jejunum. Real-time PCR and Western blot results showed that 170 mg/kg Zn supplementation significantly increased mRNA expression levels of CLDN-1 and expression of OCLN protein in jejunum, and decreased gene and protein expression of CLDN-2 compared with DSS group. The 120 mg/kg Zn significantly promoted the expressions of IL-22 and IgA. Dietary Zn-Gly supplementation significantly decreased pro-inflammatory genes IL-8 and TNF-α expression levels and TNF-α protein expression in jejunum. Additionally, Zn significantly reduced the gene and protein expression of TLR4, MYD88 and NF-κB p65.
Zn-Gly improved duck BW and alleviated intestinal injury by regulating intestinal morphology, barrier function and gut inflammation-related signal pathways TLR4/MYD88/NF-κB p65.
甘氨酸锌（Zn-Gly）具有抗炎和促生长特性；然而，在肠道炎症期间，Zn-Gly对樱桃谷鸭肠道屏障功能的作用机制尚不清楚。300只1日龄鸭被完全随机分为5组（每组6个重复，每个重复10只鸭）：对照组和硫酸葡聚糖钠（DSS）组饲喂玉米-豆粕基础日粮，实验组分别添加70、120或170mg/kg Zn-Gly形式的锌。DSS组和处理组在第15至21天每天给予2mL 0.45g/mL DSS，对照组给予生理盐水。实验持续21天。
与DSS组相比，70、120和170mg/kg锌显著增加了21日龄时的体重（BW）、绒毛高度和绒毛与隐窝比值，并显著降低了空肠隐窝深度。高碘酸-希夫染色显示，Zn-Gly组空肠绒毛中杯状细胞数量显著增加。与对照组相比，DSS组血浆中肠道通透性标志物D-乳酸（D-LA）含量和异硫氰酸荧光素（FITC-D）通量显著增加，添加170mg/kg锌显著降低了D-LA含量和FITC-D通量。与对照组相比，DSS组血浆、空肠内毒素以及空肠促炎因子IL-1β、IL-6和TNF-α含量显著增加，添加170mg/kg锌显著降低了这些指标。日粮锌显著增加了空肠中抗炎因子IL-10、IL-22和sIgA以及IgG的含量。实时荧光定量PCR和蛋白质免疫印迹结果表明，与DSS组相比，添加170mg/kg锌显著增加了空肠中CLDN-1的mRNA表达水平和OCLN蛋白的表达，降低了CLDN-2的基因和蛋白表达。120mg/kg锌显著促进了IL-22和IgA的表达。日粮添加Zn-Gly显著降低了空肠中促炎基因IL-8和TNF-α的表达水平以及TNF-α蛋白的表达。此外，锌显著降低了TLR4、MYD88和NF-κB p65的基因和蛋白表达。
Zn-Gly通过调节肠道形态、屏障功能和肠道炎症相关信号通路TLR4/MYD88/NF-κB p65改善鸭体重并减轻肠道损伤。
