Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA.
BASF Corporation, Florham Park, NJ, 07932, USA.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad035.
The objective of this study was to investigate effects of zinc glycinate (ZnGly) supplementation reducing zinc oxide (ZnO) in feeds on intestinal health and growth of nursery pigs challenged with F18+Escherichia coli (E. coli). In total, 72 nursery pigs (BW 6.5 ± 0.5 kg) were allotted in a randomized complete block design to nine treatments: (1) NC: no challenge/no supplement; (2) PC: E. coli challenge/no-supplement; (3) E. coli challenge/ZnO at 2,500 mg/kg; (4, 5, and 6) E. coli challenge/ZnGly at 400, 800, and 1,200 mg/kg; and (7, 8, and 9) E. coli challenge/ZnGly at 400 mg/kg and ZnO at 700, 1,400, and 2,357 mg/kg. Pigs were fed for 28 d based on two phases (phase 1: 14 d and phase 2: 14 d). On day 7, challenged groups were orally inoculated with F18+E. coli at 6 × 109 CFU/mL whereas NC received saline solution. The PC showed reduced ADG (P = 0.076) and G:F (P = 0.055) during phase 1 and increased fecal score (P < 0.05) during the first week of postchallenge when compared with NC, whereas supplementation of ZnGly from 0 to 1,200 mg/kg linearly increased (P = 0.092) G:F and decreased (P < 0.05) the fecal score of the pigs challenged with F18+E. coli. Supplementation of ZnGly from 0 to 1,200 mg/kg had quadratic effects on TNF-α (P = 0.065; minimum 1.13 pg/mg at 850 mg/kg ZnGly), IL-8 (P = 0.093; minimum 0.53 ng/mg at 494 mg/kg), and protein carbonyl (P = 0.054; minimum 2.30 pg/mg at 675 mg/kg) and linearly increased mRNA expressions of ZIP4 (P = 0.057) and ZnT5 (P = 0.075) in the jejunum of the pigs. Supplementation of ZnGly from 0 to 1,200 mg/kg linearly increased (P < 0.05) the relative abundance of Actinobacteria and had quadratic effects on Cyanobacteria (minimum 0.67% at 625 mg/kg ZnO) and Proteobacteria (maximum 45.6 g/d at 735 mg/kg) at the phylum level, with linearly decreased (P < 0.05) Enterobacteriaceae at the family level in the jejunal mucosa-associated microbiota of the pigs. There was no difference in growth performance during the overall period, although pigs fed with ZnO at 2,500 mg/kg had greater (P < 0.05) ADG than pigs fed with ZnGly at 400 mg/kg during the first week of the post challenge period. In conclusion, ZnGly could be an alternative to the pharmaceutical use of ZnO without negatively affecting the growth of nursery pigs by enhancing intestinal Zn absorption, reducing intestinal inflammation and oxidative stress, and providing positive changes in jejunal mucosa-associated microbiota.
本研究旨在探究饲粮中用甘氨酸锌（ZnGly）替代氧化锌（ZnO）对仔猪生产性能的影响，以及对仔猪回肠健康和受 F18+大肠杆菌（E. coli）攻毒仔猪的影响。选用 72 头体重为 6.5±0.5kg 的仔猪，采用完全随机区组设计，分为 9 个处理组：（1）NC：无攻毒，无添加；（2）PC：E. coli 攻毒，无添加；（3）E. coli 攻毒，ZnO 添加量为 2500mg/kg；（4、5、6）E. coli 攻毒，ZnGly 添加量分别为 400、800、1200mg/kg；（7、8、9）E. coli 攻毒，ZnGly 添加量为 400mg/kg，ZnO 添加量分别为 700、1400、2357mg/kg。仔猪分两个阶段进行 28d 饲养（阶段 1：14d；阶段 2：14d）。攻毒组在第 7 天通过口灌方式接种 F18+E. coli，剂量为 6×109CFU/mL，NC 组灌服生理盐水。与 NC 相比，PC 组在第 1 阶段 ADG（P=0.076）和 G:F（P=0.055）降低，攻毒后第 1 周粪便评分升高（P<0.05），而添加 01200mg/kg ZnGly 线性增加了 G:F（P=0.092），降低了受 F18+E. coli 攻毒仔猪的粪便评分（P<0.05）。添加 01200mg/kg ZnGly 对 TNF-α（P=0.065；ZnGly 为 850mg/kg 时 TNF-α最低为 1.13pg/mg）、IL-8（P=0.093；ZnGly 为 494mg/kg 时 IL-8 最低为 0.53ng/mg）和蛋白羰基（P=0.054；ZnGly 为 675mg/kg 时蛋白羰基最低为 2.30pg/mg）具有二次效应，对仔猪空肠中 ZIP4（P=0.057）和 ZnT5（P=0.075）的 mRNA 表达具有线性增加作用。添加 0~1200mg/kg ZnGly 线性增加了仔猪空肠黏膜相关菌群中厚壁菌门的相对丰度（P<0.05），对蓝藻门（ZnGly 为 625mg/kg 时最低为 0.67%）和变形菌门（ZnGly 为 735mg/kg 时最高为 45.6g/d）具有二次效应，降低了仔猪空肠黏膜相关菌群中肠杆菌科的相对丰度（P<0.05）。整个试验期仔猪的生产性能没有差异，尽管攻毒后第 1 周，饲粮添加 2500mg/kg ZnO 的仔猪 ADG 高于添加 400mg/kg ZnGly 的仔猪（P<0.05）。综上所述，甘氨酸锌可替代氧化锌在仔猪饲粮中的应用，且不会降低仔猪的生长性能，还能通过增强肠道锌吸收、减少肠道炎症和氧化应激、改善空肠黏膜相关菌群来提高仔猪的健康水平。
