Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, Bellatera, Spain.
Departament de Sanitat i d'Anatomia Animals, Universitat Autònoma de Barcelona, Bellatera, Spain.
J Anim Sci. 2020 May 1;98(5). doi: 10.1093/jas/skaa117.
A 42-d experiment was conducted to evaluate the effect of Cu and Zn source and Cu level on pig performance, mineral status, bacterial modulation, and the presence of antimicrobial-resistant genes in isolates of Enterococcus spp. At weaning, 528 pigs (5.9 ± 0.50 kg) were allotted to 48 pens of a randomized complete block design in a 2 × 2 factorial arrangement with two Cu and Zn sources (SF: sulfate and HCl: hydroxychloride) and two Cu levels (15 and 160 mg/kg). As a challenge, the pigs were reared in dirty pens used by a previous commercial batch. Two-phase diets were offered: the pre-starter (PS) phase from day 1 to 14 and the starter phase (ST) from day 14 to 42. At days 14 and 42, pigs were individually weighed and blood samples from one pig per pen were taken. At the end of the experiment, one pig per pen was euthanized to collect the samples. Feeding high levels of Cu increased body weight (BW) from 16.6 to 17.7 kg (P < 0.001). Furthermore, average daily gain, gain to feed (G:F) ratio, average daily feed intake (ADFI), and mineral status were enhanced with Cu at 160 mg/kg (P < 0.05) compared with Cu at 15 mg/kg. There was no effect of the interaction between source × level on any of the growth performance responses except for ADFI (P = 0.004) and G:F (P = 0.029) at the end of the ST period and for G:F (P = 0.006) for entire nursery period (day 0 to 42). At the end of the ST period, pigs fed Cu at 160 mg/kg as HCl had not only higher ADFI but also lower G:F than those fed Cu as SF at 160 mg/kg. Meanwhile, for the entire nursery period, G:F did not differ between pigs fed Cu at 160 mg/kg as HCl or SF. In colonic digesta, the relative abundance of Streptococcus, Enterobacter, Escherichia, among others, decreased (P-adjust < 0.05), while Lachnospira and Roseburia tended (P-adjust < 0.10) to increase in pigs fed Cu at 160 mg/kg as HCl compared with those fed Cu SF at 160 mg/kg. An increase (P-adjust < 0.05) in Methanosphaera and Roseburia was observed in pigs fed Cu at 160 mg/kg. From colon digesta, Enterococcus spp. was isolated in 40 samples, being E. faecalis the most dominating (65%) regardless of the experimental diet. Genes of ermB (7.5%) and tetM (5%) were identified. No genes for Cu (tcrB) or vancomycin (vanA, vanB, vanC1, and vanC2) were detected. In conclusion, European Union permissible levels of Cu (160 mg/kg), of both sources, were able to increase performance, mineral status, and bacterial modulation compared with nutritional level. Different effects on growth performance, mineral tissue content, and microbial modulation were observed between Cu and Zn sources.
进行了一项为期 42 天的实验，以评估铜和锌源以及铜水平对猪生产性能、矿物质状况、细菌调节以及肠球菌分离株中存在的抗菌药物抗性基因的影响。在断奶时，将 528 头猪（5.9±0.50kg）分配到 48 个随机完全块设计的栏中，采用 2×2 因子设计，有两种铜和锌源（SF：硫酸盐和 HCl：羟氯化物）和两种铜水平（15 和 160mg/kg）。作为一种挑战，猪被饲养在先前商业批次使用的肮脏围栏中。提供了两阶段的饮食：第 1 天至 14 天的预饲期（PS）和第 14 天至 42 天的育肥期（ST）。在第 14 天和第 42 天，对每头猪进行个体称重，并从每栏猪中采集一份血液样本。在实验结束时，每栏猪中随机选择一头猪进行安乐死，以收集样本。高铜水平提高了体重（BW）从 16.6 至 17.7kg（P<0.001）。此外，与 15mg/kg 铜相比，160mg/kg 铜提高了平均日增重、增重与饲料比（G:F）、平均日采食量（ADFI）和矿物质状况（P<0.05）。源×水平之间的相互作用对除了育肥期结束时的 ADFI（P=0.004）和 G:F（P=0.029）以及整个保育期（0 至 42 天）的 G:F 之外的任何生长性能反应都没有影响（P=0.006）。在育肥期结束时，与 160mg/kg 铜作为 SF 相比，饲喂 160mg/kg 铜作为 HCl 的猪不仅 ADFI 更高，而且 G:F 更低。同时，在整个保育期内，饲喂 160mg/kg 铜作为 HCl 或 SF 的猪之间的 G:F 没有差异。在结肠内容物中，链球菌、肠杆菌、大肠杆菌等的相对丰度降低（P-调整<0.05），而lachnospira 和罗斯伯里亚（Roseburia）的相对丰度（P-调整<0.10）在饲喂 160mg/kg 铜的猪中趋于增加作为 HCl 与那些用 160mg/kg 铜喂养 SF 的猪相比。饲喂 160mg/kg 铜的猪中观察到 Methanosphaera 和 Roseburia 的增加（P-调整<0.05）。从结肠内容物中分离出肠球菌属，40 个样本中有 Enterococcus spp.，无论实验饮食如何，E. faecalis 都是最主要的（65%）。鉴定出 ermB（7.5%）和 tetM（5%）基因。未检测到铜（tcrB）或万古霉素（vanA、vanB、vanC1 和 vanC2）的基因。总之，与营养水平相比，欧盟允许的铜（160mg/kg）水平，无论是哪种来源，都能提高生产性能、矿物质状况和细菌调节。铜和锌源之间观察到对生长性能、矿物质组织含量和微生物调节的不同影响。
