Department of Animal Science, University of Manitoba, Winnipeg, MB, R3T 2N2Canada.
Evonik Operations GmbH, Rodenbacher Chaussee, Hanau-Wolfgang, Hessen 63457, Germany.
J Anim Sci. 2022 Oct 1;100(10). doi: 10.1093/jas/skac285.
The aim of this experiment was to investigate the effects of dietary crude protein (CP) contents and crystalline amino acids (CAA) supplementation patterns on growth performance, intestinal histomorphology, and immune response in weaned pigs under clean (CSC) or unclean sanitary conditions (USC). A total of 144 weaned pigs (6.35 ± 0.63 kg body weight) were assigned to 6 treatments in a 3 × 2 factorial arrangement based on CP content and sanitary conditions using a randomized complete block design, giving 8 replicates per treatment with 3 pigs per pen. Pigs were fed one of three diets for 21 d: one high CP (HCP; 22%) and two low CP (LCP; 19%) diets supplemented with 9 indispensable AA or only 6 AA (Lys, Met, Thr, Trp, Val, and Ile) as CAA. The CSC room was washed weekly, whereas the USC room had sow manure spread in the pens and was not washed throughout the experiment. Body weight and feed disappearance were recorded weekly. Blood was sampled from 1 pig per pen weekly, and the same pig was euthanized for jejunal tissues sampling on day 21. Pigs raised under USC had reduced (P < 0.05) average daily gain (ADG) and gain to feed ratio (G:F) in week 2, but contrary results that greater (P < 0.05) ADG and G:F were found in pigs under USC in week 3. Overall, there was an interaction where G:F did not differ between HCP and LCP under CSC, however, LCP decreased (P < 0.05) G:F compared to HCP under USC. Pigs fed the HCP diet had higher (P < 0.05) fecal scores than those fed the LCP diets throughout the experiment. Pigs fed the LCP had higher (P < 0.05) villus height to crypt depth ratio than those fed the HCP. An interaction was observed where goblet cell density in the jejunum was higher (P < 0.05) in pigs fed LCP than HCP under CSC, but no difference was found between HCP and LCP under USC. Different CAA supplementation patterns did not influence both growth performance and histomorphology. Pigs raised under USC had greater (P < 0.05) plasma interleukin (IL)-10 and IL-6 concentrations and reduced (P < 0.05) plasma tumor necrosis factor-alpha concentration. Also, the LCP diets resulted in a greater (P < 0.05) plasma IL-10 concentration. In conclusion, overall growth performance did not differ between HCP and LCP under CSC, but LCP diets reduced G:F under USC. Feeding LCP diets to weaned pigs improved gut morphology under USC and ameliorated systemic inflammation induced by USC, whereas CAA supplementation patterns did not affect growth performance and gut morphology.
本实验旨在研究在清洁（CSC）或不清洁（USC）卫生条件下，饲粮粗蛋白（CP）含量和晶体氨基酸（CAA）补充模式对断奶仔猪生长性能、肠道组织形态和免疫反应的影响。采用完全随机区组设计，将 144 头 6.35±0.63kg 体重的断奶仔猪按 CP 含量和卫生条件分为 6 个处理组，每个处理组设 8 个重复，每个重复 3 头猪。仔猪饲喂 3 种饲粮 21d：1 种高蛋白（HCP；22%）和 2 种低蛋白（LCP；19%）饲粮，分别补充 9 种必需氨基酸或仅补充 6 种氨基酸（Lys、Met、Thr、Trp、Val 和 Ile）作为 CAA。CSC 房间每周清洗 1 次，而 USC 房间在整个试验期间将母猪粪便散布在猪圈中，不进行清洗。每周记录体重和采食量。每周从每个猪圈中抽取 1 头猪的血液样本，在第 21 天处死同一头猪进行空肠组织采样。在 USC 条件下饲养的猪在第 2 周的平均日增重（ADG）和增重与采食量比（G：F）降低（P＜0.05），但在第 3 周，USC 条件下饲养的猪的 ADG 和 G：F 更高（P＜0.05）。总体上，在 CSC 条件下，HCP 和 LCP 之间的 G：F 没有差异，但在 USC 条件下，LCP 降低（P＜0.05）G：F。饲喂 HCP 饲粮的猪整个试验期的粪便评分均高于饲喂 LCP 饲粮的猪。饲喂 LCP 的猪空肠绒毛高度与隐窝深度比值高于饲喂 HCP 的猪。在 CSC 条件下，饲喂 LCP 的猪空肠杯状细胞密度高于饲喂 HCP 的猪，存在交互作用（P＜0.05），但在 USC 条件下，HCP 和 LCP 之间没有差异。不同的 CAA 补充模式对生长性能和组织形态均无影响。在 USC 条件下饲养的猪血浆白细胞介素（IL）-10 和 IL-6 浓度更高（P＜0.05），肿瘤坏死因子-α（TNF-α）浓度更低（P＜0.05）。此外，饲喂 LCP 饲粮的猪血浆 IL-10 浓度更高（P＜0.05）。综上所述，在 CSC 条件下，HCP 和 LCP 之间的总体生长性能没有差异，但在 USC 条件下，LCP 饲粮降低了 G：F。在 USC 条件下，饲喂 LCP 饲粮可改善断奶仔猪的肠道形态，减轻 USC 引起的全身炎症反应，而 CAA 补充模式对生长性能和肠道形态没有影响。
