The present study aimed to investigate whether inflammation-associated responses in piglets are induced by high protein (HP) through activating nuclear factor kappa B (NF-κB) signaling. Sixteen piglets (35 d of age, Duroc × [Landrace × Yorkshire], weaned at d 21, initial BW = 9.70 ± 0.11 kg) were allocated to 18% and 26% CP (HP group) at random, comprising 8 replicate pens per treatment. The piglets were slaughtered to collect intestinal tissues when apparent, persistent, and stable diarrhea syndromes happened (on d 12). No significant differences were observed in their growth performance (P > 0.05), but reduction by 19.11%, 25.31%, 23.64% of ADFI, ADG, and G:F, respectively was detected in the HP group. The HP group had greater (P = 0.002) diarrhea rates. Furthermore, dietary HP had lower ileal villus height (VH; P = 0.048), ratio of villus height to crypt depth (VH/CD ratio; P = 0.016), and colonic CD (P = 0.034), as well as had the trend (P = 0.075) to reduce the ileal villus absorptive area. Moreover, HP diets significantly elevated the goblet cell numbers in the ileal villi (P = 0.016) and colonic crypts (P < 0.001) and up-regulated (P = 0.012) the mRNA expression of mucin2 (Muc2) in the ileum. In addition, HP diets increased the myeloperoxidase concentration in the ileum (P = 0.002) and colon (P = 0.007) of piglets. Dietary HP significantly down-regulated the mRNA expression of tumor necrosis factor-α (TNF-α; P < 0.001) in the ileum, induced nitric oxide synthase (iNOS; P = 0.040) and interleukin-22 (IL-22; P = 0.008) in the colon, and inclined to down-regulate interleukin-1β (IL-1β; P = 0.076) expression in the colon. The relative protein abundance of Galectin-3 (P = 0.046) in the colon and the ratio of phosphorylation NF-κB to NF-κB (p–NF–κB/NF-κB ratio) in the ileum of HP piglets were also greater (P = 0.038). These results suggest that dietary HP may cause diarrhea in piglets by activating NF-κB signaling induced intestinal inflammation.

本研究旨在调查仔猪的炎症相关反应是否是由高蛋白 (HP) 通过激活核因子 kappa B (NF-κB) 信号传导诱导的。16 头仔猪（35 日龄，杜洛克 × [长白猪 × 约克夏]，在 21 日断奶，初始体重 = 9.70 ± 0.11 kg）被随机分配到 18% 和 26% CP（HP 组），每个猪栏包括 8 个重复栏治疗。当出现明显、持续和稳定的腹泻综合征时（第 12 天），仔猪被屠宰以收集肠道组织。其生长性能无显着差异（P  > 0.05），但在 HP 组中检测到 ADFI、ADG 和 G:F 分别降低 19.11%、25.31%、23.64%。HP 组有更大的（P = 0.002) 腹泻率。此外，日粮 HP 具有较低的回肠绒毛高度 (VH; P  = 0.048)、绒毛高度与隐窝深度的比值 (VH/CD 比值; P  = 0.016) 和结肠 CD ( P  = 0.034)，并且具有以下趋势( P  = 0.075) 减少回肠绒毛吸收面积。此外，HP 饮食显着增加了回肠绒毛（P  = 0.016）和结肠隐窝（P  < 0.001）中的杯状细胞数量并上调（P  = 0.012）回肠中 mucin2 ( Muc2 )的 mRNA 表达。此外，HP 饮食增加了回肠 ( P  = 0.002) 和结肠 ( P = 0.007) 仔猪。膳食 HP 显着下调 回肠中肿瘤坏死因子-α ( TNF-α ; P < 0.001)、诱导型一氧化氮合酶 ( iNOS ; P  = 0.040) 和白细胞介素-22 ( IL-22 ; P  = 0.008)，并倾向于下调结肠中的白细胞介素-1β ( IL-1β ; P  = 0.076) 表达。 结肠中Galectin-3的相对蛋白质丰度（P = 0.046）和HP仔猪回肠中磷酸化NF-κB与NF-κB的比率（p-NF-κB / NF-κB比率）也更大（磷 = 0.038）。这些结果表明日粮 HP 可能通过激活 NF-κB 信号诱导的肠道炎症导致仔猪腹泻。