Beta-alanine is an important amino acid involved in several metabolic reactions in the body. The study aimed to investigate the effect of β-alanine supplementation on intestinal development and the immune performance of weaned piglets. Thirty-two 21-day-old healthy weaned piglets (half female and half male; Duroc × Landrace × Yorkshire) with an initial body weight of 8.11 ± 0.21 kg were randomly divided into 4 groups with 8 replicates of 1 pig each. The control group was fed a basal diet and the three experimental treatment groups were fed diets supplemented with 300, 600 and 1,200 mg/kg β-alanine, respectively. The trial lasted 28 days and the diets fed were divided into 2 phases: the late lactation period (day 1 to 14) and the nursery period (day 15 to 28), during which the weaned piglets had free access to food and water. The regulatory effects of β-alanine were further investigated in vitro using organoids obtained from the jejunum of piglets. In vivo, the addition of β-alanine to the diet had no significant effect on the growth performance of weaned piglets (P > 0.05), but significantly reduced serum levels of immunoglobulin G (IgG) (P < 0.01), immunoglobulin M (IgM) (P = 0.005), and complement 3 (C3) (P = 0.017). The serum interleukin- 6 (IL-6) levels (P < 0.01) were significantly reduced in the 1,200 mg/kg treatment group. The addition of β-alanine increased ileal villus height, with the most significant effect at a concentration of 300 mg/kg (P = 0.041). The addition of 600 mg/kg β-alanine significantly up-regulated the expression of superoxide dismutase (SOD) activity (P = 0.020) and the zonula occludens-1 (ZO-1) gene (P = 0.049) in the jejunum. Diets supplemented with 300 mg/kg β-alanine significantly increased the number of Ki67 positive cells in the jejunal crypts (P < 0.01). In vitro, β-alanine increased the organoid budding rates (P = 0.001) and the budding height of the crypt significantly (P = 0.004). In conclusion, β-alanine can improve intestinal morphology and barrier function, reduce inflammatory responses and alleviate the adverse effects of weaning stress on piglet intestinal health.

β-丙氨酸是参与体内多种代谢反应的重要氨基酸。本研究旨在研究补充β-丙氨酸对断奶仔猪肠道发育和免疫性能的影响。将32头21日龄健康断奶仔猪（母、公各半；杜洛克×长白×约克夏）初始体重8.11±0.21 kg随机分为4组，每组8个重复，每组1头。对照组喂食基础饮食，三个实验治疗组分别喂食补充了 300、600 和 1,200 mg/kg β-丙氨酸的饮食。试验持续 28 天，饲喂的日粮分为 2 个阶段：泌乳后期（第 1 至 14 天）和保育期（第 15 至 28 天），在此期间断奶仔猪可以自由进食和饮水。使用从仔猪空肠中获得的类器官进一步研究了 β-丙氨酸的体外调节作用。在体内，日粮中添加β-丙氨酸对断奶仔猪的生长性能无显着影响（P > 0.05)，但免疫球蛋白 G (IgG) ( P  < 0.01)、免疫球蛋白 M (IgM) ( P  = 0.005) 和补体 3 (C3) ( P  = 0.017) 的血清水平显着降低。 1,200 mg/kg 治疗组的血清白细胞介素 6 (IL-6) 水平 ( P < 0.01) 显着降低。添加β-丙氨酸可增加回肠绒毛高度，浓度为300 mg/kg时效果最显着（P  = 0.041）。添加 600 mg/kg β-丙氨酸显着上调超氧化物歧化酶 (SOD) 活性 ( P  = 0.020) 和 zonula occludens-1 ( ZO-1 ) 基因 ( P = 0.049) 在空肠中。添加 300 mg/kg β-丙氨酸的饮食显着增加了空肠隐窝中 Ki67 阳性细胞的数量（P  < 0.01）。在体外，β-丙氨酸显着提高了类器官出芽率 ( P  = 0.001) 和隐窝的出芽高度 ( P  = 0.004)。综上所述，β-丙氨酸可以改善肠道形态和屏障功能，减少炎症反应，减轻断奶应激对仔猪肠道健康的不利影响。