Hu Ruizhi, He Ziyu, Liu Ming, Tan Jijun, Zhang Hongfu, Hou De-Xing, He Jianhua, Wu Shusong
Hunan Collaborative Innovation Center for Utilization of Botanical Functional Ingredients, College of Animal Science and Technology, Hunan Agricultural University, Changsha, 410128 China.
Department of Food Science and Biotechnology, Faculty of Agriculture, Kagoshima University, Kagoshima, 890-0065 Japan.
J Anim Sci Biotechnol. 2020 Sep 9;11:92. doi: 10.1186/s40104-020-00492-9. eCollection 2020.
Weaning is one of the major factors that cause stress and intestinal disease in piglets. Protocatechuic acid (PCA) is an active plant phenolic acid which exists in Chinese herb, Duzhong ( Oliver), and is also considered as the main bioactive metabolite of polyphenol against oxidative stress and inflammation. This study aimed to investigate the effect of PCA on growth performance, intestinal barrier function, and gut microbiota in a weaned piglet model challenged with lipopolysaccharide (LPS).
Thirty-six piglets (Pig Improvement Company line 337 × C48, 28 d of age, 8.87 kg ± 0.11 kg BW) were randomly allocated into 3 treatments and fed with a basal diet (CTL), a diet added 50 mg/kg of aureomycin (AUR), or a diet supplemented with 4000 mg/kg of PCA, respectively. The piglets were challenged with LPS (10 μg/kg BW) on d 14 and d 21 by intraperitoneal injection during the 21-d experiment. Animals ( = 6 from each group) were sacrificed after being anesthetized by sodium pentobarbital at 2 h after the last injection of LPS. The serum was collected for antioxidant indices and inflammatory cytokines analysis, the ileum was harvested for detecting mRNA and protein levels of tight junction proteins by PCR and immunohistochemical staining, and the cecum chyme was collected for intestinal flora analysis using 16S rRNA gene sequencing.
Dietary supplementation of PCA or AUR significantly increased the expression of tight junction proteins including ZO-1 and claudin-1 in intestinal mucosa, and decreased the serum levels of thiobarbituric acid reactive substances (TBARS) and IL-6, as compared with CTL group. In addition, PCA also decreased the serum levels of IL-2 and TNF-α ( < 0.05). Analysis of gut microbiota indicated that PCA increased the Firmicutes/Bacteroidetes ratio ( < 0.05). Spearman's correlation analysis at the genus level revealed that PCA reduced the relative abundance of 9, 2, , and group ( < 0.05), and increased the relative abundance of and ( < 0.05), whereas AUR had no significant effect on these bacteria.
These results demonstrated that both PCA and AUR had protective effect on oxidative stress, inflammation and intestinal barrier function in piglets challenged with LPS, and PCA potentially exerted the protective function by modulating intestinal flora in a way different from AUR.
断奶是导致仔猪应激和肠道疾病的主要因素之一。原儿茶酸（PCA）是一种活性植物酚酸，存在于中药杜仲中，也被认为是多酚对抗氧化应激和炎症的主要生物活性代谢产物。本研究旨在探讨PCA对脂多糖（LPS）攻击的断奶仔猪模型生长性能、肠道屏障功能和肠道微生物群的影响。
36头仔猪（品系为Pig Improvement Company line 337×C48，28日龄，体重8.87 kg±0.11 kg）随机分为3组，分别饲喂基础日粮（CTL）、添加50 mg/kg金霉素的日粮（AUR）或添加4000 mg/kg PCA的日粮。在为期21天的实验中，于第14天和第21天对仔猪腹腔注射LPS（10 μg/kg体重）进行攻击。在最后一次注射LPS后2小时，用戊巴比妥钠麻醉动物（每组6头）并宰杀。采集血清用于抗氧化指标和炎性细胞因子分析，采集回肠用于通过PCR和免疫组织化学染色检测紧密连接蛋白的mRNA和蛋白水平，采集盲肠食糜用于使用16S rRNA基因测序进行肠道菌群分析。
与CTL组相比，日粮中添加PCA或AUR显著增加了肠道黏膜中紧密连接蛋白（包括ZO-1和claudin-1）的表达，降低了血清中硫代巴比妥酸反应物质（TBARS）和IL-6的水平。此外，PCA还降低了血清中IL-2和TNF-α的水平（P<0.05）。肠道微生物群分析表明，PCA增加了厚壁菌门/拟杆菌门的比例（P<0.05）。在属水平上的Spearman相关性分析显示，PCA降低了9、2、和组的相对丰度（P<0.05），增加了和的相对丰度（P<0.05），而AUR对这些细菌没有显著影响。
这些结果表明，PCA和AUR对LPS攻击的仔猪的氧化应激、炎症和肠道屏障功能均有保护作用，且PCA可能通过与AUR不同的方式调节肠道菌群发挥保护作用。
