Tannic Acid Extracted from Galla chinensis Supplementation in the Diet Improves Intestinal Development through Suppressing Inflammatory Responses via Blockage of NF-κB in Broiler Chickens

SIMPLE SUMMARY: Tannic acid (TA) is a hydrophilic polyphenolic compound present in most plants. Galla chinensis, a traditional Chinese medicine, is widely available and used in China, and TA is one of the main bioactive components of Galla chinensis. Until now, there is little information available in the scientific literature on the evaluation of the application of Galla chinensis TA in broiler production. A healthy and well-developed intestine is critical in absorbing nutrients and serves as a vital barrier against pathogen invasion. However, the intestine of the broiler is vulnerable to inflammatory damage under intensive poultry farming conditions. Therefore, we aimed to investigate the effects of adding Galla chinensis TA to the diet of broiler chickens on intestinal development and health, and highlight the application of TA sourced from Galla chinensis as a potential feed additive in poultry production. Our results showed that 300 mg/kg microencapsulated TA from Galla chinensis supplementation benefited to improve intestinal development, which might be attributed to the suppression of inflammatory responses via blockage of NF-κB in broiler chickens, and provide guidance for the application of Galla chinensis TA in poultry production. ABSTRACT: The objective of this study was to investigate the effects of adding tannic acid (TA) extracted from Galla chinensis to the diet of broiler chickens on intestinal development. A total of 324 healthy 1-day-old broilers were used in a 42 d study, and divided into two treatment groups at random (six replicates per group). Broilers were either received a basal diet or a basal diet supplemented with 300 mg/kg microencapsulated TA extracted from Galla chinensis. The results showed that dietary supplemented with 300 mg/kg TA from Galla chinensis improved intestinal morphology, promoted intestinal mucosal barrier integrity, and elevated mucosal expressions of nutrients transporters and tight junction protein CLDN3 in broilers. Besides, 300 mg/kg TA from Galla chinensis supplementation decreased the concentrations of inflammatory cytokines in serum and intestinal mucosa and reduced the mRNA expression of NF-κB in intestinal mucosa. Above all, supplementation of 300 mg/kg microencapsulated TA extracted from Galla chinensis showed beneficial effects in improving intestinal development, which might be attributed to the suppression of inflammatory responses via blockage of NF-κB in broiler chickens. These findings will support the use of TA sourced from Galla chinensis in poultry industry.