Abstract
The objective of this study was to investigate the protective effects and mechanisms of dietary administration of sodium humate (HNa) and its zinc and selenium chelate (Zn/Se-HNa) in mitigating Salmonella Typhimurium (S. Typhi) induced intestinal injury in broiler chickens. Following the gavage of 109 CFU S. Typhi to 240 broilers from 21-d to 23-d aged, various growth performance parameters such as body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), and feed ratio (FCR) were measured before and after infection. Intestinal morphology was assessed to determine the villus height, crypt depth, and chorionic cryptologic ratio. To evaluate intestinal barrier integrity, levels of serum diamine oxidase (DAO), D-lactic acid, tight junction proteins, and the related genes were measured in each group of broilers. An analysis was conducted on inflammatory-related cytokines, oxidase activity, and Nuclear Factor Kappa B (NF-κB) and Nuclear factor erythroid2-related factor 2 (Nrf2) pathway-related proteins and mRNA expression. The results revealed a significant decrease in BW, ADG, and FCR in S. typhi-infected broilers. HNa tended to increase FCR (P = 0.056) while the supplementation of Zn/Se-HNa significantly restored BW and ADG (P < 0.05). HNa and Zn/Se-HNa exhibit favorable and comparable effects in enhancing the levels of serum DAO, D-lactate, and mRNA and protein expression of jejunum and ileal tight junction. In comparison to HNa, Zn/Se-HNa demonstrates a greater reduction in S. Typhi shedding in feces, as well as superior efficacy in enhancing the intestinal morphology, increasing serum catalase (CAT) activity, inhibiting pro-inflammatory cytokines, and suppressing the activation of the NF-κB pathway. Collectively, Zn/Se-HNa was a more effective treatment than HNa to alleviate adverse impact of S. Typhi infection in broiler chickens.