Effects of dietary benzoic acid combined with cinnamon essential oil on growth performance, antioxidant capacity, immune function, and gut health in broiler, chickens with necrotic enteritis.

This study aims to investigate the efficacy and mechanism of action of a benzoic acid combined with cinnamon essential oil complex (SLLEO) in preventing and controlling necrotic enteritis (NE) in broiler chickens caused by Clostridium perfringens infection. A total of 300 one-day-old 817 broiler chickens were randomly divided into five groups, with six replicates per group and ten birds per replicate. The control group (CON) and challenge group (CP) were fed a basal diet; the low, medium, and high-dose benzoic acid combined with cinnamon essential oil groups (SLLEO-L, SLLEO-M, SLLEO-H) were fed basal feed supplemented with 0.1%, 0.2%, and 0.3% benzoic acid combined with cinnamon essential oil, respectively. The animal experiment lasted 35 days. Results indicate that supplementing feed with benzoic acid combined with cinnamon essential oil (SLLEO) effectively mitigates the adverse effects of NE infection on broiler chickens. Compared to the Clostridium perfringens infection model, SLLEO significantly increased the average daily weight gain of infected chickens while reducing abnormally elevated liver and bursa of Fabricius indices (P < 0.05). SLLEO elevated total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity in plasma, liver, and jejunal mucosa while decreasing malondialdehyde (MDA) content (P < 0.05). Significantly increased plasma immunoglobulin A (IgA) levels, markedly elevated the villus height-to-crypt depth ratio (VH/CD), and reduced intestinal lesion scores (P < 0.05). Additionally, SLLEO downregulated mRNA expression of the proinflammatory factor TNF-α in the jejunum while upregulating the expression of the anti-inflammatory factor IL-10 and tight junction proteins ZO-1, Occludin, Claudin-1, and mucin MUC-2 (P < 0.05).In summary, dietary supplementation with SLLEO effectively mitigated growth performance decline in broilers caused by Clostridium perfringens infection, improved antioxidant function, alleviated immune organ hypertrophy, regulated plasma immunoglobulin levels, restored intestinal morphology, downregulated pro-inflammatory factors while upregulating anti-inflammatory factors, and enhanced intestinal barrier function by increasing tight junction protein and mucin gene expression.