Dietary chitosan modulates immune-related gene expression and improves biochemical parameters and intestinal morphology in broilers

Introduction One of the benefits of chitosan for broilers is positive effects on growth performance, intestinal morphology and gene expression profiling. Therefore, the aim of the study was to evaluate the effects of dietary chitosan on growth performance, morphology and gene expression profiling of broiler chickens. Materials and methods A total of 250 one-day-old broilers chicken were allocated to five experimental groups including, Commercial corn-soybean meal basal diet (control group: CON), basal diet + 250 mg/kg commercial chitosan, basal diet + 100 mg/kg local chitosan, basal diet + 250 mg/kg local chitosan, basal diet + 400 mg/kg local chitosan for a 42-day rearing period. Results Chitosan supplementation numerically improved growth performance and feed conversion ratio ( p > 0.05) but significantly reduced serum cholesterol and triglyceride levels at day 42 ( p < 0.05). In the duodenum, crypt depth decreased and villus height-to-crypt depth ratio increased in chitosan-fed birds. In the jejunum, no significant differences were detected among the CON, Local 100, and Commercial 250 groups, and that the only significant effect was a reduction in the Local 250 group ( p = 0.01). Additionally, 100 mg/kg local chitosan increased bacterial population ( p < 0.05). Gene expression analysis revealed that mRNA levels of TLR2, IL6, IL8, STAR, Cytochrome P450, TLR4, IFN, TNFα, NFƙβ, BAX and BCL2 genes were increased by adding chitosan to diet. The PPI network analysis demonstrated that NFƙβ acts as a central hub, interacting with TLR2, TLR4, IL6, TNFα, and IL1B indicating activation of canonical TLR/NFƙβ signaling pathway. Conclusion Dietary chitosan supplementation significantly reduced serum cholesterol and triglyceride levels, improved duodenal morphology, and modulated the expression of selected immune-related genes in broilers. Iranian ChitoLife chitosan may warrant further investigation as a potential lower-dose alternative to commercial chitosan for enhancing immune responses in broilers.