Innovative unified impact of magnetite iron nanoparticles and quercetin on broiler chickens: performance, antioxidant and immune defense and controlling of Clostridium perfringens infection

Necrotic enteritis caused by <i>Clostridium perfringens</i> (<i>C. perfringens</i>) is characterized by poor performance and higher mortality rates in poultry farms. Novel dietary intervention involving bioactive molecules loaded into smart magnetized nano-system with a potent antioxidant function (quercetin-loaded Fe₃O₄-NPs), was evaluated for their impact on growth performance, intestinal immune and antioxidant defenses, and resistance against <i>Clostridium perfringens</i> in a necrotic enteritis challenge model. Four experimental groups comprising a total of 200 one-day-old Ross 308 broiler chickens were fed different diets: a control basal diet, a diet supplemented with quercetin (300 mg/kg), a diet with Fe₃O₄-NPs (60 mg/kg), and a diet with quercetin-loaded Fe₃O₄-NPs (300 mg/kg). These groups were then challenged with <i>C. perfringens</i> during the grower period. Dietary inclusion of quercetin-loaded Fe₃O₄-NPs prominently reduced <i>C. perfringens</i> colonization and its associated virulence genes expression, which subsequently restored the impaired growth performance and intestinal histopathological changes in challenged broilers. Quercetin-loaded Fe₃O₄-NPs supplemented group displayed higher <i>Lactobacillus</i> and <i>Bifidobacterium</i> counts, upregulation of intestinal host defense antimicrobial peptides related genes (avian <i>β</i>-defensin 6 and 12) and downregulation of intestinal inflammatory regulated genes (Interleukin-1 beta, C-X-C motif chemokine ligand 8, tumor necrosis factor-<i>α</i>, chemokine C-C motif ligand 20, inducible nitric oxide synthase and cycloox-ygenase-2). Intestinal redox balance was boosted via upregulation of catalase, superoxide dismutase, glutathione peroxidase and heme Oxygenase 1 genes along with simultaneous decrease in hydrogen peroxide_, reactive oxygen species and malondialdehyde contents in groups fed quercetin-loaded Fe₃O₄-NPs. Overall, new nutritional intervention with quercetin-loaded Fe₃O₄-NPs impacted better immune and antioxidant defenses, attenuated <i>C. perfringens</i> induced necrotic enteritis and contributed to better performance in the challenged birds.