Improving heat stress resilience in growing rabbits with rutin-loaded nano-phytosomes.

This study aimed to investigate the protective impacts of rutin-loaded nano-phytosomes (RU-PNPs) in alleviating the detrimental effects of heat stress (HS) on growing rabbits. A total of 100 male APRI rabbits (6 weeks old) were randomly assigned to four experimental groups and orally administered RU-PNPs at levels of 0 (RU-PNPs0), 25 (RU-PNPs25), 50 (RU-PNPs50), and 100 (RU-PNPs100) mg/head/day for eight consecutive weeks. The treatments significantly enhanced growth performance, feed utilization, dressing percentage and relative liver weight while effectively reducing rectal, ear, and skin temperatures. Oral administration of RU-PNPs (50–100 mg/head/day) significantly improved erythrocyte and leukocyte counts, increased blood protein, and reduced cholesterol, triglyceride, urea, and creatinine levels. Liver function was markedly enhanced by RU-PNPs treatment, with co-administration effectively restoring hepatic morphology to a near-normal state, mitigating the structural abnormalities induced by HS. RU-PNPs enhanced catalase, superoxide dismutase, and glutathione peroxidase activities while reducing malondialdehyde and hydrogen peroxide levels in heat-stressed rabbits. Additionally, immunoglobulin levels, nitric oxide, and pro inflammatory cytokines, including interferon-γ (IFN-γ), tumor necrosis factor (TNF-α), interleukin-4, interleukin-6, and nuclear factor kappa B (NF-κB) were significantly decreased in the RU-PNPs50 and RU-PNPs100-treated groups compared to the control (p < 0.05). The docking study showed that Rutin strongly binds to catalase (-10.14 kcal/mol) and interacts moderately with TNF-α (-7.61 kcal/mol), IFN-γ (-7.3 kcal/mol), and NF-κB (-6.36 kcal/mol). In conclusion, oral administration of RU-PNPs at doses ranging from 50 to 100 mg/head/day improved growth performance and health status of newly weaned rabbits during summer season.