Enhancement of Growth Performance and Health Status in Heat-Stressed Growing Rabbits Using Alpha-Lipoic Acid-Loaded Chitosan Nanoparticles.

Objective: This study is the first to study the effect of Alpha-lipoic acid-loaded chitosan nanoparticles (ALA-CHNPs) on growth performance, feed utilization, and health in heat-stressed growing rabbits.

Methods: A total of one hundred healthy 5-week-old rabbits were randomly divided into four groups of 25, each receiving diets supplemented with 0, 100, 200, or 400 mg ALA-CHNPs per kilogram.

Results: The dietary supplementation significantly improved growth performance, feed conversion ratio, physiological responses, liver weight, and dressing percentage. Supplementation with ALA-CHNPs resulted in a linear reduction in liver enzymes activities, as well as in the levels of total bilirubin, hydrogen peroxide, glutathione, catalase, superoxide dismutase, immunoglobulin G, lysozyme activity, interleukin-6 and -10. No significant differences were observed between the ALA-CHNPs200 and ALA-CHNPs400 groups (p>0.05).The levels of blood serum total protein, albumin, globulin, total antioxidant capacity, glutathione peroxidase activity, immunoglobulin A and M, and nitric oxide showed a quadratic increase, peaking at ALA-CHNPs doses ranging from 250-300 mg/kg diet. Conversely, the concentrations of triglycerides, cholesterol, glucose, malondialdehyde, interferon-gamma, tumor necrosis factor-alpha, and nuclear factor kappa B exhibited a quadratic decrease, with optimal reductions occurring at doses between 250-300 mg/kg diet. Supplementation with ALA-CHNPs reduced liver damage caused by heat stress, restoring normal hepatic morphology. The hydrophobic interactions of ALA with antioxidant enzymes and cytokines helped mitigate heat stress-induced oxidative stress.

Conclusion: adding 250-300 mg ALA-CHNPs/kg diet enhanced growth performance, redox balance, immune function, and inflammatory response in fattened rabbits raised during the summer.