Proteomic analysis of differential biological responses and fatty acid metabolism in slow-growing chickens fed dietary tuna oil directly or via glucose transporter-targeted nanoparticles

This study investigated the effects of tuna oil (PC) and tuna oil encapsulated in lipid nanoparticles (TNP) on metabolic pathways in thigh muscle of slow-growing chickens using proteomic analysis. Compared with the negative control (NC) diet containing 6% rice bran oil, the PC and TNP diets replaced half of the rice bran oil with tuna oil, thereby increasing dietary n-3 PUFAs and altering the n-6/n-3 ratio. Iliotibialis muscle samples were collected from slow-growing Korat chickens (n = 6 for each PC and TNP; n = 5 for NC). Fatty acid profiles were analyzed by gas chromatography-mass spectrometry following lipid extraction and methylation. Proteomics analysis was performed using polyacrylamide gel-based protein separation and nanoLC-MS/MS to identify and quantify differentially expressed proteins. Distinct biological responses were observed between dietary treatments. In the TNP group, energy metabolism shifted toward aerobic pathways, with increased β-oxidation and reduced reliance on alternative pathways, such as the creatine-phosphate system, to support the tricarboxylic acid cycle. In contrast, the PC group exhibited high lipid peroxidation and by-products, triggering robust antioxidant and detoxification responses, as well as membrane repair mechanisms. Although the TNP group also activated antioxidant defenses, the response was less pronounced and was accompanied by increased expression of proteins involved in vesicle trafficking. Lipid peroxidation in the PC group was associated with calcium influx to maintain calcium homeostasis and stabilize muscle contraction under oxidative stress. This was evidenced by the upregulation of proteins related to sarcoplasmic reticulum calcium pumps and muscle contraction stabilization. Conversely, the TNP group demonstrated adaptive responses to increased contractile activity with lower oxidative burden. Regarding immune function, the PC group showed stronger MHC-based immunosurveillance, reflecting heightened oxidative stress. Although immune responses were less pronounced in the TNP group, immune surveillance was maintained through selective protein expression. Overall, these findings demonstrate distinct cellular strategies in response to oxidative stress and immune challenges between PC and TNP treatments, highlighting the potential of lipid nanoparticle systems to optimize dietary lipid delivery in poultry.