Combined effects of fenugreek-milk thistle-ginkgo and thyme-cinnamon-oregano feed additives on physicochemical and oxidative stability profiles of broiler meat.

Chicken breast meat is susceptible to lipid and protein oxidation during post-mortem processing and storage, which adversely affects its physicochemical properties, nutritional value, and market acceptability. Most existing research has concentrated on single-component plant extracts as feed additives, whereas the combined effects of multi-plant additives remain insufficiently characterized. This study evaluated the effects of two composite plant-derived feed additives (Group A: Trigonella foenum-graecum, Silybum marianum, and Ginkgo biloba; Group K: Thymus vulgaris, Cinnamomum verum, and Origanum vulgare) and their combined supplementation (Group A+K) on the quality and oxidative stability of broiler breast meat, with particular emphasis on myofibrillar protein (MP) structure and water dynamics. A total of 32,000 one-day-old Ross 308 broilers were assigned to four dietary treatments (control, A, K, and A+K) and fed for 35 d. The analyzed indicators included shear force, texture profile, water-holding capacity (WHC), MP secondary structure, oxidative markers (carbonyl and thiol contents), surface hydrophobicity, solubility, particle size, and water distribution. Group A showed the greatest tenderization response, with an approximately 50% reduction in shear force compared with the control (P < 0.05). The A+K group showed enhanced combined responses, including a 9% increase in WHC and an 8.02% decrease in carbonyl content compared with the control (P < 0.05). All treatment groups exhibited an increased MP alpha-helix proportion, reduced surface hydrophobicity and particle size, and improved solubility (P < 0.05). The A+K group also improved adhesiveness and cohesiveness. LF-NMR analysis indicated that the dietary treatments promoted a shift from free water toward immobilized water, which was associated with improved WHC. Overall, these composite plant-derived additives, especially the A+K combination, may regulate broiler meat quality through multiple targets by attenuating protein oxidation, maintaining MP structural stability, and optimizing water distribution. These findings provide a practical basis for developing plant-derived feed formulations for high-quality and oxidatively stable broiler meat.