Effects of dietary supplementation with carnosine on growth performance, meat quality, antioxidant capacity and muscle fiber characteristics in broiler chickens

BACKGROUND The effects of dietary carnosine were evaluated on the growth performance, meat quality, antioxidant capacity and muscle fiber characteristics in thigh muscle of 256 one‐day‐old male broilers assigned to four diets – basal diets supplemented with 0, 100, 200 or 400 mg kg−1 carnosine respectively – during a 42 day experiment. RESULTS Carnosine concentration and carnosine synthase expression in thigh muscle were linearly increased (P < 0.05) and the feed/gain ratio was decreased (P < 0.05) in the starter period by carnosine addition. Dietary supplementation with carnosine resulted in linear increases in pH45 min, redness and cohesiveness and decreases in drip loss, cooking loss, shear force and hardness (P < 0.05). Carnosine addition elevated the activities of antioxidant enzymes and reduced contents of malondialdehyde and carbonyl compounds (P < 0.05). Dietary carnosine linearly decreased diameters and increased densities of muscle fibers (P < 0.01). The ratios of myosin heavy chain (MyHC) I and IIa were increased while that of MyHC IIb was decreased (P < 0.01). The mRNA expressions of genes related to fiber type transformation were linearly up‐regulated (P < 0.05). CONCLUSION These findings indicated that carnosine supplementation was beneficial to improve the growth performance, meat quality, antioxidant capacity and muscle fiber characteristics of broilers.