Effect of dietary beta-alanine supplementation on growth performance, meat quality, carnosine content, and gene expression of carnosine-related enzymes in broilers

The objective of the current study was to investigate the effect of dietary beta-alanine supplementation on growth performance, meat quality, antioxidant ability, carnosine content, and gene expression of carnosine-related enzymes in broiler chicks. We randomly assigned 540 1-day-old Arbor Acres broilers to 5 dietary treatments supplemented with 0 (control group), 250, 500, 1,000, or 2,000 mg/kg of beta-alanine (mg beta-alanine per kg feed). Each treatment included 6 replicates of 18 birds. The feeding trial lasted for 42 d. Dietary beta-alanine supplementation linearly and quadratically increased the average daily gain (ADG) during the starting period (d 1 to 21, P = 0.02 and P = 0.002). The feed conversion ratio (FCR) decreased quadratically in response to dietary beta-alanine supplementation during the starting and entire periods (P < 0.001 and P = 0.003, respectively). For the entire period, the predicted best FCR would be achieved when beta-alanine was fed at a level of 1,100 mg/kg from quadratic regression. The concentrations of carnosine and beta-alanine in breast muscle increased quadrati-cally with dietary beta-alanine supplementation (d 42, P < 0.001 and P = 0.001, respectively). The predicted dietary beta-alanine level for highest breast carnosine content was 1,196 mg/kg. Dietary supplementation with beta-alanine reduced the taurine concentrations in plasma (d 42, linear and quadratic, P < 0.001). Breast muscle yield increased linearly and quadratically in response to dietary beta-alanine addition (d 21, P = 0.017 and P = 0.007). Dietary supplementation with beta-alanine quadratically reduced the shear force (P = 0.003), whereas a*(45 min) and a*(24 h) values increased quadratically in response to dietary beta-alanine supplementation (d 42, P = 0.020 and P = 0.021, respectively). Dietary beta-alanine addition quadratically enhanced the expression of carnosine synthase and taurine transporter mRNAs (P < 0.05). Overall, dietary beta-alanine supplementation improved growth performance and carnosine content, ameliorated antioxidant capacity and meat quality, and upregulated the gene expression of carnosine synthesis-related enzymes in broiler chicks.