Dietary guanidinoacetic acid supplementation improved carcass characteristics, meat quality and muscle fibre traits in growing-finishing gilts.

This study was designed to evaluate the effects of guanidinoacetic acid (GAA) on growth performance, carcass characteristics, meat and muscle fibre traits of growing-finishing gilts. 300 female PIC pigs were randomly divided (30.10 ± 2.94 kg) into 2 treatments with 6 replicates of 25 each for a 100-day trial. Two dietary treatments were comprised of a control diet and a control diet fortified with 450 mg/kg GAA. Growth performance was evaluated for each phase. Carcass characteristics and meat quality were determined at last phase. Gilts had free access to feed and water during the experiment. The result indicated that GAA did not affect growth performance (p > 0.05). GAA not only increased longissimus dorsi (LM) muscle weight but also decreased its shear force, b*value and drip loss (p < 0.05). Mandibular fat index was decreased by GAA (p < 0.05). GAA upregulated myosin heavy chain (MyHC) I mRNA expression with lower myofibre cross-sectional area and fibre diameter in LM muscle (p < .05). In conclusion, GAA can improve carcass characteristics and meat quality by changing muscle fibre characteristics and reducing mandibular fat index in finishing gilts.