Effects of dietary supplementation of guanidinoacetic acid and combination of guanidinoacetic acid and betaine on postmortem glycolysis and meat quality of finishing pigs

This work sought to evaluate the effects of guanidinoacetic acid (GAA) and combination of GAA and betaine on postmortem glycolysis and meat quality of finishing pigs. A total of 180 cross-bred, castrated male pigs were randomly assigned to one of three experimental diets (pigs were adapted to the control diet for 7 days and experimental diets were given for 15 days): a control (CON; basal diet consisting of a ground corn-soybean base), a GAA diet (GAA; basal diet supplemented with 1 g of GAA per kg of feed), and a combination diet (CGB; basal diet supplemented with 1 g of GAA and 0.5 g of betaine per kg of feed). Each treatment was replicated in three pens with 20 pigs each. Compared with the control group, GAA and CGB supplementation increased pH value at 45 min (pH(45min)) and 24h (pH(24h)) (P<0.05) and reduced drip loss (P<0.05), cooking loss (P<0.05) and shear force values (P<0.01) in longissimus dorsi. In addition, dietary GAA and CGB increased the content of creatine (P<0.01), phosphocreatine (P<0.01), adenosine triphosphate (P<0.01) and the activity of creatine kinase (P<0.05). Both GAA and CGB diets increased mRNA expression of creatine transporter in longissimus dorsi (P<0.01) and kidney (P<0.05). The mRNA expression of L-arginine:glycine amidinotransferase was decreased in both experimental groups (P<0.01). The GAA and CGB diets reduced the activity of hexokinase (P<0.01) and the content of lactic acid (P<0.05). These results indicated that the dietary supplementation with GAA and CGB could improve meat quality via regulating some aspects of energy metabolism which delays muscle glycolysis. (C) 2015 Elsevier B.V. All rights reserved.