Skeletal muscles respond differently when piglets are offered a diet 30 % deficient in total sulfur amino acid for 10 days
Résumé
[b][i]Purpose[/i][/b]. Although amino acids (AA) are required for growth, little is known about the effect of a deficient AA supply on the composition and the contractile and metabolic properties of skeletal muscles.[br/]
[b][i]Methods[/i][/b]. Protein metabolism, oxidative catabolism, glutathione system, and fiber-type composition of the longissimus (LM), rhomboideus (RM), and semitendinous (SM) muscles were compared between 42-day-old piglets pair-fed for 10 days either with a diet with a 28 % deficient supply of total sulfur AA (TSAA-) or with a diet with a sufficient supply of total sulfur AA (TSAA+).[br/]
[b][i]Results[/i][/b]. The relative weight, protein mass, and protein synthesis of LM were 10-32 % lower in TSAA- pigs compared with TSAA+ pigs, while RM and SM were not affected by the TSAA supply. The TSAA supply affected the AA composition of muscles. Concentrations of Met and branched-chain AA were, respectively, 7 and 3 % lower in TSAA- pigs compared with TSAA+ pigs. The His concentration was 30 % higher in LM and SM in TSAA- pigs compared with TSAA+ pigs and unaffected in RM. The activity of citrate synthase was 14 % higher in all three muscles of TSAA- pigs. In these pigs, the β-hydroxy-acyl-CoA dehydrogenase activity was 20 % higher in RM compared with TSAA+ pigs while that of lactate dehydrogenase was 21 % lower in LM. Total and reduced glutathione concentrations were more than 70 % greater in RM than in LM or SM, and these concentrations were approximately 10 % lower in TSAA- pigs than in TSAA+ pigs.[br/]
[b][i]Conclusions[/i][/b]. Results of this study indicate that a TSAA deficiency affects muscle properties in a muscle-dependent manner increasing the oxidative capacity of RM and reducing growth and glycolytic metabolism of LM.