Comparative Study on Arginine Metabolism in Different Breeds of Suckling Piglets

Chinese indigenous pig breeds have significantly different growth rate than foreign breeds. Considering the important role of arginine in growth and development of piglet, twelve 14-day-old suckling piglets (6males and 6females) from six breeds, including Ningxiang pig, Xiangxi black pig, Lantang pig, Bama mini-pig, Huanjiang mini-pig and Landrace pig were used, respectively, in the present study. The blood was sampled via precava and the serum was collected after centrifuge in order to analyze the free arginine and nitric oxide (NO). The tissues of intestine, muscle, liver and kidney were sampled to determine the concentration of free arginine and activity of NO synthetase (NOS), as well as the mRNA expression level of N-acetylglutamate synthetase (NAGS, rate-limiting enzyme in endogenous arginine synthesis). The results showed that the serum concentrations of free arginine (P<0.05) and NO (P＞0.05) in Landrance pig were higher than those in indigenous breeds of pig; the activities of NOS were significantly higher in proximal jejunum than in liver; the NOS activity of proximal jejunum in Landrance pig was lower than that of Ningxiang pig, and of liver were higher than that of Ningxiang pig; NAGS mRNA were ubiquitously distributed in all tissues tested, and centralized in intestine and liver. This study presented the serum concentrations of arginine and NO, free arginine content and NOS activity in three major tissues, and expression profiles of NAGS mRNA in twelve tissues in six breeds of suckling piglets, which provided some nutritional and biochemical knowledge for explaining the various phenotype of different breeds of pig.