Different Fatty Acid Supplementation in Low-Protein Diets Regulate Nutrient Utilization and Lipid and Amino Acid Metabolism in Weaned Pigs Model

This study was conducted to evaluate the effects of a low-protein (LP) diet supplemented with sodium butyrate (SB), medium-chain fatty acids (MCFAs) and n-3 polyunsaturated fatty acids (PUFAs) on nutrient utilization and lipid and amino acid metabolism in weaned pigs. A total of 120 Duroc x Landrace x Yorkshire pigs (initial body weight: 7.93 +/- 0.65 kg) were randomly assigned to five dietary treatments, including the control diet (CON), LP diet, LP + 0.2% SB diet (LP + SB), LP + 0.2% MCFA diet (LP + MCFA) and LP + 0.2% n-3 PUFA diet (LP + PUFA). The results show that the LP + MCFA diet increased (p < 0.05) the digestibility of dry matter and total P in pigs compared with the CON and LP diets. In the liver of the pigs, the metabolites involved in sugar metabolism and oxidative phosphorylation significantly changed with the LP diet compared with the CON diet. Compared with the LP diet, the altered metabolites in the liver of the pigs fed with the LP + SB diet were mainly associated with sugar metabolism and pyrimidine metabolism; the altered metabolites in the liver of pigs fed with the LP + MCFA and LP + PUFA diets were mainly associated with lipid metabolism and amino acid metabolism. In addition, the LP + PUFA diet increased (p < 0.05) the concentration of glutamate dehydrogenase in the liver of pigs compared with the LP diet. Furthermore, the LP + MCFA and LP + PUFA diets increased (p < 0.05) the mRNA abundance of sterol regulatory element-binding protein 1 and acetyl-CoA carboxylase in the liver compared with the CON diet. The LP + PUFA diet increased (p < 0.05) mRNA abundances of fatty acid synthase in the liver compared with the CON and LP diets. Collectively, the LP diet supplemented with MCFAs improved nutrient digestibility, and the LP diet supplemented with MCFAs and n-3 PUFAs promoted lipid and amino acid metabolisms.

Automated summary

This study evaluated the effects of a low-protein diet supplemented with sodium butyrate, medium-chain fatty acids, and n-3 polyunsaturated fatty acids on nutrient utilization and lipid and amino acid metabolism in weaned pigs. The results showed that the supplementation of medium-chain fatty acids improved the digestibility of dry matter and total phosphorus in pigs. The metabolites related to sugar metabolism and oxidative phosphorylation in the liver significantly changed with the low-protein diet. The supplementation of sodium butyrate, medium-chain fatty acids, and n-3 polyunsaturated fatty acids altered the metabolites associated with sugar metabolism, pyrimidine metabolism, lipid metabolism, and amino acid metabolism in the liver of pigs. Furthermore, the supplementation of n-3 polyunsaturated fatty acids increased the concentration of glutamate dehydrogenase and the mRNA abundances of sterol regulatory element-binding protein 1, acetyl-CoA carboxylase, and fatty acid synthase in the liver. Overall, the low-protein diet supplemented with medium-chain fatty acids improved nutrient digestibility, and the supplementation of medium-chain fatty acids and n-3 polyunsaturated fatty acids promoted lipid and amino acid metabolisms.