Amino acid release patterns of growing pig diets formulated with different dietary protein sources

Abstract

This study elucidated the dynamics of AA release in low-protein growing pig diets formulated with different protein sources. Four protein sources including soybean meal (SM), corn gluten meal (CGM), fish meal (FM) and fermented soybean meal (FSM) were used to formulate growing pig diets and subjected to in vitro digestion for 4, 8, 12, 16, 20, 24, and 28 h at 39°C. The AA contents were measured by ultra-high performance liquid chromatography (UPLC). FSM group recorded the highest AA release rate at 4-12 h digestion while the CGM group recorded the lowest at 8-20 h digestion (p < 0.05). AA release in the SM group was significantly higher than that in the FM group at 8, 12 and 20 h digestion (p < 0.05). Lysine, methionine and phenylalanine contents in the dietary groups showed significant variations within the first 8 h of digestion due to synthetic AA supplementation. However, after 8 h, the essential AA (EAA) release rate in the FSM group was consistently higher while those in the CGM group were consistently lower (p < 0.05). Based on the results, the AA release patterns of diets can be effectively regulated to meet animal demand by adjusting the structure of the dietary protein source.

Keywords

• essential amino acids
• free amino acids
• low-protein diets
• release patterns
• synthetic amino acids