Digestibility of threonine from protein concentrates for growing pigs. 1. The flow of endogenous amino acids to the terminal ileum of growing pigs

Abstract

Six pigs (25 kg initial weight) were fitted with T cannulas in the terminal ileum. Each pig was fed a nitrogen (N) free diet or one of eight diets containing increasing amounts of threonine from milk (four diets) or cottonseed meal (four diets). The flow of endogenous nitrogen from the terminal ileum was 1.1 g/kg dry matter DM intake in the pigs given the nitrogen-free diet and 0.9 g/kg DM intake when estimated by extrapolation in the pigs given the milk or cottonseed meal diet. There were no significant differences in the flow of individual endogenous amino acids from the terminal ileum when measured in pigs given a nitrogen-free diet or when extrapolated from data for pigs given diets containing milk or cottonseed meal. The flow of endogenous threonine from the terminal ileum was between 0.39 and 0.45 g/kg DM intake as estimated in pigs given diets with similar threonine intakes from cottonseed meal or milk and the nitrogen-free diet.