Nitrogen balance of pigs as affected by feedstuffs causing different endogenous nitrogen flow at the terminal ileum

Abstract

The effect of ileal endogenous nitrogen (N) flow on N balance in pigs was investigated. In two experiments pigs (BW 12 to 24 kg) were fed a maize starch-based diet containing either wheat gluten (WG), peas, or rapeseed meal (RSM). In Experiment 1, apparent ileal N digestibility was measured with 12 ileal cannulated pigs. Amount of ileal endogenous N was measured in six of these pigs with the 15 N-isotope dilution technique. Apparent and true ileal N digestibilities were 91.4 and 98.6 for the WG diet, 80.5 and 95.6 for the pea diet, 67.2 and 80.1% for the RSM diet, respectively. Significant differences ( P < 0.05) were observed in ileal flows of dietary N, endogenous N, and DM. In Experiment 2, thirty pigs were used to study N balance. Diets were balanced for the contents of apparent ileal digestible (ID) CP (10.8%) and ID essential amino acids. Faecal N digestibility decreased from 92.9 to 82.1 and 72.4% in the WG, pea and RSM diets, respectively, corresponding to increased urinary N excretion and decreased N retention. The efficiencies of ID CP utilization were 83.5, 79.7 and 75.0%, respectively. The study showed that pigs fed diets with an increased flow of endogenous ileal N concomitant increase in excretion of urinary N. Nitrogen retention and utilization of ileal digestible N in those pigs were also decreased.