Effect of body weight on ileal endogenous nitrogen and amino acid loss in PVTC-cannulated pigs

Six castrated male pigs were fitted with post-valve caecal T cannulas (PVTC) and used to determine the endogenous ileal flow of nitrogen (ILE(N)) and amino acids (ILE(AA)) in pigs at 25.9 kg (SD 1.5) and 93.2 kg (SD 6.4) body weight (BW). Pigs were fed a nutritionally balanced purified casein-based diet twice daily. The ILE(N) (g N kg(-1) DM intake) was higher (P = 0.03) at low BW (1.41 vs. 0.86). The ILE(AA) g kg(-1) DM intake) for all essential and non-essential AA was higher (P<0.05) at the low BW. Despite BW effects on absolute ILE(AA) the relative proportion (g 16 g N(-1)) of individual AA in ileal digesta was similar at both BW's. The data indicates that the ILE(N) used to calculate standardized ileal digestibility (SID) values has to be adjusted for BW, while the relative proportions of individual AA could be kept constant. (C) 2010 Elsevier B.V. All rights reserved.