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

Abstract 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 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.