Evaluating the effects of adaptation length, dietary electrolyte balance, and energy source on ileal endogenous amino acid losses in pigs fed nitrogen-free diets

Sixteen cannulated pigs were used to evaluate the effect of dietary electrolyte balance (DEB, low vs. high), energy source (cornstarch vs. dextrose), and adaptation length (3–4 or 6–7 d) to the diets on basal ileal endogenous amino acid (EAA) losses in pigs fed nitrogen-free diets (NFD) in a randomized complete block design with a 2 × 2 × 2 factorial arrangement of treatments. Each of the two phases lasted 7 d with a 12 h digesta collection on days 3, 4, 6, and 7. Pigs received a daily feed allowance of 4% of their body weight. There was no significant three-way interaction. Longer adaptation length increased (P < 0.05) ileal endogenous losses of N, arginine (Arg), glycine (Gly), proline (Pro), and total amino acid (AA). Dextrose-based NFD resulted in higher (P < 0.05) ileal dry matter digestibility and EAA losses (13 of 18 AAs) compared with pigs fed cornstarch-based NFD. High DEB resulted in a decrease (P < 0.05) in endogenous threonine, cysteine, Gly, and serine losses. The two-way interaction between energy source and DEB was significant for N, total AA, and five AAs with a combination of dextrose and low DEB resulting in higher (P < 0.05) losses. Results from this study show that NFD could be fed for a shorter period of time (3–4 d) with results that are comparable to a 7 d adaptation period except for N, Arg, Gly, and Pro.