2.3. Sample collection
Each period consisted of 5 d of adaptation to the diets followed by 2 d of ileal digesta collection. Ileal digesta collection
was initiated at 0800 and ceased at 1600 h each day. For collection of samples, a plastic bag of 232 ml was attached to the
cannula barrel using a cable tie. Bags were removed when they were filled or every 30 min and stored at −20 ◦C to prevent
bacterial degradation of AA.