The effect of feed intake on ileal rate of passage and apparent amino acid digestibility determined with or without correction factors in pigs

The apparent ileal digestibilities of amino acids and rate of passage were evaluated in pigs (BW = 78.3 +/- 7.4 kg) fed a semipurified diet. The pigs were fed 1.82, 2.73, or 3.65 kg DMI/d. The highest level of feed intake was considered to be ad libitum feeding. The pigs were fed according to a 3 x 3 Latin square design and were allowed to adapt to each experimental diet for 5 d. This was followed by 1 d of continuous collection of ileal digesta and a 2nd d of continuous collection separated into six 2-h postprandial time blocks. Ytterbium chloride hexahydrate was used to determine rate of passage. The ileal digestibilities of amino acids and rate of passage were unaffected (P > 0.05) by level of feed intake. The use of correction factors to more accurately express amino acid concentrations in the diet and digesta affected (P < 0.05) the apparent ileal digestibility coefficients of some amino acids.