The effect of dietary fat content on amino acid digestibility in young pigs

Studies were carried out with 12 pigs (Yorkshire x Landrace) to determine the effect of dietary fat content on amino acid digestibility. The pigs were weaned at 21 d of age and fitted with a simple T-cannula at the distal ileum at 27 or 28 d of age. After a 7-d recuperation period, the pigs were fed one of four isonitrogenous cornstarch-based soybean meal diets (22.5% CP) containing 3.2, 6.2, 9.2, or 12.2% canola oil according to a balanced two-period change-over design. The pigs were fed four times daily, equal amounts, at 6-h intervals. The diets were supplied at a rate of 5% of the average body weight that was determined at the initiation of the first (11.0 kg) and second (12.5 kg) experimental period. Each experimental period consisted of 10 d. Feces were collected for 48 h on d 6 and 7 and ileal digesta for 24 h during d 8, 9, and 10. Chromic oxide was used as digestibility marker. The apparent ileal digestibilities of most of the amino acids increased linearly (P < .05) with increasing dietary fat levels. There were differences (P < .05) in the ileal digestibilities of most of the amino acids between the diets containing 3.2 and 12.2% canola oil. Conversely, the dietary level of inclusion of canola oil did not affect (P > .05) the fecal amino acid digestibilities. The protein-sparing effect of additional canola oil inclusion results, in part, from an increase in ileal amino acid digestibility.