In growing pigs, the true ileal and total tract digestibility of acid hydrolyzed ether extract in extracted corn oil is greater than in intact sources of corn oil or soybean oil1

Abstract

An experiment was conducted to determine the true ileal digestibility (TID) and the true total tract digestibility (TTTD) of acid-hydrolyzed ether extract (AEE) in extracted corn oil, high-oil corn, distillers dried grains with solubles (DDGS), corn germ, and high protein distillers dried grains (HP DDG) and to compare these values to the TID and TTTD of AEE in full-fat soybeans. Nineteen barrows with an initial BW of 52.2 kg (SD = 3.8) were fitted with a T-cannula in the distal ileum and allotted to a 19 × 11 Youden square design with 19 diets and 11 periods. A basal diet based on cornstarch, casein, sucrose, and corn bran was formulated. Eighteen additional diets were formulated by adding 3 levels of extracted corn oil, high-oil corn, DDGS, corn germ, HP DDG, or full-fat soybeans to the basal diet. The apparent ileal and the apparent total tract digestibility of AEE were calculated for each diet. The endogenous flow of AEE associated with each ingredient and values for TID and TTTD were calculated using the regression procedure. Results indicated that digested AEE in ileal digesta and feces linearly increased as AEE intake increased regardless of ingredient (P < 0.001) and the regression of ileal and fecal AEE output against AEE intake was significant for all ingredients (P < 0.001; r(2) > 0.77). However, the ileal and fecal endogenous losses of AEE were different (P < 0.05) from 0 only for extracted corn oil, HP DDG, and full-fat soybeans. The TID of AEE was greater (P < 0.05) for extracted corn oil (95.4%) than for all other ingredients. The TID of AEE in HP DDG (76.5%) was not different from the TID of AEE in full-fat soybeans (85.2%) but greater (P < 0.05) than high-oil corn, DDGS, and corn germ (53.0, 62.1, and 50.1%, respectively). The TTTD of AEE was greater (P < 0.05) for extracted corn oil (94.3%) than for all other ingredients, and the TTTD in full-fat soybeans (79.7%) was greater (P < 0.05) than the TTTD of AEE in high-oil corn, DDGS, corn germ, and HP DDG (41.4, 51.9, 43.9, and 70.2%, respectively). The TTTD of AEE in HP DDG was also greater (P < 0.05) than in high-oil corn, DDGS, and corn germ. In conclusion, the intact sources of oil originating from high-oil corn, DDGS, corn germ, or HP DDG are much less digestible than extracted corn oil, and with the exception of HP DDG, these sources of corn oil are also less digestible than the intact oil in full fat soybeans.