Effects of Aspergillus oryzae prebiotic on dietary energy and nutrient digestibility of growing pigs

The objective of this study was to determine the effects of Aspergillus oryzae prebiotic (AOP) on nutrient digestibility in growing pigs fed high-fiber diets. Eighteen growing barrows (initial body weight = 50.6 ± 4.9 kg) were surgically equipped with a T-cannula at the distal ileum. Corn and soybean meal-based diets were formulated with fiber from cereal grain byproducts corn (distillers dried grains with solubles, DDGS), rice (rice bran, RB), or wheat (wheat middlings, WM) to meet or exceed all nutrient requirements for 50 to 75 kg growing pigs. Three additional diets were formulated to contain 0.05% AOP supplemented at the expense of corn in the DDGS diet (DDGS + AOP), RB diet (RB + AOP), and WM diet (WM + AOP). All diets contained 0.5% of titanium dioxide as an indigestible marker. Pigs were allotted randomly to a triplicated 6 × 2 Youden square design with six diets and two successive periods. Ileal digesta and fecal samples were collected for 2 d after a 21-d adaptation period, and dry matter (DM), gross energy (GE), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), and ash were analyzed to calculate apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD). Standardized ileal digestibility (SID) of amino acids (AA) was calculated by correcting AID with basal endogenous AA losses from the same set of pigs. Pigs fed the DDGS+AOP diet had greater (P < 0.05) AID of EE compared with those fed the DDGS diet. However, supplementation of AOP did not (P > 0.05) affect AID of GE, DM, CP, NDF, ash or SID of AA of any high-fiber diet. Supplementation of 0.05% AOP increased (P < 0.05) ATTD of DM, GE, CP, NDF, and ash in DDGS, RB, and WM diets. Diet digestible energy was 35 kcal/kg greater (P < 0.05) in pigs fed AOP supplemented diets compared with those fed diets without AOP. In conclusion, supplementation of AOP increased ATTD of nutrients and energy value in high-fiber diets containing DDGS, RB, or WM.