The Effect of Various Inclusion Levels of β-Mannanase on Nutrient Digestibility in Diets Consisting of Corn, Soybean Meal and Palm Kernel Expellers Fed to Growing Pigs

An experiment was conducted to determine the effects of various inclusion levels of I²-mannanase on the energy and mannan digestibility in diets containing corn, Soybean Meal (SBM) and Palm Kernel Expellers (PKE) fed to growing pigs. The PKE contained 92.6% dry matter, 4,417 kcal gross energy kg-1, 4.02% ash and 31.3% mannan on an as-fed basis. Six barrows with an initial body weight of 41.4±1.7 kg were individually housed in metabolism crates equipped with a feeder and a nipple drinker. Pigs were randomly allotted to a 6A—6 Latin square design with 6 dietary treatments and 6 periods. An experimental period consisted of a 4-d adaptation period and a 5-d collection period. Pigs were fed corn-SBM-based diets containing 15% PKE with 0, 400, 800, 1,600, 2,400 or 3,200 U kg-1 of I²-mannanase. A chromic oxide was added as an indigestible marker for fecal collection according to a marker-to-marker procedure. Urine was also collected from each period. Each of the 6 diets contained 3.60, 3.91, 4.06, 2.57, 3.57 and 2.59% of mannan, respectively. No linear and quadratic effects of I²-mannanase supplementation on apparent total tract digestibility of energy were observed. The digestibility of mannan was also not affected by the increasing level of I²-mannanase supplementation. In conclusion, exogenous I²-mannanase did not affect the energy and mannan digestibility in corn-SBM-based diets containing 15% of PKE fed to growing pigs.