Combination of phytase and β-mannanase supplementation on energy and nutrient digestibility in pig diets containing palm kernel expellers

The present study was conducted to investigate the effects of supplemental phytase and β-mannanase on apparent total tract digestibility (ATTD) of nutrients in corn-soybean meal-based diets containing 100. g/kg palm kernel expellers (PKE) fed to two different breeds of growing pigs. Four purebred Duroc boars and four crossbred barrows with an initial body weight of 74.7. kg (standard deviation =12.4) were randomly allotted to each single 4×4 Latin square design with four diets and our periods. Four experimental diets were prepared in a 2×2 factorial arrangement with two supplemental levels of phytase at 0 or 500 phytase units/kg and two supplemental levels of β-mannanase at 0 or 800. units/kg. All diets were based on corn, soybean meal, and PKE without inorganic P sources. Each period consisted of 4-d adaptation period and 4. d of total collection of feces. There was no phytase×β-mannanase interaction for the digestibility of nutrients and energy. Phytase supplementation improved the ATTD of P and ash (P<0.05), while β-mannanase had no effect on the ATTD of nutrients in the experimental diets. Purebred Duroc boars had higher ATTD of Ca, P, and ash than crossbred barrows (P<0.01). The metabolizable energy:gross energy was higher in the purebred Duroc boars compared with the crossbred barrows, but digestible energy:gross energy did not differ between the two breeds. The combination of phytase and β-mannanase supplementation to diets containing PKE did not have any interactive effects on ATTD of nutrients and energy in growing pigs.