165 Digestibility of energy and dietary fiber by growing pigs and concentrations of digestible and metabolizable energy in corn- or sorghum-based diets without or with microbial enzymes

Abstract

Abstract An experiment was conducted to test the hypothesis that inclusion of an enzyme premix (xylanase and cellulase) in diets based on corn or sorghum and fed to growing pigs improves the apparent total tract digestibility (ATTD) of energy and total dietary fiber (TDF) and concentration of digestible energy (DE) and metabolizable energy (ME). Two basal diets based on corn and soybean meal or sorghum and soybean meal were formulated. Four additional diets were formulated by adding 40% distillers dried grains with solubles (DDGS) or 40% wheat middlings to each of the 2 basal diets. Each of these 6 diets were formulated either without or with an enzyme premix that contained xylanase and cellulase. A total of 144 pigs (61.7 ± 5.3 kg) were allotted to a randomized complete block design with 12 diets and 12 replicate pigs per diet. Pigs were housed individually and adapted to the diets for 12-d, then moved to metabolism crates and after 4 d, urine and feces were collected for 5 d. Data were analyzed as 2 × 2 × 3 factorial with 2 types of diets, two enzymes treatments, and three by-product inclusions. The pig was the experimental unit. The ATTD of gross energy (GE), and DE and ME improved (P < 0.01) if enzymes were added to the diets regardless of the grain source or by-product inclusion (Table 1). No effect of enzymes on ATTD of TDF was observed, ATTD of TDF was greater if DDGS rather than wheat middlings was added to the corn diet (grain source × by-product interaction, P < 0.05). In conclusion, addition of enzymes may have the potential to improve the ATTD of GE, and DE and ME in mixed diets based on corn or sorghum and both without and with inclusion of DDGS or wheat middlings. 3Enz = enzyme premix supplied by ADM Animal Nutrition, Quincy, IL, USA.