Digestible, Metabolizable, and Net Energy in Diets Containing 0, 15, or 30% Wheat Bran Fed to Growing Pigs
An experiment was conducted to determine the effects of including 0, 15, or 30% wheat bran in a corn-soybean meal based diet fed to growing pigs. Eighteen barrows (initial BW: 54.4 ± 4.3 kg) were individually housed in metabolism cages and randomly allotted to 1 of 3 dietary treatments in a completely randomized design. The experiment had 3 periods and 6 replicate pigs per diet. The control diet contained corn, soybean meal, and no wheat bran, and 2 additional diets were formulated by mixing 15 or 30% wheat bran with 85 or 70% of the control diet, respectively. Each period lasted 15 d. During the initial 7 d, pigs were adapted to their experimental diets and housed in metabolism crates in an environmentally controlled room and fed 573 kcal/kg BW0.6 per d. On d 8, metabolism crates with the pigs were moved into open-circuit respiration chambers for measurement of O2 consumption and CO2 and CH4 production. The feeding level was the same as in the adaptation period and feces and urine were also collected during this period. On d 13 and 14, pigs were fed 225 kcal/kg BW0.6 per d, and pigs were then fasted for 24 h to obtain fasting heat production. The apparent total tract digestibility of DM, GE, crude fiber, ADF, and NDF linearly decreased (P < 0.01) as wheat bran inclusion increased in the diets. The DE (3,454, 3,257, and 3,161 kcal/kg), ME (3,400, 3,209, and 3,091 kcal/kg), and NE (1,808, 1,575, and 1,458 kcal/kg) of diets linearly decreased (P < 0.01) as wheat bran inclusion increased. The daily O2 consumption and CO2 and CH4 production by pigs fed increasing concentrations of wheat bran linearly decreased (P < 0.01). However, there was no effect of wheat bran on daily heat production per kg BW0.6. In conclusion, increasing inclusion of wheat bran decreased DE, ME, and NE in diets, but did not change daily heat production if expressed as kg BW0.6.
Keywords: dietary fiber, energy concentration, heat production