Evaluation on Net Energy of Defatted Rice Bran from Different Origins and Processing Technologies Fed to Growing Pigs

The study was conducted to determine and compare the net energy (NE) of defatted rice bran (DFRB) from different sources and different processing technology fed to growing pigs using indirect calorimetry. Thirty-six growing barrows (30.7 ± 3.9 kg) were randomly allotted to 1 of 6 diets with 6 replicate pigs per diet. Diets included a corn-soybean meal basal diet and 5 test diets containing 30% DFRB, respectively. These five samples come from 4 different provinces (i.e., Heilongjiang, Jiangsu, Jilin, and Liaoning province within China) and two of them with the same origin but different processing technologies (i.e., extruded or pelleted). During each period, pigs were kept individually in metabolism crates for 21 days, including 14 days to adapt to the diets. On day 15, pigs were transferred to the open-circuit respiration chambers for adaptation, and the next day were ready to determine daily total heat production (HP) and were fed 1 of the 6 diets at 2.3 MJ metabolizable energy (ME)/kg body weight (BW)^0.6/day. Total feces and urine were collected for the determination of digestible energy (DE) and ME and daily total HP was measured from day 16 to day 20 and fasted on day 21 for the measurement of fasting heat production (FHP). The NE contents of extruded DFRB from different provinces were within the range of values (8.24 to 10.22 MJ/kg DM). There is a discrepancy of approximately 10.01% in the NE content between the DFRB origins. The NE contents of extruded DFRB and pelleted DFRB from the same province were 8.24 vs. 6.56 MJ/kg DM. Retained energy (RE) and FHP of diets containing extruded DFRB and pelleted DFRB were 1105 vs. 892 kJ/kg BW^0.6/day and 746 vs. 726 kJ/kg BW^0.6/day respectively, and those in extruded DFRB from different origins were within the range of values (947 to 1105 kJ/kg BW^0.6/day and 726 to 755 kJ/kg BW^0.6/day, respectively). In conclusion, NE values are affected by origin and processing technology of DFRB.