The objective of this experiment was to determine the effects of increased fiber content in diets on heat production (HP) and NE:ME ratio and to determine the NE content and NE:ME ratio of full-fat rice bran (FFRB), defatted rice bran (DFRB), corn gluten feed (CGF), and corn germ meal (CGM) fed to growing barrows using indirect calorimetry (IC). Thirty growing barrows (28.5 ± 2.4 kg BW) were allotted in a completely randomized design to 5 dietary treatments that included a corn-soybean meal basal diet and 4 experimental diets with a constant ratio of corn and soybean meal (difference method) containing 30% FFRB, DFRB, CGF, and CGF. Pigs were housed in individual metabolism crates for 20 d including 14-d adaptation to the diet and 6 d to determine the HP and total collection of feces and urine in respiration chambers. Pigs were fed their respective diets at 550 kcal ME•kg BW 0.60−1 •d −1 on the basis of BW measured on days 0, 7, and 14. The apparent total tract digestibility (ATTD) of DM, GE, and OM were greater (P < 0.01) in pigs fed the basal diet. The ATTD of DM, GE, and OM in pigs fed the DFRB diet were lesser (P < 0.01) when compared with those fed the basal and FFRB diets. The ATTD of ether extract (EE) in pigs fed the FFRB diet was greater (P < 0.01) compared with those fed basal, DFRB, CGF, and CGM diets. The HP adjusted for the same ME intake was greater (P < 0.01) in pigs fed the DFRB, CGF, and CGM diets compared with those fed basal and FFRB diets. The NE:ME ratio in pigs fed the FFRB diet was greater (P < 0.01) when compared with those fed the DFRB, CGF, and CGM diets. The NE content of FFRB, DFRB, CGF, and CGM determined using the IC method were 2,952, 1,100, 1,747, and 2,079 kcal/ kg DM, respectively. The NE content of FFRB, CGF, and CGM determined using the IC method were 3.5%, 3.8%, and 1.8% greater, respectively, than the predicted values, whereas NE content of DFRB determined using the IC method was 2.1% lower than the predicted values. In conclusion, pigs fed the fiber-rich ingredients had greater HP and lower nutrient digestibility. However, pigs fed FFRB diets containing greater fat content had a lower heat increment and, therefore, higher utilization efficiency. The NE:ME ratio ranged from 71.6% to 82.4%. The NE of FFRB, DFRB, CGF, and CGM determined using the IC method were 2,952, 1,100, 1,747, and 2,079 kcal/kg DM, respectively.

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The objectives of this experiment were: (i) to determine the net energy (NE) of soybean oil (SBO) fed to growing pigs using indirect calorimetry (IC); and (ii) to evaluate the effects of inclusion rate of SBO on heat production, oxidative status and nutrient digestibility in growing pigs. Eighteen growing barrows were allotted to three diets based on completely randomized design with six replicate pigs (period) per diet. Diets included a corn-soybean meal basal diet and two test diets containing 5% or 10% SBO at the expense of corn and soybean meal. During each period, pigs were individually housed in metabolism crates for 14 days, including 7 days to adapt to feed, metabolism crate and environmental conditions. On day 8, pigs were transferred to the open-circuit respiration chambers for measurement of daily O 2 consumption and CO 2 and CH 4 production. During this time, pigs were fed one of the three diets at 2.4 MJ metabolizable energy/kg body weight (BW) 0.6 /day. Total feces and urine were collected and daily total heat production (THP) was measured from days 9 to 13 and fasted on day 14 to evaluate their fasting heat production (FHP). The results show that trends of decreased apparent total tract digestibility of neutral detergent fiber (linear, P = 0.09) and acid detergent fiber (linear, P = 0.07) were observed as the content of dietary lipids increased. The average THP for the three diets were 1326, 1208 and 1193 kJ/kg BW 0.6 /day, respectively. The FHP of pigs averaged 843 kJ/kg BW 0.6 /day and was not affected by diet characteristics. A reduction of the respiratory quotients in the fed state as the inclusion level of SBO increased was observed. In conclusion, the NE values of SBO we determined by indirect calorimetry were 33.45 and 34.05 MJ/kg dry matter under two inclusion levels. THP could be largely reduced when SBO is added in the feed, but the THP of SBO included at 5% in a corn-soybean meal diet is not different from the THP of SBO included at 10%.

The objective of this study was to evaluate the effects of brown rice particle size on the apparent total tract digestibility (ATTD) of energy and nutrients in diets fed to pigs at four different stages and determine the optimal particle size (OPS) of brown rice for young pigs and adult sows. Eighteen weanling piglets (initial body weight (BW):10.2 ± 0.4 kg), 18 growing barrows (initial BW: 35.6 ± 1.5 kg), 24 gestating sows (initial BW: 220 ± 2.8 kg), and 24 lactating sows (initial BW: 208 ± 3.8 kg) were allotted to 1 of 3 or 4 diets based on completely randomized design with six replicates per diet.Within each stage, brown rice-soybean meal diets were formulated, and the only difference among diets was the brown rice used was ground to the specified particle size.Each stage lasted 19 days, including 7 days for cage adaptation, 7 days for diet adaptation, and 5 days for total feces and urine collection. For weanling and growing pigs, the results showed that pigs fed brown rice milled to 600 μm had a greater ATTD of dry matter (DM), gross energy (GE), and crude protein (CP) than pigs fed brown rice ground to 800 μm. However, there was no improvement in the ATTD of energy and nutrients for pigs fed brown rice milled to 600 μm versus 400 μm. The concentration of nitrogen (N) in feces significantly reduced (p < 0.01) as brown rice particle size decreased from 800 to 400 μm. However, there were no differences in phosphorus (P) output and absorbed P among diets. For gestating and lactating sows, a reduction in particle size from 1,000 to 800 μm significantly improved (p < 0.01) the ATTD of DM, GE, and CP in diets. However, there was also no improvement in the ATTD of energy and nutrients for pigs fed brown rice milled from 800 to 400 μm. In conclusion, considering the energy required for milling and nutrient digestibility, milling brown rice to 600 and 800 μm are recommended in diets for young pigs and adult sows, respectively. The OPS of brown rice for pigs at different physiological stages should be considered to economically and accurately formulate diets.