The objectives of this study were to determine: 1) the effects of konjac flour residues and ramie on digestible energy (DE), metabolizable energy (ME) and apparent total tract digestibility (ATTD) of nutrients in diets fed to growing pigs, 2) the DE and ME contents of konjac flour residues and ramie. Thirty barrows were allotted to 1 of 5 treatments with 6 replicates per treatment. The 5 diets include a corn-soybean meal basal diet (CTL), konjac flour residues diets containing 15% konjac flour residues (LK) or 30% konjac flour residues (HK), and ramie diets containing 15% ramie (LR) or 30% ramie (HR). The experiment lasted 19 days, including 7 days for cage adaptation, 7 days for diet adaptation, and 5 days for total feces and urine collection. The energy values and ATTD of nutrients in each diet were determined, and DE and ME contents of konjac flour residues and ramie were calculated. The results showed that consumption of konjac flour residues significantly increased (P < 0.01) the fecal moisture content compared with the ramie treatment. The LK, HK and HR diets had lower (P < 0.01) DE values compared with the CTL diet. The HR diet had greater (P < 0.01) DE value compared with the HK diet. The LK and LR diets showed greater (P < 0.01) ATTD of DM, OM, GE and CP compared with the HK and HR diets. The HK diet had the lowest (P < 0.01) ATTD of ether extract (EE) among the 5 diets. No differences were observed for the ATTD of NDF and ADF among the 5 diets. Moreover, the DE and ME values of konjac flour residues under 2 inclusion levels (15% and 30%) were 11.66, 11.87 MJ/kg and 10.41, 10.03 MJ/kg, respectively. The corresponding values for ramie were 13.27, 13.16 MJ/kg and 13.07, 12.82 MJ/kg, respectively. In conclusion, the differences in fecal moisture content and the ATTD of EE among the 5 diets were mainly due to the different chemical compositions of konjac flour residues and ramie. Compared with konjac flour residues, ramie has greater DE and ME values under the same inclusion level.
Keywords: Apparent total tract digestibility; Digestible energy; Konjac flour residues; Metabolizable energy; Ramie.