Effects of Feeding Level and Physiological Stage on Digestibility of Gross Energy and Nutrients and Concentration of Digestible and Metabolizable Energy in Full Fat Rice Bran and Defatted Rice Bran Fed to Gestating Sows and Growing Gilts

: The objective was to determine the apparent total tract digestibility (ATTD) of GE, DM, OM, and NDF in full fat rice bran (FFRB) and defatted rice bran (DFRB) fed to gestating sows at 2 levels of feed intake. The second objective was to compare the ATTD of GE and nutrients and the concentrations of DE and ME in FFRB and DFRB fed to growing gilts or gestating sows at 3.5 × the maintenance requirement for ME. Forty eight gestating sows (35 ± 0.8 d of pregnancy; 239 ± 27 kg BW; parity 2 to 6), were randomly allotted to 2 levels of feed intake (1.5 or 3.5 × the maintenance energy requirement for ME) and 3 diets (corn-soybean meal basal diet or diets containing 60% basal diet and 40% FFRB or DFRB). Twenty four growing gilts (51.53 ± 3.1 kg BW) were randomly allotted to the same 3 diets and fed at 3.5 the maintenance energy requirement. Diets were fed for 24 d with 18 d of adaptation and fecal collection for 5 d using the marker to marker approach. Data were analyzed as a randomized complete block design in a 2 × 3 factorial for diets and a 2 × 2 factorial for ingredients. Results indicated that there were no effects of level of feed intake of sows on ATTD of GE, DM, OM, or NDF or on the concentrations of DE and ME. However, the concentrations of DE and ME were greater (P < 0.05) in FFRB (4,185 and 4,062 kcal/kg DM) than in DFRB (3,224 and 3,158 kcal/kg DM) regardless of intake level. The ATTD of GE and the concentrations of ME of FFRB and DFRB were greater (P < 0.05) in gestating sows (4,119 and 3,228 kcal/kg DM), than in growing gilts (3,871 and 2,933 kcal/kg DM). In conclusion, the level of feed intake by gestating sows did not affect digestibility of GE and nutrients or the concentrations of DE and ME in diets or in FFRB or DFRB. The ATTD of GE and the concentration of DE and ME in diets and in FFRB and DFRB were greater in gestating sows than in growing gilts.