LAUSR

The first objective of this experiment was to test the hypothesis that apparent total tract digestibility (ATTD) of GE and nutrients in full fat rice bran (FFRB) and defatted rice bran (DFRB) determined in gestating sows is greater if feed is provided at 1.5 × the ME required for maintenance than at 3.5 × the ME requirement. The second objective was to test the hypothesis that the ATTD of GE and nutrients and the concentrations of DE and ME in FFRB and DFRB is not different between growing gilts and gestating sows if both groups of animals are fed 3.5 × the maintenance requirement for ME. Forty eight gestating sows (parity 2 to 6) were allotted to 3 diets and 2 levels of feed intake (i.e., 1.5 or 3.5 × the maintenance requirement for ME) in a randomized complete block design, with 4 blocks of 12 sows and 2 replicate sows per block for a total of 8 replicate sows per diet. Twenty four growing gilts (51.53 ± 3.1 kg BW) were randomly allotted to the same 3 diets, but all gilts were fed at 3.5 × the maintenance requirement for ME. A basal diet containing corn and soybean meal and 2 diets that consisted of 60% basal diet and 40% FFRB or DFRB were used. Results of the experiment indicated that there were no effects of level of feed intake of sows on ATTD of GE, DM, OM, or NDF, or on concentrations of DE and ME. However, concentrations of DE and ME were greater ( < 0.05) in FFRB than in DFRB regardless of feed intake level. The ATTD of GE, OM, DM, and NDF of diets containing FFRB or DFRB was less ( < 0.05) than in the basal diet, regardless of the physiological stage of the animals. However, the ATTD of GE, OM, and NDF of the basal diet and diets containing FFRB or DRFB was greater ( < 0.05) in gestating sows than in growing gilts. Concentrations of DE and ME in the diets were also greater ( < 0.05) if determined in gestating sows than in growing gilts. The ATTD of GE and the concentrations of DE and ME of FFRB were greater ( < 0.05) than in DFRB and these values were also greater ( < 0.05) in gestating sows than in growing gilts. In conclusion, the level of feed intake by gestating sows did not affect the digestibility of GE and nutrients or the concentrations of DE and ME in diets or in FFRB or DFRB, but 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.