Evaluation of Nitrogen-Corrected Apparent Metabolizable Energy and Standardized Ileal Amino Acid Digestibility of Different Sources of Rice and Rice Milling Byproducts in Broilers.

Rice, broken rice (BR), and full-fat rice bran (FFRB) from six different origins were analyzed for their chemical composition, nitrogen-corrected apparent metabolized energy (AMEn), and standardized amino acid digestibility (SIAAD) in 14-day-old and 28-day-old Arbor Acres broilers. Results showed broilers fed with rice and BR had a similar AMEn regardless of the rice and BR having different CP, EE, NDF, ADF, and ash content. FFRB containing significantly different CP, EE, NDF, ADFm and starch presented variable AMEn ( < 0.05), suggesting that starch content in rice and its byproducts contributed most to the AMEn of broilers. The regression equation of AMEn = 14.312 - (0.198 × NDF) and AMEn = 6.491 + (0.103 × Starch) were feasible to integrally predict AMEn of broilers fed to rice and its byproducts. Moreover, 28-day-old broilers had higher SIAAD than 14-day-old ones. The SIAAD of rice were higher than BR and FFRB except for Met, Cys, Thr, and Tyr in 14-day-old broilers ( < 0.05), and the SIAAD of His, Asp, and Ser in BR were higher than FFRB ( < 0.05). In 28-day-old broilers, the SIAAD of Leu, Trp, Asp, Gly, and Pro of rice were still higher than BR and FFRB ( < 0.05), but BR and FFRB had no significant differences ( > 0.05). The regression equations to estimate the SIAAD of Thr, Lys, and Met were: Met = 81.46 + (0.578 × CP), Thr = 0.863 + (6.311 × CP), and Trp = 102.883 - (1.77 × CP), indicating that CP content in rice and its byproducts was likely a major factor for prediction of SIAAD.