Metabolizable energy value and ileal amino acid digestibility of fibrous feed ingredients in 22-day-old broiler chickens.

OBJECTIVE: Fibrous feed ingredients may benefit gut development and reduce feed costs in broiler production; however, some ingredients contain antinutritional factors that can impair nutrient utilization. Therefore, accurate evaluation of their nutritive values is warranted prior to incorporating these ingredients into broiler diets. This study aimed to determine the apparent metabolizable energy (AME) concentrations and ileal amino acid (AA) digestibility in fibrous feed ingredients for 22-d-old broilers. METHODS: On day 18 post-hatch, 288 Arbor Acres male broilers were assigned to six dietary treatments, with eight replicate cages (six birds per cage). Five experimental diets were formulated with wheat bran (WB), rice bran (RB), soybean hull (SH), corn gluten feed (CGF), and sugar beet pulp (SBP) as the sole source of energy and AA. Thereafter, the retention of dry matter (DM) and nitrogen (N) in the fibrous-ingredient-based diets was determined. RESULTS: The DM and N retention of WB and RB exceeded (p < 0.05) those of SH, CGF, and SBP. The SBP had the lowest DM and N availability among the tested feed ingredients. The highest and lowest AME were found in RB and SH, respectively (p < 0.05). Additionally, the AME values recalculated based on N retention equivalent to a standardized 50% of N intake or zero N retention showed the same ranking of energy concentration among feed ingredients as the determined AME values. For indispensable AA, CGF showed the highest digestibility, whereas SH demonstrated the lowest (p < 0.05). For dispensable AA, WB exhibited the highest digestibility, while SH remained the lowest (p < 0.05). CONCLUSION: For indispensable AA, the highest digestibility was observed in CGF, followed by RB, WB, SBP, and SH. Contrastingly, for dispensable AA, WB showed the greatest digestibility, followed by CGF, RB, SBP, and SH.