ScholarWorks@중앙대학교

초록

This study aimed to assess and compare the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) in laying hens at different ages. A total of 180 28-wk-old Hy-Line Brown laying hens were randomly assigned to 3 age groups of 30, 50, and 70 wks. At each designated age, 60 hens were randomly allotted to 2 treatment diets: nitrogen-free diet (NFD) for estimating basal endogenous losses (BEL) of AA and corn-soybean meal-based diet (CSD). It was observed that the BEL of most AA increased with age, with significant increases (P < 0.05) for Arg, Lys, Thr, Asp, and Ser by an average of 118.3 % for these 5 AA in 70-wk-old hens than in 30-wk-old hens. The AID and SID of most AA in CSD decreased as hens were aged, with 70-wk-old hens exhibiting significant reductions (P < 0.05) in the AID of Arg and Lys by an average of 10.4 %, and in the SID of these 2 AA by 7.6 % compared with 30-wk-old hens. The AID and SID of Met were also lower (P < 0.05) in 70-wk-old hens by an average of 12.5 % and 10.7 %, respectively, than in both 30-wk-old and 50-wk-old hens. In conclusion, the BEL of AA increased, whereas AA digestibility decreased with advancing age in laying hens. Specifically, 70-wk-old hens showed decreased digestibility of limiting AA (Arg, Lys, and Met) compared with younger hens. Therefore, age-dependent AA digestibility in laying hens should be considered to improve the precision of feed formulation. Copyright © 2025. Published by Elsevier Inc.

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