Determination of the standardized ileal amino acid digestibility of corn in 13-day-old broilers and establishment of the prediction equations

This study was conducted to evaluate apparent ileal amino acid digestibility (AID AA) and standardized ileal amino acid digestibility (SID AA) in corn with different sources fed to broilers and to establish prediction equations of SID AA based on the chemical composition of corn. Ten different sources of corn were evaluated. A total of 660 1-day-old male broilers (Arbor Acres) were randomly divided into 11 treatments (6 replicates, 10 birds per replicate). The broilers were fed the experimental diets and nitrogen-free diet (NFD), and the experimental period was 3 days (from d10 to d13). The amino acid digestibility was determined by adding titanium dioxide as an exogenous indicator in the diets. There was considerable variation in the chemical composition of corn. The variable coefficient of the content of acid detergent fiber and Pro was more than 20 %. The AID AA and SID AA ranged from 56.73 % to 86.99 % and 86.31 % to 96.35 %, respectively. Corn source had a significant effect on AID AA (P < 0.05). A positive correlation was observed between EE and SID of Val, Ile, Leu, Lys, His, Glu and Ala. A negative correlation was found between ADF and SID of Gly, Val, Ile, Leu, Lys, Asp, Glu, Ala and Tyr. The R² of stepwise regression equations for predicting SID AA was the best for Asp (R²=0.989) and the least for His (R²=0.403). The prediction equations based on the chemical composition of corn provide valuable reference points for realizing efficient utilization and precise nutrition in broilers.