Standardized Ileal Amino Acid Digestibilities of Sorghums from Different Sources in Yellow-Feathered Chickens and Their Prediction Models.

Prediction models for standardized ileal amino acid digestibilities (SIAADs) of sorghums in yellow-feathered chickens have not been previously reported. This study characterized the chemical composition of 10 sorghum samples from different sources, assessed their SIAADs in medium-growing yellow-feathered chickens, and subsequently developed and validated prediction models based on chemical composition and amino acid profiles. A total of 276 Tianluma roosters (60 d of age) were randomly assigned by body weight (average 1.32 kg per bird) to 11 dietary treatments, including a nitrogen-free diet (NFD) group and 10 sorghum-based diet groups. Each treatment included 6 replicate cages, with 4 birds per replicate cage for the sorghum-based diet groups and 6 birds per replicate cage for the NFD. Birds were fed the experimental diets from d 63 to 67, after which ileal digesta were collected to determine SIAADs of 10 sorghum samples. Data from 9 sorghum samples were used to establish prediction equations using stepwise regression, while the remaining sample was used for model validation. Sorghum source significantly influenced (