Abstract Dried Distillers Grains with Solubles (DDGS), a rapidly expanding co-product of the ethanol industry, represents a strategic component in modern swine nutrition. Despite its contribution of energy and amino acids (AA), variability in processing technologies can alter nutrient digestibility and protein quality, emphasizing the importance of ingredient-specific evaluation to ensure precision feeding and sustainable production systems. This study aimed to determine the metabolizable energy and standardized ileal digestibility (SID) of AA in DDGS for growing pigs. Sixteen barrows 30 kg were individually housed in metabolism cages equipped for total feces and urine collection. A randomized block design with two treatments and eight replicates per treatment was used. In phase 1, pigs were fed a basal diet or a 70% basal + 30% DDGS diet to determine metabolizable energy; in phase 2, pigs received a nitrogen-free diet (N-free) or 70% N-free + 30% DDGS diet to determine AA digestibility. Each phase lasted 16 days. During phase 1, pigs were adapted to their respective diets for 7 days, followed by 5 days of total feces and urine collection to determine metabolizable energy. In phase 2, pigs were adapted for 4 days to the diets used to evaluate SID, after which they were euthanized for ileal digesta collection. Feces, urine, and ileal digesta were analyzed for dry matter, nitrogen, crude protein, and gross energy following AOAC (1997). Metabolizable energy was calculated using Matterson et al. (1965). The DDGS contained 32.0% crude protein and 3,353 kcal/kg of metabolizable energy. The average standardized ileal digestibility (SID) coefficient of amino acids was 69.3%, which was comparable to the 73.8% reported in the Brazilian Tables (2024). Among individual amino acids, arginine (84.3%), leucine (78.3%), and methionine (75.5%) presented the highest digestibility values, followed by lysine (59.3%), threonine (62.4%), and cystine (56.8%). The SID of crude protein was 67.8%. Overall, DDGS provides high metabolizable energy and consistent amino acid digestibility, confirming its nutritional reliability for growing pigs. When properly characterized, it supports precision formulation, improves nutrient efficiency, and strengthens sustainable, economically viable swine production systems.
Motta et al. (Wed,) studied this question.