Evaluation of nutritive value of heat pretreated and enzyme pre-digested whole stillage for broiler chickens

This study investigated the effects of heat pretreatment (140°C, 70 psi for 15 minutes) and exogenous enzyme predigestion (1% multienzyme complex in acetate buffer, 55°C for 12 hours) on the nutritional value of whole stillage (WS) for broiler chickens. The experimental diets consisted of four corn starch-based diets, each containing 25% of dried distillers grains with solubles (DDGS), untreated (WS-C), heat treated (WS-H) or enzyme treated (WS-E) whole stillage; and a nitrogen-free diet. Male Ross 308 broiler chicks were fed the experimental diets from day 14 to 21 of age. Chemical analysis revealed that WS had higher dietary fiber concentration than DDGS. Heat pretreatment increased acid detergent fiber content and reduced gross energy, and decreased insoluble non-starch polysaccharides (NSP) and hence total NSP. In contrast, enzymatic predigestion increased total NSP by elevating the soluble fraction. The apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of most amino acids were lower in DDGS compared to untreated WS (P < 0.001). Heat pretreatment decreased amino acid AID and SID in WS (P < 0.001), whereas enzymatic predigestion did not affect AID and SID of amino acids. Nitrogen retention was higher in enzymatic predigested WS compared to heat pretreated WS, although no significant differences were observed in dry matter retention, gross energy retention, or nitrogen-corrected apparent metabolizable energy values among treatments. In conclusion, enzymatic predigestion represents a superior processing strategy compared to heat pretreatment for enhancing the nutritional value of WS in broiler diets, primarily through preservation of amino acid quality and improvement of nitrogen retention efficiency.