Chemical composition and porcine in vitro digestibility of corn whole stillage pretreated with heat at various temperatures and times

•Whole stillage that is processed into DDGS is poorly digested by pigs.•Pretreatment of whole stillage with heat at high pressure improved its digestibility by pigs.•Pretreatment conditions for maximum digestibility of the whole stillage were ∼160 °C for ∼20 min.