A means for determining the nutritional requirements of an industrial animal is provided. The object can be achieved by identifying an mRNA of which the expression changes before and after change of a physiological condition in an industrial animal by comparing mRNA expression data obtained before and after the change of the physiological condition, identifying a metabolic pathway of which the expression changes before and after the change of the physiological condition on the basis of the identified mRNA, and identifying a metabolite highly required by the industrial animal before or after the change of the physiological condition on the basis of the identified metabolic pathway.
