Background: Decreased feed intake is a common stress response presented after weaning that leads to a negative effect on performances. Health management and feed supplementation were commonly used to solve such problems. The objectives of this research were to study the effects of nutritional stress and the benefit of fermented potato protein supplementation in intact nursery gilts. Methods: Prepubertal nursery gilts were assigned into the following feed treatments for 30 days: 1) normal feed, 2) normal feed with fermented potato protein (FPP) supplementation, 3) restricted feed which received 60% amount of normal feed and 4) restricted feed with FPP supplementation. Result: Serum IGF-1 and IGF1 mRNA expression of semitendinosus muscle were significantly increased by FPP supplementation (P less than 0.05). All pig groups showed no different on serum cortisol and hypothalamic Kiss1 mRNA expression levels. The degree of feed restriction was suggested to be an important determinant of response of serum IGF-1, cortisol and hypothalamic Kiss1 mRNA expression. In this study, an elevated serum IGF-1 concentration correlated with IGF1 mRNA upregulation in a muscle rather than in a liver.