[Objectives] Food quality is one of the most important factors affecting the thermogenesis and digestion of birds. However, the plasticity of the birds' response to food quality is still unclear. This study aims to understand how birds adapt their thermogenesis and digestion in response to changes in food resources. [Methods] We modified the nutrient content of the food by adjusting the percentage of fat and protein (Table 1), 20 male Japanese Quails Coturnix japonica were randomly divided into 2 groups:high nutrition group (HNG, n = 10) and low nutrition group (LNG, n = 10). In this study, we measured body weight, basal metabolic rate (BMR), body fat content, tissue weight (liver, heart, kidney, muscle, and small intestine), mitochondrial state 4 respiration (S4R), cytochrome C oxidase (COX) activity, and the activities of digestive enzymes (cellulase, aminopeptidase, amylase, and lipase) in the small intestine of Japanese Quails. We conducted covariance analysis using body weight as a covariable to analyze BMR and tissue weight. Additionally, we used t-test to compare body fat content, S4R and COX activity of tissues, and the activity of small intestinal digestive enzymes in Japanese Quail fed different diets. [Results] The results showed that the high nutrition diet significantly increased the body weight and body fat content of Japanese Quails (Fig. 1c), but no increase was found in mitochondrial S4R and COX activity in liver, muscle, and heart (Table 2). Compared with the low nutrition group, the weight of the digestive tract (Fig. 2), and the activities of aminopeptidase and lipase per unit mass of small intestine were significantly increased in the high nutrition group (Figs. 3b, d). However, the activities of amylase were significantly decreased in the high nutrition group (Fig. 3c), while the activities of cellulase, aminopeptidase and amylase in the whole small intestine were significantly decreased (Figs. 3a﹣c). [Conclusion] In conclusion, in order to adapt to changes in food resources and quality, Japanese Quails can develop plastic adaptations by regulating metabolic thermogenesis and digestive tract functions at multiple levels, including whole, organ, cellular, and enzymatic.