Food restriction delays breeding and affects insulin-like growth factor-1, oxidative damage, and haematocrit value before egg-laying in female canaries

Environmental challenges, such as fluctuations in food availability, could influence reproductive investment. If resource availability is poor, individuals need to decide in which life-history process they invest more energy and vital compounds, which determine the cost of reproduction. In resource allocation, the physiological pathways have important roles. The aim of our study was to examine whether food availability influenced physiological traits (insulin-like growth factor-1 (IGF-1) concentration, antioxidant capacity (OXY), level of oxidative damage (ROM) and haematocrit value) prior to egg-laying in female canaries (Serinus canaria). We also tested whether these physiological traits were associated with traits reflecting the reproductive investment in egg macro- (egg mass and yolk mass) and micronutrient content (eggshell biliverdin- and protoporphyrin-based colouration). To test these questions we conducted a food restriction experiment with control and food-restricted (72% of c...