Body composition and exercise in racing pigeons

Exercise-related changes in body protein ‘turnover’ and in the absolute amounts of body protein were studied in racing pigeons. Whole body radioactivity was followed in racing and control (limited exercise) birds after protein labelling by the injection of 75 Seselenomethionine. Because of re-utilisation of the label this does not give a true picture of body protein turnover but the comparative data suggested an increased turnover in racing compared to control birds. Carcase analysis on a group of pigeons demonstrated a water content for lean body mass of 72·7 per cent ± 3·54. Lean body mass and exchangeable body potassium were used as indices of total body protein in a group of pigeons participating in an endurance race (15 + hours of flying). The results indicated that no body protein had been used as an energy source. These findings are compatible with the presence in pigeons of a small labile pool or pools of protein. The presence and characteristics of such pools remains to be determined.