Evaluation of putative appetite suppressants in the domestic fowl ( Gallus domesticus )

The effectiveness of the appetite suppressants fenflur‐amine, furanone and crotonolactone were evaluated in a series of experiments with adult male layers and growing broilers of both sexes fed on diets with concentrations of up to 1000 mg/kg. 2. Fenfluramine produced a curvilinear decrease in food intake and body weight in adult layers and growing broilers. 3. Inconsistent responses to furanone and crotonolactone were obtained with adult layers and broilers in cages, but a similar decrease in food intake and body weight for both drugs was recorded in male broilers raised in floor pens. 4. The responses to subcutaneous injection of 20 mg/kg of each drug on food intake over 24 h were comparable to those for dietary inclusion. Fenfluramine, however, produced a greater response in male compared with female broilers and induced signs of hyper‐thermia in broilers and layers. 5. Subcutaneous injection of 50 mg crotonolactone/kg was associated with decreases in the food intakes of 4 strains and there was evidence of different responses between lines. 6. It was concluded that none of the drugs used were likely to be suitable for the control of food intake in broiler breeder flocks.