Abstract
1. Genetically lean or fat male chickens were fed from 3 to 8 weeks of age on four diets of different protein content: 152, 172, 191 or 211 g/kg.
2. The two lower protein contents depressed growth of lean chickens but had no adverse effects on fat chickens.
3. In both lines increasing dietary protein decreased food:gain ratio and abdominal fat desposition relative to live body weight.
4. Protein deposited and the efficiency of utilisation of dietary protein were higher in all instances in lean birds.