Body weight, digestive organ weights, and activities of disaccharidases (maltase and saccharase) activities were determined from day of hatch to 21 d of age in meat- and egg-type chickens. Blood plasma was analysed for enzyme activities and metabolite concentration. 2. In meat-type chickens food intake and growth rate were about 3-fold those in egg-type chickens. Food efficiency was superior in meat-type chickens throughout the experimental period. 3. Meat-type chickens hatched with disaccharidase activities exceeding those found in their egg-type counterparts 2- to 5-fold. From 7 d of age on, this trend reversed, i.e. activity was much higher in egg-type than in meat-type chickens. 4. Blood plasma amylase activity increased gradually in meat-type chickens and was higher than in egg-type chickens to 14 d of age. No breed differences were observed for alkaline phosphatase or lactate dehydrogenase activities during the experimental period. 5. Blood plasma concentrations of total protein, albumin, glucose, and calcium, were lower in meat than in egg-type chickens.
