Clinicochemical follow-up of broiler rearing--a five-week study.

Commercial broilers were raised in a 5-week period and a detailed clinicochemical follow-up was carried out, to characterise a flock selected for one-sided muscle mass production. Blood samples were drawn at the ages of 1 day, 1, 2, 3, 4 and 5 weeks, and plasma enzyme activities, metabolite and ion concentrations were determined. Early increases were found for all plasma nitrogenous compounds (total protein, albumin, creatinine and urate). Triglyceride showed a posthatch peak with a significant effect of age. Plasma total cholesterol was characterised by a marked post-hatch concentration peak, while during the first week its concentration decreased markedly. Plasma AST showed an increase during the rearing, while a one-magnitude increment was found for creatine kinase activity during the study. The main results of the study outlined a typical precocial bird (post-hatch triglyceride peak; decreasing cholesterol and early peaking plasma protein and urate concentrations) with very quick skeletal muscle mass growth (increasing creatine kinase and AST activities, slight hyperkalaemia).