Sample storage and fasting times affect blood serum and plasma components in fasted and non-fasted broiler chickens

We determined the impacts of blood fraction, fasting and samples storage times on the total protein, albumin, globulin, uric acid, creatinine concentrations, and alkaline phosphatase activity in 70 45-d-old male Cobb 500® broiler chickens. Blood was collected at 2-h intervals (0, 2, 4, 6, 8, 10, and 12 h). Serum and plasma fractions were stored at -20°C and analyzed on 0, 30, and 60 days. Serum and plasma uric acid concentrations increased with increasing storage time, while a reduction in creatinine concentration and serum alkaline phosphatase activity was observed. Serum creatinine and alkaline phosphatase showed a quadratic effect, with a peak concentration of 0.208 mg dL^-1 at 4 h and 32 min of fasting, and the lowest concentration of 2933 U l^-1 at 8 h of fasting, respectively. Plasma total protein, albumin, and creatinine showed a quadratic effect, with a peak concentration of 35.46 g l^-1 at 7 h and 48 min, 15.36 g l^-1 at 10 h and 48 min, and 0.18 mg dL^-1 at 7 h and 46 min, respectively. Overall, serum and plasma can be used for the analysis of total protein, albumin and globulin, with a fasting time of 12 h and storage for up to 60 days at -20°C. Both serum and plasma fractions can be used for uric acid analysis, but immediate analysis after sample collection is recommended, and a 12-h fast can be used. It is recommended to use serum for creatinine and alkaline phosphatase analysis, with storage for up to 30 days at -20°C.