At the end of growing, fattening and finishing periods, blood samples (20 mL) were taken from the jugular veins of steers using syringe and then transferring the blood into heparin coated sterile vacutainer (Becton Dickinson, NJ, USA) wrapped with foil. Next, plasma was harvested by centrifugation (3,000 rpm, 20 min). All harvested plasma was rapidly frozen and stored at −70°C until further assay.
Blood biochemical components including aspartic acid transaminase (AST), alanine transaminase, blood urea nitrogen (BUN), glucose, total protein, albumin, cholesterol, and triglyceride were analyzed with the Automatic Biochemical Analyzer (HI System, Technicon, Tarrytown, NY, USA).
Plasma insulin and leptin were assayed by enzyme-immunoassay using Multi-species Insulin RIA kit and Multi-species Leptin RIA kit (Linco Research, Inc, St. Charles, MO, USA), respectively. I125 radioactivity was monitored using γ-counter (COBRATM II, Packard Bioscience, Downers Grove, IL, USA).
Blood biochemical components including aspartic acid transaminase (AST), alanine transaminase, blood urea nitrogen (BUN), glucose, total protein, albumin, cholesterol, and triglyceride were analyzed with the Automatic Biochemical Analyzer (HI System, Technicon, Tarrytown, NY, USA).
Plasma insulin and leptin were assayed by enzyme-immunoassay using Multi-species Insulin RIA kit and Multi-species Leptin RIA kit (Linco Research, Inc, St. Charles, MO, USA), respectively. I125 radioactivity was monitored using γ-counter (COBRATM II, Packard Bioscience, Downers Grove, IL, USA).