Comparison of susceptibility to stress in two genetic lines of turkey broilers, BUT-9 and Big-6

The aim of the study was to compare the level of susceptibility to stress in two broiler turkey lines-BUT-9 and Big-6. The experiment was performed on 120 turkey toms aged ca. 8 weeks. Each of the genetic lines was represented by 60 birds divided into 4 groups--one control and three experimental ones, 15 birds in each. The open field test was conducted in the control groups (not exposed to any stress) in order to determine the motor activity of turkeys. The other groups were subjected to the stress of transport, crowding and overheating. When the experiment was over, following indices were determined in blood plasma obtained from all the birds: the concentration of corticosterone, adrenaline and noradrenaline, the level of glucose, cholesterol, total lipids and triglycerides as well as the activity of creatine kinase. The study revealed that the lighter and slower growing BUT-9 turkeys showed a higher resistance to stress than the Big-6. They were characterised by higher motor activity, a higher initial level of catecholamines in blood and heavier adrenals. The increase in corticosterone was much lower in these birds in response to stress. A lower reactivity was also observed in the biochemical indices (the level of cholesterol, triglycerides and glucose and the activity of creatine kinase). This confirms that BUT-9 turkeys are less sensitive to adverse environmental effects than are the Big-6, an interesting feature for poultry production.