Submitted to: Brain Behavior and Immunity
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/6/2003
Publication Date: 10/1/2003
Citation: HUFF, G.R., HUFF, W.E., BALOG, J.M., RATH, N.C. THE EFFECTS OF BEHAVIOR AND ENVIRONMENTAL ENRICHMENT IN DISEASE RESISTANCE OF TURKEYS. BRAIN BEHAVIOR AND IMMUNITY. 2003. v. 17. p. 339-349. Interpretive Summary: Newly-hatched turkeys were provided with various enrichment objects in their pens in order to stimulate them and hopefully make them better able to resist infection. At 2 days of age, they were tested in a T-maze, and depending on the amount of time it took to finish the test, they were labeled as either SLOW or FAST. At 5 weeks of age, they were treated with a compound that mimics stress and were also challenged with Escherichia coli, a bacterium that causes respiratory disease in poultry. Birds that were provided with the enrichment objects had higher body weights, but also had more disease and lower numbers of white blood cells than did non-enriched birds. When the enriched birds were treated with the compound and bacteria, those among them that had been FAST in the T-maze test had more disease than did the SLOW birds. The SLOW birds that did not have enrichment objects in their environments were the only group that responded to the bacterial challenge with a normal increase in white blood cells. This study shows that enrichment of the environment or excessive stimulation during the first 2 weeks of life may not be beneficial to turkey poults and may increase their susceptibility to disease, and that FAST birds may be more susceptible to stress-related bacterial infections.
Technical Abstract: Turkey poults were provided with environmental enrichment for the first 14 days after hatch. At 2 days of age each bird was tested for the speed in which it would cross a T-maze. At 5 wk of age birds were treated dexamethasone and challenged with Escherichia coli. Enriched birds had higher body weights and incidence of disease and mortality and lower numbers of leukocytes when challenged. Challenged and enriched birds that tested Fast had higher mortality and air sacculitis scores and lower body weights than Slow birds. Non-enriched, Slow birds were the only ones to respond to challenge with increases in leukocyte counts and heterophil/ lymphocyte ratios. These data suggest that environmental enrichment during the first 2 weeks after hatch may be detrimental, especially to those birds with a high stress response, and that poults with a Fast response in the T-maze may be susceptible to stress-related bacterial infection.