Effect of early handling of turkey poults on later responses to a dexamethasone-Escherichia coli challenge. 1. Production values and physiological response.

The stress responses of mice and rats has been shown to be permanently altered by brief, gentle handling during the first 10 d of life, resulting in increased BW and resistance to stress-induced immunosuppression. The purpose of this study was to determine whether early handling of turkey poults could permanently affect production values and physiology of adult turkeys. Turkey poults were handled 0, 1 (1x), or 2 (2x) times daily for the first 10 d after hatch. Handling consisted of gently catching each poult and holding it for 10 s. On Day 11 after hatch, half of the birds from each handling treatment were treated with three injections of 2 mg dexamethasone (DEX)/kg BW on alternating days. On the day of the third DEX injection, duplicate pens of birds were also inoculated in the airsac with 0 or 50 cfu of Escherichia coli. The same birds were treated with a second series of DEX injections at 5 wk of age. Two weeks later, all birds were weighed, and 3 wk later four birds per pen were bled and 10 birds per pen were necropsied; relative organ weights were then determined. Surviving birds were treated with a third series of DEX injections at 10 wk of age; 2 wk later, all surviving turkeys were bled, weighed, and necropsied. Feed consumption was determined weekly. There were no differences due to handling treatment on the body weights or on the relative organ weights of birds that died after the first DEX treatment. Birds treated with a second DEX injection at 5 wk of age and handled 1x daily had decreased BW. Those handled 1x or 2x daily had higher feed conversion ratios. Surviving birds that were given a third DEX treatment had higher BW and no difference in feed conversion when handled 1x or 2x daily. Relative liver, heart, and spleen weights were affected by handling of DEX-E. coli-treated birds, as were serum chemistry values for calcium, iron, glucose, total protein, blood urea nitogen, uric acid, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and gamma-glutamyltransferase. Handling also affected the numbers of white blood cells of DEX-treated birds. These results indicate that brief and gentle handling of turkey poults during the first 10 d after hatch has lasting effects on production values and physiology of adult turkeys and that these effects can be positive or negative. These results suggest a genetic divergence in the response to stress and its effect on production values and physiology of commercial turkey populations.