Effects of Escherichia coli challenge and transport stress on hematology and serum chemistry values of three genetic lines of turkeys.

ABSTRACT

Three lines of turkeys were compared for response to an Escherichia coli challenge followed by transport stress (transport). The turkey lines were a slow-growing line selected for increased egg production (egg line), a fast-growing line selected for increased 16-wk BW (F line), and a commercial line (Comm line). Birds were challenged at 14 wk of age with an air sac injection of 5,000 to 10,000 cfu of E. coli. At 8 d postchallenge, birds were subjected to a transport stress procedure that included 12 h of holding time in a transport vehicle. The following morning all birds (n = 10 to 19 birds/line) were bled. Whole blood was analyzed using the Cell-Dyn 3500 blood analysis system (Abbott Diagnostics), and serum chemistry was measured using the Express Plus analyzer (Ciba-Corning Diagnostics Corp.). Transport significantly decreased the levels of hematocrit, hemoglobin, mean cell volume, mean corpuscular hemoglobin, glucose, triglycerides, cholesterol, phosphorus, iron, albumin, and alkaline phosphatase (AP) and increased the levels of uric acid, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, and creatine kinase. Line differences were variable, but the levels of both iron and AP were least in the fastest-growing Comm line birds and greatest in the slowest-growing egg-line birds with intermediate values in the F line. Iron and AP were also the only parameters influenced by sex, with males having greater levels of both compared with females. The creatine kinase levels were more than 6-fold greater in transported Comm line birds, and iron levels of transported Comm males were 3-fold less than controls. Previously, the growth rate of these lines was positively correlated with increased heterophil to lymphocyte ratios and susceptibility to colibacillosis. The differences seen in the Comm line for these commonly measured blood parameters suggest that they may be useful for profiling flocks to determine their response to transport stress and feed withdrawal.