ARS | Publication request: Behavior, plasma cortisol, and immune cell populations of pigs experimentally infected with Salmonella Typhimurum

Submitted to: Applied Animal Behaviour Science
Publication Type: Abstract
Publication Acceptance Date: May 20, 2008
Publication Date: August 5, 2008
Citation: Lay, Jr, D.C., Rostagno, M.H., Eicher, S.D., McMunn, K.A. 2008. Behavior, plasma cortisol, and immune cell populations of pigs experimentally infected with Salmonella Typhimurum [abstract]. Applied Animal Behaviour Science. p. 192.

Technical Abstract: This study was designed to determine characteristics of pigs infected with Salmonella as compared with pigs not infected. Four-month old swine were either infected with Salmonella Typhimurum (n = 24) or served as non-infected controls (n = 15). All pigs were housed in individual pens (approximately 1.52 x 1.82 m); infected and control swine were housed in separate buildings to prevent cross infection. General activity and response to a novel object test were recorded at 1000, 1400, 1800, and 2200 h on days -1, 0, 1 and 2. Rectal temperatures were recorded at 0 h (immediately prior to infection), and then every 8 h until 56 h. Blood samples were collected at 0 h, 8 h, 16 h, 24 h, 48 h, then weekly until 6 weeks post-infection. At 0800 on the day of infection, infected pigs were given 108 cfu/pig. Infected pigs spent more time lying sternal, standing, and sitting than controls (P < .01). Control pigs spent more time lying lateral than infected pigs (P < .01). Infected pigs were also more active than control pigs (P < .01). A diurnal response for latency to approach the novel object within .3 m was shown for pigs in both treatments (P < .01), infected pigs approached the novel object more quickly than control pigs (P < .05). No treatment differences were detected for rectal temperature or plasma cortisol (P > .10). The number of monocytes tended to be lower in infected pigs (P < .08), with no differences for the number of neutrophils, leukocytes, lymphocytes, eosinophils or basophils (P > .10) as compared to control pigs. These data indicate that the behavior of the pig, as opposed to changes in cortisol or immune cell populations, is a more sensitive measure of infection with Salmonella Typhimurum.