Effects of stress resulting from short-term restraint on in vitro functional capacity of leukocytes obtained from pigs

Abstract

Objective - To investigate whether the procedure used to snare and restrain pigs during collection of blood samples would alter in vitro functional capacity of leukocytes in the samples. Animals - 8 gilts. Procedure - Catheters were surgically inserted into the jugular vein of gilts to enable blood sample collection without restraint. After collection of a control sample, gilts were restrained by use of a snare and samples were collected at 0.5, 3.5, and 6.5 minutes after start of restraint (0 minutes). At each time point, plasma β-endorphin and cortisol concentrations as well as WBC counts were recorded, and functional capacity of leukocytes in cultures of whole blood was assessed by means of mitogen-induced proliferation and interleukin-2 activity, virus-induced interferon-α concentration, and phagocytosis of zymosan particles. Results - Concentrations of plasma β-endorphin and cortisol were increased at 3.5 and 6.5 minutes after start of restraint. At these times, virus-induced interferon-α concentration was decreased, whereas proliferative response to Concanavalin A and phytohemagglutinin increased in samples collected at 6.5 minutes. Conclusion and Clinical Relevance - It was possible to snare pigs for the purpose of collecting blood samples and restrain them without causing excessive stress that would affect immunologic variables, provided that the collection procedure was completed within a few minutes.