Clinical chemistry reference values in two breeds of swine and their changes during percutaneous exposure to soman

Clinical chemistry reference values in blood from 48 nonfasting Chester White/Yorkshire and 48 Hanford Miniature swine were determined. Subsequently, 40 animals of each breed were restrained in a cloth sling and fasted for 24 hours while exposed percutaneously to pinacolyl methylphosphonofluoridate (soman). The range of dosages for the Hanford Miniature swine was 2.0 to 15.8 mg/kg, and for the Chester White/Yorkshire swine, the range was 4.0 to 25.0 mg/kg. Sham-exposed groups, consisting of 8 animals of each breed, were treated in an identical manner, except no anticholinesterase agent was administered. Samples of blood were drawn at 1, 7, 14, and 28 days after soman or sham exposure. In the sham-exposed groups, significant changes from the reference values were observed as a result of the 24-hour restraint. In both breeds, skeletal muscle enzyme activities were increased, plasma cholinesterase activity (ChEPL) was decreased, calcium concentration was decreased, and phosphorus concentration was increased. Percutaneous exposure to soman resulted in decreases of ChEPL and erythrocyte cholinesterase activities (ChERBC). The ChEPL recovered more quickly than the ChERBC in both breeds. Even in asymptomatic swine, the decrease of ChERBC was greater than 60% after 24 hours. In the swine of each breed given the largest dosage, hyperglycemia was apparent in blood samples taken at the onset of apnea, especially when the animal survived for greater than 2 hours. We conclude that both breeds of swine, on the basis of dispersion in clinical chemistry reference values, were equally suited for this type of dermatotoxicity study. The sling method of restraint, however, caused some undesirable changes in biochemical values.