Effects of Pasteurella multocida endotoxins on turkey poults.

Studies of turkey poult responses to Pasteurella multocida endotoxins indicated that lipopolysaccharide (LPS) preparations from two highly pathogenic strains and free endotoxin from one of these strains were all similar in lethal toxicity. Lethal intravenous doses were generally high, 1 mg or more for 1-week-old poults (13.3 mg/kg). The toxic effects of LPS were not increased by repeated administration of small hourly doses. For both forms of endotoxin, the relationship between dose and response was considered erratic. Attempts to increase the susceptibility of poults to LPS by administering a liver-damaging substance (galactosamine) or a histamine-releasing substance (compound 48/80) or by performing surgical bursectomy were not effective. The LPS did not provoke a dermal Shwartzman reaction, even though doses used were 10 times those that produced a characteristic reaction in a rabbit.