Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/1996
Publication Date: N/A
Interpretive Summary: Turkey osteomyelitis complex (TOC) is the result of infection by many different kinds of bacteria. We believe that the natural ability to kill common bacteria which invade turkeys through the air, water, or feed may be lower in turkeys that get this disease. We did a number of tests of immune function and determined that the birds wit TOC had lower function of one type of white blood cell and lower numbers of these cells in their blood than did healthy turkeys. They had higher numbers of other white blood cells than healthy turkeys and were better able to produce antibody against sheep red blood cells but not against killed bacteria. Tests designed to determine the ability to engulf and kill bacteria did not show differences between turkeys with TOC and normal turkeys, however, turkeys with TOC engulfed fewer particles per cell than did normal turkeys. Birds with TOC had lower body weights and bursal weights and higher liver and spleen weights than healthy turkeys. We also determined differences in some blood chemistry tests, with some responses of TOC birds being higher and some lower than healthy turkeys. Many of the differences we detected can be explained by the normal host reaction to infection. Since the birds we tested were already sick, we don't know if they had these differences before they got sick of if the responses were caused by their illness. However, this study has given us direction in our search for genetic differences that may lead to a susceptibility to TOC.
Technical Abstract: Lame and normal turkeys were sampled from commercial flocks just prior to processing in two separate trials. After testing for functions of both humoral and cellular immunity, the turkeys were necropsied and examined for lesions of turkey osteomyelitis complex (TOC). There were significantly higher relative spleen and liver weights and significantly lower body weights and relative bursal weights in birds with TIC. The birds with TIC had lower response to phytohemagglutinin-P in both in vivo and in vitro tests as well as lower circulating lymphocyte counts and higher monocyte, heterophil, and total white blood cell counts. there was a significantly higher antibody response to sheep red blood cells in turkeys with TIC whereas antibody response to salmonella pullorum antigen was not different. There were no significant differences in the percentages of mononuclear cells or heterophils able to phagocytize bacteria or latex particles, or kill bacteria. However the heterophils from turkeys with TOC lesions did phagocytize significantly fewer latex particles per cell than did the healthy turkeys. Total serum protein, uric acid and blood urea nitrogen levels were higher in birds with TOC, while hemoglobin, iron, alkaline phosphatase, and gamma-glutamyl-transferase levels were lower. Although many of the differences in the birds with TOC can be caused by the normal host reaction to infection, further study may reveal innate differences which contribute to susceptibility to TOC.