Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/6/2005
Publication Date: 3/15/2005
Citation: Huff, G.R., Huff, W.E., Rath, N.C. 2005. Osteomyelitis in commercial turkeys. In: Proceedings of the Midwest Poultry Federation Convention, March 15-17, 2005, Minneapolis, Minnesota. p. 66-76. Interpretive Summary: Turkey osteomyelitis complex (TOC) is a turkey disease which results in bone, joint, and muscle infections. Because many different opportunistic bacteria have been isolated from the infections, we believe that turkeys which get this condition are unable to fight infection. We have shown that the immune system of turkeys with TOC is different from that of normal turkeys and that these changes may result from the selection of turkeys with faster growth rates. We have been able to reproduce all of the types of infection that occur in TOC by treatment of turkeys with a compound known to mimic the physical changes caused by stress. These studies suggest that decreasing the level of stress experienced by the birds may also decrease infection. We were able to decrease the level of disease and increase body weight by giving the turkeys extra vitamin D in their drinking water. Differences in the ability to utilize vitamin D may be important in general disease resistance and may also enable the genetic selection of turkeys which are better able to withstand the stressses of intensive turkey production. Turkeys that were selected for faster growth had higher mortality and more TOC in two different models of stress than did birds that were selected for egg production. The fast growing birds also had more bacteria in their joints. There are many ways to decrease stress in turkey production and being mindful of the harmful affects of stress on turkey health and food safety will also result in improvement of turkey welfare.
Technical Abstract: Turkey osteomyelitis complex (TOC) is a disease syndrome characterized by the presence of green liver, synovitis, osteomyelitis of the proximal tibia, and soft tissue abscesses in the carcasses of processed turkeys. We have established that these lesions are caused by opportunistic bacterial infections in turkeys whose immune systems have been compromised due to stress. We have developed an experimental model in which all of the lesions of TOC can be reproduced using immunosuppression with a synthetic glucocorticoid, dexamethasone (DEX). When poults were given 2064 IU/l vitamin D3 in their drinking water for the first 5 days of brooding and supplemented again at 4128 IU/l before during and after each stressful event, including weekly weighing and DEX treatment, there was no effect on birds given a single DEX treatment at 5 weeks of age and necropsied 2 weeks later. However, when surviving birds were given a second DEX treatment at 12 weeks, vitamin D3 supplementation significantly increased disease resistance and body weight, and decreased heterophil/lymphocyte ratios of DEX-treated birds. Selection for fast growth has been accompanied by decreased disease resistance. Birds that were selected for fast growth were compared to those selected for egg production for their response to stress and E.coli challenge in two stress models. The fast growing birds had higher mortality and TOC incidence and had more bacteria in their joints, suggesting that stress may impact food safety.