Experimental Reproduction of Proventriculitis Using Homogenates of Proventricuiar Tissue

Abstract

Proventriculitis is a problem affecting the processing of broiler carcasses, particularly those processed at 4 to 5 wk of age. The proventriculus and the gastric isthmus connecting the proventriculus to the gizzard are enlarged and swollen and often rupture during processing, causing carcass contamination. This study suggested that a filterable agent found in homogenated proventriculi can cause lesions similar to those seen in field cases. Proventriculitis was produced independently of an effect on growth, and only unfiltered homogenate caused stunting. Field birds with severe proventriculitis were shown to have increased body weights compared with birds without proventriculitis or with milder lesions. Intestinal weakness was not associated with proventriculitis and field birds with the most severe proventriculitis had stronger intestines. Although infectious proventriculitis has generally been reported as one of the lesions associated with stunting syndrome, these data suggest that it may have an independent etiology.

Proventriculitis in Broiler Chickens: Immunohistochemical Characterization of the Lymphocytes Infiltrating the Proventricular Glands

“…4,11 T-cell-mediated immune responses to viral pathogens are well established and occur by a number of mechanisms, including induction of cytotoxic Fig. 7.…”

“…19 Viral particles have been detected in acute lesions using electron microscopy, but isolation of a virus from affected proventriculi has been unsuccessful. 10,11 Proventriculitis has been reproduced by inoculation of proventricular homogenates produced from diseased chickens 4,11,20 and bacteria-free filtrates of these homogenates, showing that the initiating cause is transmissible and viral. 11 However, lesions are more severe after exposure to unfiltered homogenate, suggesting that proventriculitis has a complex etiology involving both viral and bacterial agents.…”

“…10,11 Microscopically, degeneration and necrosis of the proventricular glandular epithelium is accompanied by marked lymphocytic infiltration. 4,10,11,20 The etiology of proventriculitis is currently unknown. Several agents have been implicated as potential causes.…”

“…11 Transmissible proventriculitis is characterized by a marked lymphocytic infiltrate in the proventricular glands. 4,10,11,20 The purpose of this study was to characterize the lymphocytes composing this infiltrate in order to determine what immunologic mechanisms chickens use to respond to this infection. To accomplish this we experimentally infected commercial broiler chickens with proventricular homogenates from affected broilers and studied the proventricular lesions using histopathology, by staining for lymphocyte cellsurface markers, and by identifying the distribution of these different lymphocyte subsets.…”

“…Noninfectious causes include oral exposure to biogenic amines, 2 mycotoxins, 21 lack of dietary fiber, 22 and excessive copper sulfate. 5,12 Infectious agents that have been implicated include adenovirus, 15 reovirus, 14 infectious bronchitis virus (IBV), 29 infectious bursal disease virus, 4,11 and megabacterium. 24 However, none of these noninfectious or infectious agents have been found consistently.…”