Incidence and Pathological Features of Broiler Chicken Proventriculitis in Northeast Algeria

Abstract

Abstract A digestive disease known as transmissible viral proventriculitis (TVP) is a viral infection that affects chickens, especially broilers, and has substantial repercussions for the health and production of poultry. It causes economic losses in the chicken industry as a result of decreased digestion, poor growth performance, and lower feed conversion efficiency. These symptoms are hallmarks of the disease. Upon macroscopical examination, the disease may be recognized by the presence of proventricular enlargement, fragility, thickness, and pallor. Additionally, the condition is often accompanied with weakening and dilatation of the gastric isthmus. Nevertheless, while these lesions may indicate TVP, they are not definitive. The most accurate and reliable way to diagnose is still through histopathology. The most common signs of a problem are the necrosis of oxynticopeptic cells, the invasion of lymphocytes, and the replacement of glandular epithelium with hyperplastic ductal structures. An investigation of the epidemiological, clinical, gross, and histological characteristics of proventriculitis in broiler flocks in the east of Algeria was the purpose of this research. Additionally, the study aimed to evaluate the probable role that infectious agents have in the etiology of the disease. Within the scope of this study, a total of 69 chicken flocks were investigated. These flocks included 62 broiler farms, four laying hen flocks, and three broiler breeder flocks. Data were obtained by field trips, post-mortem exams, and histological analysis of proventricular tissue specimens. The microscopic examination facilitated the categorization of the proventricular lesions into three unique histological classifications: • TVP: Defined by the coexistence of lymphocytic infiltration and necrosis; • LP (Lymphocytic Proventriculitis): Exhibits lymphocytic infiltration absent of necrosis; • WP (Without Proventriculitis): Characterized by the absence of both lymphocytic infiltration and necrosis. iii The prevalence of these categories was documented at 23.6% (TVP), 52.8% (LP), and 23.6% (WP), respectively. It was discovered that the total frequency of proventriculitis among broiler flocks that were between 15 and 40 days old was 20.9%, and the death rates ranged from 0.1 percent to 0.5 percent at the time of discovery. Particularly noteworthy is the fact that both TVP and LP were linked to a significant amount of proventricular wall hypertrophy and a significant amount of lymphocyte infiltration, both of which point to an infectious mechanism of action. On the other hand, instances of WP did not exhibit similar lesions, which suggests that the infection was not infectious or that the reasons were complex and unrelated to viral agents. Infectious agents may function as aggravating rather than main causing elements in the development of proventriculitis, according to the results of this investigation, which provide credence to the concept that infectious agents operate in this manner under the particular circumstances that were seen in this study. This thesis offers novel insights into the occurrence, categorization, and pathological characterization of proventriculitis in broiler flocks. The persistent association of lymphocytic inflammation, tissue necrosis, and proventricular hypertrophy with TVP and LP patients highlights the significance of infectious processes. These findings provide a significant basis for further virological research and for the development of enhanced diagnostic and preventative measures against this economically critical avian disease. Keywords: Transmissible viral proventriculitis; Lymphocytic proventriculitis; Without proventriculitis; Histopathology; Proventriculus.