Pathological changes in broiler chickens fed ochratoxin A and inoculated withEscherichia coli

Abstract

A study was conducted to evaluate the effects of ochratoxin A (OA) on Escherichia coli -challenged broiler chickens. One hundred and eighty-four one-day-old broiler chicks were divided into two groups of 92 chicks each, with one group fed a control mash diet and the other fed a mash diet containing 2 parts/10 6 OA. On day 14, each group was further subdivided into two groups with one group inoculated with E. coli O78 (1/10 7 colony-forming units/0.5 ml) by the intraperitoneal route, whereas the other group was not inoculated with E. coli. Four birds from each group were sacrificed at 1, 2, 3, 5, 7, 10, 14 and 21 days post-inoculation to record pathological changes in the liver, kidneys, heart, lungs, bursa, spleen and thymus. E. coli infection induced perihepatitis and pericarditis in the liver and heart, respectively, in chickens infected with E. coli alone or in OAfed birds from 1 day post-infection (DPI) onwards. At 1 DPI, a thin fibrin layer covered the liver and heart; however, at subsequent days, the layer became thicker. E. coli infection did not produce appreciable changes in the kidneys, bursa or thymus. However, there was congestion of the lungs along with mononuclear cell infiltration. Ochratoxin feeding induced changes from 10 DPI onwards in chicks fed OA alone and those infected with E. coli. The changes in kidneys included swollen proximal convoluted tubules, degeneration of tubular epithelium and interstitial nephritis. Degenerative changes and mononuclear cell infiltration were recorded in the liver. There was atrophy of the lymphoid organs along with depletion of lymphocytes. Gross and histopathological changes were more severe in chickens fed OA and inoculated with E. coli than the chickens fed OA alone or those infected with E. coli, indicating combined action of these two.

Experimental ochratoxicosis in broiler chickens

“…In contrast to its effect on the gizzard, OTA caused a significant reduction in the relative weight of the thymus in the broiler chicks. Similar results were reported when OTA was administered to specific pathogen-free Plymouth Rock chicks at 1 or 5 parts/10 6 (Stoev et al ., 2002) or to broiler chicks at 2 and/or 4 parts/10 6 (Dwivedi & Burns, 1984a;Elkady, 1993;Kumar et al ., 2004) for periods ranging from 21 to 70 days. Results from all previous reports agreed that the greater the dose used, the greater the decrease in thymus weight, and this was found to be true also when lower doses (130, 305, and 790 ppb) were used by Stoev et al .…”

“…Suppression of humoral and cellular immunity by OTA reduces the immune response of chickens to vaccination against Newcastle disease virus strain B1 (Stoev et al, 2000(Stoev et al, , 2002 or LaSota strain (Santin et al ., 2002), and allows development of secondary bacterial infections (Kumar et al ., 2003(Kumar et al ., , 2004 Two findings that were reported in this study, a reduced leucocyte count and thymus weight, implied that the functioning of the immune system is altered. Regression of other lymphoid organs, the spleen and bursa of Fabricius, were reported during ochratoxicosis (Dwivedi & Burns, 1984a;Singh et al ., 1990;Elkady, 1993;Stoev et al ., 2000Stoev et al ., , 2002Kumar et al ., 2004;Verma et al ., 2004) and was found to be accompanied by a decrease in the number of lymphoid cells present (Peckam et al ., 1971;Stoev et al ., 2000Stoev et al ., , 2002Kumar et al, 2004) and in the immunoglobulin-containing cells (Dwivedi & Burns, 1984b). Closer histopathological examination revealed degenerative changes in the germinal centres of the thymus and spleen, and hence a possible explanation for the dietary OTA-induced lymphocytopaenia (Stoev et al ., 2000(Stoev et al ., , 2002.…”

Immunological responses of male White Leghorn chicks kept on ochratoxin A (OTA)-contaminated feed

“…OTA is characterized by numerous toxicities. Various studies have illustrated its nephrotoxic, hepatotoxic, immunotoxic, teratogenic, genotoxic, mutagenic, and/or neurotoxic effects, as well as its capacity to impart growth suppressive effects in different avian and mammalian species (Gilani et al, 1978;Kumar et al, 2004;Robbiano et al, 2004;Wangikar et al, 2005;ul-Hassan et al, 2010ul-Hassan et al, , 2011.…”

Immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)-contaminated feed

“…Presence of ochratoxin A (OTA), the most toxic among ochratoxins, in the poultry feed and feed ingredients has been reported throughout the globe, including Pakistan (Hanif et al, 2006;Saleemi et al, 2009). The primary effect of OTA is nephrotoxicity, although its immunotoxic, teratogenic, hepatotoxic, neurotoxic, genotoxic, and mutagenic effects have been well reported in various avian and mammalian species (Gilani et al, 1978;Kumar et al, 2004;Elaroussi et al, 2006).…”