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1992 - 19985
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Subject: Veterinary Pathology × Author: KAU × End date: 1998 × Start date: 1990 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Immunopathological response of the duck (Anas platyrrhyncos domesticus) to sublethal dose of selected agro-chemicals
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1998) Vijayan, N; KAU; Valsala, K V
    The study was conducted with the objective of assessing the teratologic, embryotoxic and immunopathologic effects of two agro-chemicals carbofuran and 2,4-D used in agricultural operations, on duck embryos and ducklings. The embryological studies included the observation on the embryonic defects and weight of the lymphoid organs along with the histopathologic and ultrastructural studies of the lymphoid organs like the bursa, spleen and thymus. The results showed that the contamination of the eggs with the above chemicals caused moderate deleterious effects on the lymphoid system, though no teratologic effects could be observed. The histological and ultrastructural changes also confirmed the deleterious effects at the tissue and cellular level. The immune system of the ducks exposed to the above chemicals for two different durations were assessed using a battery of tests. The humoral immune system was assessed based on the body weight, lymphoid organ weight, haematological evaluation, serum biochemical evaluation and the evaluation of HI titre against NDV. The cell-mediated immune system was assessed by the skin reactivity tests to DNCB and PHA. LMIT and GVHR were also employed to assess the cell-mediated immune system. The histological and ultrastructural studies were also conducted after six weeks and ten weeks of the experiment. The assessment of the immunological profile employing these elegant tests revealed that these agro-chemicals caused mild but significant suppression of the cell-mediated and humoral immune response. By this investigation it was clarified that these agro-chemicals have mild to moderate degree of immunotoxic effect when exposed for a short duration, but the changes were severe when exposed for longer duration. From the .studies, it was demonstrated that the immunotoxic effect of carbofuran is more compared to 2,4-D (herbicide) and the changes were dose and time dependent.
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    ThesisItemOpen Access
    Ochratoxicosis in quails (Coturnix coturnix japonica) with special reference to Inununopathological response
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1992) Amir Abbas, Farshid; KAU; Rajan, A
    In this investigation the pathological effects of OA in quail embryo and adult quail were studied with special reference to the immune system. Ochratoxin A (OA) was inoculated into the quail embryos, at the dose rate of 0.02 ^g per embryo. There was 68.66 per cent mortality which clearly indicated the direct action of OA. The embryos which were sacrificed on the 13th and 16th day of incubation showed significant reduction in the body weight, weight of bursa of Fabricius, spleen and thymus. Histological changes in these lymphoid organs were, atrophy, necrosis and depletion of lymphoid elements. Ultrastructurally the changes were time dependent. There were changes in the shape of the nucleus with condensation of granular and fibrillar components of the nucleoli. The adverse immunobiological effect of OA on the developing lymphoid organs was established by histological and ultra structural studies. OA at the dose rate of 50 /ag/bird/day for a period of 60 days was administered through oesophageal intubation. Pathological changes were sequentially documented with special reference to the immune system. In the OA fed quails, the clinical signs included emaciation and hyperexcitation at the later part of the experiment. There was highly significant reduction in the body weight, weight of bursa of Fabricius, spleen and thymus. The reduction in the weight of lymphoid organs gave evidence to the adverse effects of OA on the immune system. There was reduction in the total erythrocyte count (TEC), haemoglobin (Hb) concentration and packed cell volume in OA fed birds indicating the significant damaging effect on the haemopoietic sytem. Estimation of total serum protein (TSP), serum globulin (SGI) and serum immunoglobulin fractions clarified the biological adverse effect of OA on the humoral immune system. Highly significant reduction in total leukocyte count (TLC) and T cell dependent lymphopenia proved the immunosuppressive effect of OA. There was reduction in T cells, increase migration indices in response to Fowl pox antigen in leukocyte migration inhibition test (LMIT), the reduction in the cutaneous response to 2,4-dinitrochlorobenzene (DNCB) and phytohaemagglutinin-M (PHA-M) and spleen indices in the graft versus host reaction (GVHR), clarified the immunotoxicity of OA on the cell-mediated immune system.
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    ThesisItemOpen Access
    Comparative pathology of aflatoxicosis in the duck and fish with special reference to the immune system
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1998) George, K C; KAU; Rajan, A
    Pathological responses of ducklings and juvenile Indian carps Labeo rohita in experimental aflatoxicosis were studied. Both the ducklings and fishes were given sublethal toxic levels of aflatoxin B1. The ducklings and fishes were exposed to aflatoxin B1 for 2, 4, 6 and 8 weeks respectively and they were sacrificed at the end of the experiment and samples for haematological, serum protein profile, histological and ultrastructural investigations were collected. Pathological changes were studied with special reference to the humoral and cell – mediated immune responses. Among the haematological parameters, total erythrocyte count, total leucocyte count and packed cell volume were found to be reduced in fishes. The reduction was directly proportional to the duration of aflatoxin treatment. In the fishes, there was moderate fall in the total proteins and the albumin. The electrophoretic picture of the serum of the fishes also showed fall in the albumin fractions. In the ducks there was severe reduction in the albumin level and this was reflected in the electrophoretic picture as well as A: G ratio. In both the ducks and the fishes humoral immune response was suppressed due to aflatoxin treatment. Antibody titres against sheep RBC fell in the experimental groups of the ducks and the fishes. The cell - mediated immunity was assessed in the ducks and the fishes by intradermal PHA – M response, count of ANAE positive lymphocytes in the peripheral blood and leucocyte migration inhibition test. In the ducks and the fishes of the aflatoxin treated groups, there was significant fall in the skin sensitivity response and also in the number of ANAE positive lymphocyte. These findings clearly established that CMI was suppressed by aflatoxin . The histological and electron microscopic studies revealed severe degenerative and necrotic changes in the hepatocytes in the ducks and fishes. However, hepatosis was more severe in the fishes whereas in the ducks biliary proliferation was a prominent feature. The hepatic changes could be correlated with the changes in the plasma protein profile in the duck and the fish. The lymphoid organs of the duck and the fish (thymus, spleen, bursa of Fabricius and anterior kidney) showed extensive necrosis and degenerative changes. These changes clearly established the reason for the immunosuppression and low leucocytic counts observed in the aflatoxin fed ducks and fishes. The kidneys of the duck and the fish exhibited nephrotic changes. Degenerative changes were also observed in the brain and the heart of the two species. The pathologic changes due to aflatoxicosis were comparable in the ducks and fishes.
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    ThesisItemOpen Access
    Comparative study of the immunopathological response in ochrathoxin A, cadmium and mercury toxicities in ducks (Anas platyrrhynchos domesticus)
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1996) Vyas Madhavrao Shingatgeri; KAU; Rajan, A
    The present investigation was undertaken for the first time to assess the level of contamination of mercury (Hg) and Cadmium (Cd) in the soil, water, plants and biosamples in localities where there is significant duck population and to study the pathological effects of these chemicals and ochratoxin A (OA) with special reference to immune response in the ducks and duck embroys. The residues of these chemicals in various tissues of the ducks were also assessed. Hg and Cd were detected in all the samples from all the localities surveyed and its presence especially in the soil, vegetation, fish, liver and kidney of the ducks from these areas indicated its public health significance. After the administration of OA, HgCl2 and CdCl2, there was dose dependent embryo mortality and reduction in hatchability rate. The mortality percentage in the highest dose group of embryos inoculated with HgCl2, Cdcl2 and OA was 55%, 51.6% and 48.3% respectively while the hatchbility rate was 29.92%, 35% and 47.83% respectively. This clearly indicated the embryotoxic action of these chemicals. The body weight, weight of the thymus, and the bursa of Fabricius was found lowered in the embryos inoculated with these chemicals. The variations noticed in the weights at different periods of observation between the chemicals were also dose dependant. The weight of the spleen of the embryos inoculated with OA and HgCl2 was comparable to the normal embryo but with CdCl2, it was found significantly lowered in the highest dose group at the 28th day of incubation. These observations, therefore indicated that Cd has an adverse significant biological effect on the lymphoid organs of the developing embryo. Similar effect was observed with Hg and OA but was relatively low. Histologically, depletion of the lymphoid elements consequent to degeneration, necrosis and cytolysis was the characteristic feature in the bursa of Fabricius and thymus, however, it was comparatively less in the spleen. Ultrastructural changes in the lymphoid cells in all these organs showed membrane alterations, mild to severe mitochondrial changes, ribosomal detachment and fragmentation of RER and nucleolar and nuclear changes indicative of cell damage, and marked reduction in differentiation into plasma cells. Epithelial cells were also found affected. The toxic effects of these chemicals were more or less similar in the bursa of fabricius, intensity and severity being more with CdCl2 followed by HgCl2 and OA in that order. In the thymus, also, CdCl2 caused severe pathological effects while with HgCl2 intensity was least. In the spleen there was increased erythrophagocytosis in addition to these changes and was more severe with HgCl2. In the liver, severe necrobiotic changes were found in the hepatic cells associated with ultrastructural picture of organellar damage and lytic changes in the nucleus. Intensity of these changes was more severe in CdCl2 treated embryos followed by those treated with OA and with HgCl2. In the kidney, the cellular alterations were more in the proximal convoluted tubules and the intensity of these alterations was less in OA and CdCl2 treated embryos compared to those treated with HgCl2. The embryos inoculated with OA, HgCl2 and CdCl2, revealed degenerative changes in the lymphoid and other organs. The adverse immunobiological effects of OA, Hg and Cd on the developing embryo were established by histological and ultrastructural studies. In the ducks, OA, HgCl2 and CdCl2 were fed orally (at the rate of 300 ug, 10mg and 15 mg/kg body weight respectively) for 90 days. Clinically ducks showed dullness, restlessness and unusual hyperresponsiveness and inco – ordination of movement, in OA, HgCl2 and CdCl2 fed ducks respectively at the later stage of the experiment. Progressive reduction in the gain of the body weight, of the bursa of Fabricius was noticed in all the groups (OA, HgCl2 and CdCl2 treated) while that of the thymus was noticed mainly in CdCl2 and OA treated ducks. There was highly significant reduction in the total erythrocyte count (TEC), Haemoglobin (Hb) concentration and Packed Cell Volume (PCV) in the groups fed OA, HgCl2 and CdCl2. Highly significant leucopaenia with relative heterophilia and lymphocytopenia was observed in OA and HgCl2 fed ducks, while highly significant leucocytosis with heterophilia and lymphocytopenia was seen with CdCl2 fed ducks. These alterations revealed the toxic action of these chemicals on the haemopoietic cells and the formed elements of the blood. Estimation of the haemagglutination inhibition (HI) antibody titre, total serum protein (TSP), serum globulin (SG) and serum IgG and IgM levels clarified the adverse effect of OA, Hg and Cd on the humoral immune system, which was evident at an early stage in Cd and Hg treated ducks while at a later stage in OA fed ducks. There was marked reduction in the serum IgM and IgG level in response to New Castle disease Virus (NDV) in ducks fed HgCl2 and CdCl2 respectively. The highly significant reduction in the T – lymphocyte count in the peripheral blood, increase in the migration indices in response to NDV in leucocyte migration inhibition test (LMIT), reduction in cutaneous response to phytohaemagglutinin – M (PHA – M), 2, 4 – dinitrochlorobenzene (DNCB) and the decreased spleen indices in Graft versus host reaction (GVHR) indicated the toxicity of OA and Cd on the cell – mediated immunity, which was more pronounced and evident at an early stage in Cd treated ducks than compared to OA treated ducks. However, the results of the migration indices, PHA – M cutaneous response and GVHR demonstrated that the CMI response escape the toxic insult of the Hg and is dependant on the duration of exposure, which was clarified by T – cell dependant lymphocytopaenia and reduction in cutaneous response to DNCB at the last week of the experiment. Significant reduction in the phagocytic ability in all the ducks treated either with OA, HgCl2 or CdCl2 was observed by carbon clearance assay. There was reduction in the weight of the bursa of Fabricius and spleen. The thymus showed focal areas of congestion and petechiae in Cd induced toxicity, and was found appreciably reduced and atrophied with Cd and at later stages with OA. Degenerative and retrograde changes indicative of necrobiosis were observed histologically. Ultrastructural changes were more severe with CdCl2 followed by HgCl2 and OA in that order. In the spleen of ducks fed CdCl2 there were proliferative changes initially followed by degenerative changes at later stages. In the thymus, effect of the Cd was more severe on the lymphocytes followed by OA and was least with HgCl2. Histological and ultrastructural studies revealed degenerative nephropathic changes in the kidney associated with Hg, OA and Cd toxicity. Intensity of alterations was more with Cd. The hepatic lesions characterised by moderate to severe hepatosis were more pronounced in the case of Hg and Cd in an increasing order. Histological and electron microscopic studies elucidated the neuropathological changes associated with Hg, Cd and OA toxicity. Estimation of OA, Hg and Cd residues indicated a steady increase in the accumulation of these substances in the various tissues depending on the dose and duration of exposure. Highest concentration of OA, Hg and Cd was detected in the kidney, followed by liver. Residues of these substances at varying concentrations were also detected in the muscles, brain, spleen, bursa of Fabricius and thymus. This study brought to light the immunosuppressive effect of OA, Hg and Cd which would compromise the dichotomous defence mechanism of the ducks. Also adverse effects on hepatic, haemopoietic, reneal and nervous system were documented. It was clarified by this investigation that immunotoxic effect of these chemicals could lead to breakdown of immunity and outbreak of diseases when the ducks are maintained in a polluted environment. The need for the systematic monitoring of the environment and taking appropriate steps to prevent environmental pollution were stressed. The public health importance of residues of these chemicals was brought to light.
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    ThesisItemOpen Access
    Assessment of the role of aflatoxin in the aetiology of carcinoma of the mucosa of the ethmoid
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1995) Surinder K, Chaudhary; KAU; Rajan, A
    The present investigations were planned to assess the role of aflatoxin B1 (AFB1) and /or virus in the aetiology of ethmoid carcinoma using pig as a model in vivo and bovine ethmoid mucosa culture in vitro. Thirty – two, large white Yorkshire piglings of two – three months age were procured from the University pig Breeding Farm, Mannuthy and divided at random into four groups of eight each. The pigs in group I and group II were administered aflatoxin B1 (0.070 mg/kg b.wt/inoculums by intravenous route at weekly interval for six months) and /or ethmoid tumour extract (2 ml/pig/inoculums, intranasally, at fortnight interval for three months). The pigs in group III were administered ethmoid tumour extract alone, while the pigs in group IV were kept as negative controls. During the period of observations of 18 months all the pigs of different groups given AFB1 and /or ethmoid tumour extract appeared healthy and no clinical manifestation of the carcinoma of the mucosa of ethmoid was observed. However, there was appreciable reduction in the weight and mild degree of depression. In the AFB1 treated pigs, sacrificed at 9, 12, 15 and 18 months of investigation, the ethmoid mucosa had grayish white, soft and oedematous appearance along with scattered small pale elevations at necropsy. Histologically, the ethmoid mucosa exhibited hyperaemia, varying degree of mononuclear cell infiltration and fatty degeneration in the initial stages. In the later stages, there was proliferation of mucous glands showing acinar, tubular or papillary arrangements. Occasionally papillary projection of the surface epithelium and focal squamous metaplasia were also observed. Ultrastructural features of the cells of the ethmoid mucosa consisted of both productive and degenerative changes. The cells had sparse cytoplasmic organelles. The poor cytoplasmic contents and irregular nucleus with nucleolar margination were the other electron microscopic features observed in the ethmoid mucosa of AFB1 treated pigs. AFB1 in the range of 43.12 – 139.43 ppb could be detected in the blood of 52.37 percent of the ethmoid tumour bearing cattle analysed in the present study. The blood samples from the AFB1 treated pigs were positive for AFB1 (40-160 ppb) upto 10 days after the withdrawal of treatment whereas AFM1 could be detected in blood sample of one pig only upto 3 days after the treatment. The ethmoid mucosa analysed after 3 months and at subsequent specified intervals was consistently negative for AFB1 and AFM1. By concerted efforts cells of the mucosa of the ethmoid were established in vitro. AFB1 treatment of long term epithelial cultures intiated from the primary culture of bovine ethmoid mucosa origin resulted in morphological transformation accompanied by increased growth in soft agar and cytochemical positivity of gamma glutamyl transpeptidase. This confirmed the tumourigenicity of AFB1. The xenotransplantation of these in vitro transformed epithelial cells in mice was not successful. Electron microscopic studies of the cells of the carcinoma of the ethmoid mucosa in spontaneous cases of cattle revealed varying ultrastructural features. The neoplastic cells were either well differentiated secretary structures or undifferentiated ones. Desmosomes and tight junctions were seen between the epithelial cells. Endoplasmic reticulum and mitochondria varied in their contents and degree of disorganization. Nucleus was highly pleomorphic and predominantly euchromatinic. The retroviral like particles were demonstrated intracellularly and occasionally in extracellular spaces in the neoplastic cells of 7 tumour bearing cattle. Similar particles were also seen in the cell free ethmoid tumour extract in three of21 tissues examined.