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1998 - 19998
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Subject: Veterinary Pathology × End date: 1999 × Start date: 1998 ×
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Now showing 1 - 8 of 8
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    ThesisItemOpen Access
    Pathology of the Harderian Gland in chicken and duck
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences,Mannuthy, 1998) Mohan S; Valsala K V
    The lymphoid tissue of the upper respiratory tract includes paraocular and paranasallymphoid structures as well as some lymphoid accumulations in the pharynx and larynx. However, of all these paraocular lymphoid tissue, the Harderian gland is highly immunopotent. The role of the Harderian gland in the immunopathological response was evaluated taking chicken and duck as models and RD, IBD and Duck plague vaccines as antigens. The sequential cellular response following ocular antigenic stimulation was clarified. Significant increase in the plasma cell number, enlargement of the lymphoid foci and Russell body formation following ocular antigenic stimulation were the hall marks of the immune response of the Harderian gland of the chicken but this was not so much significant in the case of ducks. Harderian gland was highly reactive especially in the chicken but not so much in the case of ducks. Intraocular vaccination was found to be comparatively more effective in immunological protection in chicken. It would therefore, appear that through local administration of the antigen at the Harderian gland the duck may not respond in the same way as in the case of chicken. It was pointed out that the local antibody produced by the Harderian gland contributed in a major way to the immunological defence at the oculonasal and oropharyngeal areas and it has an obvious relevance to the epidemiology and the control of respiratory viral diseases in the avian species.
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    ThesisItemOpen Access
    Prevalence and patholoygy of polioencephalomalacia in goats
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences,Mannuthy, 1999) Divakaran Nair N; Rajan A
    Polioencephalomalacia (PEM) is a significant emerging diseases problem in goats. Although, PEM in goats was recognized and reported as early as 1956, its etiology is poorly understood and symptomatology, pathological features and therapeutic approach have not been well defined and documented. Hence an investigation was undertaken to assess the prevalence of the disease based on the data available from 76 Veterinary hospitals of the state for a period from 1991 to 1994. This data documented revealed an increasing trend in the occurance of the disease and significantly high incidence was recorded in the first five months of which the peak incidence was observed in the month of April. Spontaneous cases of the disease were studied in detail and experiments were conducted taking goat as a model using selected incriminating agents such as Amprolium (350mg/kg body weight), Amprolium and rice gruel (350 mg/kg and ad libitum rice gruel), rice gruel (ad libitum), sodium sulphate (150 mg/kg body weight followed by 500 mg/kg body weight on the 10th day) BHC (2.5 mg/kg followed by 5 mg/kg body weight on the 10th day) and Ficus tsiela Roxb. The experiment was for a period of 45 days. Symptomatology, weight of the animals at fortnightly intervals, weight of the brain, CSF protein concentration, brain autofluorescence, gross and histopathological alterations of the brain and ultrastructural pathology were the markers utilized for evaluating the disease processes. The sodium sulphate, BHC and Amprolium and rice gruel treated group showed symptoms and lesions more or less similar to the spontaneous cases. Only few animals in each group developed the disease such as two in amprolium and rice gruel treated group, four in BHC treated group and three in sodium sulphate group. This showed that individual idiosyncracy plays an important role in the manifestation of the disease. The symptoms developed at different latent periods were not progressive as compared to the spontaneous cases where the symptoms were progressive. The symptoms included lethargy, depression, knuckling at the fetlock, frequent tremors, opisthotonous and loss of eye preservation reflex. Blindness was seen in one of the natural cases. The histological lesions of the brain in all the cases were comparable in different segments of the brain. Mostly it was characterized by diffuse laminar cortical degeneration and necrosis, occasional neuronal swelling glial cell reaction and white matter vacuolation. Vascular changes predominated in the sodium sulphate group and also in the natural cases. There was glial cell response in the form of nodules in sodium sulphate group and natural cases. A predominant perivascular and neuropil accumulation of lymphocytes, gitter cells and monocytes were seen in the natural cases. These were considered as secondary deposition following a toxic degenerative neuropathy. The necrotic focicould well be delineated in few of these cases by the bluish or creamy autofluroscence of the affected brain, but was not found to be of any primary diagnostic value as all the affected brain did not show flurescence. Ultrastructural investigation revealed the basic reaction of the brain tissue to be similar in both the experimental and natural cases except for their intensity. Ultrastructural lesions were characterized by neuronal swelling, membrane lysis, segregation of the filamentous and granular component of nucleolus, cytoplasmic oganellar damage such as fragmentation of RER, partial degranulation of ribosomes, mitochondrial of RER, partial degranulation of ribosomes, mitochondrial swelling, cristolysis and complete disappearance of organelle. Neuropil spongiosis and splitting of myelin at the intraperiod line and formation of multiple vacuolations of the white matter were characteristic. From this observations it was clearly delineated that the primary insult was a biochemical one which caused much damage to the volume control mechanism of the cell and subsequent cellular damage. The CSF protein evaluation revealed high protein level in the spontaneous cases whereas in the experimental cases, the concentration remained within the normal range indicating that it has no diagnostic value. In this investigation it has not been possible to induce PEM with Amprolium even at a dose rate of 350 mg/kg bodyweight and it was proved that amprolium is not a cause for PEM. Rice gruel ad libitum was found to be tolerated by the animal except one which showed dullness and abdominal distension towards the end of the experiment. Diffuse neuronal degeneration was observed in the brain of this animal. Based on this observation it was concluded that rice gruel consumption every day as a component of the concentrate feed in goats might not cause any detrimental effects and the problem comes only when it is fed in large quantities on a single day. Ficus tsiela Roxb. Though produced vascular damage and diffuse neuronal degeneration in one of the experimental animals, goats were found to be highly resistant to ficus tsiela Roxb. Toxicity and the variation in the susceptibility of different species to this toxicity was brought to light. From this investigation it was also clarified that sodium sulphate, BHC, rice and amprolium could be initiating agents of PEM under certain circumstances and no single cause seems to be responsible for PEM.
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    ThesisItemOpen Access
    Determination Of Permissible Level Of Aflatoxin In Broiler Chicken Feed
    (Department of Pathology, College of Veterinary and Animal Sciences,Mannuthy, 1999) Arulmozhi A; KAU; Koshy Varghese
    The study was undertaken to assess the effect of various levels of aflatoxin on the performance of broilers and to establish the permissible level of aflatoxin in the broiler feed. One hundred and eighty day old broiler chicks were divided into six groups of 30 birds each and were given feed containing graded levels of aflatoxin at 0, 20, 40, 60, 80 and 100 ppb for a period of 45 days. Feed intake, weekly body weight gain, feed efficiency, haemogram, serum profile, organ weight, residual aflatoxin in tissues and pathological changes in liver, kidney, bursa and spleen were studied at fortnightly intervals to evaluate its dose related effects. A dose dependent decrease in the daily feed intake and mean body weights were noticed in all the groups. The cumulative FeR was extremely poor at 80 and 100 ppb levels at sixth week of age. The toxicopathological changes in the birds varied in its intensity in relation with the level of aflatoxin in the feed, with most severe changes being at higher dose levels. The values of haemoglobin, PCV, total leucocyte count, Iymphocytes, total serum protein and albumin showed a decrease whereas the ESR, heterophil and serum enzyme were increased. The aflatoxin, even at 20 ppb levels caused degenerative and necrotic changes in liver and kidneys and the intensity of the lesions increased with higher levels of toxin. Attempt for regeneration and repair processes were well pronounced by the 30th and 45th day. Lymphoid depletion was a characteristic feature in bursa and spleen. Degeneration and lysis of lymphocytes with cys; formation was also seen in bursal follicles. Residual aflatoxin was detected in the liver and muscle in all groups by the 45th day. The net returns from the toxin treated birds showed a dose related decline compared to control and the loss in profit at 20 ppb level was marginal About 24 per cent of the poultry feed samples tested during the period from January to July 1999 were contaminated with aflatoxin quantitatively ranging from 20 to 200 ppb. The results of the present study shows that even at 20 ppb aflatoxin causes cellular and subcellular damage to the tissues. However, the economic loss at this level was marginal when compared to higher dose levels. Hence 20 ppb can be considered as permissible level in broiler chicken feed.
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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
    Pathological effects of aflatoxicosis in ducks
    (Department of Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1999) Latha, K; KAU; Mammen, J Abraham
    In this investigation the pathological effects of aflatoxicosis and permissible levels of aflatoxin were studied at different dose levels viz. 5ppb, 10ppb, 20ppb and 40ppb. In the aflatoxin fed ducks, reduced feed intake and diarrhoea were noticed. There was a significant reduction in the body weight and carcass weight which were indicative of the toxic injury to the gastrointestinal tract. There was a significant increase in the liver weight reflecting the damage to the hepatic system. There was reduction in the haemoglobin concentration, total erythrocyte count, packed cell volume and significant increase in the erythrocyte sedimentation rate indicating the adverse effect of aflatoxin on the haemopoietic system. Leucocytosis with heterophilia and lymphopenia were observed suggesting the deleterious effect of aflatoxin on the lymphoid organs. Highly significant reduction in serum total protein, albumin values, AlG ratio and significant increase in globulin were observed indicating hepatic damage. Grossly, the aflatoxin fed birds showed pale enlarged liver, focal necrotic areas, subcapsular haemorrhage, fatty liver, greenish discolotation and surface granularity and nodularity of varying intensity depending on the dose and duration of the treatment. In the kidney and spleen, mild congestion were observed. Bursa showed atrophic changes. Histopathological alterations in the liver consisted of biliary hyperplasia, fatty changes, congestion of the hepatic sinusoids portal venous congestion, portal fibrosis, focal collection of mononuclear cells, dissociation of hepatocytes, hepatocytomegaly and fibrous tissue proliferation of varying intensity depending on the dose and duration of the treatment. In the spleen, congestion, vascular sclerosis and depletion of Iymphocytes in the cortical and paracortical areas were noticed, whereas in the kidney besides nephrosis, mild peritubular accumulation of mononuclear cell were noticed at 20ppb level of aflatoxin while tubular degeneration, swelling of the tubular epithelium, mild fibroblastic proliferation with cellular infiltration in the interstitium were noticed at 40ppb level. Generally, bursa of fabricius of the treated birds revealed lymphoid depletion in the follicles, interfollicular edema and proliferation of interfollicular connective tissue. Aflatoxin treated groups showed dose and duration dependant degrees of ultra structural changes. The ultrastructural changes noticed were intact cell nucleus with prominent nuclear pores, increased amounts of heterochromatin that appeared as clumps, dilatation and degranulation of rough endoplasmic reticulum (RER), rounded, oval or elongated mitochondria which were either normal or swollen containing swollen cristae along with the presence of electron dense material within the matrix, smooth endoplasmic reticulum (SER) that appeared as small tortuous vesiculated structures and scattered lipid droplets. Aflatoxin B1(AFB1) residues were detected in the liver, muscle pooled samples of th.e kidney and blood of birds maintained with feeds containing • aflatoxin at levels of 20 and 40 ppb during the fourth, sixth and eighth month. No residual toxin could be detected in birds treated with aflatoxin at a level of 5ppbthroughout the experiment. At dose level of 10ppb, no AFB1 residues could be detected by the second and fourth month, but during the sixth and eighth month negligible amount of residues could be detected in the liver and muscle. This study highlights the pathological effects of aflatoxicosis in ducks. Moreover, the adverse effects on the hepatic, haemopoietic and renal systems could be documented. By considering the above facts aflatoxin level of 10ppb is fixed as permissible level in ducks. However, permissible level can vary with the season, diseased conditions of the bird and storage practices of feed. Therefore, this study emphasizes the need for regular screening of feed for aflatoxin content.
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    ThesisItemOpen Access
    Pathology of bacterial mastitis in bovines
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1998) Nandakumar, S; KAU; Sreekumaran, T
    The pathology of bacterial mastitis in bovines was studied considering the following aspects such as bacterial isolation; changes in milk, antibiotic sensitivity pattern, haematology, whey protein pattern and histopathological examination of the mammary gland and supramammary Iymphnodes. Two hundred and sixty two samples were found to be subclinically positive based on California Mastitis Test. The organisms isolated from clinical and subclinical cases were Staphylococcus, E. Coli, Gram negative bacilli, mixed infections, Streptococcus, Yeast and Gram positive bacilli in the decreasing order of prevalence. All the major pathogens were sensitive to pefloxacin, gentamycin and chloramphenicol and resistant to penicillin. Leucopenia could be noticed in clinical and subclinical cases of mastitis. Relative neutrophilia could be observed in mastitic animals. Total plasma protein was also increased. There was an increase in T-Iymphocyte count in mastitis affected animals. ~omatic cell count was increased in clinical and subclinical cases, but was not indicative of infection, unless confirmed by bacteriological examination. SOS-PAGE on whey proteins revealed an increase in protein content in mastitic milk as a result of the plasma proteins, cellular proteins, bacterial proteins. There was marked increase in immunoglobulins in mastitic milk, when compared to normal. Histopathology of mammary glands revealed the presence of inflammatory cells in the acini and interstitium of mammary glands as the main lesion. Varying degrees of inflammatory reaction could be noticed in almost all the quarters. Supra mammary lymph nodes revealed distension of subcapsular sinuses, active secondary follicles in the cortex, sinus catarrh and medullary hyperplasia in mastitis affected animals.
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    ThesisItemOpen Access
    Immunopathological response of the Japanese Quail (Coturnix coturnix japonica) in experimental Aflatoxicosis
    (1999) Sureshkumar, KAU M; Divakaran Nair, N
    One month old Japanese quails vaccinated with Ranikhet disease vaccine (Lasota strain) on 7th day, were divided into three groups viz., A, B and C of 35 birds each for assessing the immunopathological responses in experimental aflatoxicosis. Birds of group Band C were administered aflatoxin Bl by oral intubation at the rate of 0.5 ppm twice weekly for two months and group .A were vaccinated with R2B strain vaccine at the age of 46 days. Seven birds from each group were sacrificed at fortnightly intervals for the evaluation of various organ weights, haematological, biochemical and haemagglutination inhibition titre values. Liver weights and spleen weights were significantly increased in the toxin treated birds while bursal weights were significantly depressed from that of controls. Packed cell volume, erythrocyte count and leucocyte counts were significantly increased in the toxin treated birds at the end of the experiment with a significant increase in erythrocyte sedimentation rate at the 45th and 60th day of the experiment. A relative heterophilia and lymphopenia were observed in the toxin treated birds. Serum total protein, albumin and globulin levels were significantly depressed in the toxin treated birds but the albumin-globulin ratio was unaltered. A relative decrease in the haemagglutination inhibition titre values of the toxin treated birds was recorded. The gross and histopathological lesions in the liver of the toxin treated birds were suggestive of progressive hepatic degeneration, necrosis and fatty changes. There was lymphoid depletion and vascular sclerosis in the spleen while the bursae of the treated birds showed lymphoid depletion, necrosis of lymphocytes, intra and interfollicular cyst formation in increasing intensities in a time dependant manner. The pathomorphological alterations and a relative depression of HI titres in the aflatoxin treated quails indicates a moderate depression of the immune status by aflatoxin at such a low dose level.
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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.