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Open Access
Pathology of hypothyroidism in pigs
(Centre of Excellence in Pathology, College of Veterinary and Animal Sciences,Mannuthy, 1995) Prasanna, K S; KAU; Sreekumaran, T
An experimental model of hypothyroid state was induced in piglets, using thiourea with the objectives of studying the sequence of clinico pathological changes and its influence on the animal health and growth. Tweleve Large White Yorkshire male piglets of 2 – 3 months age were selected for the study. The animals were divided into control group of six animals and experimental group of six animals. Experimental hypothyroidism was induced by feeding thiourea daily for a period of three months at the dose level of 50 mg per kg body weight. Haemogram, body weight, plasma proteins, serum cholesterol and serum thyroxine values were estimated at periodic intervals. The piglets were subjected to detailed autopsy after sacrifice. Gross lesions were recorded and detailed histopathological examination of tissues was carried out. During the course of experiment all the experimental animals recorded stunted growth and appreciable reduction in feed intake and alopecia of neck and shoulder regions. There was significant increase in blood cholesterol values and plasma protein level in thiourea fed group. A significant reduction in serum thyroxine level was also recorded. There was significant increase in the relative weight of thyroid, adrenal and pituitary glands of experimental animals. Gelatinisation of subcutaneous fat and dilatation of right ventricles were common findings at autopsy. Histologically the thyroid glands exhibited varying degree of hyperplastic changes and depletion of colloid in the follicles. Hyperplasia and hypertrophy of the lining epithelium was also observed. Predominant histological changes in the pituitary was hyperplasia and hypertrophy of the basophil cells and degranulation of the acidophil cells. Adrenal glands showed diffuse hyperplasia of zonafasiculata and accessory cortical nodule formation. Skin revealed acanthosis, hyperkeratosis and keratinisation of harifollicles. In all the hypothyroid animals testis showed varying degree of tubular degeneration. A random survey study was conducted to assess the thyroid status of pigs from different parts of Kerala using serum thyroxine as the marker. This concluded that most of the animals had the normal range of serum thyroxine levels.
Open 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.
Open 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.
Open 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.
Open 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.
Open Access
Prevalence and pathology of dermatological disorders in cattle
(Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1996) Anilkumar, R; KAU; Rajan, A
A study was undertaken to assess the prevalence and pathology of dermatological disorders encountered m cattle m Kerala To study the prevalence of various types of skin disorders data were collected from the Disease Surveillence Report published by the Directorate of Animal Husbandry during the period 1989 1993 The various skin disorders encountered according to this data were tail necrosis (1 44 per cent) cutaneous mycosis (10 58 per cent) Eczematosis (6 09 per cent) pox (4 75 per cent) tick infestation (37 22 per cent) lice infestation (25 72 per cent) mangy dermatitis (13 82 per cent) wart (0 36 per cent) In this study tick infestation was found to be highly prevalent. Dunng the course of this investigation skin biopsies collected from 97 cattle were subjected to detailed gross and histopathological examination They were classified as Cutaneous ulceration (22 68 per cent) Fly bite dermatitis (15 46 per cent) Decubitus ulcers (12 47 per cent) Hyperkeratosis (9 3 percent) Papillomatosis (9 27 per cent) Hypertrichosis (8 25 per cent) Ectoparasitic mjuiy (6 19 per cent) Teat lesions (6 19 per cent) Fibroma (2 07 per cent) Dermatophilosis (1 03 per cent) Squamous cell carcinoma (1 03 per cent) and Fibrosarcoma (1 03 per cent) Cutaneous ulceration was the most common disorder encountered and Biopsies revealed epidermal lysis In fifteen animals fly bite dermatitis was noticed with greyish white necrotic papules and wheals on the neck shoulder ears and around eyes Perivascular changes were seen microscopically Nine cases of hyperkeratosis were studied which may be associated with hypovitammosis A Udder and teat papillomatosis was encountered m nine animals with ballooning degeneration and clumping of keratohyahn granules microscopically Eight crossbred cattle recovered from the foot and mouth disease had hypertrichosis Hair coat was shaggy and wavy Ectoparasztic injury was encountered m cattle mainly due Boophilus infestation Teat lesions encountered were mamly due to traumatic injury and chapping Two cases of fibroma and one case of fibrosarcoma were encountered on the teat of cattle A growth on the vulval region was diagnosed as squamous cell carcinoma An expenmental study on the cutaneous hypersensitivity reaction m cattle to PHA, 2 4 DNCB and BCG was earned out Mast cell response to these mitogens was also studied Effect of Agropesticides Furadan and BHC on local application on the skin of calves were studied Dermatosis was the charactenstic response The need for taking care to avoid pesticide contamination on the skin of animals was stressed
Open Access
Aflatoxin induced cytological alterations in ducks
(Department of Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1996) Vigil Anbiah, S; KAU; Manomohan, C B
An experimental study was conducted in desi ducks to assess the cytological alterations induced by aflatoxin Bl (AFB1) and 4 dimethyl amino azo benzene (4 DAB) One hundred and eight desi ducks of one month age were selected for the study The birds were divided into two treatment groups which were given A1 Bl (l0ug/kg body weight and l5ug/ kg body weight) and 4 DAB (5 mg and 10 mg/kg body weight) and a control group each group consisted of thirty six birds Body weight haemogram clotting time total serum protein serum albumin serum globulin albumin-globulin ratio serum aspartate amino transferase serum alanine amino transferase serum bilirubin and cytogenetic assay were estimated at periodic intervals The ducks were subjected to detailed autopsy and histopathology Clinically the exprimental birds were healthy Anaemia leucocytosis and increased blood clotting time were noticed in birds which received 15 ug/kg body weight o f AFB1 and both the dose levels of 4 DAB Total serum protein was reduced in all the treated birds In the aflatoxin group serum albumin and globulin levels were decreased Albumin globulin ratio was increased in 4 DAB tieated buds Serum aspartate ammo transferase level was elevated in buds winch moved 10ug/kg body weight of A1 Bl and 10 mg/kg body weight of 4 DAB Birds which received ATB1 as well as 10 ing/kg body weight of 4 DAB showed an elevation in serum alanine amino transferase level Serum bilirubin was incieased in all the treated birds Those ducks which were fed with AFB1 at 1 5ug/kg body weight showed tendency of hepatoma formation during the experiment The ducks which received 5 mg/kg body weight of 4 DAB exhibited gross and histopathological lesions suggestive of hepatosis and mild curhosis 1 he birds given 10 mg/kg body weight of 4 DAB tevealed gross as well as histopathological lesions of hepatic degeneiutiou and necrosis and indications of neoplatic changes Trend towaids polyploidy was the major chromosomal aberration observed in ducks which received 15g/kg body weight of AFB
Open 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.
Open Access
Neuropathology and diagnosis of rabies in domestic animals
(Department of Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1996) Silamban, S; KAU; Ramachandran, K M (Guide)
An investigation was made to study the epidemiology, clinical signs, pathologic lesions and diagnosis of rabies in domestic animals in the state of Kerala. Epidemiology of rabies for the last 12 year period from July 1983 to June 1995 was assessed from the post – mortem records maintained at the department of Pathology. Regional distribution, Prevalence in each species and year – wise occurrence were studied. Canine rabies was found preponderant. Rabies was recorded in wild animals also. Detailed clinical signs and gross pathological changes in the rabies positive cases were studied. One hundred and six rabies suspected carcasses of different species of animals were examined for the disease employing Sellers’ impression smear staining, histopathology, fluorescent antibody test (FA test) and immunoperoxidase test (IP test). Twenty – two of them were confirmed positive for rabies. Negribodies were demonstrated with Sellers’ staining and histopathological staining. Sellers’ staining was identified to be the simple and rapid staining method that could be employed in the field laboratories. In addition to H & E, Mann’s stain and Sellers’ stain were applied for staining histological sections. H & E was found to be satisfactory for routine staining. Histological changes in the brain (cerebrum, cerebellum and hippocampus), salivary gland (parotid and submaxillary) and trigeminal nerve of rabies positive animals were studied. The efficacy of the diagnostic techniques used for rabies diagnosis was compared. FA test confirmed maximum number of rabies positive cases. The results of the rabies diagnosis was cross – checked by Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Oregon State University, USA.

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