Loading...
Theses
Browse
2 results
Search Results
ThesisItem Open Access Ochratoxicosis in the goat(Department of Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1983) Maryamma, K I; KAU; Krishnan Nair, MAn experimental study was carried out to delineate the pathological effects of ochratoxin in goats. A comparative assessment of ochratoxin production by A. ochraceus and A. sulphureus on what and rice under static and shake cultures was also made. A. ochraceus was found to be a better toxin producing strain in both substrates under static and shake cultures systems and wheat was a better substrate than rice. Toxicity studies were conducted in Sannen – Malabari cross-bred goats of 1 to 3 months age. Purified ochratoxin produced in the laboratory was administered by oral, intra-peritoneal and intravenous routes. The different dose levels adopted were 2.5 mg/kg body weight, 1 mg/kg body weight and 0.5 mg/kg body weight. The synergistic effect of ochratoxin and aflatoxin in goats was studied by adminstering the crystalline toxins simultaneously (Makor Chemicals, Israel) by itraperitoneal route. The parameters of study were: clinical signs, haematological and biochemical alterations, pathological changes in urine, and macroscopic, microscopic and ultra-structural alterations in organs. Varying degree of clinocopathological changes were noticed in the test animals. The animals became weak and listless and in general there was reduction of total erythrocyte count, PCV, haemoglobin and lymphocyte count. Serum protein level was lowered while BUN and creatinine and blood coagulation time were high. There was rise in ALP, SGOT and SGPT in some of the test animals. The changes and degree of variation depended on the dose, total quantity and rate of administration of the toxin and duration of the experiment. More severe alterations were noticed when ochratoxin and aflatoxin were administered simultaneously. Important changes in the urine were lowering of pH, albuminurea and presence of epithelial cells and casts. Pathological changes varied in severity in different organs and were observed in the following descending order: kidney, liver, intestines, stomach, lymph nodes, spleen, thymus, genital organs, endocrines. In the kidneys, the order of intensity of pathological alterations was: proximal convoluted tubules, Henle’s loop, distal convoluted tubule, glomeruli, collecting tubules. Retrogressive changes of different degree and necrosis of the lining epithelial cells of tubules and endothelium and epithelium of glomeruli were the important lesions. Changes in glomeruli and Bowman’s capsule noticed in the higher dose group included shrinkage of glomeruli and presence of proteinaceous material in the capsular space. Eosinophilic granular casts and PAS positive bodies were present in the lumen of tubules. The necrobiotic renal changes were more intense when orchatoxin and aflatoxin were administered simultaneously. Hepatic lesions were mainly fatty infiltration, necrosis of hepatocytes and haemorrhage. The changes were most severe in combined toxicity. Mallory bodies and mild biliary hyperplasia were noticed in a few sections. Necrosis and subsequent depletion of lymphocytes wee the lesions in lymph nodes, spleen and thymus in some test animals. Degenerative changes were also noticed in testis, ovary, pituitary, adrenals and pancreas in experimental groups. In the combined toxicity group the pathological effect was more intense. At the ultra-structural level, the hepatcytes as well as the epithelial cells in the kidney showed severe changes. The cell organelles were either completely damaged or showed partial configurational alterations. Mitochondria showed changed in the density of matrix as well as disorientation and destruction of the limiting membranes and cristae. Cytolysosomes incorporating damaged cell organelles were abundant. Disaggregation of ribosomes and fragmentation of ER were noticed. In the glomerulus, there was destruction of the basement membrane and disruption of the regular arrangement of the foot processes of podocytes. In the cytoplasm of hepatocytes, Mallory bodies and lipid droplets were present. Varying degree of nuclear changes like clumping, condensation and disappearance of chromatin and fragmentation of nucleolus and nuclear membrane were observed. Changes occurred in the tight junctions of epithelial cells of bile ducts. Pathological alterations were more pronounced when ochratoxin was administered by the pwerenteral route. Oral administration of toxin also effected structural alterations which indicated that some fraction of ochratoxin escaped degradation in the rumen. From this study it became evident that aflatoxin potentiated the effect of ochratoxin. The structural damage to the cells might be due to the inhibition of oxidative enzymes which is reflected by the extensive ultra- structural alteration observed in the mitochondria and RER. Biochemical changes like high BUN and creatinine were evidently due to necrobiotic changes in the kidney. Interference in the synthesis of proteins due to damage of hepatic cells and escape of protein molecules due to alteration in the podocyte foot processes and basement membranes may account for the reduced serum protein levels. The nature of organellar destruction and configurational changes in the cells indicate the toxic potency of the mycotoxin on the biological system.ThesisItem Open Access Studies on purple top roll (PTR) of potato in Karnataka(Department of Plant Pathology, University of Agricultural Sciences, Bangalore, 1983) Sreedharan, A; KAU; Reddy, H R1. Survey for the incidence of potato purple top roll revealed that the disease was present in Bangalore, Belgaum, Dharwad, Hassan and Kolar districts of Karnataka. The average percentage of incidence varied from 8.94 to 50.07. The survey also indicated that there was low incidence of the disease in summer and high incidence in kharif and rabi. 2. The pathogen was transmissible by wedge, side and core grafting. 3. The disease was transmitted through dodder, Cuscuta chinensis Lam. 4. The disease was not transmissible through sap and aphids Myzus persicae Sulz. And Aphis gossypil Glov. 5. The etiological agent was transmitted by the leafhopper, Orosius albicinctus Distant and not by Hishimonus phycitis Distant. 6. The vector, O. albicinctus could acquire the pathogen in two hr and inoculate to healthy plants in 30 min. The percentage of active transmission was 35 – 40 and the minimum incubation period in the plant was between 20 and 25 days. Maximum percentage of transmission was obtained on 40th day after inoculation. 7. Characteristic symptoms of the disease was inward rolling of basal parts of top leaflets, purple/pink pigmentation, smalling of leaves, excessive proliferation of axillary buds, erect appearance, production of purple coloured, aerial tubers and stunting and dwarfing of plants. 8. The etiological agent infected tomato, tree tomato, Datura stramonium and D. metel by grafting. 9. The pattern of spread of the disease in the field was from external source in the beginning and later the spread was within. 10. The vector population was correlated with the disease incidence in the field. The increase in the incidence of the disease followed the increase in the vector population. 11. The leafhopper vector, O. albicinctus Distant was high in the months from late June to December and low from January to early June. 12. The high population of leafhoppers was correlated with low temperature and high humidity and low population was correlated with high temperature and low humidity. 13. The disease appeared 40 days after planting in the field and then it gradually increased reaching the peak by 90th day. 14. The pathogen was transmitted through tubers for two successive generations but to a lower percentage in the second generation. 15. Of the 36 cultivars/varieties of potato tested under field conditions, none were found to be resistant, However, the vars. JF 542, JF 4612, JG 676, JG 900, JC 750 and JE 812 had less than five per cent infection. Kufri Chandramukhi and Kufri Jyoti were highly susceptible having 48.3 and 47.6 per cent incidence, respectively. The highest average incidence of PTR in these cultivars in farmer’s fields was 35.85 and 26.03 per cent, respectively. 16. There was considerable loss in yield in many cvs. Viz., JC 750, BS/F 100, JC 182 and EM/F 2120. 17. The weight of tubers produced by the infected plants was always less than the tubers obtained from the adjacent healthy plants. The infected plants produced more number of smaller tubers which aggregated close to the main stem attached on short stolons. 18. Complete remission was obtained at 500, 1000 and 2000 ppm, incomplete remission at 100 and 250 ppm and no remission at 50 ppm of tetracycline given alternatively for 20 days.