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Theses

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19993
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Subject: Veterinary Pathology × End date: 1999 × Start date: 1999 × Thesis Type: M.V.Sc. ×
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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
    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
    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.