Studies on the effects of ochratoxin - A ,ascorbic acid and zinc sulphate on the pathology and pathogenesis of hydropericardium syndrome in broiler chicken
Abstract
A study has been conducted to find out the effects of ochratoxin–a, ascorbic acid and zinc sulphate on the pathology and pathogenesis of hydropericardium syndrome in broiler chicken. A total of 320 , day old broiler chicks were divided into four groups of 80 chicks each. The chicks in group AC, ZC and OC were given ascorbic acid@330 ppm , zinc sulphate @700 ppm and ochratoxin A @1.5 ppm in the feed ,respectively from day 1 till the end of the experiment. Group XC served as control. At the age of 21, chicks in all the groups were further divided into 2 subgroups XC & XH, AC & AH, ZC & ZH and OC&OH respectively. The birds in groups XH, AH, ZH and OH were inoculated with 0.5 ml of diluted HPSL inoculum subcutaneously at day 21 of age . Except for decreased growth rate in OC group no other clinical signs were observed in control groups. Following infection with HPSL inoculum chicks in infected groups exhibited clinical signs which were more severe in group OH followed by XH, ZH and AH in descending order. A high mortality (60.60%) in group OH, moderate (30.30 %) in group XH and low mortality (12.12%&18.18%)was observed in groups AH and ZH. Significant decrease in body weights in group OC was observed as compared to other control groups. Within infected groups decrease in body weight was more in groups OH &XH as compared to groups AH & ZH. Serum enzymatic analysis showed significant decrease in TSP, albumin and globulins in OC group birds as compared to other control groups. A significant decrease in TSP, albumin and increase in AST, ALT &LDH activities was observed in all infected groups as compared to their respective control groups. Among infected groups incorporation of feed with ascorbic acid or zinc sulphate caused improvement in enzymatic activities whereas ochratoxin A caused increase in severity of disease. Immunological studies indicated decrease in humoral and cell mediated immune response in infected groups as compared to their respective control groups. Grossly, the lesions were similar in all infected groups though they persisted for long duration in OA treated birds .However ,less number of birds showed gross lesions in ascorbic acid and zinc sulphate supplemented groups and recovery from infection was also early in these groups.
Significant increase in relative liver and spleen weight and decrease in bursa weight was observed in infected groups as compared to control groups. Histopatholgical alterations comprising basophilic I/N inclusion in the hepatocytes, depletion of lymphocytes in bursa, spleen, thymus ,degenerative changes in kidney tubules and necrosis of myocardium were more severe and persisted for longer duration in OH group birds whereas these were less severe in AH and ZH groups birds. In conclusion ochratoxin A enhanced the severity whereas ascorbic acid and zinc sulphate supplementation reduced the mortality, development of lesions in HPS infected birds.