Studies on clinical signs, growth response and haematological changes in vaccinated and unvaccinated chickens following infection with Salmonella gallinarum var duisburg

Clinical signs, growth response and haematological alterations were studied in virulence plasmid-cured vaccinated and unvaccinated chickens following infection with Salmonella galinarum var duisburg. Clinical disease with a high mortality (65.33%) was observed in the unvacinated birds. A few vaccinated birds also exhibited clinical signs but the mortality was very low (20%).A significantly decrease in body weight gain was noticed in the unvaccinated challenged birds whereas, the growth response in the vaccinated challenged birds was comparable to that of unchallenged birds. A sharp and significant decrease in Hb and PCV was recorded in both the challenged groups but the anaemia was of lesser intensity in the vaccinated birds. A state of leucocytosis was observed in both the vaccinated and unvaccinated birds following challenge which was due to increase in the relative percentage of heterophils and decrease in the relative percentage of lymphocytes. However, absolute counts of heterophils and lymphocytes indicated increase in the number of both these cells; the heterophilia contributed more towards leucocytosis.