The project was designed to study the effect of Doxin on the 1.txuxuine system and if any, its toxicity (in normal and excessive doses) in broiler chickens. A total number of' 150 day old broJer chicks were randomly divided into six equal groups, A through F, each containing 25 birds. Group A arid B were kept as control i.e. A was non-medicated (Doxin) and vaccinated against ND while B was non-medicated (Doxin) and non vaccinated against ND. Groups C and E were medicated I)oxin at different levels (0.5gm/I and 4 gm/I) at 1st to 5th day and 22nd to 26th day respectively. Both groups were vaccinated against ND. Groups D and F were medicated Doxin at different levels (0.5gm/i and 4 gm/i) at 1st to 5th day and 22nd to 26th day respectively, both groups were non vaccinated against ND. The experimental period was 42 days. Organ body weight indices, gross lesions on liver, spleen, thymus, bursa of Fabricius and kidneys, determination ol immune response against Newcastle disease, serum total protein, albumin, globulin, A/G ratio, alkaline phosphatase, alanine amino transferase, aspaitate amino transferase, uric acid and urea levels were conducted.

The statistical analysis of organ body weight index for liver showed significant difference between the medicated and nonmedicated (control) groups. The highest. liver body weight index was achieved in the birds of group E. The organ body weight indices of spleen, thymus and bursa of Fabricius are quite irregular. The data obtained by the the analysis of serum statistically indicated that the mean levels of serum total protein and albumin of control and medicated groups were not significantly different from each other. The mean levels of Globulin, A/G ratio of vaccinated and non- vaccinated groups carry statistical significant difference. There was no significant difference in alkaline phosphatase (ALP), alanine amino transferase (ALT) and asparate amino transferase (AST) levels of all medicated and non-medicated groups. The mean levels of urea and uric acid were increased in the medicated groups, highest in the high dose medication. The data obtained by the analysis of antibody titre against Newcastle disease on 0, 14th, 28th and 42nd day of experiment showed that geometric mean HI titres of all medicated groups decreased that of control groups.