ANJANEYULU, Y(MAJOR)MADHURI, DGOPALA REDDY, ANIVEDITHA, M2018-10-082018-10-082007-10http://krishikosh.egranth.ac.in/handle/1/5810074987THESESABSTRACT : The present study was designed to study the cadmium toxicity in broiler chicken and to evaluate the efficacy of ascorbic acid to counteract the damage caused by cadmium. Seventy five, day – old Vencob male broiler chicks were divided into five groups consisting of 15 chicks each. Group I served as control, which was devoid of cadmium (Cd) as well as ascorbic acid (AA) group II fed with Cd @ 50 ppm, group III was fed with AA @ 300 ppm, group IV was fed with Cd @ 50 ppm and AA @ 300 ppm, while group V was fed with Cd @ 50 ppm for 1-28 days followed by AA @ 300 ppm. Weekly body weights and feed consumption were recorded in each group. The body weight gain, feed consumption and feed conversion efficiency at the end of the experimental period were significantly (P<0.05) reduced in Cd supplemented group (group II) while group IV and V showed significant improvement in these parameters, when compared with group II. Five birds from each group were randomly sacrificed on 14th, 28th and 42nd days. Blood and serum were collected from each bird separately for haematological and biochemical estimations. A detailed necropsy was conducted on each of five birds and tissue samples from liver, kidney, bursa of Fabricius spleen, intestine, heart, lung, muscle and brain were collected in formal saline for histopathology. Haematological studies showed that overall mean values of Hb, PCV and TEC were significantly (P<0.05) reduced in group II as compared with other groups. Group I and III did not show any significant difference. The treatment groups (group IV and V) showed significant increase in haematological parameters as compared to group II. The biochemical analysis showed a significant (P<0.05) elevation in total protein, globulin, ALP, ALT, BUN, Creatinine levels in group II and significant (P<0.05) reduction in albumin levels was seen. Whereas these values in group I and III remained normal. The treatment group (group IV and V) showed significant (P<0.05) improvement in all these parameters. The gross pathological changes in group II birds showed streaks of haemorrhages and rounded borders in liver, enlarged kidney with petechial haemorrhages, splenomegaly, mild congestion of bursa of Fabricius, focal echymotic haemorrhages in breast muscles and thigh muscles, and mild congestion in intestines. The treatment groups (group IV and V) showed mild lesions compared to group II. The remaining groups (I & III) did not reveal any gross lesions of pathological significance. The histopathological examination of group II revealed varying degrees of degenerative changes, in various organs. Liver sections showed moderate congestion of central vein, dilation of sinusoidal spaces. Focal areas of lymphoid aggregates, congestion and inter tubular haemorrhages were observed in kidney. Spleen showed depletion of germinal centers. Bursa of Fabricius showed depletion of lymphoid follicles with cystic spaces in follicular epithelium. Moderate interfibrillar haemorrhages were observed in the sections of heart. Intestine sections showed mild haemorrhages in the sub mucosal region. Lung sections showed mild congestion. Brain showed moderately congested cerebral vessels. The treatment groups showed mild lesions in various organs, which can be attributed to the protective effect of AA. From the present study it can be concluded that AA when supplemented to a diet containing Cd @ 50 ppm level is moderately effective in alleviating the toxic affects of cadmiumennullThesis