The worldwide increase in the use of antibiotics as an integral part of poultry and livestock production industry has recently received increasing attention as a contributory factor in the international emergence of antibiotic-resistant bacteria in human beings. To gauge the presence of the aforementioned scenario in the Indian context, a preliminary survey was conducted to assess the use of chlortetracycline (CTC) in 12 commercial layer farms and to quantify and confirm its residue in the egg. Samples of feed and eggs were collected at day 0 (prior to CTC addition), 3rd, 5th and 7th day during treatment and on the 9th and 14th day (2nd and 7th day after withdrawal of CTC) from each of the 12 commercial poultry farms studied. Concentration of CTC in feed was significantly (P less than 0.01) high on the 3rd, 5th and 7th day. On the 9th day and 14th day CTC concentration in feed was significantly (P less than 0.01) lower compared to the earlier 3 days studied. A highly significant difference (P less than 0.01) of the antibiotic residue in egg was observed in all the 5 days with high residual levels of CTC in egg. CTC in feed and its residue in egg were detected even on the 9th and 14th day respectively.

Aim: A safety pharmacology trial was conducted to evaluate the impact of enrofloxacin on zootechnical performance, behaviour and immunohistopathological response in Newcastle disease virus vaccinated broiler chicken after pulsed water medication. Materials and Methods: Experimental group birds were administered with enrofloxacin at recommended therapeutic dose 10mg/Kg body weight, through drinking water for five consecutive days from 43rd to 47th day of age. Zootechnical performance parameters, behavioural and humoral immune response in terms of haemagglutination inhibition (HI) titre were assessed at different time interval during pre-treatment, treatment, post-treatment period. Bursa of Fabricius and spleen tissues collected at each sampling point viz. 1, 3, 5, 7 and 9 days post treatment were subjected to histopathological examination. Results: A significant reduction in HI titre was noticed in enrofloxacin administered birds. The decreased HI titre was further substantiated by the histopathological changes observed in bursa of Fabricius and spleen which showed a lymphocytic dispersion and depletion with several areas of lymphoblastic degeneration. Conversely, a down regulatory effect on humoral immunity was observed as evidenced by increased HI titre value noticed from 5th day post treatment onwards and a congruent reversible trend in histopathological changes as indicated by repopulation with lymphocytes on 9th day post treatment. However, there was no significant change in body weight, cumulative feed intake, feed efficiency and behaviour in enrofloxacin administered groups. Conclusion: The present study suggests that the immuno suppressive activity of enrofloxacin may alter the immune response to vaccines, if it is coadministered during vaccination of broilers. On the other hand, enrofloxacin, though it decreased the humoral immune response, it did not have any appreciable effect on broiler's performance. [Vet World 2013; 6(6.000): 337-342

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Aim: A pharmacological study was undertaken to evaluate the safety and adverse effects of enrofloxacin administration in broiler chickens by assessing the serum biochemical parameters, associated histopathological and ultra structural changes in liver and kidney. Materials and Methods:Birds in the treatment group were administered with enrofloxacin at the recommended therapeutic dose 10mg/kg body weight via drinking water for five successive days, while the control group (untreated group) received non medicated water. Serum biochemical parameters viz., total protein, albumin, lactate dehydrogenase, alkaline phosphatase, creatine kinase, lipase, triglyceride, gamma glutamyl transferase, urea, uric acid and creatinine were estimated at 24hour and 48hour intervals during the dosing and withdrawal periods, respectively. Liver and kidney tissue samples collected from 1, 3, 5, 7, and 9 days post treatment groups were subjected to histopathological and ultrastructural examinations.Results: There was no significant change (p>0.05) in total protein, albumin, lactate dehydrogenase, alkaline phosphatase, creatine kinase, lipase, triglyceride and urea levels in the enrofloxacin administered broiler chickens at all the time points evaluated. However, a significant increase (p<0.05) in gamma glutamyl transferase, uric acid and creatinine levels were th observed after the 4 dose of the enrofloxacin and on day 1 post treatment. During the withdrawal period, the elevated levels declined gradually and showed the trend towards control values as evidenced by a statistically insignificant difference on 3, 5, 7 and 9 days post treatment when compared to that of control group. These biochemical changes were substantiated by histopathological and ultrastructural changes elicited in liver and kidney. Conclusion:The reversible trend observed in serum biochemical parameters, histopathological and ultra structural alterations in liver and kidney during the withdrawal period suggests that enrofloxacin is safe if administered to broiler chickens at the recommended therapeutic dose and if the stipulated withdrawal period is strictly adhered to.

A total of 48 commercial poultry feed samples collected from different poultry feed manufactures in Tamil Nadu, India were examined for the contamination of aflatoxin B1 (AFB1) and Aspergillus flavus. AFB1 in the samples was estimated by sandwich ELISA and the presence of A. flavus was detected by Real-Time PCR assay. Real-Time PCR analysis using A. flavus- specific omt primers confirmed the presence of A. flavus in all the samples tested. ELISA results indicated that the AFB1 contents in the poultry feeds ranged from 1.0 to18.7 ppb, which were below the permissible safe limits for poultry bird consumption and health. The results suggest adoption of good man-ufacturing practices by the commercial poultry feed manufacturers during procurement of feed ingredients, handling, storage and processing which might have suppressed the growth of A. flavus and aflatoxin contamination.