Studies on the respiratory tract infections in poultry in relation to mycotoxins in feed
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Date
2013
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Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana
Abstract
A total of fifty two (52) isolates of bacteria associated with various respiratory tract infections in chicken were isolated from twenty two (22) different outbreaks in and around Ludhiana comprising of Staphylococcus aureus (46%), avian pathogenic E. coli (APEC, 29%), Proteus sp. (9%), Klebsiella pneumoniae (6%), Streptococcus equi subsp. zooepidemicus and Pseudomonas aeruginosa (each 4%) and Citrobacter koseri (2%). Antibiogram showed an increasing trend of resistance to various antimicrobial drugs and emergence of multi-drug resistant bacteria. Phenotyping of APEC showed all the isolates as Congo red binding positive (Crb+) suggesting their invasive nature. Virulence typing of APEC showed 7/15 isolates to contain all the five plasmid associated virulent genes. Present study also reported molecular detection of the organism Avibacterium paragallinarum (1.29%), although the organism could not be isolated. Occurrence of Mycoplasma gallisepticum was 59.15% while that of Mycoplasma synoviae was 33.8% confirmed through PCR. Multiple sequence alignment of partial sequence data revealed 99%-100% sequence homology with respect to M. gallisepticum and/or M. synoviae. A total of fifty (50) poultry feed samples from the affected farms were analyzed initially for presence of any mycotoxins by screening through pressure mini columns (PMCs) in which the level of aflatoxin was in the range of 25 ± 25 ppb to 600 ± 25 ppb. Results of thin layer chromatography (TLC) revealed occurrence of aflatoxin B2 to be the highest (88%) followed by aflatoxin B1 (84%), ochratoxins (74%) and citrinin (10%). The levels of aflatoxin B1 and B2 were found in the range of 25-600 ppb with an average of 178.57 ± 23.8 ppb and 202.27 ± 25.43 ppb, respectively. Ochratoxins were in the range of 50-600 ppb with an average of 206.08 ± 20.6 ppb while citrinin was in the range of 50-200 ppb with an average of 150 ± 31.56 ppb. Histopathology findings revealed a marked immunosuppression in the birds with respiratory tract affections.