Studies on Salmonella infections in poultry in relation to aflatoxin in feed

The present study was carried out to isolate Salmonella from poultry birds, to detect and quantify aflatoxins present in the poultry feed and to identify aflatoxigenic Aspergillus spp. from poultry feed. A total of 4 isolates of Salmonella spp. were isolated which indicated overall prevalence of 2.6% in poultry birds. Among these isolates, 2 (7.1%) isolates were obtained from ovary/yolk contents and 2 (2.1%) isolates were from liver samples. Antimicrobial studies suggested an increasing trend of resistance to various antimicrobial drugs. All isolates were serotyped as Salmonella Bazenheid. Virulence typing of all the Salmonella isolates showed higher prevalence of spiA, sipB genes and lower prevalence of for hilA, avrA, sseD and spvC genes. A total of 60 feed samples were screened for the presence of aflatoxins by PMC method and 29 (48.33%) samples were found positive for aflatoxins and the level of aflatoxins in tested feed samples were in the range of 25 ±30 ppb to 25 ± 100 ppb. Quantification of aflatoxins by ELISA revealed that 49/60 (81.66%) were positive for aflatoxins and the range of aflatoxins in different feed samples was 2.97 - 74.05 ppb. Overall 16 isolates of Aspergillus spp. were obtained by culturing of feed samples on SDA. Among 16 isolates, seven isolates were positive for atleast one toxigenic gene. Two isolates showed positivity for all four genes (aflM, aflP, aflR & aflD) while remaining 5 isolates were positive for aflR and aflP genes. All the birds from which Salmonella was isolated were fed on aflatoxin contaminated feed.

Keywords: Salmonella, PMC, ELISA, Aspergillus M.V.Sc.