Liver function and bacteriology of organs in broiler inoculated with nalidixic acid-resistant Salmonella Typhimurium and treated with organic acids

Abstract

An experiment was carried out with 630 oneday- old chicks to evaluate the effects of organic acids when birds were experimentally inoculated with Salmonella Typhimurium. Liver damage and the persistence of the bacterium in the organs were evaluated as well. Broilers were distributed in a completely randomised experimental design in a 3×2 factorial arrangement of six treatments with seven replicates of 15 birds each. Birds were inoculated with saline solution or the bacterium via gavage at 1 day of age, or were offered a feed containing or not the organic acid blend for the period of 7 to 14 days of age. A dose of 5.0x102 colony-forming units (CFU)/0.5 mL of Salmonella Typhimurium was used for inoculation both via gavage and feed. The parameters evaluated are weight, liver histopathology, liver and serum biochemistry, and bacteriological analyses of the caeca, crop, spleen, and liver and heart pool. At 21 and 28 days of age, the liver of the non-inoculated groups was significantly lighter as compared to the other treatments. Birds fed organic acids presented lower bacterial isolation rates in all organs tested. Birds inoculated in the crop and treated with organic acids presented lower E. coli CFU counts (P<0.05). Birds inoculated with Salmonella presented significant changes (P<0.05) in liver enzymes, as detected by serum biochemistry, and in liver histopathology. It was concluded that organic acids effectively controlled Salmonella Typhimurium and did not cause any liver damage. © T.M. Rocha et al.