Efficacy of quebracho and chestnut extracts to control Salmonella in poultry.

CASANOVA, N; REDONDO, LEANDRO M.; DOMINGUEZ, J E; REDONDO, ENZO A.; JOAQUIM, P; FERNANDEZ-MIYAKAWA, MARIANO E.; CHACANA, P

Torino

Congreso; VI Mediterranean Poultry Summit; 2018

Mediterranean Poultry Network of the WPSA

Salmonella infection is a major cause of bacterial enteric illness in both humans and animals;and this food-borne microorganism is usually associated with poultry production. Amongother measures, antimicrobials are traditionally used to control Salmonella which provides aselection pressure resulting in the selection and spread of resistant microorganisms.Therefore, new alternatives to antimicrobials are needed to guarantee the safety for theconsumers. The aim of this study was to determine the activity against Salmonella of chestnutor quebracho tannins and their efficacy to control the pathogen. The minimal inhibitoryconcentration (MIC) for both tannins was determined by broth microdilution method on 15Salmonella strains isolated from poultry. MIC values for chestnut were of 2 mg/mL in alltested strains whereas MIC for quebracho ranged from 4 to1 mg/mL. In addition, anaugmented inhibitory effect on Salmonella was observed when both tannins were combined.The efficacy of the tannins to reduce the excretion of Salmonella enteritidis was assessed inan experimental infection model in 1-day old broiler chicks. Groups of 15 chickens were fedfrom the first day of life with regular feed added with 0.1% of chestnut, quebracho or a blendof both tannins. A control group of non-treated birds was also included. At day 6, chickenswere individually challenged by oral gavage with 107 CFU of S. enteritidis and individualsamples were taken by cloacal swabbing at the 5th and 12th day post-infection (dpi) todetermine the excretion of the microorganism. In the control group, 70.5% and 82% of thebirds were positive for Salmonella at the 5th and 12th dpi respectively. Significant reductionof the excretion of the pathogen was only observed when the birds were treated withquebracho tannins: 23% at the 5th dpi (P