Effect of Probiotic on Salmonellas in Chicken Model

In this study an in vitro model of poultry digestive tract was used to determine the survival of a probiotic strain of Lactobacillus plantarum and its effect on Salmonella Typhimurium in simulated digestive system of chicken.

Ten gram feed added to 70ml water and subjected to an in vitro model of the poultry digestive tract: Fermented moist feed (FMF) plus 10^6 cfu/ml Salmonella Typhimurium; Drinking water (Dw) with Lactobacillus salivarius, plus 10^6 cfu/g Salmonella Typhimurium; and S. Typhimurium alone.

 The model divided to 3 stages: Stage 1 crop: pH 4.6 (80µl 37% HCl) for 45min at 41.4ºC. Stage 2 gizzard: pH 2.5 plus 0.320g pepsin for 90min at 41ºC. Stage 3 small intestine: pH 6.2 (with NaHCO₃) plus 0.320g pancreatin and 0.220g bile salts for 120 min at 41ºC. With the exception of Lactobacillus plantarum for FMF all bacteria were added at the beginning of stage 1. FMF was prepared by inoculating moist feed (1 feed: 1.2 water) with Lactobacillus plantarum and incubating for 24h at 30ºC. Lactobacilli and Salmonella were enumerated at 0, 45, 135 and 285min. All treatments were applied in triplicate.

At the end of stage 2 there were 1.4 log reductions in Lactobacillus plantarum in FMF and only 0.4 log reductions in Drinking water, after which numbers recovered. Numbers of Salmonella were reduced in the acidic parts of simulated digestive tract but then recovered when pH was buffered above pH 6.

 Addition of Lactobacillus prevented recovery of Salmonella Typhimirium, suggesting an inhibitory effect on Salmonella Typhimurium. When FMF was added Salmonella Tyhimurium was not detectable at the end of stage 2. It is likely that lactic acid present in FMF increased inhibitory effect of Lactobacillus plantarum.

The results indicate on the effect of Lactobacillus plantarum to reduce pathogens in poultry and possibility to use probiotic as alternative for antibiotics.