Effect of potential probiotic activity of Enterococcus faecium EE3 strain against Salmonella infection in Japanese quails

Abstract

Thirty-two one-day-old Japanese quails were divided into 4 equal groups. The first group was the reference control group. The second control group (PT4CG) was infected per os with Salmonella PT4 strain (1.0 x 10 7 cfu/ml), the third control group (EE3CG) was treated with Enterococcus faecium EE3 strain (1.0 x 10 8 cfu/ml) and the fourth experimental group (EG) was infected with PT4 strain 8 h before the application of EE3 strain. The birds of the EG and EE3CG received 100 µl of an overnight culture of EE3 strain. The birds in the PT4CG received a placebo. Faecal samples were taken at 0, 16, 72, 118 and 168 h after the first application of EE3 strain. The quails were sacrificed and the survival of EE3 strain as well as PT4 strain was estimated not only in faeces but also in the caecum. The inhibitory effect of EE3 strain against Salmonella PT4 in the EG was found after 16 h; the difference 0.24 log cycles between PT4 and EE3 counting was detected. This effect was prolonged up to the end of the experiment. In the caecum no influence of S. enterica due to EE3 strain was detected. The increase of average daily weight in birds was 7.6% in the EE3CG in comparison to the average daily gain in the reference control group. The average daily gain was higher (10%) in the EG in comparison to the average daily gain in the PT4CG. Comparing the EG and the EE3CG, a 11% lower daily gain in birds was noted in the EG. The lowest value of lactic acid (LA) was in the reference samples. On the other hand, the highest value of LA was observed in the EG of birds (58.12 ± 10.91 mmol/l). In both control groups; that is, in the EE3CG as well as in the PT4CG similar counts of LA were found (40.55 ± 8.576; 41.83 ± 5.98 mmol/l). Glutathioneperoxidase (Px) activity as well as the evidently good health of Japanese quails indicated that oxidative stress was not evoked by Salmonella infection in this experiment.