Effect of Enterococcus faecium EF 55 on morphometry and proliferative activity of intestinal mucosa in broilers infected with Salmonella Enteritidis

Introduction: The present study aimed to investigate the effect of Enterococcus faecium EF55 on chickens, as well as its influence on proliferative activity of epithelial intestinal cells after infection with Salmonella enterica serovar Enteritidis phage type 4 (SE PT4). Moreover, the length and area of duodenal and jejunal villi of the birds were examined.

Material and Methods: A pool of 80 birds was divided randomly into four groups. Probiotic group (EF) and Salmonella + probiotic group (EFSE) received E. faecium EF55 (10⁹ CFU – 3 g per group/day) during 22 d. Salmonella group (SE) and EFSE group were infected with Salmonella Enteritidis PT4 (10⁸ CFU in 0.2 mL PBS) in a single dose per os on day four of the experiment, whereas control birds (C group) received only 0.2 mL of PBS on that day. Samples were taken on the 4^th and 18^th day post infection.

Results: Supplementation of feed with E. faecium EF 55 confirmed its selective antibacterial activity against SE PT4. The chickens infected with SE PT4 and fed E. faecium EF55 supplemented diet showed increased proliferative activity of enterocytes in the jejunum in both samplings. Applied probiotic strain demonstrated positive impact on intestinal morphometry in the jejunum of both non-infected groups and in Salmonella-infected chickens. In the latter group, the beneficial effect of E. faecium EF 55 was manifested by more efficient tissue turnover in the jejunum.