Impact of Enterococcus faecium AL41 on growth performance, immune parameters, morphology, and tight junction proteins in intestine of chicks

In the study we investigated how post-hatch preventive administration of Enterococcus faecium AL41 affects growth performance, the intestinal immune parameters and barrier factors, and morphology of jejunum in chickens. Chicks were divided into two groups as control (C) and Enterococcus faecium AL41 (EF). Samples (n=10) from blood and small intestine were taken at days 5, 8, and 11 of the life. Body weight gain increased in EF treated chicks on day 11. From day 8 to 11quantity of IgA in intestinal flush was lower in EF group. Relative expression of occludin gene was up-regulated at day11 in EF group and in same group claudin 1 gene was up-regulated at days 5 and 11. Jejunal CD3⁺lamina propria lymphocytes (LPL) showed stimulation at days 5 and 11. Similarly, CD4⁺, CD8⁺LPL cells were increased at day 8 in experimental group. IgA cells were stimulated at days 8 and 11in EF group. Finally, CD45⁺ LPL cells showed increase at day 11 of life in EF group. Morphological parameters of jejunum were increased in EF group as height of villi at day 1, cutting surface at days 5, 11 and depth of crypts at days 8 and 11. On the other hand, adding of E. faecium AL41to broilers did not show any impact on white blood cell counts in peripheral blood, phagocytic and metabolic activity, quantity of MUC-2, and intraepithelial lymphocytes (IEL). Our trial indicated that early administration of EFAL41after hatching affects growth performance improves health function as intestinal morphology, barrier integrity of gut and intestinal immunity.