The use of antibiotics in farm animals is one of the main reasons for the development of resistant bacterial strains (e.g., zoonotic pathogens). Therefore, save alternatives are needed. Here, we examined how post-hatch application (day one to seven of life) of the probiotic Enterococcus faecium AL41 (EF) affects the development and tissue properties of the broiler pectoralis major muscle (PM). Expression of regulators, namely IGF-1, PAX7, and MYF5, was also investigated. At day 1 (n = 6), and days 5, 8, and 12 (n = 10), muscle samples were taken from control and EF supplemented chicks. From day 5 on, myonuclei number per fiber was elevated in EF chicks. Improved capillarization (from day 8), larger myofibers, increased body and PM weights (day 12) were found in the EF group. Part of our findings is explainable by higher intramuscular expression of IGF-1 and lower MYF5 expression in EF birds. In both groups IGF-1 expression decreases with age, thereby increasing the cellular myogenic potential. However, a strong increase in PAX7 expression and more PAX7-positive nuclei were found in EF chicks at day 12. We conclude that EF supplementation improves PM growth and health due to positive effects on bioavailability and fusion capacity of SATC progeny and better tissue perfusion.

The effect of inorganic zinc and Ascaridia galli infection was studied on MUC1, MUC2 (mucin), sIgA (secretory immunoglobulin A), and metallothionein in the intestines of broilers. Thirty-five-day-old chickens (n = 24), COBB 500 breed, were included in a 14-day experiment. Chickens were divided into 4 groups of 6 chickens each: control ©, Ascaridia galli (AG), Zinc group (Zn), and combined group (AG + Zn). Samples from the intestine for determination of MUC1, MUC2, sIgA, and metallothionein were taken at 7 and 14 days during necropsy. Samples from the jejunum for determination of MUC1, MUC2, sIgA, and metallothionein were taken at 7 and 14 days during necropsy. The results demonstrated that 12 days’ administration of inorganic zinc increased production of MUC1 (p < 0.0001) and MUC2 (p < 0.001) in the Ascaridia galli-infected group (Ag + Zn) in comparison to control (C). The beneficial effect of zinc was also revealed in the production of sIgA (p < 0.0001) in the combined group (AG + Zn) at 7 days. The concentration of metallothionein increased mainly in the zinc group (p < 0.01) of first sampling and was upregulated in Zn and AG + Zn groups. The obtained data indicate the use of inorganic zinc as a suitable immunomodulator of intestinal immunity in Ascaridia galli-infected chickens.

Summary: The study examined subpopulations of lymphocytes in peripheral blood, spleen, and jejunum including morphology of that segment in broiler chicken farm after treatment with flubendazole (Flimabend) and natural extract from chestnut wood (Farmatan). A total of 24 forty-day-old Kalimero-Super Master hybrid chickens were divided into 4 groups (n=6): the Fli group received Flimabend per os , 100 mg/g suspension in 1.43 mg of active substance/kg body weight during 7 day of experiment, Far group received Farmatan per os at 0.2 % concentration for 6 hours per day during 5 day (experimental days – from 3 to 7); the Far+Fli group received a combination of doses administered in the same way as for the first two groups; and control –C group with no active substance administration. The results demonstrated mild increase of leukocytes, lymphocytes, monocytes, leucocyte common antigen CD45, IgM+ and IgA+ cells in peripheral blood after administration of Flimabend. Similarly, subpopulations of followed lymphocytes (CD3+, CD4+, CD8+, IgM+) were increased in the jejunum after application of that drug. On the other hand, administration of Farmatan revealed opposite effect on determined immunocompetent cells what proves anti-inflammatory effect. Morphology of villi was also negatively influenced by administration of Flimabend. Administration of Farmatan suggests also its preventive administration in chickens. This tanin-containing drug as plant natural product may be used due to its antibacterial activity and as promising alternative to conventional drug with possible antihelminthic effect.

Probiotic bacteria, including the Enterococcus faecium strain, can improve intestinal mucosal health by several mechanisms, including modulation of the immune response, as well as by improving the protective function of the epithelial barrier. In this study, we tested the effect of Enterococcus faecium AL41 on the acute phase proteins response (blood), gene expression of selected molecules of mucosal immunity (immunoglobulin A, mucin-2, insulin-like growth factor 2) and mucus production (all parts of the small intestine) in broilers. Eighty broiler chicks were divided into two groups: a control and E. faecium AL41 (birds were inoculated with AL41 for 7 days) group. The whole experiment lasted 11 days. Our results revealed that the administration of E. faecium AL41 had no substantial effect on the concentrations of acute phase proteins, but we recorded a significant increase in β- and γ-globulin fractions at the end of the experiment, which may indicate an improvement in the immune status. A significant prolonged stimulatory effect of E. faecium AL41 on the relative expression of molecules (immunoglobulin A, mucin-2) as well as on the dynamic of mucus production in the chicken intestine was observed. In addition, AL41 significantly reduced the total number of enterococci in the cecum and faeces.

Ascaridiosis in poultry results in a reduction in body weight gain, egg production, as well as microelement levels. Infected poultry have higher demands on feed with the addition of essential elements including zinc. The effects of the infection by Ascaridia galli and the supplementation of inorganic zinc on the immune status of broilers were monitored through evaluation of the relative expression of selected genes (interleukins, IFN-γ, and TNF-α) by real-time PCR, haematology parameters by microscopy, and quantitative changes of lamina propria lymphocytes by flow cytometry in day 7 and day 14 of the study. We observed that the enrichment of the diet with inorganic zinc has a positive effect on the relative percentage of CD4+ lamina propria lymphocytes in the jejunum and on heterophil counts in blood. In addition, it was concluded that inorganic zinc has an anti-inflammatory effect (downregulation of TNF-α and IL-17) and activates IgA-producing cells in the jejunum of chicks infected with A. galli.

Immune response of day-old chicks infected with Salmonella Enteritidis PT4 and preventive administration of Enterococcus faecium AL41 were studied using hematology and flow cytometry of immunocompetent cells in blood, cecum, bursa and spleen for 11 days, and included 220 animals divided into four groups (n = 55). E. faecium AL41 was administered for 7 days to EF and EFSE groups and on day 4 SE and EFSE groups were infected with Salmonella Enteritidis. Values of monocytes at 4 dpi significantly increased in EFSE and lymphocytes at 7 dpi in EF groups. Blood CD3, CD4, CD8 and IgM lymphocytes improved in EF and EFSE groups and IgA in EF group at 4 dpi. Phagocytic activity of probiotic groups was improved in both samples. Cecal IEL and LPL lymphocytes showed at 7 dpi stimulation of CD3, CD4 and CD8 subpopulations in probiotic groups, especially in EFSE group, IgA IEL and IgA with IgM LPL in EF groups. Bursa Fabricii at 7 dpi presented overstimulation of IgG subpopulation in SE group, spleen CD3 and CD8 in EF and EFSE groups. E. faecium AL41 revealed the protective effect and positive influence on the local and systemic immune response in Salmonella Enteritidis PT4 infected chickens.