The present study aimed to investigate the effect of probiotic
Lactobacilli
addition on
Listeria monocytogenes
load, inflammatory reaction, and virulence properties in broilers from 1 to 14 D of age. A total of 480 broiler chicks were randomly allocated to 4 treatments of 6 replicates each. All birds were infected with
L. monocytogenes
on the first day and supplemented an equal amount mixture of
Lactobacillus acidophilus
and
Lactobacillus plantarum
at doses of 0 (control), 10
6
, 10
8
, 10
10
cfu/kg of diet. The results showed that on 7 and 14 D after administration,
Lactobacilli
addition at the 3 doses decreased (
P
< 0.05)
L. monocytogenes
loads in the cecum, skin, liver, and spleen by 0.065 to 0.933 log
10
cfu, and the pathogen linearly reduced (
P
≤ 0.015) with the increasing doses of probiotics in the skin. Serum cytokines including IL-1β, IL-6, tumor necrosis factor-α, and interferon-γ in probiotics treatments were decreased (
P
< 0.05) by 25.4 to 51.1%. Transcriptional levels of genes related to anti-inflammatory reactions including IL-10, hypoxia inducible factor 1 alpha (
HIF1A
), prostaglandin E receptor 2, and prostaglandin-endoperoxide synthase 2 in the intestinal mucosa were upregulated (
P
< 0.05) in
Lactobacilli
treatments, and linear and quadratic responses (
P
≤ 0.019) were found on HIF1A. Furthermore, the probiotics attenuated (
P
< 0.05) listerial adhesion, pore-forming, and invasion properties by downregulating autolysin Ami, listeriolysin O, internalin A and B, and a linear (
P
= 0.006) dose response of probiotics was exhibited on flagellin. The findings indicate that dietary coadministration of
L. acidophilus
and
L. plantarum
can attenuate
L. monocytogenes
infection by depressing its intestinal inoculation, translocation, inflammatory reaction, and virulence property in broilers and suggest that the probiotics can be an alternative against listerial infection in broilers.
