Examination of the Expression of Immunity Genes and Bacterial Profiles in the Caecum
of Growing Chickens Infected with Salmonella Enteritidis and Fed a Phytobiotic
Laptev, Georgi Yu; Filippova, Valentina A.; Kochish, Ivan I.; Yildirim, Elena A.; Ilina, Larisa A.; Dubrovin, Andrei; Brazhnik, Evgeni A.; Novikova, Natalia; Novikova, Oksana B.; Dmitrieva, Margarita E.; Smolensky, Vladimir; Surai, Peter F.; Griffin, Darren K. ✉; Romanov, Michael N.
Simple Summary Salmonellosis is among the most common infectious poultry diseases
that also represent a high risk to human health. The pathological process caused by
Salmonella enterica serovar Enteritidis (SE) triggers in the caecum the expression
of certain genes, e.g., avian beta-defensins (gallinacins), cytokines (interleukins),
etc. On the other hand, gut microbiota influences the infection potential of pathogens.
The present study aimed at revealing the differential expression of genes associated
with the immune system and changes in the bacterial communities in the intestine of
growing chickens in response to SE infection. We also tested a feed additive, essential
oils-based phytobiotic Intebio, as a potential alternative to antibiotics and showed
effects of its administration on the caecal microbiome composition and the expression
of some genes related to immunity. The phytobiotic showed its efficiency for application
in poultry rearing and production. This study was performed to investigate the differential
expression of eight immunity genes and the bacterial profiles in the caecum of growing
chickens challenged with Salmonella enterica serovar Enteritidis (SE) at 1 and 23
days post inoculation (dpi) in response to SE infection at 19 days of age and administration
of the phytobiotic Intebio. Following infection, the genes CASP6 and IRF7 were upregulated
by greater than twofold. Chicks fed Intebio showed at 1 dpi upregulation of AvBD10,
IL6, IL8L2, CASP6 and IRF7. At 23 dpi, expression of AvBD11, IL6, IL8L2, CASP6 and
IRF7 lowered in the experiment subgroups as compared with the control. Examination
of the caecal contents at 1 dpi demonstrated a significant decrease in the microbial
biodiversity in the infected subgroup fed normal diet. Bacterial content of Lactobacillus
and Bacillus declined, while that of Enterobacteriaceae rose. In the infected subgroup
fed Intebio, a pronounced change in composition of the microflora was not observed.
In the early infection stages, the phytobiotic seemed to promote response to infection.
Subsequently, an earlier suppression of the inflammatory reaction took place in chickens
fed Intebio. Thus, use of Intebio as a drug with phytobiotic activity in chickens,
including those infected with Salmonella, proved to be promising.