Influence of sodium butyrate administered <i>in ovo</i> on gene expression in the brain of broiler chickens

Abstract The gut-brain axis is a bidirectional interaction and information transfer system between the gastrointestinal tract and the central nervous system. It is also known that bioactive substances affect the colonization of the gut by bacterial microorganisms. The following research assessed the effect of sodium butyrate (SB) on the expression of genes related to innate immune response and small heat shock proteins in the brains of broiler chickens. For this purpose 1000 eggs were incubated and divided into 4 groups. Three were injected with either 0.1, 0.3, or 0.5% doses of SB and the last one only with saline. Samples were collected post-mortem on day 42 of rearing. RNA isolated from the brain was tested for gene expression using a panel of the following: HSPB1, HSPB5, HSPB8, HSPB9, HSP70, IL-1β, IL-2, IL-4, IL-6, IL-8, IFNγ, IFNβ, TLR4, GR, BDNF, GSK3β, NR2A, CRH, NF-κB p65 . SB stimulation induced significant changes in gene expression levels, especially in the 0.3% SB group, where down-regulation of most genes is evident. It can be assumed that changes in the level of gene expression are determined by the concentration of SB in the injection dose.