Selenium deficiency increased duodenal permeability and decreased expression of antimicrobial peptides by activating ROS/NF-κB signal pathway in chickens.

Selenium (Se) is an essential trace element for the body. Various organs of the body, including the intestine, are affected by its deficiency. Se deficiency can induce oxidative stress and inflammatory responses in the intestine. It can also increase intestinal permeability and decrease intestinal immune function in mammals. However, the detailed studies, conducted on the intestinal molecular mechanisms of Se deficiency-induced injury in poultry, are limited. This study explored the adverse effects of Se deficiency on intestinal permeability and its mechanism. A Se-deficient chicken model was established, and the morphological changes in the chicken duodenum tissues were observed using a light microscope and transmission electron microscope (TEM). Western blotting, qRT-PCR, and other methods were used to detect the expression levels of selenoproteins, oxidative stress indicators, inflammatory factors, tight junction (TJ) proteins, antimicrobial peptides, and other related indicators in intestinal tissues. The results showed that Se deficiency could decrease the expression levels of selenoproteins and antioxidant capacity, activate the nuclear factor kappa-B (NF-κB) pathway, cause inflammation, and decrease the expression levels of TJ proteins and antimicrobial peptides in the duodenum tissues. The study also demonstrated that Se deficiency could increase intestinal permeability and decrease antimicrobial peptides via reactive oxygen species (ROS)/NF-κB. This study provided a theoretical basis for the scientific prevention and control of Se deficiency in poultry. Se deficiency decreased the expression levels of selenoproteins and increased ROS levels to activate the NF-κB pathway, resulting in the production of pro-inflammatory cytokines, reducing the expression levels of TJ protein, and weakening the expression of antimicrobial peptides, which contributed to the higher intestinal permeability. Oxidative stress weakened the expression of antimicrobial peptides.