Identification of three novel avian beta-defensins from goose and their significance in the pathogenesis of Salmonella

•Three novel anser_avian β-defensins (anser_AvBDs) were identified from goose.•The three anser_AvBDs showed antibacterial activity against most of the bacteria investigated.•The anser_AvBDs and TLR4 showed different expressions after S. enteritidis infection.•β-Defensins may play a pivotal role in the host defense mechanisms of the goose.

Here, we report the characterization of three avian β-defensins (AvBDs) from the goose, named anser_AvBD1, AvBD3, and AvBD6, respectively. All of anser_AvBDs exhibited broad antibacterial activity. In addition, the antibacterial activity of all of the AvBDs against Staphylococcus aureus and Proteus mirabilis decreased significantly in the presence of 100 mM NaCl (P < 0.01). None of the AvBDs showed hemolytic activity. In order to assess the significance of these anser_AvBDs in the infection of Salmonella enteritidis, mRNA expression of Toll-like receptor (TLR) 4 and anser_AvBDs in tissues of both control and infected geese was evaluated. We observed a significant up-regulation of TLR4, anser_AvBD1, 3, and 6 in some immune tissues evaluated, in response to S. enteritidis infection. These data demonstrated that TLR4 may serve a possible role in eliciting host immune responses to pathogens, and β-defensins may play a pivotal role in the host defense mechanisms of the goose.