Changes in the antimicrobial potential of egg albumen during the early stages of incubation and its impact on the growth and virulence response of Salmonella Enteritidis

Abstract

The antimicrobial activity of egg albumen has been widely documented. However, the changes of chemical nature and antimicrobial activity of egg albumen and the way it controls bacteria during incubation period were not well understood up to now. The purpose of the present investigation was to analyze the antimicrobial potential of egg albumen during early incubation stages (0-5d). The changes of ovotransferrin and lysozyme content in egg albumen were quantified via high-performance liquid chromatography (HPLC). The results showed that the concentration of ovotransferrin in egg albumen was increased closely with the time of incubation but that of lysozyme remained substantially unchanged and was very similar to that of the non-incubated eggs. The iron ion binding capacity and specific lysozyme activity of the egg albumen during early incubation stages was also investigated. The changes occurred in egg albumen during early incubation could influence the growth of Salmonella enteritidis. Very little difference was observed in the virulence response of Salmonella enteritidis to egg albumen collected at different incubation periods by using the expression of hilA gene as an indicator. Since the first few days of incubation are likely to place heavy demands on the immune capacities of the egg, due to the immunologically defenceless of developing embryo, the changes of antimicrobial activity in egg albumen shine a bright light on the innate immune mechanism of the fertilized egg during the early embryonic development.

Keywords

• Egg albumen
• Incubation
• Antimicrobial protein
• Antimicrobial activity
• Salmonella Enteritidis