Microorganisms are considered to be crucial selective factor affecting reproductive success of birds. It is hypothesized that egg-white antimicrobial proteins and incubation behavior are the most important defense mechanisms that eliminates the risk of microbial trans-shell infection. The latest studies supposed that incubation temperatures may significantly affect the antimicrobial activity of egg white proteins. The concentration of egg white antimicrobial proteins as well as incubation patterns differ among altricial and precocial species of birds. However, experimental study testing the effect of incubation temperature on the antimicrobial potential of antimicrobial egg white proteins in altricial and precocial birds is missing. In this study we tested in manipulative experiment the effect of partial and full incubation, the concentration of lysozyme and ovotransferrin and their interactions on the antimicrobial activity of egg whites of two model species - Japanese quail (Coturnix japonica) and home pigeon (Columba livia). Antimicrobial protein activity was determined by the agar well diffusion method against two Gram-positive bacteria - Bacillus subtilis and Micrococcus luteus that have been documented as pathogenic egg-white invaders of several birds. Moreover, we analyzed the effect of...