The Relative Roles of Vitamins, Protein, and the Salmonellosis Resistance Factor in the Natural Resistance of Mice to Salmonellosis

The results and analysis of this factorial experiment can be summarized in the following set of statements, each of which can be asserted at the 99% confidence level. In a factorial analysis of the relative roles of the Salmonellosis resistance factor (SRF), protein levels, and vitamin levels in survivorship in mouse salmonellosis, only SRF emerged with certitude as a resistance-promoting factor. At “normal” vitamin levels, increasing dietary protein levels ranging from 5 to 30% affected survivorship frequency linearly, but divergently: increasing survivorship obtained in the presence of SRF and decreasing survivorship in its absence. This two-way, SRF × protein, interaction was obliterated by increasing the vitamin levels tenfold. The consequence was a three-way interaction, SRF × protein × vitamins, the only other significant result to emerge from the factorial experiment.