Organic zinc supplementation modifies the metalloproteome of royal jelly produced by Apis mellifera

In this study, we analyzed Apis mellifera royal jelly proteome alterations induced by supplementation with different concentrations of dietary organic zinc (0, 25, 50, and 75 ppm). Proteins extracted from royal jelly were separated by electrophoresis and isoelectric focusing, and zinc-containing protein spots were identified by tandem mass spectrometry. Organic zinc-containing diets modified total royal jelly protein content and altered the expression of five major royal jelly proteins (MRJP1, MRJP2, MRJP3, MRJP5, and MRJP8). While the diet with the lowest tested zinc content (Zn25) increased total royal jelly protein content and expression of MRJP1, diets with higher zinc contents (Zn50 and Zn75) decreased MRJP expression. Our results demonstrate that important proteins and metabolic processes are modified in royal jelly produced by honey bees supplemented with different concentrations of organic zinc source, affecting nutrition and maintenance of colonies.