Royal jelly as a food additive and its possible biostimulating effects

Abstract

The experiment represents a contribution to knowledge about metabolic changes in insects reared on a artificial diet containing royal jelly. The larvae of the cerambycid beetle Cerambyx cerdo, of average mass 0.458 g, were divided into four groups. One (AD) was placed under control conditions on a standard substrate, while two other groups (RJ1 and RJ2) (n=4) were given substrates with added royal jelly (RJ). Group RJ1 was reared on the substrate with RJ till the end of the experiment, while group RJ2 was returned to control conditions with the standard food substrate after 48 days on the substrate with RJ. Larvae from natural population collected at the same locality and fed natural wood mass (NC) were also included in the experiment for comparison. The experiment lasted 151 days.. The mass gain within each group was measured individually approximately every 7 days, when the food substrate was also changed. The larval mass gains were calculated relative to the initial values of the average weights of individual groups. The data were analyzed by statistical methods. The results of the analysis showed a high degree of statistical confidence for the differences obtained. They are graphically presented. After the period of 151 days, all three experimental groups and the group from the natural population were sacrificed. The midgut protein content, proteolytic activity of midgut enyzmes and amylase specific activity were determined biochemically. It was concluded that the presence of royal jelly in the artificial diet for C. cerdo accelerates the development process, increases the number of moults and decreases the protease activity. The presence of royal jelly in the substrate does not significantly affect the specific activity of amylase.