Our aim is to obtain a better understanding of the effects of probiotic microorganisms and diet composition on Tenebrio molitor-pathogens interactions in mass-rearing conditions for increasing performance (survival, growth, conversion efficiency) and decreasing disease risk.
After establishing the Tenebrio molitor colony at INRAE, experiments were focused on culturing the pathogens, the bacterium Bacillus thuringiensis and the fungus Metarhizium brunneum. The pathogenicity of both were tested individually in order to detect the lethal dose for different larval stages and to be able to perform co-infection in the upcoming experiments.
Potential probiotic bacterial strains have been selected from previous studies to assess their effects on Tenebrio molitor performance, immune responses and microbial community composition in normal and challenged conditions.
In vitro assays allowed to determine probiotics-pathogens relationships under optimal conditions. Ongoing bioassays are exploring and recording the best time for providing probiotics in the diet, the effect of the strains on the insects and the outcome of host-pathogen interactions.
The last period of the project will be focused on the provision of several diets differing in nutrient contents for observing probiotic and prebiotic role in host-pathogen interactions.