Microbial partners in immunity: probiotic effects on yellow mealworm and black soldier fly physiology

In these years, the identification of potential probiotic microorganisms within the microbiome of farmed insects, as well as their application in mass-rearing systems, has been increasingly investigated to evaluate their effects on insect growth, reproduction and overall health with the additional aim of mitigating multiple stressors such as entomopathogens, temperature fluctuations and high rearing densities. The PRIN 2022 Project InProFarm (Insect Probiotic-assisted Farming: a promising tool to enhance edible insect health and performances) explored the interactions between beneficial bacterial symbionts and two mass-reared species, Tenebrio molitor (yellow mealworm) and Hermetia illucens (black soldier fly), and their impact on humoral and cellular immune responses. Beneficial bacterial symbionts were screened from larvae of both species, and their probiotic potential was assessed through in vitro and in vivo assays, including feed administration, evaluation of insect performance, and analysis of microbiota composition. In addition to growth performance, genes involved in growth and immune pathways were analysed to uncover the effects of probiotic supplementation on key traits relevant to insects breeding, such as antimicrobial peptides production and reproduction. Overall, the study highlights the importance of promoting healthy and safe insect production systems for feed and food applications. This work was funded by the PRIN 2022 Project InProFarm (Insect Probiotic-assisted Farming: a promising tool to enhance edible insect health and performances), grant number 2022L4NJMK, funded by the European Union — Next Generation EU, Mission 4 Component 1.