Callegari Matteo, Jucker Costanza, Fusi Marco, Leonardi Maria Giovanna, Daffonchio Daniele, Borin Sara, Savoldelli Sara, Crotti Elena
Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Università degli Studi di Milano, Milan, Italy.
Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
Front Microbiol. 2020 Aug 12;11:1965. doi: 10.3389/fmicb.2020.01965. eCollection 2020.
Larvae of the black soldier fly (BSF) (L.) convert organic waste into high valuable insect biomass that can be used as alternative protein source for animal nutrition or as feedstock for biodiesel production. Since insect biology and physiology are influenced by the gut microbiome, knowledge about the functional role of BSF-associated microorganisms could be exploited to enhance the insect performance and growth. Although an increasing number of culture-independent studies are unveiling the microbiota structure and composition of the BSF gut microbiota, a knowledge gap remains on the experimental validation of the contribution of the microorganisms to the insect growth and development. We aimed at assessing if BSF gut-associated bacteria potentially involved in the breakdown of diet components are able to improve host nutrition. A total of 193 bacterial strains were obtained from guts of BSF larvae reared on a nutritious diet using selective and enrichment media. Most of the bacterial isolates are typically found in the insect gut, with major representatives belonging to the Gammaproteobacteria and Bacilli classes. The hydrolytic profile of the bacterial collection was assessed on compounds typically present in the diet. Finally, we tested the hypothesis that the addition to a nutritionally poor diet of the two isolates HI169 and HI121, selected for their complementary metabolic activities, could enhance BSF growth. HI169 positively influenced the larval final weight and growth rate when compared to the control. Conversely, the addition of HI121 to the nutritionally poor diet did not result in a growth enhancement in terms of larval weight and pupal weight and length in comparison to the control, whereas the combination of the two strains positively affected the larval final weight and the pupal weight and length. In conclusion, we isolated BSF-associated bacterial strains with potential positive properties for the host nutrition and we showed that selected isolates may enhance BSF growth, suggesting the importance to evaluate the effect of the bacterial administration on the insect performance.
黑水虻（Hermetia illucens (L.)）的幼虫能将有机废物转化为高价值的昆虫生物质，可用作动物营养的替代蛋白质来源或生物柴油生产的原料。由于昆虫的生物学和生理学受肠道微生物群影响，因此关于黑水虻相关微生物功能作用的知识可用于提高昆虫的性能和生长。尽管越来越多的非培养研究揭示了黑水虻肠道微生物群的微生物群结构和组成，但在微生物对昆虫生长发育贡献的实验验证方面仍存在知识空白。我们旨在评估与黑水虻肠道相关、可能参与饮食成分分解的细菌是否能够改善宿主营养。使用选择性和富集培养基，从以营养饮食饲养的黑水虻幼虫肠道中总共获得了193株细菌菌株。大多数细菌分离株通常存在于昆虫肠道中，主要代表属于γ-变形菌纲和芽孢杆菌纲。对该细菌集合的水解谱进行了针对饮食中典型存在的化合物的评估。最后，我们测试了以下假设：将因互补代谢活性而选择的两种分离株HI169和HI121添加到营养贫乏的饮食中，可以促进黑水虻的生长。与对照相比，HI169对幼虫的最终体重和生长速率有积极影响。相反，与对照相比，在营养贫乏的饮食中添加HI121在幼虫体重、蛹重和蛹长方面并未导致生长增强，而两种菌株的组合对幼虫最终体重、蛹重和蛹长有积极影响。总之，我们分离出了对宿主营养具有潜在积极特性的与黑水虻相关的细菌菌株，并且我们表明选择的分离株可能促进黑水虻生长，这表明评估细菌施用对昆虫性能的影响很重要。
