RESUMEN
Larvae of Hermetia illucens, commonly known as black soldier fly, efficiently convert organic waste into nutrient-rich supplements for different applications. Here we performed a preliminary experiment to investigate the dynamics of the H. illucens gut microbiota and changes in the composition of the bacterial community in the residue of the larval feed during rearing. We furthermore quantified the presence of antibiotic resistance and disinfectant genes in the gut and feed microbiota during the rearing process to elucidate if rearing leads to a reduction, increase, and/or transfer of resistance genes from the feed to larvae and vice versa. We found that the gut and feed residue bacterial communities were distinct throughout the rearing process. The gut microbiome remained more stable compared to the feed residue microbiome varying in both bacterial abundance and community structure during rearing. Antibiotic-resistance genes were present in both, gut and feed residues, with a significant increase in pupae and residue samples taken at the end of the rearing process. Disinfectant-resistance genes were present in the feed residue and even increased during the rearing process but were not transferred to the gut microbiome. We conclude that H. illucens larvae have a stable gut microbiome that does not change significantly over the course of larval development, whereas bacterial communities in the feed residue are strongly affected by rearing. If the presence of antibiotics and disinfectants during rearing, can promote the spread of antibiotic/disinfectant-resistance genes among feed and larvae needs to be evaluated in further experiments.
Asunto(s)
Alimentación Animal/microbiología , Dípteros/microbiología , Farmacorresistencia Microbiana/genética , Microbioma Gastrointestinal/genética , Larva/microbiología , Animales , Biodiversidad , ADN Bacteriano/genética , Dosificación de Gen , Genes Bacterianos , Microbiota , Filogenia , ARN Ribosómico 16S/genéticaRESUMEN
Two Gram-stain-negative, facultative anaerobic, motile, rod-shaped strains, S-B4-1UT and JOB-63a, forming small whitish transparent colonies on marine agar, were isolated from a sponge of the genus Haliclona. The strains shared 99.7% 16S rRNA gene sequence identity and a DNA-DNA hybridization value of 100%, but were differentiated by genomic fingerprinting using rep-PCRs. 16S rRNA gene sequence phylogeny placed the strains as a sister branch to the monophyletic genus Endozoicomonas (Oceanospirillales; Gammaproteobacteria) with 92.3-94.3% 16S rRNA gene sequence similarity to Endozoicomonas spp., 91.9 and 92.1% to Candidatus Endonucleobacter bathymodiolin, and 91.9 to 92.1% to the type strains of Kistimonas spp. Core genome based phylogeny of strain S-B4-1UT confirmed the phylogenetic placement. Major fatty acids were summed feature 3 (C16:1 ω7c/C16:1 ω6c) and 8 (C18:1 ω7c/C18:1 ω6c) followed by C10:0 3-OH, C16:0, and C18:0. The G+C content was 50.1-51.4mol%. The peptidoglycan diamino acid of strain S-B4-1UT was meso-diaminopimelic acid, the predominant polyamine spermidine, the major respiratory quinone ubiquinone Q-9; phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine were major polar lipids. Based on the clear phylogenetic distinction, the genus Parendozoicomonas gen. nov. is proposed, with Parendozoicomonas haliclonae sp. nov. as type species and strain S-B4-1UT (=CCM 8713T=DSM 103671T=LMG 29769T) as type strain and JOB-63a as a second strain of the species. Based on the 16S rRNA gene sequence phylogeny of the Oceanospirillales within the Gammaproteobacteria, the Endozoicomonaceae fam. nov. is proposed including the genera Endozoicomonas, Parendozoicomonas, and Kistimonas as well as the Candidatus genus Endonucleobacter.