Influence of Dietary Microalgae on Acartia tonsa Copepod Microbiome

This study investigates the effect of different microalgae diets on the microbiomes associated with the marine copepod Acartia tonsa. Copepods were fed with two different mixed-diet compositions: (i) Isochrysis galbana (ISO) and Rhinomonas reticulata (RHI)—(ISO + RHI) and (ii) ISO and Rhodomonas baltica (RHO)—(ISO + RHO). 16S rDNA metabarcoding and comparative statistic have been adopted to study microbial diversity associated with algae and copepods. Diversity index, taxonomic profiling, and statistically significant taxa differential abundances were evaluated with reference to the different algal and copepod microbiomes. Results showed that the different feeding regimes shape different copepod microbial communities. The abundance of Vermiphilaceae, OM190, KI89A_clade, Cyanobium_PCC-6307, and Cyclobacteriaceae increased in copepod microbiomes independently by the feeding regimes. On the other hand, Tistlia sp., Bradymonadales, and Alteromonadaceae were differentially enriched in copepod microbiomes in relation to the different feeding regimes. Differences in the microbial community composition between ISO + RHI and ISO + RHO were observed, suggesting that the specific algal diet plays a pivotal role in shaping microbiome structure.