Turbot post-larvae microbial community and the development of post-larval phenotypes

A growing number of studies emphasize the important role of the host microbiome in influencing organismal health, development, physiology, and reproduction. Building upon this understanding, our study aimed to investigate the association between the host-associated microbiome and certain fish post-larvae phenotypes related to pigmentation, deformity, and size. Twenty-eight random larviculture tanks rearing turbot post-larvae were sampled thirty days after hatching (DAH) during a four-month period (April to June). Post-larvae were selectively sampled based on specific phenotypic traits: malformation, size, and pigmentation. In total five categories were established: Malformed (normal size fish with normal pigmentation and at least one detectable skeletal malformation); Small (small size fish with normal pigmentation with no skeletal malformation); Depigmented (normal size fish with irregular pigmentation and no skeletal malformation); Large (large size fish with normal pigmentation and no skeletal malformation) and Normal (normal size fish with normal pigmentation and no skeletal malformation). Data from the high throughput sequencing of the 16S gene of bacterial DNA extracted from the whole fish was analyzed to access associations between bacterial diversity, composition, and predicted functions with fish phenology.