Comparative analysis of vertebral transcriptome in Japanese seabass (Lateolabrax japonicus) fed diets with varying phosphorus/calcium levels

A comprehensive coding and microRNA transcriptome of vertebral bone in postlarvae and juveniles of Senegalese sole (Solea senegalensis)

Understanding vertebral bone development is essential to prevent skeletal malformations in farmed fish related to genetic and environmental factors. This is an important issue in Solea senegalensis, with special impact of spinal anomalies in postlarval and juvenile stages. Vertebral bone transcriptomics in farmed fish mainly comes from coding genes, and barely on miRNA expression. Here, we used RNA-seq of spinal samples to obtain the first comprehensive coding and miRNA transcriptomic repertoire for postlarval and juvenile vertebral bone, covering different vertebral phenotypes and egg-incubation temperatures related to skeleton health in S. senegalensis. Coding genes, miRNA and pathways regulating bone development and growth were identified. Differential transcriptomic profiles and suggestive mRNA-miRNA interactions were found between postlarvae and juveniles. Bone-related genes and functions were associated with the extracellular matrix, development and regulatory processes, calcium binding, retinol and lipid metabolism or response to stimulus, including those revealed by the miRNA targets related to signaling, cellular and metabolic processes, growth, cell proliferation and biological adhesion. Pathway enrichment associated with fish skeleton were identified when comparing postlarvae and juveniles: growth and bone development functions in postlarvae, while actin cytoskeleton, focal adhesion and proteasome related to bone remodeling in juveniles. The transcriptome data disclosed candidate coding and miRNA gene markers related to bone cell processes, references for functional studies of the anosteocytic bone of S. senegalensis. This study establishes a broad transcriptomic foundation to study healthy and anomalous spines under early thermal conditions across life-stages in S. senegalensis, and for comparative analysis of skeleton homeostasis and pathology in fish and vertebrates.

Vertebrae Morphometric Measurement and Ca/P Levels of Different Age European Seabass (Dicentrarchus labrax)

The European seabass is one of the most important species of the Mediterranean, specifically Greece. Individuals with different numbers of vertebrae have been reported. This number ranges from 24 to 26 vertebrae. In this study a sample of 73 individual seabass were collected from fish farms and divided into three age groups. The first group included fingerling individuals, the second group, juvenile individuals and the third group, adult individuals. The number and the length of their vertebrae were measured by radiographs. The individuals were divided into subgroups according to their vertebrae number, and from each one the tenth vertebra was taken. Ca and P levels (%) of each tenth vertebra were measured by X-ray spectroscopy (EDS), and the Ca/P ratio was determined. Vertebrae length, Ca and P levels and Ca/P ratio were compared among age groups and among individuals with different numbers of vertebrae. It was shown that the European seabass’s vertebral column can be divided to three sections—cervical, abdominal and caudal—following the striped bass (Morone saxatilis) model.