Histomorphologic hepatic features and growth performances of juvenile Senegalese sole (Solea senegalensis) fed isogenertic practical diets with variable protein ⁄ lipid levels

Histological and morphometric techniques were employed in juvenile Senegalese sole (Solea senegalensis) livers to evaluate diet-related adaptive changes and to establish how an inte- grated morphofunctional approach could improve the under- standing of rearing strategies. Four isoenergetic diets with variable protein ⁄ lipid content (44 ⁄ 22, 49 ⁄ 20, 54 ⁄ 18 and 59 ⁄ 16) were formulated. Data compared statistically showed that an increase in protein and decrease of lipid in the diet was associated with a significantly higher specific growth rate (SGR) and reduced feed conversion rate (FCR). Histologic evaluation (visual scoring of lipid storage) and morphometry (area and perimeter) of hepatocytes showed that a high lipid diet resulted in increased lipid storage. The data confirmed that a concomitant decrease of protein with an increase in lipids in the diet led to a massive storage of unused lipid within hepatocytes associated with a reduced growth performance.