Agar-based Biocomposites slow down Progression in the Reproductive Cycle Facilitating Synchronization of the Gonads of Reared Specimens of Paracentrotus lividus

Background: Biopolymers have many fields of application. In Echiniculture they are usually employed to bind trial diets, although a systematic study on the performances of biopolymers as feed binders is lacking. Methods: Several biopolymers (sodium alginate, agar, gellan, apple pectin and citrus pectin with different esterification degree) were employed as binders in the manufacture of biocomposites to be used as Paracentrotus lividus feed. Biocomposites were first produced with varying percentages of feed ingredients (5-25%) and polymers (2-3%), either alone or in blends of two types. Biocomposites were tested for stability, swelling and nutrient release in water. In order to evaluate their palatability, biocomposites were administered to sea urchins and eating activity checked up to 48 h. GI and gonad composition were evaluated in a 14-week rearing trial.