Effect of the concentration of agar, alginate and carrageenan on the stability, toughness and nutrient leaching in artificial diets for abalone

Abstract

In order to evaluate the effect of different binders on the quality of artificial diets for abalone in terms of stability, nutrient leaching and toughness, three phycocolloids (agar, alginate and carrageenan) were used at different concentrations (0.5%, 1.0%, 1.5%, 2.0% and 2.5%), mixed with fish meal or abalone viscera silage as protein sources. Both stability and pellet toughness were influenced more by the protein source than by the type and concentration of the binder, as diets containing abalone viscera silage lost 20% dry matter, compared to the 10% lost in diets containing fish meal. However, nutrient leaching was not affected by the phycocolloid concentration. This result coincides with previous reports that leaching speed does not depend on stability. In general, all the binders used were effective at low concentrations (0.5%); therefore, the use of phycocolloids at low concentrations is recommended. Attention should also be given to the ingredients used, as these may have a greater influence on stability and toughness than the binders themselves.