This is the case of diets made with Sq and silage, which we can suppose does not cover the energetic requirements of octopus, thus stimulating its ingestion in an attempt to compensate for the deficiency. The case of the CrSq diet is different — animals had a higher growth rate than the rest of the treatments suggesting that such a high ingested energy is more a consequence of stimuli provoked by the ingredients, which, besides being nutritionally adequate, were highly attractive to O. maya. Previous studies have demonstrated that, besides its nutritional role, Gly is one of the attractant amino acids used in diets for fish ( Hughes, 1985). Although there are no formal studies that demonstrate the role of Gly in the attraction of O. maya, we can assume that the increase in values of ingested energy in animals fed CrSq was at least in part stimulated by the use of gelatin in the diet, which has a high Gly content.