36 p., 7 tables, 5 figures and bibliographyEffects of two binders (gelatine and alginate), were tested on growth, survival, partial energy balance and lipid composition of mantle and digestive gland of Octopus vulgaris. Octopus average weight was of 713.0±127.9 g at the start of the experiment. The three diets tested (10 octopuses per diet) were: 1) CON, (Loligo gahi) as a control diet, 2) GEL, composed of squid paste (L. gahi) (30%), fish hydrolyse CPSP® (10%), and high quality fish meal\ud (50%), agglutinated with 10% of gelatine and 3) ALG, composed of squid paste (L. gahi) (30%), fish hydrolyse CPSP® (10%), and high quality fish meal (50%), all agglutinated with 10% of alginate. Growth rates were 1.4±0.2, 02±0.2 and -0.2±0.2 % bw d-1, for octopuses fed CON, GEL and ALG diets, respectively, and were higher when fed CON, compared to the two artificial diets. The GEL diet promoted higher growth and none of the artificial diets tested promoted significant growth. The digestive gland of octopuses had higher concentrations of fatty acids than the mantle. Fatty acid composition of the mantle was similar between CON and the two artificial diets. Digestive gland of animals fed CON had higher concentrations of fatty acids, than those fed the artificial diets.The authors wish to thank the “Plan Nacional de pulpo” – JACUMAR – Project “Engorde de pulpo, Octopus vulgaris.” 2007/2009, and the project CONACYT –Basico 50118 of C.R. from the Mexican government, for the funding for this research. Sandra García whishes to thank the “Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria” (INIA) for the Pre-doctoral grant nº 47 (BOE nº 308 26/12/2006)