RESEARCH ARTICLE R. Rosa Æ P. R. Costa Æ M. L. Nunes Effect of sexual maturation on the tissue biochemical composition of Octopus vulgaris and O. defilippi (Mollusca: Cephalopoda) Received: 14 November 2003 / Accepted: 23 February 2004 / Published online: 1 April 2004 Ó Springer-Verlag 2004 Abstract Changes in the protein, lipid, glycogen, cho- lesterol and energy contents, total amino acid and fatty acid profiles of Octopus vulgaris and O. defilippi tissues (gonad, digestive gland and muscle) during sexual mat- uration (spermatogenesis and oogenesis) were investi- gated. Both species showed an increase of amino acids and protein content in the gonad throughout sexual maturation (namely in oogenesis), but allocation of these nitrogen compounds from the digestive gland and muscle was not evident. The major essential amino acids in the three tissues were leucine, lysine and arginine. The major non-essential amino acids were glutamic acid, aspartic acid and alanine. With respect to carbon com- pounds, a significant increasing trend (P<0.05) in the lipid and fatty acid contents in the three tissues was observed, and, consequently, there was also little evi- dence of accumulated lipid storage reserves being used for egg production. It seems that for egg production both Octopus species use energy directly from food, ra- ther than from stored products. This direct acquisition model contrasts with the previous model for Octopus vulgaris proposed by O’Dor and Wells (1978: J Exp Biol 77:15–31). Most of saturated fatty acid content of the three tissues was presented as 16:0 and 18:0, monoun- saturated fatty acid content as 18:1 and 20:1 and poly- unsaturated fatty acid content as arachidonic acid (20:4n-6), eicosapentaenoic acid (20:5n-3) and docosa- hexaenoic acid (22:6n-3). Though cholesterol is an important precursor of steroid hormones, this sterol content exhibited variations that do not seem to be re- lated with the maturation process. Moreover, significant differences (P<0.05) were obtained between genders, suggesting that perhaps there is a greater physiological demand for cholesterol during spermatogenesis than oogenesis. If the component sterols of octopus are of a dietary origin, considerable variation in the cholesterol content between species might be expected on the basis of the sterol composition of their prey. The glycogen reserves increased significantly in the gonad and de- creased significantly (P<0.05) in the digestive gland and muscle of O. vulgaris (these trends were not evident in O. defilippi). Glycogen may play an important role in the maturation process and embryogenesis of these organ- isms, because carbohydrates are precursors of metabolic intermediates in the production of energy. It was evident that sexual maturation had a significant effect upon the gonad energy content, but the non-significant energy variation (P>0.05) in the digestive gland and muscle revealed no evidence that storage reserves are trans- ferred from tissue to tissue. The biochemical composi- tion of digestive gland and muscle may not be influenced by sexual maturation, but rather by other biotic factors, such as feeding activity, food availability, spawning and brooding. Introduction The common octopus, Octopus vulgaris Cuvier, 1797 has a world-wide distribution in temperate, subtropical and tropical waters of the Atlantic, Indian and Pacific Oceans. The distribution of Octopus defilippi is restricted to the Atlantic Ocean, from Portugal to Angola (including the Mediterranean Sea and Cape Verde Is- lands) and from the Bahamas to Brazil (including the Gulf of Mexico). Both octopus species are typical inhabitants of littoral waters, existing up to the limit of the continental shelf (Mangold 1998). O. vulgaris has a Communicated by S.A. Poulet, Roscoff R. Rosa (&) Æ P. R. Costa Æ M. L. Nunes Departamento de Inovac¸a˜o Tecnolo´gica e Valorizac¸a˜o dos Produtos da Pesca, IPIMAR, Avenida de Brası´lia, 1449-006 Lisbon, Portugal E-mail: rrosa@ipimar.pt Tel.: +351-1-3027000 Fax: +351-1-3015948 P. R. Costa Departamento de Ambiente Aqua´tico, IPIMAR, Avenida de Brası´lia, 1449-006 Lisbon, Portugal Marine Biology (2004) 145: 563–574 DOI 10.1007/s00227-004-1340-8