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)

The long-chain (≥C₂₀) polyunsaturated fatty acid biosynthesis capacity of fish varies among species, with trophic level hypothesised as a major factor. The biosynthesis capacity is largely dependent upon the presence of functionally diversified fatty acyl desaturase 2 (Fads2) enzymes, since many teleosts have lost the gene encoding a Δ5 desaturase (Fads1). The present study aimed to characterise Fads2 from four teleosts occupying different trophic levels, namely Sarpa salpa, Chelon labrosus, Pegusa lascaris and Atherina presbyter, which were selected based on available data on functions of Fads2 from closely related species. Therefore, we had insight into the variability of Fads2 within the same phylogenetic group. Our results showed that Fads2 from S. salpa and C. labrosus were both Δ6 desaturases with further Δ8 activity while P. lascaris and A. presbyter Fads2 showed Δ4 activity. Fads2 activities of herbivorous S. salpa are consistent with those reported for carnivorous Sparidae species. The results suggested that trophic level might not directly drive diversification of teleost Fads2 as initially hypothesised, and other factors such as the species’ phylogeny appeared to be more influential. In agreement, Fads2 activities from P. lascaris and A. presbyter were similar to their corresponding phylogenetic counterparts Solea senegalensis and Chirostoma estor.

The common octopus (Octopus vulgaris, Cuvier 1797) is a promising species for aquaculture diversification, but the massive mortality during the first life stage is the main bottleneck for its commercial production. The aim of the present study was to compare the effects of different live preys (Artemia and crustacean zoeae) and/or Artemia enrichment protocols in the paralarval growth by using a meta‐analysis approach. A total of 26 independent assays were used, including data from the bibliography and from experiments carried out by our group. Three comparisons were established: (i) crustacean zoeae vs. Artemia, (ii) different crustacean zoeae species and (iii) Artemia enriched with marine lecithin (rich in polar lipids‐PL and docosahexaenoic acid‐DHA) vs. previously used Artemia enrichments. The meta‐analysis approach allowed a quantitative review of independent studies with reliable conclusions, avoiding the subjectivity inherent to classical reviews. The outputs provided statistical confirmation of the better suitability of crustacean zoeae with respect to Artemia. However, not all crustacean species showed the same results, given that the high variability on Grapsus zoeae hampered finding significant differences with respect to the control treatment (Artemia). Nutrient composition and biometry of the different types of prey are discussed as possible causes of the differences arising from the meta‐analysis. Finally, the present results suggest that marine lecithin has a beneficial effect on paralarval growth with respect to previously used enrichments, which could be related to the increase in DHA and PL in Artemia, given the essential role of these lipid components in octopus paralarval physiology.