Effect of two fresh diets and sexual maturation on the proximate and fatty acid profile of several tissues in Octopus vulgaris: specific retention of arachidonic acid in the gonads

Abstract

Most nutritional studies on Octopus vulgaris were based on males to avoid interaction with reproductive processes, focusing on muscle and digestive gland tissues. This study intends to evaluate the effect of two fresh diets, a fish diet (bogue Boops boops) and a mixed diet (600 g kg−1 crab Portunus pelagicus and 400 g kg−1 bogue), on the biochemical composition of muscle, digestive gland and gonad in males and females of O. vulgaris. Six octopuses per diet were selected (n = 3 per sex) after 60 days of rearing in floating cages. Weight increase was higher in males (3–3.2 kg) than in females (0.9 kg) regardless of diet associated with sexual maturation. Gondosomatic Index in females was 11.3–13.4%. High‐lipid content in fish (440 g kg−1 dw) was reflected in digestive gland regardless of the diet, while muscle and testis showed a relatively stable composition. The increase in protein content in the ovary was related to sexual maturation. The low arachidonic content in bogue was reflected in all tissues, with no apparent negative effect on growth and welfare. However, specific retention of arachidonic in the gonads, related to high arachidonic content in crab, underlined the importance of this fatty acid in for gonad development in O. vulgaris.