Desempenho do polvo Octopus vulgaris alimentado com monodieta de mexilhão (Perna perna) / Performance of the Octopus vulgaris octopus fed on mussel (Perna perna) as monodiet

The octopus Octopus cf. vulgaris is a potential species to diversify aquaculture. Due to absence of balanced commercial diet, growth of the O. cf. vulgaris is based on natural diet with local and low-cost inputs. In Brazil, studies on experimental octopus ongrowing are recent and there is little available data. We evaluated the performance, survival and food consumption of O. vulgaris fed on mussel Perna perna for 20 days. Six octopuses with initial weight of 415±12.73g (mean±standard deviation) were divided into two groups (n=3 octopuses/group) according to the diet: MC Group (frozen mussels) and MV Group (live mussels). The Weight Gain of octopuses was 273.33±94.52g and 340.00±26.46g; the Absolute Growth Rate was 13.67±4.73 and 17.00±1.32g.dia-1 and the Specific Growth Rate of 2.95±0.58 and 2.64±0.37%.day-1 to MC and MV groups, respectively. There was no significant difference in performance between groups and the survival rate was 100%. Octopuses well accepted both diets and despite the amount of frozen mussels (129±31) was higher than in live mussels (100±19), there was no significant difference regarding the consumption between groups. Our results demonstrate that the mussel Perna perna can be used frozen or live as monodiet in O. cf. vulgaris ongrowing.(AU)

Comportamento alimentar de paralarvas do polvo Octopus vulgaris Tipo II (Cuvier, 1797) alimentadas com artêmia enriquecida com microalgas e suplementada com DHA / Feeding behavior of octopus Octopus vulgaris Type II (Cuvier, 1797) paralarvae fed on Artemia enriched with microalgae and supplemented with DHA

The inexistence of nutritionally adequate diets in paralarval rearing is the main bottleneck for commercial production of the common octopus Octopus cf. vulgaris. We report the feeding behavior of O. vulgaris Type II paralarvae fed on Artemia sp (0.1 individual. mL-1) nauplii enriched with microalgae Isocrysis galbana and Pavlova lutheri microalgae from 0 to 7 Day After Hatching (DAH).; metanauplii enriched with microalgae and DHA SELCO® lipid emulsion from the 8 DAH. The paralarvae showed active swimming and predation by the 14 DAH, feeding in the most superficial portion of the water column. From the 15 DAH, the paralarvae remained near the bottom and there a decrease in the consumption of artemia was observed. The mortality observed from the 18 DAH and mass mortality of paralarvae on 20 DAH can be attributed mainly to the nutritional composition of the diet. Studies analyzing the biochemical composition and ontogeny of the digestive system during the early life stages should shed some light on the running for an appropriate feeding protocol to the paralarval rearing.(AU)