Relationships between spawn quality and biochemical composition of eggs and hatchlings of Octopus vulgaris under different parental diets

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Pulpos: Una reproducción que les cuesta la vida

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Growth and survival of cuttlefish (Sepia officinalis) of different ages fed crustaceans and fish. Effects of frozen and live prey

Three feeding experiments, using live mysid shrimp, grass shrimp or fish fry as prey for 1-, 30- and 60-day-old cuttlefish were conducted to determine the efficiency of each dietary source in relation to cuttlefish size and age. Additionally, a fourth experiment using fish fry and grass shrimp, but previously frozen, was also conducted. The results showed that when 1-day-old cuttlefish were fed mysids, grass shrimp or fish for 4 weeks, mysids were the best prey, but only during the first week. From this moment until the end of the experiment, the best growth rate was when cuttlefish were fed grass shrimp. Cuttlefish fed fish fry showed the poorest growth rate throughout the experiment. Similarly, cuttlefish aged 30 or 60 days fed grass shrimp or fish fry had the best growth rates when fed grass shrimp. When cuttlefish were fed live fish, survival increased with size of cuttlefish (73.3%, 91.7% and 100% for 1, 30 and 60 days cuttlefish, respectively). In the fourth experiment, using frozen diets, overall acceptance of each diet (feeding rates) was the same for fish and shrimp. However, lower growth was obtained when cuttlefish were fed fish compared to grass shrimp. This lower growth was due to a lower food conversion (28% vs. 41%). Since cephalopod paralarvae and juvenile most likely need prey rich in polyunsaturated fatty acids (PUFA), phospholipids and cholesterol, and a moderate content in neutral lipids, we have analyzed the biochemical compositions of the different prey to evaluate the influence of this factor on growth and survival.En prensa2,04

In vivo metabolism of unsaturated fatty acids in Sepia officinalis hatchlings

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Comments on the calculation of the specific growth rate in experiments with untagged individuals

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Fixation of bioactive compounds to the cuticle of Artemia

Artemia is extensively used in aquaculture to feed early stages of cultured marine species. A problem associated with this practice is that Artemia fails to supply some essential nutrients. As a possible solution, we have devised a procedure to make Artemia a vehicle for exogenous nutrients and other bioactive compounds. It consists of the construction of chimeric proteins composed of a chitin-binding domain, which binds to the cuticle of Artemia, and a carrier domain that conveys a functional property. As confirmatory examples, we describe the successful fixation to Artemia's metanauplii of two hybrid proteins: a β-galactosidase from the thermophilic bacterium Thermotoga maritima and the jellyfish green fluorescent protein (GFP), both linked to the CBM2 chitin-binding domain from the hyperthermophilic archaeon Pyrococcus furiosus. Positive results of experiments carried out ex vivo and in vivo show the validity of this approach. The methodology used could become a general procedure for the attachment of different kinds of bioactive compounds, such as enzymes, hormones, antibiotics, etc., to the cuticle of Artemia as well as other arthropods. Statement of relevance: Our results overcome shortcomings of Artemia as a feedstock.En prensa2,04