79
5 Nutrition as a Key Factor for Cephalopod Aquaculture
rates are most probably due to highly efficient ingestion, digestion (Boucher-Rodoni et al. 1987) and assimilation of protein (Domingues et al. 2005), which have to be
supplied by a diet with balanced levels of amino acids, despite the capacity of some
cephalopods to perform integumental amino acid uptake from seawater (de Eguileor et al. 2000; Villanueva et al. 2004). Recent results point to the possibility that
cuttlefish might not be able to use protein that has been denaturated (Domingues
et al. 2009) and to the favour on amino acid use through the pyruvate and tricarboxylic acid pathways in detriment of the ketogenic pathway in starving O� vulgaris (García-Garrido et al. 2012). Given its importance for cephalopods metabolism (Lee 1994), there is a need for characterization of the amino acids pool (these
should be predominantly used as metabolic fuel, but they should also be utilized for
body protein synthesis) at different life stages of different species and preys used for
cephalopod rearing. The latter assumes greater importance since marine fish larvae
seem to have a lower capacity to digest and absorb complex proteins than juvenile
fish (Conceição et al. 2010), and display high amino acid requirements for protein
deposition, turnover and catabolism to attain rapid growth (Rønnestad et al. 2003).
In a similar way to demersal fish eggs (Rønnestad et al. 1999), the FAA and protein amino acid pools of S� officinalis wild and culture eggs are largely dominated
by taurine (more than 50 %; Sykes et al. unpublished data). Taurine is an amino acid
analogue that is not incorporated into protein, but well known for its multiple roles
that include inotropy of high and low calcium, modulator of neuron excitability, resistance to anoxia and hypoxia, bile salt synthesis and simulation of glycolysis and
glycogenesis (Huxtable 1992). Taurine is also abundant during planktonic stages of
the common octopus where it might play a role in osmoregulation (Villanueva et al.
2004). Nonetheless, its effect on metabolism and growth performance in a fish like
gilthead seabream was only related to the increasing methionine availability for several important physiological purposes (Pinto et al. 2013).
5.3 Lipids
Little is known about the lipid requirements of cephalopods, apart from the general
information drawn from the analysis of their body composition and assumptions
made from their feeding habits. It is then difficult to separate early stages from adult
requirements, or establish specific differences. Efforts devoted to the culture of certain species like O� vulgaris and S� officinalis have provided some information.
Very low levels of total lipids (TL) are present in the mantle of adults (BoucaudCamou 1990; Sykes et al. 2009b) and hatchlings (Navarro and Villanueva 2000,
2003). This fact, combined with their poor capacity for mitochondrial lipid oxidation (O’Dor et al. 1984; Hochachka 1994), has somehow put aside research on
cephalopod lipid nutrition until recently, when research on the causes of the massive
mortalities encountered during the culture of early stages of merobenthic species
has brought back the protagonism of these essential components on cephalopod nutrition, perhaps with an overemphasis on quantitative rather than qualitative points
of view, given the poor essential lipid composition of the live preys commonly used
5 Nutrition as a Key Factor for Cephalopod Aquaculture
rates are most probably due to highly efficient ingestion, digestion (Boucher-Rodoni et al. 1987) and assimilation of protein (Domingues et al. 2005), which have to be
supplied by a diet with balanced levels of amino acids, despite the capacity of some
cephalopods to perform integumental amino acid uptake from seawater (de Eguileor et al. 2000; Villanueva et al. 2004). Recent results point to the possibility that
cuttlefish might not be able to use protein that has been denaturated (Domingues
et al. 2009) and to the favour on amino acid use through the pyruvate and tricarboxylic acid pathways in detriment of the ketogenic pathway in starving O� vulgaris (García-Garrido et al. 2012). Given its importance for cephalopods metabolism (Lee 1994), there is a need for characterization of the amino acids pool (these
should be predominantly used as metabolic fuel, but they should also be utilized for
body protein synthesis) at different life stages of different species and preys used for
cephalopod rearing. The latter assumes greater importance since marine fish larvae
seem to have a lower capacity to digest and absorb complex proteins than juvenile
fish (Conceição et al. 2010), and display high amino acid requirements for protein
deposition, turnover and catabolism to attain rapid growth (Rønnestad et al. 2003).
In a similar way to demersal fish eggs (Rønnestad et al. 1999), the FAA and protein amino acid pools of S� officinalis wild and culture eggs are largely dominated
by taurine (more than 50 %; Sykes et al. unpublished data). Taurine is an amino acid
analogue that is not incorporated into protein, but well known for its multiple roles
that include inotropy of high and low calcium, modulator of neuron excitability, resistance to anoxia and hypoxia, bile salt synthesis and simulation of glycolysis and
glycogenesis (Huxtable 1992). Taurine is also abundant during planktonic stages of
the common octopus where it might play a role in osmoregulation (Villanueva et al.
2004). Nonetheless, its effect on metabolism and growth performance in a fish like
gilthead seabream was only related to the increasing methionine availability for several important physiological purposes (Pinto et al. 2013).
5.3 Lipids
Little is known about the lipid requirements of cephalopods, apart from the general
information drawn from the analysis of their body composition and assumptions
made from their feeding habits. It is then difficult to separate early stages from adult
requirements, or establish specific differences. Efforts devoted to the culture of certain species like O� vulgaris and S� officinalis have provided some information.
Very low levels of total lipids (TL) are present in the mantle of adults (BoucaudCamou 1990; Sykes et al. 2009b) and hatchlings (Navarro and Villanueva 2000,
2003). This fact, combined with their poor capacity for mitochondrial lipid oxidation (O’Dor et al. 1984; Hochachka 1994), has somehow put aside research on
cephalopod lipid nutrition until recently, when research on the causes of the massive
mortalities encountered during the culture of early stages of merobenthic species
has brought back the protagonism of these essential components on cephalopod nutrition, perhaps with an overemphasis on quantitative rather than qualitative points
of view, given the poor essential lipid composition of the live preys commonly used