85
5 Nutrition as a Key Factor for Cephalopod Aquaculture
5.7 Vitamins
Villanueva et al. (2009) reported that information on the vitamin composition of
cephalopods is mainly limited to the subadult and adult forms in relation to their
edible body portions (mantle and arms) or selected organs (Fisher 1956; Sidwell
et al. 1978; Motoe et al. 1997; Cho et al. 2001; Pandit and Magar 1972; Passi et al.
2002; Sikorski and Kolodziejska 1986). These authors analysed the vitamin content
of the early stages of cephalopods as an approach to establish their requirements
in culture. Antioxidants such as tocopherols are regarded to be very important for
the prevention of lipid oxidation, particularly α-tocopherol since it is degraded to
protect PUFA against oxidation in fish larvae (Sargent et al. 1997). In fact, it has
been reported that the α-tocopherol requirement may depend on the dietary PUFA
level (Stéphan et al. 1995; Halver 2002; Brown et al. 2005). Vitamin A and E (αand γ-tocopherols) profiles of the European cuttlefish S� officinalis, European squid
L� vulgaris and common octopus O� vulgaris laboratory hatchlings and wild juveniles were determined. The vitamin A content in early stages of cephalopods was
not much different from that observed in other marine molluscs and fish larvae.
Besides, relatively high content of vitamin E was observed in the hatchlings and
juveniles. These authors postulated that the high levels of vitamin E are probably
associated with the high percentage of oxidation-prone PUFA that are particularly
high in paralarval and juvenile cephalopods. In general terms, they concluded that
the natural and artificial preys ( Artemia spp.) of early stages of cephalopods either fulfilled their vitamin requirements directly or provided precursors (i.e. carotenoids) that could be transformed in vitamins.
5.8 Populational Metabolism Differences
Captive cephalopods have a different physiology than those from the wild and their
tissues are characterized by thicker mantles, a greater proportion of mitochondriarich tissue, muscle fibres with smaller mitochondrial cores and fewer small muscle
fibres (Pecl and Moltschaniwskyj 1999). This suggests a reduced rate of new fibre
generation, indicating an alteration to the cellular growth mechanisms and not simply a change in the physiological growth rate observed in several laboratory and
field studies (Semmens et al. 2004). Growth registered in captive individuals is usually lower than that estimated or verified for those from nature (an example of this
is presented in Chap. 11, in the part of cuttlefish culture in earthen ponds).
As stated by Sykes et al. (2006), the particular metabolism of cephalopods needs
to be considered if a successful artificial diet is to be designed. The partitioning of the
dietary energy intake by cephalopods in the various types of metabolism, excretion
and growth was reviewed by O’Dor and Wells (1987). Bearing that in mind, the nutritional content of the diet must be good enough to sustain the existing cephalopod
metabolic costs, so the animal is able to allocate an optimal distribution of surplus
5 Nutrition as a Key Factor for Cephalopod Aquaculture
5.7 Vitamins
Villanueva et al. (2009) reported that information on the vitamin composition of
cephalopods is mainly limited to the subadult and adult forms in relation to their
edible body portions (mantle and arms) or selected organs (Fisher 1956; Sidwell
et al. 1978; Motoe et al. 1997; Cho et al. 2001; Pandit and Magar 1972; Passi et al.
2002; Sikorski and Kolodziejska 1986). These authors analysed the vitamin content
of the early stages of cephalopods as an approach to establish their requirements
in culture. Antioxidants such as tocopherols are regarded to be very important for
the prevention of lipid oxidation, particularly α-tocopherol since it is degraded to
protect PUFA against oxidation in fish larvae (Sargent et al. 1997). In fact, it has
been reported that the α-tocopherol requirement may depend on the dietary PUFA
level (Stéphan et al. 1995; Halver 2002; Brown et al. 2005). Vitamin A and E (αand γ-tocopherols) profiles of the European cuttlefish S� officinalis, European squid
L� vulgaris and common octopus O� vulgaris laboratory hatchlings and wild juveniles were determined. The vitamin A content in early stages of cephalopods was
not much different from that observed in other marine molluscs and fish larvae.
Besides, relatively high content of vitamin E was observed in the hatchlings and
juveniles. These authors postulated that the high levels of vitamin E are probably
associated with the high percentage of oxidation-prone PUFA that are particularly
high in paralarval and juvenile cephalopods. In general terms, they concluded that
the natural and artificial preys ( Artemia spp.) of early stages of cephalopods either fulfilled their vitamin requirements directly or provided precursors (i.e. carotenoids) that could be transformed in vitamins.
5.8 Populational Metabolism Differences
Captive cephalopods have a different physiology than those from the wild and their
tissues are characterized by thicker mantles, a greater proportion of mitochondriarich tissue, muscle fibres with smaller mitochondrial cores and fewer small muscle
fibres (Pecl and Moltschaniwskyj 1999). This suggests a reduced rate of new fibre
generation, indicating an alteration to the cellular growth mechanisms and not simply a change in the physiological growth rate observed in several laboratory and
field studies (Semmens et al. 2004). Growth registered in captive individuals is usually lower than that estimated or verified for those from nature (an example of this
is presented in Chap. 11, in the part of cuttlefish culture in earthen ponds).
As stated by Sykes et al. (2006), the particular metabolism of cephalopods needs
to be considered if a successful artificial diet is to be designed. The partitioning of the
dietary energy intake by cephalopods in the various types of metabolism, excretion
and growth was reviewed by O’Dor and Wells (1987). Bearing that in mind, the nutritional content of the diet must be good enough to sustain the existing cephalopod
metabolic costs, so the animal is able to allocate an optimal distribution of surplus