458
F. J. Sánchez et al.
Domingues et al. 2005, 2007, 2008; Aguila et al. 2007; Rosas et al. 2007). All these
works had one outcome in common: poor ingestion and growth rates, whether wet
or formulated dry feeds were used, the results being markedly poorer than when natural diets were provided. Some of these results were attributed to poor palatability
or, if the feeds were accepted, to their deficient nutritional content. The influence of
certain chemical attractants on the acceptance or rejection of the feeds became evident (Lee et al. 1991; Domingues et al. 2007). It had previously been demonstrated
that octopuses have a high chemoreceptor capacity towards many stimuli, including
acids, sugars, crab extracts, amino acids and nucleotides (Wells 1963; Wells et al.
1965; Boyle 1983; Chase and Wells 1986; Lee 1992). Studies on the biochemical
composition of cephalopods (Lee 1994; Rosa et al. 2005; Sieiro et al. 2006), their
digestive enzymes (Boucher-Rodoni 1982; Caruso et al. 2004), digestibility (O’Dor
et al. 1984; Hernández and García García 2004; Mazón et al. 2007) and bioenergetic
subjects (Katsanevakis et al. 2005; Petza et al. 2006; García García et al. 2011)
demonstrated the predominant role of the protein metabolism and of amino acids,
emphasising the importance that these would have in the design of diets.
Between 2007 and 2010, two separate but complementary research lines were
encouraged by the Spanish National Plans for Aquaculture, JACUMAR (2007–
2009). One was dedicated to the study of acceptability and performance of different
forms of feed and the other focused on a biochemical study of cephalopods, their
natural diets and possible prime materials for formulating feeds. It was deduced
that such feeds should be stable in water and with a firm and homogeneous (nongranular) texture, and have a degree of flexibility so as not to disaggregate during
manipulation, as in the case of fish feed. Also, the presence of chemical substances
that might lead to rejection had to be avoided. As a result, feeds were developed in
formats that were acceptable to the octopuses and produced good growth (0.7–1.5 %
BW day
−1
; Cerezo Valverde et al. 2008; Quintana et al. 2008; Estefanell et al. 2013).
All these feeds used a fish, crustacean or mollusc paste mixed with different binders
(alginates or gelatines), which gave a moist feed (> 70 % water) with a texture that
was suitable for manipulation and ingestion.
Gelatine was found to be more suitable than alginates for elaborating feeds
because of its better digestibility and acceptability (Rosas et al. 2008; Seiça Neves
et al. 2010; García-Garrido et al. 2010a), although alginate is more stable in water.
Heating the mixtures gave them greater stability although it also led to a loss in nutritive value (Cerezo Valverde et al. 2008; Domingues et al. 2009b). The biochemical
studies carried out showed that phospholipids and polyunsaturated fatty acids (docosahexaenoic acid (DHA) and eicosapentaneoic acid (EPA)) were the key nutrients
(Navarro and Villanueva 2003; Estefanell et al. 2013; Cerezo Valverde et al. 2012a).
Supplementation with arginine and the complementation of crustacean or bivalve
protein with fish or animal meals were proposed as alternatives to increasing the
protein yield (Cerezo Valverde et al. 2013).
Great advances have been made regarding knowledge of the nutritional requirements of cephalopods as a result of developing feed with a known nutritional composition. The incorporation of free amino acids, such as glutamate or arginine, had
no effect on the feed rates but was associated with increased growth and protein
F. J. Sánchez et al.
Domingues et al. 2005, 2007, 2008; Aguila et al. 2007; Rosas et al. 2007). All these
works had one outcome in common: poor ingestion and growth rates, whether wet
or formulated dry feeds were used, the results being markedly poorer than when natural diets were provided. Some of these results were attributed to poor palatability
or, if the feeds were accepted, to their deficient nutritional content. The influence of
certain chemical attractants on the acceptance or rejection of the feeds became evident (Lee et al. 1991; Domingues et al. 2007). It had previously been demonstrated
that octopuses have a high chemoreceptor capacity towards many stimuli, including
acids, sugars, crab extracts, amino acids and nucleotides (Wells 1963; Wells et al.
1965; Boyle 1983; Chase and Wells 1986; Lee 1992). Studies on the biochemical
composition of cephalopods (Lee 1994; Rosa et al. 2005; Sieiro et al. 2006), their
digestive enzymes (Boucher-Rodoni 1982; Caruso et al. 2004), digestibility (O’Dor
et al. 1984; Hernández and García García 2004; Mazón et al. 2007) and bioenergetic
subjects (Katsanevakis et al. 2005; Petza et al. 2006; García García et al. 2011)
demonstrated the predominant role of the protein metabolism and of amino acids,
emphasising the importance that these would have in the design of diets.
Between 2007 and 2010, two separate but complementary research lines were
encouraged by the Spanish National Plans for Aquaculture, JACUMAR (2007–
2009). One was dedicated to the study of acceptability and performance of different
forms of feed and the other focused on a biochemical study of cephalopods, their
natural diets and possible prime materials for formulating feeds. It was deduced
that such feeds should be stable in water and with a firm and homogeneous (nongranular) texture, and have a degree of flexibility so as not to disaggregate during
manipulation, as in the case of fish feed. Also, the presence of chemical substances
that might lead to rejection had to be avoided. As a result, feeds were developed in
formats that were acceptable to the octopuses and produced good growth (0.7–1.5 %
BW day
−1
; Cerezo Valverde et al. 2008; Quintana et al. 2008; Estefanell et al. 2013).
All these feeds used a fish, crustacean or mollusc paste mixed with different binders
(alginates or gelatines), which gave a moist feed (> 70 % water) with a texture that
was suitable for manipulation and ingestion.
Gelatine was found to be more suitable than alginates for elaborating feeds
because of its better digestibility and acceptability (Rosas et al. 2008; Seiça Neves
et al. 2010; García-Garrido et al. 2010a), although alginate is more stable in water.
Heating the mixtures gave them greater stability although it also led to a loss in nutritive value (Cerezo Valverde et al. 2008; Domingues et al. 2009b). The biochemical
studies carried out showed that phospholipids and polyunsaturated fatty acids (docosahexaenoic acid (DHA) and eicosapentaneoic acid (EPA)) were the key nutrients
(Navarro and Villanueva 2003; Estefanell et al. 2013; Cerezo Valverde et al. 2012a).
Supplementation with arginine and the complementation of crustacean or bivalve
protein with fish or animal meals were proposed as alternatives to increasing the
protein yield (Cerezo Valverde et al. 2013).
Great advances have been made regarding knowledge of the nutritional requirements of cephalopods as a result of developing feed with a known nutritional composition. The incorporation of free amino acids, such as glutamate or arginine, had
no effect on the feed rates but was associated with increased growth and protein