The use of alternative diets to culture juvenile cuttlefish, Sepia officinalis: effects on growth and lipid composition

Abstract

The effects of feeding three natural frozen diets, grass shrimp (Palaemonetes sp.), crayfish (Procambarus clarkii) and fish (Sardina pilchardus) and two semi-humid artificial diets (based on fish or shrimp powder) to the cuttlefish, Sepia officinalis, were analysed. Growth rate and feeding rate [FR; % body weight (BW) day )1 ] and food conversions (FC, %) were determined. Cuttlefish fed shrimp grew larger (3.8% BW day )1 ) and had the highest FC, followed by those fed crayfish, and sardine. The highest FR was obtained for cuttlefish fed crayfish (10.5% BW day )1 ). Although both artificial diets were accepted, none produced growth. Digestive gland-to-body weight ratio (DG/ BW ratio) was calculated for animals fed each diet. A positive correlation (r = 0.94) between cuttlefish ingestion FR and DG weight was obtained. Mortality occurred mainly during the last week, and some cannibalism occurred among cuttlefish fed artificial diets. Finally, lipid composition of diets, DG and mantle of each group were analysed. Sardine diet was characterized by high levels of triacylglycerol (TG), whereas the main difference between shrimp and crayfish was the higher n-3/n-6 ratio found in shrimp. Changes in the lipid composition of DG were related to diet, but did not correlate with growth data. A strong loss of TG in the DG of artificial diets groups was notable. No differences in mantle lipid composition among the natural diets were found, but artificial diet groups showed higher contents of neutral lipids in their mantle respect to natural diets. According to results obtained, crayfish (P. clarkii) could be used as an alternative prey for rearing S. officinalis compared with shrimp. Artificial diets showed the worst effects in growth and mortality as well as the stronger influence on DG and mantle lipid composition of cuttlefish. KEY WORDS

Lipid composition of the mantle and digestive gland of Octopus vulgaris juveniles (Cuvier, 1797) exposed to prolonged starvation

“…In this sense, it is interesting to notice that DHA/EPA ratios for this experiment (*1.5), even after 27 days of starvation, are close to the ones reported for the mantle of O. vulgaris by Miliou et al (2006), between 1.5 and 1.9, Zlatanos et al (2006) In general terms, mantle of cephalopods is characterized by no significant variations, despite the lipid composition of the diet, food ratios or maturation cycle (Moreno et al 1998;Sinanoglou and Miniadis-Meimaroglou 1998;Moltschaniwskyj and Jackson 2000;Almansa et al 2006;Ferreira et al 2009). …”

“…There is evidence that the DG could be used for short-term lipid storage in some cephalopods (Castro et al 1992;Fluckiger et al 2008). Several studies (Fluckiger et al 2008;Ferreira et al 2009) have shown that the European cuttlefish DG is rich in PL (especially PC and PE according to Ferreira et al (2009)) and NL, especially TG and SE (and in CHO by Ferreira et al (2009)). The present work confirms that O. vulgaris DG displays a similar NL and PL pattern (Table 3).…”

“…Both polar and neutral lipid fraction seemed to be equal in mantle content throughout the fasting (&50% each) (Almansa et al 2006). Several studies Miniadis-Meimaroglou 1998, 2000;Navarro and Villanueva 2000;Almansa et al 2006;Ferreira et al 2009) have shown that mantle of cephalopods is rich in phospholipids, especially phosphatidylcholine (PC), phosphatidylethanolamine (PE) and cholesterol (CHO). Data from the present study confirm this profile for O. vulgaris.…”

“…There is evidence that this organ is used for short-term lipid storage (Boucher-Rodoni et al 1987;Fluckiger et al 2008), and it is considered to be a good indicator of nutritional status ). Furthermore, the importance of lipids in cephalopod metabolism has been demonstrated, both in early stages of development Villanueva 2000, 2003;Villanueva et al 2002) or juveniles and adults (Domingues et al 2003;Almansa et al 2006;Ferreira et al 2009;García et al 2009). …”

“…It presents high growth rates (Aguado-Giménez and García-García 2003;Iglesias et al 2006Iglesias et al , 2007 and market price (FAO 2008), associated with a great demand throughout many regions of the world. The common octopus has a planktonic larval stage termed as paralarva (Young and Harman 1988) which lasts for 33-40 days when reared at a mean temperature of 24.7°C (Itami et al 1963) prior to the benthic juvenile stage.…”