High feeding and growth rates in common octopus (Octopus vulgaris ) fed formulated feeds with an improved amino acid profile and mixture of binders

Abstract

Four semi-moist formulated feeds were supplied to Octopus vulgaris subadults (664 ± 70 g; 18.4 ± 0.7°C) in two different experiments. In the experiment #1, two diets were prepared with a new mixture of binders (gelatine 150 g kg−1, starch 100 g kg−1 and gum 50 g kg−1). The GEL15-Squid and GEL15-Hake feeds included 100 g kg−1 freeze-dried squid (Todarodes sagittatus) or hake (Merluccius sp.) respectively. Both feeds showed low water disintegration rates at 24 h (13.6–15.0% dry weight). The specific feeding rate was higher in animals fed GEL15-Hake (2.7%BW day−1), but the growth and feed efficiency were significantly better in animals fed GEL15-Squid (1.4%BW day−1 and 61.2% respectively; P < 0.05). The proximate composition of the digestive gland, carcass and whole animals was similar. In the experiment #2, the GEL15-Squid amino acid profile was improved by replacing 50 g kg−1 gelatine by 50 g kg−1 freeze-dried squid (GEL10-Squid) or freeze-dried fish (GEL10-Fish). These feeds showed higher water disintegration rates (31.7–36.3% dry weight). The feeding rates (2.2–2.3%BW day−1), growth (1.5%BW day−1) and feed efficiency were similar for both diets. Total lipids were higher in the digestive gland and whole animals fed GEL10-Fish diet (P < 0.05). Future effort could be directed towards alternative binders that allow improve amino acid balance with a minimum gelatine content or even supplementation trials including essential amino acids.