Effects of dietary protein sources on growth, survival and digestive capacity ofOctopus mayajuveniles (Mollusca: Cephalopoda)

Abstract

We propose two hypotheses to explain the inexistence of adequate prepared diet for Octopus maya at this date: Hypothesis 1 is related to changes in protein structure during protein cooking, which affects the digestibility. Hypothesis 2 is related to changes on nutritional characteristics during ingredient process, which affects the nutritional composition of diet. To test hypothesis 1, experiments one and two were directed to determine if protein cooking reduces digestibility and growth of animals when compared to fresh or lyophilized protein sources. For hypothesis 2, three experiments were conducted, testing seven different dietary protein sources offered in isolation or combined in artificial diets fed to O. maya. Results demonstrated that the diets that promoted growth were the ones based on fresh crab paste, and both lyophilized crab and squid tentacles paste. In consequence hypothesis 1 was accepted. The cooking process also changed nutritional characteristics of protein sources, affecting the growth of O. maya. Results obtained when squid and crab were mixed suggest that nutritional requirements of octopuses were covered with that diet in similar forms compared to when using fresh or lyophilized crab, also confirming hypothesis 2. Based on growth rates obtained, we can conclude that nutritional requirements of O. maya must be between 80% and 86% Protein (P), 5.1–5.6% Lipids and a protein: energy ratio between (P/E) 38.9 and 42.2 g MJ−1.

Replacing live feed with formulated diets in juvenile Patagonian red octopus (Enteroctopus megalocyathus)

“…These results have also shown that the optimal protein/energy ratio for the Patagonian red octopus would be 36.97 g protein MJ −1 , which is higher than for O. vulgaris , but not as high as reported for O. maya by Rosas et al. () and for cuttlefish by Lee (). It has been proposed that octopuses have high phospholipid (PL) and cholesterol (CHO) requirements in their diet, which explains greater efficiencies obtained with crustacean‐based diets.…”

“…Documented studies of octopus growth or ongrowing in suspended systems at sea or in tanks on land show highly diverse results, primarily depending on the diets used. However, other reports agree that the natural fresh diet is still the most reliable, especially when based on crustaceans (Gutiérrez et al., ; Sánchez et al., ), and that replacement with formulated diets must be done using diets based on crustaceans and squid or fish, using freeze‐dried meals (Estefanell et al., , ; Rodríguez‐González et al., ; Rosas et al., ).…”

“…Two formulated diets and a natural diet (C) consisting of live specimens of Chilean crab Cancer edwarsii were used in the experiment. The formulated diets (Table ) were CP and C&S, consisting of two experimental formulations based on crab meat paste (Farías et al., ) and a mixture of freeze‐dried crab and squid ( Dosidicus gigas ) meals (Rosas et al., ), respectively.…”

“…() showed that the onset of enzymatic activity in gastric juice occurs after soluble proteins of the feed enter the digestive tract, activating enzyme activity of enzymes accumulated at crop. On the other hand, studies have shown that freeze‐dried meals are superior to those produced by thermal means (Rosas et al., ).…”

Performance of raw material thermal treatment on formulated feeds for common octopus (Octopus vulgaris) ongrowing

“…However, results regarding the effects of thermal treatment applied to natural food for cuttlefish (Domingues et al, 2009) should not be overlooked because commercial meals are normally processed applying high temperature (≈100°C). Indeed, the latter has led Rosas et al (2013) to perform specific experiments related to changes in protein structure during cooking (which affects protein digestibility) and by alterations on nutritional characteristics during ingredient process (which affects the nutritional composition of diets). In fact, Morillo-Velarde et al (2013a) found greater feed acceptability by octopuses when freezedried ingredients were used, contrasting with a significant rejection of almost all commercial meals when these were used as raw materials in tested diets.…”