Cephalopod Farming

DWhatley

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DWhatley

Cthulhu
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#2
Australia

Octopus Farming is Catching on, AquacultureHub Nov 2011, three year project to grow octopuses for the food industry. The species is not named but looks like vulgaris and is a small egg species. The current technology is to catch them small and grow them to eating size. They are attempting to hatch the eggs without the mother and are getting hatchlings but not settlement.
 
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DWhatley

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@Tintenfisch, Somewhere I have seen another farm that was an in situ experiement that I want to add but have misplaced :roll: the link and found this in looking for that thread. I almost did not post it because of the "what a wonderful animal, yummm" presentation but I want to start keeping information on octo aquaculturing and the information was worth keeping.

While in Colorodo, years ago, we visited a steak restaurant and both Neal and I still remark on the comment by one of the 4H kids thanking the restaurant for buying the cow that he raised. Farmers have to have a different outlook, I know, but it is hard for us that consume the end product to separate the "pet" concept of raising an animal to something that goes on our plate. Some members have mentioned the need for, "if you would not kill it yourself don't eat it" attitude and I can emphasize with the idea but not the reality. I have to go with, "if you eat it, don't object to the killing that brings it to your table". It gives a little more latitude for survival but still provides a way to object (by not consuming as well as allowing open objection) when collection methods or care are in opposition to desired standards/sustainability. Unfortunately, it also gives the consumer an out to not think about what they consume.
 

SandV

Wonderpus
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#5
In the video it mentions that it is possibly the first time the eggs have hatched without the mother? I know mothers brood with their eggs but has anyone lost a mother and the eggs still hatch?

I ask because I have been helping out at our new aquarium and we got a "common brown octopus" who promptly layed eggs and passed. The first egg hatched yesterday. Small egg little baby :( giving it a try tho
 

DWhatley

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#6
SandV, welcome back (again :grin:)
I think that is more of a brag than a reality. I know Ceph was able to hatch O. briareus (large) eggs 20+ years ago without the mother but we recommend keeping them with the female as the hatch rate is better and there is no need for trying to adjust equipment. Keeping the hatchlings alive through to adulthood is another story, even with many of the large egg species.

All initially pelagic species suffer from our lack of understanding as to what to do to keep them alive until they become benthic. Seahorses have the most luck of the ones I am aware of but the numbers are still abysmal and few people succeed. Martin Moe still works with trying to find the secret with Diadema (long spined sea urchins) and our members always give it a try when faced with the "opportunity". The focus continues to be first foods and lack of harmful bacteria. There has been some success (at least to a point) with the GPO using newly hatched crabs as food but I have not been able to find anything close to frozen (let alone live) crab zoea.

One thing I found interesting with the laying of the last eggs was the simultaneous spawning of a pencil urchin. Assuming this is not cooincidence (and the spawning of peppermint shrimp with my last eggs suggests something is being triggered), I am beginning to think we need other animals in the water column when egg laying takes place.
 

SandV

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I have been lurking around....but thanks

I didn't plan on having them without their mother but they seem to be developing and hatching out fine, but of course I have little hope for them surviving.
 

DWhatley

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#8
If you have the time and some thoughts using whatever is at hand, use the opportunity to experiement a little. Changing salinity, different foods, anything you can think of. You will have anywhere from 2 days to 2 weeks to try something so go for it if you can. Currently, the primary thought is food but we see them eat and they still die. Even where I had survivors with the large egg animals, I lost 5 or so that made it past the initial die offs and were eating well (hand feeding) but still did not make it.

One thing I wanted to try last time but lost them too soon was to put a couple in a filter sock that went unchanged. It would be continually bombarded with new tank water but contain left over food, pods and detritus. Both my surviving O.briareus spent time (unintentionally) in this environment which suggests there is a possible advantage.

If you are going to experiment at all, start immediately after hatching, leaving some in the tank as more or less a control group.
 

ceph

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Cephalopods have an incredibly high food to biomass conversion rates - especially for protein. In other words, they are very good at turning what they eat into growth. They have fast life spans and high growth rates - these two traits make them an excellent candidate for commercial aquaculture. . . so far so good. . .

But they have other traits that make commercial rearing of them difficult.

The challenge for commercial rearing of cephalopods isn't getting the eggs to hatch. This is easily done by leaving them with the mother - the best option. However, they can also be raised artificially much like one would do for cichlid eggs. TONMO members that are interested in raising their ceph eggs may want to remove some of them and raise them at a colder temperature. One of the challenges with raising octopuses is that most people only get one shot at it. By separating some of the eggs and slowing down their development, you can give yourself a chance to learn from the first hatch and give yourself a second chance if things go wrong.

So what are the challenges?

One challenge is what to feed the hatchlings. Live food is required. Live mysid shrimp and amphipods work well, but they often cost more than the octopuses they are being fed to. Curstacean meat is worth more than octopus meat. Mysids often sell for 8 cents each which doesn't sound like much but really is. At the Aquarium of the Pacific our Mysid bill for our seadragosn was 6 figures. There is currently no simple frozen or prepared diet that can be fed to hatchling cephalopods.

Another challenge is that the small egged species have planktonic larvae. While these species are more prolific, their offspring are much smaller and a lot harder to raise in captivity. While I have raised a number of large egged species, including a deep-sea species, I have not raised any planktonic species. I can and has been done, but it ain't easy.

For experiments, I second the suggestion an unfed control. Hatchlings will live for some time, perhaps a week, on their reserves. A control gives experiments something meaningful to compare to.

James
 

DWhatley

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Summary of current farming activities

From the Aquaculture hub blog, Octopus Farming is Catching On - November 11, 2011

Nice short summary of the three countries now working with the challenges of farming octopuses for food. The Spain (O. vulgaris) and Australia (O. tetricus) teams are all working with small egg species where Mexico does not have to fight this battle with O. maya.
 

DWhatley

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Chile - First Patagonian red octopus juvenile specimens obtained at laboratory

This SUGGESTS that they may have been able to raise a small egg species to juvenile. This is big news if they have achieve this for a quantity of hatchlings. I did find this rather interesting qualification of the big/small egg question in the Journal of Plankton Research:

Although the mode of life of newly hatched cephalopods is often categorized as either planktonic or benthic, the hatchlings in aquaria showed no preference for swimming or settling. Additionally, the size of eggs and hatchlings which is correlated with the mode of life at hatching in other octopodid species, fitted both planktonic and benthic in E. megalocyathus. Furthermore, morphological and behavioural characteristics were similar to the pre-settlement stage of planktonic hatchlings of Octopus vulgaris. Therefore, we suggest that hatchlings of E. megalocyathus have an unusual, suprabenthic mode of life.

First Patagonian red octopus juvenile specimens obtained at laboratory

CHILE
Friday, March 01, 2013, 04:00 (GMT + 9)


In order to diversify aquaculture through cephalopods farming, the Institute of Aquaculture of Universidad Austral de Chile carried out a scientific-technological project for the sustainable production of Patagonian red octopus (Enteroctopus megalocyathus) juvenile specimens.

After three years working in the Marine Invertebrate Hatchery of the Aquaculture Institute of Universidad Austral de Chile, located in Puerto Montt (HIM-UACh), the first cephalopod juveniles were born.

Chile has two traditional octopus species of high commercially valued octopus, which are the Octopus mimus and the Enteroctopus megalocyathus. The latter, the Patagonian red octopus, is a cold water species that is rapidly growing in the Chilean Patagonia.

Dr. Iker Uriarte, head of research, pointed out that the cephalopod is harvested when it reaches between 2 and 4 kg and "in the medium term it will be able to be produced through economically and environmentally sustainable farming methods," Aqua reported.

Uriarte explained the octopus sustainable production requires a high effort as to R&D&I to produce abundant controlled farmed juvenile specimens.

The researcher added that in 2012 the first descriptions of the innate immune system of the species were obtained, developed in conjunction with Dr. Rodolfo Amthauer of the Institute of Biochemistry and the scientists Alex Romero and Ricardo Enríquez of the UACh Institute of Animal Pathology.

With this knowledge platform, in December 2012 it was possible to obtain juveniles under laboratory conditions for the first time for the species. This was achieved after enhancing breeders, hatching eggs and farming planktonic paralarvae and benthic juveniles.

"The specimens that have now reached 1 gram and measure 4.5 cm will be the first ones to provide information on the time required to get from one newly settled juvenile up to a 50 gram specimen that may enter the fattening farming phase," said Dr. Uriarte.

This research was funded by Fondef D09 I of 1153, which the University was allocated in the XVIII Research and Development Contest 2010.

The project was led by a larviculture and nutrition team joined by Dr. Iker Uriarte, Ana Farías and Jorge Hernández, and engineers in aquaculture, Viviana Espinoza and Jessica Dörner.

The investigation also included the participation of international scientists, such as Dr. Carlos Rosas of the National Autonomous University of Mexico, an expert in farming the Octopus maya.

Now, Uriarte just been allocated the project Fondecyt No. 1131094, where it is intended to study the ecophysiological aspects regulating the embryonic paralarvario growth and development and that of the early juveniles of this species that is common in the southern area of South America, and that has great economic importance both for Chile and for Argentina.


By Silvina Corniola
editorial@fis.com
www.fis.com
Enteroctopus megalocyathus TONMO Octopodidae

Effects of alimentary regime on feeding, growth, and proximal composition of Octopus mimus Gould, 1852 National Shellfisheries Association, Inc. 2010 (article)

INTRODUCTION

Most cephalopods have a growth rate superior to other shellfishes, reaching their maximum size in a short period of time (Lee et al. 1991, Cortez et al. 1995b, Iglesias et al. 2000, Vega & Mendo 2002, Semmens et al. 2004). They also have an efficient feeding system with predominance in the assimilation of amino acids, as a result of which the protein content of the body is very high: 75 85% of dry weight (e.g., Octopus vulgaris) (Villanueva et al. 2002). As a result, the asymptotic phase of growth, which is a predominant characteristic in the life cycle of most molluscs and teleost fishes, is absent or is almost imperceptible (Moltschaniwskyj 2004). This fast growth, which may be greater than 5% of body weight per day (Villanueva 1995, Iglesias et al. 2000), high conversion rate of ingested food (40-60% assimilation) (Garcia Garcia & Aguado Gimenez 2002), short life cycle (2-3 y) (Boyle & Knobloch 1982, Forsythe & Hanlon 1988, Cortez et al. 1995a), rapid adaptation to culture conditions (Iglesias et al. 2000), and their value as one of the most important resources of the world's fisheries (Vecchione 1991, Villanueva et al. 2002) have resulted in cephalopods, especially octopuses, being considered serious candidates for production under controlled conditions (cultivation) on an industrial scale (Nabhitabhata 1995, Zuniga et al. 1995, Olivares et al. 1996, Defeo & Castilla 1998, Cortez et al. 1999b, Baltazar et al. 2000, Iglesias et al. 2000, Vaz-Pires et al. 2004).

The Chilean octopus fishery is currently based on 2 species--the Northern octopus (Octopus mimus Gould, 1852) and the Southern octopus (Enteroctopus megalocyathus Gould, 1852)--with O. mimus showing more signs of overexploitation as a result of the high demand of national and international markets (Osorio 2002, Araya 2003, SERNAP 2003, Cardoso et al. 2004). The increase in captures has affected the abundance of both species and has also produced a reduction in maximum size, as result of the capture of the largest individuals (Rocha & Vega 2003).

The difficulty in obtaining juveniles of O. mimus in captivity has restricted its cultivation to the on-growth of subadult individuals of approximately 1 kg captured in the field, obtaining individuals of 2-3 kg in 3-4 mo (Olivares et al. 1996, Cortez et al. 1999a).

Laboratory observations have shown that the origin and quality of food items are important in the growth of octopuses, because different items produce different rates of food conversion (Cortez et al. 1995b). This distinction is fundamental in cephalopods, because they digest lipids poorly and their capacity to catabolize them is limited (Navarro & Villanueva 2000, Garcia Garcia & Aguado Gimenez 2002).

The goal of this study was to determine the specific feeding rate (SFR), the specific growth rate (SGR), and the proximal composition of O. mimus fed with 3 different diets in captivity to assess culture potential.
Rearing and Growth of the Octopus Robsonella fontaniana (Cephalopoda: Octopodidae) From Planktonic Hatchlings to Benthic Juveniles
Iker Uriarte1,Jorge Hernández1,Jessica Dörner,Kurt Paschke,Ana Farías,Enzo Crovetto,Carlos Rosas 2010 (full article)
SUCCESS RAISING SMALL EGG paralarvae using crab zoeae (see crab raising in referenced paper)
Paralarval rearing
Three hundred R. fontaniana paralarvae (obtained as explained above and hatched on the same day) were placed in 1-l glass recipients using three densities: 25 paralarvae l−1 (10 flasks), 5 paralarvae l−1 (6 flasks), and 1 paralarva l−1 (6 flasks). The cylindrical glass flasks (diameter 9 cm, height 20 cm) were covered with black plastic lids; these conditions provided the paralarvae with a semi-dark environment in which they could recognize their prey but were less likely to be damaged by the tank walls. Once a day, the paralarvae were fed three live L. santolla zoeae per paralarva. The paralarvae were fed only L. santolla zoeae until settlement. For all growth stages, the seawater was replaced daily (100%) with UV-sterilized seawater at 11 °C and 30‰ salinity, and the aeration was provided in the form of a mild flow through a Pasteur pipette. Survival was evaluated periodically until 22 days after hatching (DAH). Afterward, 14 paralarvae (22 DAH) were used for a new experiment. These specimens were placed in 3-l flasks (1 paralava per flask) and fed exclusively L. santolla zoeae; seawater was changed daily and survival was evaluated at 24, 34, 42, 52, 62, and 72 DAH. After 70 days of rearing, the paralarvae that had been swimming in the seawater column adopted benthic behavior, tending to stay mainly at the bottom of the tank and using one of the shelters (half-inch PVC joints) provided. This was referred to as settlement behavior and marked the end of the paralarval period. Eight of the 72 DAH octopuses that settled were used for a new experiment. These specimens were placed in individual 5-l tanks (16 cm width × 31 cm length × 14 cm depth) with a PVC shelter (12 mm diameter × 5 cm length). Two-thirds of the water was changed daily using filtered, UV-sterilized seawater at 11 °C and 30‰ salinity. Survival was evaluated over a period of 92 days, when the juvenile octopuses were 78, 95, 101, 108, 120, 135, and 160 DAH.

Live feed production
L. santolla zoeae (3.1–5.6 mm) were produced throughout the experiment using the standardized conditions detailed in Paschke et al. (2006) (ddw: PDF here). Briefly, lecithotrophic Zoea I larvae were reared at 12 °C and 30‰ for a maximum of 3 days; thereafter, Zoea I molted to Zoea II. The Zoea I were characterized by a lack of spines (Campodonico, 1971), positive geotaxis (Paschke et al., 2006), a maximum swimming velocity of 2.1 cm s-1 (Escobar, 2005), carapace length 2.4 mm, carapace width 1.61 mm, (Surot, 2006), dry weight 1040 to 878 μg larvae−1 (Kattner et al., 2003; Surot, 2006), and protein content 41% of the dry weight; triacylglycerols accounted for about 75% of the lipid fraction, and monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids were 48.3% and 29.8% of the total fatty acid content, respectively (Kattner et al., 2003).

At the beginning of the benthic stage, the juvenile octopuses were fed a mix of king crab zoeae and live wild juveniles of the crab Petrolisthes laevigatus; later they were fed only juvenile crabs weighing between 0.23 and 0.56 g wet weight. The juvenile crabs were caught in the rocky intertidal and kept at 11 °C and 30‰ salinity. The octopuses were fed 1 to 2 crabs per day.
 

DWhatley

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#12
Feeding of cephalopods under culture conditions
Journal of FisheriesScience.com 2012 Vol. 7 No. 3 pp245-252 Record number 20133235594
Authors: Sen, H; Kop, A.

Abstract
The deficiency of the artificial diet to supply growing of cephalopods is the main factor in the commercial cephalopod culture. It is required that the special metabolism of these species should be well known for manufacturing of the diet successively. Although, feeding trials with shrimp, squid, crab, mussel, and fish are positive effects on the growth, it is not economical for common feed due to expensive. Additionally, in spite of fact that it is not possible to obtain these feeds in due time and amount, the production of pellet and/or artificial food is obligatory points for culture of cephalopods. Studies focused on preparation of optimal composition of artificial feed for obtaining optimal growing of cephalopods have been progressing during the recent years.
 
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DWhatley

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#13
Pathogens and immune response of cephalopods Sheila Castellanos-Martínez,Camino Gestal

1. Introduction Scientific interest for cephalopods is increased over the last century for, at least, a couple of reasons: i. their value as experimental animals for biomedical and behavioral research (for review see for example: Grant et al., 2006, Hanlon and Messenger, 1996, Hochner, 2008, Hochner et al., 2006 and Mather, 1995); ii. their position in the world marked as a major fishery resource (e.g. Boyle and Rodhouse, 2005).
Since the decline of traditional fisheries (Balguerias et al., 2000 and Caddy and Rodhouse, 1998), cephalopods have gained attention in aquaculture practice. Among other cephalopods, Octopus vulgaris has been considered the ‘candidate’ species in European aquaculture because of its easy acclimatization to farming conditions, its rapid growth and its good value for the market (Vaz-Pires et al., 2004). The octopus on-growing is currently developed in Galicia (NW Spain) on an industrial scale ( Garcia and Garcia, 2011 and Garcia et al., 2004).
Despite the benefits, one of the disadvantages of aquaculture is the increase in the incidence of pathologies produced by bacteria and/or transmissible parasites that could be a serious risk for the production. On the other hand, the EU Directive on the use of animals for experimental purposes European Parliament and Council of the European Union, 2010, requires capture of animals from the wild to be minimized. Thus, it becomes urgent that practices of culturing animals be further expanded. Finally, an important outcome of the Directive 2010/63/EU is that appropriate care and maintenance of cephalopods for research purposes will require proper knowledge and practice in terms of assessment of health and disease prevention of the animals.
 

DWhatley

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#14
Sepia Officinalis - Cuttlefish Farming

Center of Marine Sciences Research Proposal
Abstract
Much cuttlefish research during the last few years has focused on its introduction as a new species for aquaculture. This is because the species displays biological and economical aspects with potential for industrial culture. Sykes et al. (2006a) reviewed this potential and identified reproduction as a technological bottleneck for the European cuttlefish, Sepia officinalis. This was mostly due to several biological aspects of the species, such as: semelparity; low fecundity and fertility in captive conditions; and suspicions of inbreeding (after egg non-viability after 6 consecutive generations - Sykes et al. 2006b). Control of reproductive function in captivity is essential for the sustainability of commercial aquaculture production. It relies on species specific biological and physiological knowledge and culture conditions, which will ultimately influence animal welfare (Conte 2004). Nonetheless, no previous studies on cuttlefish reproduction in captivity have used a multidisciplinary approach to solve these problems. With the present proposal we aim at an approach that will take zoo-technology, behavior, physiology, and population genetics, into account.

Regarding the effect of culture conditions, early experiments (Forsythe et al. 1991 and 1994; Correia et al. 2005) and recent data (Sykes et al. 2006a & 2006b, 2009 and unpublished results; Domingues & Márquez 2010) indicate that the type of tank, environmental and biological conditions may influence fecundity and fertility. On the other hand, the effects of optimal bottom area/tank volume, density, and natural male/female ratio; are still to be unveiled and these culture conditions will have an effect on cuttlefish physiology.

Knowledge regarding cuttlefish behaviour and chemical communication has been reported both in nature and captivity. In nature, cuttlefish only become social for reproduction, while in captivity they show complex intraspecific visual displays (Hanlon et al. 1999) and form short-term female-male pair associations (Boal, 1997). Males use visual displays to establish size-based dominance hierarchies, where large males mate more frequently (Adamo & Hanlon, 1996; Boal, 1997). During copulation, males display sperm removal behaviour (Hanlon et al. 1999). Despite the wealth of information regarding the role of vision in cuttlefish behaviour, little is known about the role(s) of olfaction. Apparently, olfaction is involved both in female mate-choice and social recognition (Boal & Golden, 1999; Boal, 2006). Recently, a peptide (ILME) was identified in cuttlefish, which is a chemical messenger released by the oocytes and eggs and which acts at both paracrine and pheromonal levels (Zatilny et al. 2000a) So, to what extent does all of this influence reproduction in captivity and how can we use it to manipulate cuttlefish reproduction? On the other hand, to what extent will culture conditions influence cuttlefish behavior and chemical communication?

If we are able to succeed in raising reproduction numbers in captivity to what is recorded in nature, then the future cuttlefish aquaculture industry will have to rely on a breeding selection protocol that still needs development. S. officinalis is a semelparous species and this implies a different brood stock management that used for most finfish. Until now, it has been a common practice to use cultured broodstocks to obtain animals for the subsequent generations (Sykes et al. 2006b). Such closed-cycle practice with captive breeders may have led to reproductive isolation from wild populations and a resultant loss of genetic variability due to the low effective breeding population size and inbreeding. We need to address this issue, by determining the effective number of breeders contributing for reproduction in an integrative way, by using behavioral analysis and paternity studies, and quantifying the loss of genetic variation in consecutive cultured generations at given culture conditions. To achieve this objective, we will have two lines of breeders: one according to Sykes et al. (2006a) and another were we will establish the minimum level of outbreeding by adding “new blood” at different generations.

After, we will use the data to redesign the existing cuttlefish husbandry protocol based on a statistical approach that will determine the importance of each variable under study in this project and the magnitude of influence in cuttlefish reproduction in captivity.

The accomplishment of the objectives of the current proposal will allow not only a better understanding of cuttlefish biology, behaviour and genetics, but will also be of extreme importance for other cephalopod species and industry application in the future.
 

DWhatley

Cthulhu
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#16
@FatFish, these primarily come from our daily News bot (octobot) finds or my own Google Scholar results so they are as up to date as I can make them. Everyone is encouraged to add to the list of finds. Sadly most of them are behind subscription walls but many of our academics do have access.
 

DWhatley

Cthulhu
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#17
Large-scale octopus farming could be three years away
Under Current News June 26, 2014 Alicia Villegas

...
The key to succeed in commercial aquaculture production is to achieve full cultivation across the octopus’ life cycle. The research institute is focusing on this now — in fact they managed to complete full cultivation across the life cycle of several octopuses for the first time ever in 2001.
This was achieved after using live crustacean zoeae — larvae — as single or complementary prey, but it is very difficult to obtain them in large quantities. “To produce at large scale, that would be very expensive, so our focus is now to analyze the crustacean larvae so our farmed crustacean artemia has the same composition,” Iglesias said.
The new focus will be key for commercial octopus production. ...
 

DWhatley

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#18
Productive performance of juvenile Patagonian red octopus (Enteroctopus megalocyathus) fed with fresh preys: are relevant the quantity of protein and energy on diets? - Chile

Another study to find appropriate food to cheaply farm octopuses


Abstract
This study was conducted to investigate if the productive performance of Patagonian red octopus (Enteroctopus megalocyathus) is related to the quantitative contents of protein and energy of fresh diets based in marine preys. Six diets with P/E ratios of 35 (100% crab = C100), 41 (100% fish = F100), 44 (25% squid and 75% fish = S25:F75), 46 (50% squid and 50% fish = S50:F50), 48 (75% squid and 25% fish = S75:F25) and 51 (100% squid = S100) g protein MJ1 during 83 days were evaluated in octopuses weighing 297 ± 120 g. The growth and body biochemistry of the octopuses were not affected by the diets, however, food and lipid intake were affected, with crab diet obtaining the highest intake in both cases. The higher values of dry matter digestibility were achieved in S100 and S50:F50 diets, the highest protein digestibility was obtained with S100 and C100 diets, while the highest energy digestibility was achieved by diet S75:F25 and F100. Feed efficiency varied between the diets and protein/energy ratio alone explained 82.8% of the total variance. Besides, octopus fed F100 and C100 showed the highest body protein deposition. So, although it had no significant differences in growth and survival between the different diets, the feed efficiency and nitrogen deposition changed in relation with the protein/energy ratio of fresh diets. It is discussed that is possible to maintain growth of octopuses and to improve the feed efficiency and protein deposition parameters by optimizing the P/E values of diet.
 

DWhatley

Cthulhu
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#19
Selection of marine species and meals for cephalopod feeding based on their essential mineral composition
J. Cerezo Valverde, A. Tomás Vidal, S. Martínez-Llorens, M.C. Pascual, J.I. Gairín, J. Estefanell, D. Garrido, J.F. Carrasco, F. Aguado-Giménez, B. García García 2014 (subscription)
Abstract
A quantitative analysis of the essential mineral content (mg kg−1 dry weight) was carried out in 31 samples, including molluscs, crustaceans, fish and meals in an attempt to identify those most suitable for formulating cephalopod diets. The mineral ratios (MR: content in the test sample/content in whole Octopus vulgaris) were used as index of nutritional quality. Both crustaceans and oysters presented an optimal profile that covered the macro- and microelements composition of O. vulgaris. These samples differed from the rest by their higher Ca, Mg, B, Cu and Zn contents based on a principal component analysis. Fish were deficient in macroelements, such as Na (MR: 70–420 g kg−1) and Mg (MR: 220–690 g kg−1), but would be good source of K, Ca and P. Most fish were also deficient in Fe, Zn and Cu, although the copper content would be the most affected (MR: 3–130 g kg−1). Fish and krill meals showed a high content of Ca and P, although both would be deficient in Na (MR: 440–470 g kg−1) and Cu (130–540 g kg−1), along with K, Fe and Zn in krill and Mg and B in fish. Among the plant meals, sunflower and soybean were the most appropriate, presenting higher total content of minerals and MRs above 1000 g kg−1 for all minerals, except Na, Cu and Zn.
 

DWhatley

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#20
An insight on Octopus vulgaris paralarvae lipid requirements under rearing conditions
D.B. Reis, I. García-Herrero, R. Riera, B.C. Felipe, C. Rodríguez, A.V. Sykes, M.V. Martín, J.P. Andrade, E. Almansa 2014 (subscription)

Abstract
In this study, two new alternative preys: Grapsus adscensionis zoeae (as sole prey) and Palaemon elegans zoeae (in cofeeding with Artemia sp.), as well as, Artemia sp. juveniles were used as feed for octopus paralarvae, as a way to understand its lipid requirements. Total lipid (TL) content, lipid class (LC) and fatty acid (FA) profiles of preys, octopus hatchlings and 9-day-old paralarvae were analysed. Growth and survival of the paralarvae were also determined. Regardless the prey provided, a notable shift in the lipid profile of paralarvae was registered after 9 days of rearing. The highest index of growth rate (IGR) recorded when decapod crustacean zoeae were supplied might have some relation with levels of 20:4n-6 (ARA) and DHA/EPA ratio observed. In this sense, Grapsus adscensionis zoeae leaded to a higher content of ARA and a lower content of EPA, which may indicate a possible competition between these two FA. For that a balanced EPA/ARA ratio might be significant in this species nutrition without disconsidering DHA levels as an essential fatty acid. Finally, the changes observed in paralarvae FA profile might not only be related to prey FA profile, but also with changes occurring in the lipid classes contents.
 

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