Influence of Diet on Ongrowing and Nutrient Utilization in the Common Octopus

7/27/2019 Influence of Diet on Ongrowing and Nutrient Utilization in the Common Octopus

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Influence of diet on ongrowing and nutrient utilization in the common octopus

(Octopus vulgaris )

Benjam n Garca Garca*, Felipe Aguado GimenezC.I.D.A.-Acuicultura, Consejer a de Agricultura, Agua y Medio Ambiente de la Regio n de Murcia,

Puerto de San Pedro del Pinatar, Apdo 65, 30740 San Pedro del Pinatar, Murcia, Spain

Received 11 April 2001; received in revised form 22 August 2001; accepted 22 August 2001

Abstract

Octopus vulgaris ongrowing has recently begun to develop in Spanish coastal waters. The need todiversify aquaculture products in terms of its biological and market potential makes octopus a seriouscandidate for rearing. Ongrowing success depends on several factors, such as environmental rearingconditions, diet and nutritive utilization. Two fresh diets of low market value ( Boops boops and Sardina pilchardus ) were used to assess growth rate, feeding rate and efficiency by means of multipleregression analysis. Factors considered were sex and diet as qualitative variables, and body weight andtemperature as quantitative ones. No significant differences were observed regarding growth and sexalthough it was slightly higher in males. Nevertheless, food intake was higher in females as well as inthe sardine-fed females. Growth with bogue-fed octopus was significantly higher. Smaller specimensgrew more than the larger ones in proportion to initial body weight. The rise in temperature increasedgrowth and food intake over our experimental range. Differences in growth may have been due to thedifferent lipid content of the diets since digestibility of lipid in cephalopods is poor and their main

energy source is protein. Thehigher food intake in females may be caused by metabolicchanges relatedto the reproduction period although this remains to be confirmed.D 2002 Elsevier Science B.V. All rights reserved.

Keywords: Octopus vulgaris ; Ongrowing; Feeding and nutrition; Growth; Temperature; Body weight; Mediter-ranean Sea

0044-8486/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved.PII: S004 4-848 6(01) 00788- 8

* Corresponding author. Centro de Recursos Marinos, Puerto de San Pedro del Pinatar, Apdo 65, 30740 SanPedro del Pinatar, Murcia, Spain. Tel.: +34-968-184518; fax: +34-968-184518.

E-mail address: [email protected] (B. Garc a Garca).

www.elsevier.com/locate/aqua-online

Aquaculture 211 (2002) 171182


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1. Introduction

The common octopus ( Octopus vulgaris ) has many suitable characteristics for rearingsuch as high fecun dity rate (producing 100,000500,000 eggs per female) (Wells,1978) , fast growth (Mangold, 1983; Iglesias et al., 1997) , high food conv ersion rate(assimilating 4060% of ingested food) (Mangold and von Boletzky, 1973) , and goodmarket prices and increasing demand. In Spanish Atlantic coastal waters, some trialshave been carried out, providing excellent results (Iglesias et al., 1997; Luaces-Canosaand Rey-Me ndez, 1999; Rodrguez and Carrasco, 1999) . Octopuses were fed mainlycrabs, and to a lesser extent, fish and other cephalo pods, similar to their natural diet (Nigmatullin and Ostapenko, 1976; Guerra, 1978) . Under experimental conditions,Cagnetta and Sublimi (1999) observed better growth in octopus when fed crabs thanfish.

In the Mediterranean, crab supply is poor and expensive due to low catches.Therefore, Mediterranean industrial octopus ongrowing must be carried out by mainlyfeeding low market value fish, such as the small pelagic fishes Boops boops , Sardina pilchardus , Sardinella aurita , Trachurus mediterraneus , etc. Among these species, twogroups can be distinguished according to their lipid content: the bluefish group formed byS. pilchardus and S. aurita have a higher lipid content than the whitefish group formed by B. boops and T. mediterraneus . This distinction is important since cephalopod lipiddigestibility is very poor (ODor et al., 1984) and their capacity to catabolize lipid islimited ( Ballantyne et al., 1981; Mommsen and Hochachka, 1981 ; Navarro and

Villanueva, 2000). Protein is the principal energy source for cephalopods. However,lipid and protein content of food must have some influence in on-growing and nutrient utilization.

This work investigates growth and nutrient utilization of O. vulgaris fed with two diets based on low market value fish with different lipid content as B. boops and S. pilchardusin Southeastern Mediterranean. In addition, the influence of culture variables isconsidered, such as body weight, sex and water temperature.

2. Materials and methods

The octopuses ( O. vulgaris ) were caught in November by professional fishing boatsusing drag nets. Until arrival at the port, the octopuses were kept in 100-l tanks with thewater being renewed every 1530 min. From the port (Cartagena) to the laboratory inSan Pedro del Pinatar 35 km away, the octopuses were transported in 1000-l tanks inseawater supplied with oxygen. The temperature did not exceed 16 j C and oxygen never fell below 70%. Survival, which in such conditions is inversely and lineally related withtemperature (Aguado et al., 2001) , was 90%. Before the experiment started, theoctopuses were kept together in a raceway tank of 4 m 3 for 15 days. During this periodof acclimation, the water temperature was 16 j C, the dissolved oxygen was of 80%

saturation, and no mortality was observed. Twenty-four specimens were used, distributedindividually in 400-l cylindrical tanks with open seawater flow. Each tank had a 20-cmdiameter PVC tube as refugee. Initial experimental conditions are showed in Table 1 .

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The trial was carried out from December 1998 to May 1999. The flow-through of seawater in tanks was adjusted so that oxygen saturation was never below 80% at theoutlet, for which measurements were taken twice a day. The photoperiod (37 j 50 V N,0 j 46 V W) and water temperature (ranging from 13 j C in February to 19 j C in May)were natural (see Table 3 ).

The octopuses were fed to satiation, the food being provided once a day during themorning. Fish were provided without tails or heads since octopuses do not usuallyconsume these parts. Every day, more fish were introduced into the tanks than theoctopus could consume. The following day, uneaten fish were removed from the tanksand dried with absorbent paper before weighing. The amount of food consumed wascalculated as the difference between food supplied and that removed. The amount of food provided daily was adjusted so that the octopuses were always fed to satiation. Table 2shows the nutritional composition of both food fishes. Protein content was determined bythe Kjeldhal method using the factor conversion of 6.25. Lipid was obtained with ether extraction (SOXTEC System-HTC). Moisture was obtained by drying (105 F 1 j C, 24 h)until constant weight, and ash by incineration (loss in weight: 450 F 1 j C, 24 h). Net energy was estimated using Miglavs and Jobling (1989) energy coefficients: protein 23.6kJ/g and lipid 38.9 kJ/g.

Assays lasted for 176 days and octopuses were sampled every 30 days. During theexperiment, the octopuses that died were replaced by others of similar body weight. In

Table 2Macronutrient composition of each diet (percent wet substance F S.D.)

Sardine Bogue

Crude lipid 19.64 F 3.02 5.94 F 2.56Crude protein 17.77 F 0.66 18.48 F 1.11Ash 2.73 F 0.35 3.29 F 0.05Moisture 60.51 F 2.01 70.52 F 3.60Gross energy (GE)

(kJ/100 g food)

1183.37 667.19

Protein/energy ratio( P / E ) (g protein/MJ)

15.02 27.70

Table 1Initial experimental conditions

Experimental group

(sex and diet)

Specimen

number

Average weight F S.D. (g)

FS 6 316 F 57FB 6 378 F 77MB 6 418 F 69MS 6 346 F 47

FS= female with diet of sardine; FB= female with diet of bogue; MB= male with diet of bogue; andMS= male with diet of sardine.S.D.= standard deviation.

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total, seven octopuses died, six of which were replaced; the last specimen died at the endof the experiment and so was not replaced. After each sampling, the following indiceswere calculated:

Absolute growth rate (AGR): W f W i / t Specific growth rate (SGR): (ln W f lnW i)100 / t Absolute feeding rate (AFR): IF / t Specific feeding rate (SFR): AFR 100 / W a Feed efficiency (FE): ( W f W i)100 / IF

Table 3Average values F S.D. for each index of each experimental period and overall results

Period Group AGR SGR AFR SFR FE

December, T = 15 j C(1316 j C)

FS 3.43 F 0.77 0.95 F 0.14 6.96 F 1.50 1.94 F 0.36 49.27 F 2.63

FB 3.97 F 0.96 0.96 F 0.19 9.85 F 2.72 2.32 F 0.28 41.68 F 9.48MB 7.36 F 2.02 1.50 F 0.33 9.55 F 2.31 1.91 F 0.34 80.55 F 26.08MS 3.29 F 1.72 0.76 F 0.35 8.60 F 2.23 2.02 F 0.29 38.65 F 19.55

January, T = 14 j C(1215 j C)

FS 0.99 F 0.41 0.24 F 0.10 8.50 F 1.15 2.11 F 0.50 11.60 F 4.59

FB 2.59 F 1.28 0.50 F 0.18 8.23 F 1.88 1.63 F 0.20 30.58 F 11.48

MB 2.24F

0.43 0.37F

0.05 9.93F

1.66 1.63F

0.11 22.65F

2.61MS 1.38 F 0.52 0.30 F 0.13 8.49 F 1.56 1.81 F 0.39 17.47 F 8.13February, T = 13 j C(1214 j C)

FS 1.97 F 0.85 0.45 F 0.20 10.47 F 2.10 2.38 F 0.35 19.91 F 10.37


March, T = 15 j C(1416 j C)

FS 3.48 F 1.51 0.66 F 0.26 14.81 F 1.67 2.84 F 0.33 24.26 F 12.45


April, T = 17j

C(1619 j C)

FS 9.40 F 2.22 1.33 F 0.35 18.42 F 21.2 2.56 F 0.32 53.14 F 20.86

FB 9.25 F 3.53 0.95 F 0.33 21.24 F 3.11 2.23 F 0.29 42.56 F 14.67MB 10.65 F 4.05 0.91 F 0.32 21.37 F 2.60 1.86 F 0.19 49.71 F 18.20MS 7.80 F 3.85 0.86 F 0.30 17.21 F 22 1.97 F 0.22 44.37 F 19.53

May, T = 19 j C(1721 j C)

FS 6.53 F 3.84 0.68 F 0.40 28.83 F 4.56 3.04 F 0.49 22.09 F 11.04


Overall FS 4.25 F 0.62 0.72 F 0.08 14.58 F 1.90 2.17 F 0.13 29.18 F 1.94FB 6.10 F 1.63 0.76 F 0.14 16.06 F 2.66 1.77 F 0.20 37.84 F 8.03MB 7.12 F 1.30 0.79 F 0.09 16.40 F 1.32 1.58 F 0.14 43.27 F 5.32MS 4.36 F 1.39 0.65 F 0.08 13.73 F 1.90 1.94 F 0.40 31.65 F 9.48

Mean temperature and range of each experimental period.



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where W f = final weight (g); W i = initial weight (g); W a = average weight (g); t = time indays; and IF = ingested food (difference between food supplied and food consumed).

2.1. Statistical analyses

Considered variables that may have some influence on growth and food intake wereaverage body weight between sampling ( W a ) and temperature ( T

a ) as quantitativefactors, and sex ( S ) and diet ( D) as qualitative factors. Partial correlation tests (PCT)were used in order to assess the influence of these variables. Changes in growth and

Fig. 1. Weight gained of experimental groups (bars = standard deviation).

Table 4Results of partial correlation test (PCT)

AGR SGR AFR SFR FE

Temperature ( j C) 0.32 0.41 0.56 0.56 0.17 P < 0.001 P < 0.001 P < 0.001 P < 0.001 n.s.

Weight 0.45 0.23 0.70 0.24 0.12 P < 0.001 P


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feedin g rates could be explained with mathematical equ ations like lnY = lna + blnW a +clnT a (Garc a Garca, 1994; Petridis and Rogdakis, 1996) . Therefore, data were adjusted by means of multiple regression analyses to a model like ln Y = lna + blnW a + cln-T a + dS + eD (S = 0 for males, S = 1 for females, D =0 for B. boops and D =1 for S. pilchardus ). ANOVA was used to test the significance of models and the Students t -test for the coefficient significance. Statistical analyses were done with STATISTICAversion 5.0 program.

3. Results

Average values of growth, feeding rates and f eed efficiency of each experimental gr oupfor each period between sampling are shown in Table 3 , as well as the overall valu es. Fig.1 shows body weight evolution of each group throughout the experiment, and Table 4shows the results of PCT between different variables considered.

Bogue-fed individuals achieved significantly higher growth rates and final weight thanthose fed sardine. For the same kind of food, males obtained higher final weight thanfemales. Nevertheless, PCT displayed no significant correlation between sex and AGR or SGR although there was significance between sex and AFR and SFR: females had higher feeding rates than males.

The type of diet correlated significantly with growth and feeding rate, resulting in higher growth for bogue-fed and higher food intake for sardine-fed individuals. Body weight and

Table 5Results of multiple regression analyses

Coefficients AGR SGR AFR SFR

lna 10.082 F 1.078 5.504 F 1.084 7.073 F 0.369 2.468 F 0.369Intercept P < 0.0001 P < 0.0001 P < 0.0001 P < 0.0001b 0.677 F 0.186 0.323 F 0.187 0.806 F 0.064 0.194 F 0.064Weight P < 0.001 P = 0.087, n.s. P < 0.0001 P < 0.01c 2.668 F 0.587 2.679 F 0.590 1.579 F 0.201 1.579 F 0.201

Temperature P < 0.0001 P < 0.0001 P < 0.0001 P < 0.0001d 0.041 F 0.102 0.041 F 0.102 0.135 F 0.035 0.135 F 0.035Sex P = 0.688, n.s. P = 0.693, n.s. P < 0.001 P < 0.001e 0.306 F 0.108 0.307 F 0.108 0.121 F 0.037 0.121 F 0.037Diet P < 0.01 P


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temperature were significantly correlated with growth and feeding rate. As body weight increased, AGR increased and SGR decreased, that is, like most cultured marine animals,younger specimens grew proportionally more than the older ones. Over our temperaturerange, as temperature increased, growth and feeding rates increased. Feeding rate correlatedsignificantly and positively with sex and diet: females and sardine-fed showed higher AFR and SFR.

FE only correlated significantly with diet and sex, indicating better food utilization in bogue-fed animals and males. Usually, FE correlates significantly with body weight andtem peratur e, but this effect was not observed in this study.

Table 5 shows results of multiple regression analyses. ANOVA shows that all modelsare highly significant ( P < 0.0001). Nevertheless, fitting was better when we used absoluteterms (AGR and AFR, Eqs. (1) and (3)).

lnAGR 10:82 0:67lnW 2:668ln T a 0:041S 0:306 D 1

lnSGR 5:504 0:323ln W 2:679ln T a 0:041S 0:307 D 2

lnAFR 7:703 0:806ln W 1:579ln T a 0:135S 0:121 D 3

lnSFR 2:468 0:194ln W 1:579ln T a 0:135S 0:121 D 4

In AGR equations, sex coefficient was negative and very low in absolute terms, andnot significantly different from zero, so it may be disregarded. Males had higher growth

Fig. 2. Effect of temperature on AGR, AFR and FE in males and females of 1000-g body weight.



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Fig. 4. Effect of body weight on AGR, AFR and FE in specimens fed with bogue and sardine at a constant seatemperature of 18 j C.

Fig. 3. Effect of temperature on AGR, AFR and FE in males bogue- and sardine-fed of 1000-g body weight.



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rates but not more significant than females. On the other hand, in the AFR equation, sexcoefficient was significantly different from zero: females fed more than males.

From Eqs. (1) and (3) , we estimat ed AGR and AFR, and FE from AGR and AFR for three different situations (Figs. 24) .

4. Discussion

The trend in growth and food ingestion change according to body weight andtemperature in this experiment is similar to that observed in other cultured species.The body weight coefficient in the AGR model was 0. 677, similar but slightly higher than that in salmon ids (0.60, Brett and Groves, 1979 ) or gilthead sea bream ( 0.55,Muller-Feuga, 1990 ; 0.60, Garc a Garca, 1994 ; 0.62, Lupatsch and Kissil, 1998 ), andin the AFR model, the coefficient was 0.806, which was within the observed range for fish (0.471, Brett and Groves, 1979 ). These coefficient values confirm that absolutegrowth increases with body weight and food intake and specific growth decreasesexponentially.

Temperature coefficients in the AGR (2.66) and AFR (1.57) models were also similar to cultured fish as Sparus aurata (2.43 and 1.47, respectively, Garc a Garca, 1994). For our wide temperature range, this parameter induced higher food intake and if it was not limited, it also increased growth (Figs. 2 and 3) . However, growth rate in O. vulgaris washigher than in cultured fish such as sea bass or gilthead sea bream. According to Lee

(1994) , cephalopod growth rates are comparable with those of terrestrial mammals andare higher than in fish.FE did not correlate significantly with either body weight or temperature. Never-

theless, when estimated from the AGR and AFR models, it changed like in fish (Figs.24) , i.e., when body weight is constant and temperature range is optimal, increases intemperature result in better nutritive utilization. When temperature is constant, FEdecreases when body weight increases. Mangold and von Boletzky (1973) suggestedthat the conversion index (CI = 1/FE) in O. vulgaris does not depend on temperature anddoes not seem to be reduced with body weight but is influenced by diet. It is alsosuggested that CI shows great individual variability. Precisely because of this variability,

it was not possible to establish a clear relationship between CI or FE with body weight and temperature, as has been done with other ectotherm organisms like fish (Goolish andAdelman, 1984; Hidalgo et al., 1987; Xie and Sun, 1992; Garc a Garca, 1994) . It seems, therefore, more appropriate to establish growth and food intake models andestimate FE.

Sex did not seem to have any influence on growth rate for our experimentalconditions but showed influence on feeding rate, being higher in females. Some authorshave observed that males reach higher body weight than females (Mangold, 1983;Forsythe and Van Heukelem, 1987) because females experience stronger metabolicchanges during sexual maturing, stopping somatic growth (ODor and Wells, 1978) and

decreasing their trophic activity (Mangold and von Boletzky, 1973) . Before sexualmaturation, females grew as much as males. The reasons for higher feeding rates infemales with both diets are unclear. It may be due to higher energy requirements,



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hormonal changes, lower digestibility, etc. In any case, this observation must beascertained and corroborated.

Diet was demonstrated to have a clear influence on growth, food intake and FE. Better results were obtained in bogue-fed specimens than in sardine-fe d ones. These differencesmay be related to lipid content more than protein content (Table 2) . Differences in protein/energy ratio ( P / E ) between b oth diets may als o be important. Sardine-fedoctopuses produced floating oily feces. ODor et al. (1984) suggested that lipid digestionin octopus was low and inefficient, probably due to the scarcity of emulsifier in itsdigestive tract. However, some cephalopods store significant quantities of lipid in thedigestive gland, which are reduced during starvation. These same authors observed a dropin digestive gland lipid content after 6 days of starvation, from 0.3% body weight to0.06% in O. vulgaris .

In homeotherms, optimum P / E is between 10 and 15 (NRC, 1983; Halver, 1989) . Infish and crustaceans, this ratio is higher, around 20 30 (Cowey et al., 1985) . Incephalopods, P / E optimum value must be higher. In Sepia officinalis , optimum growthwas achieved when P / E reached 50 (Lee, 1994) . Our best results were obtained withfeeding with bogue, of which P / E was 27.7, whereas with sardines, it was 15.02. Thenatural diet of O. vulgaris is composed mainly of crabs. The P / E value for crabs obtainedfrom macronutrient composition data from ODor et al. (1984) is 35, so it is possible that P / E optimum for O. vulgaris was around it and thus higher than in fish. These high valuesmight be explained by the predominance of amino acid metabolism for energy production(Lee, 1994) . High quantities of protein obtained from a natural diet with low carbohydrates

together with low lipid digestibility suggest that protein is the main energy source in O.vulgaris (ODor et al., 1984) . Lee (1994) suggested that P / E might not be accurate incephalopods to establish energetic requirements, and rather that a balance of amino acidlevels provide those amino acids that were better in obtaining energy for routinemetabolism (proline, aspartate and arginine) and essential amino acids for proteinsynthesis.

Acknowledgements

This work has been financed by JACUMAR Spanish National Plans for Aquaculture(1999). Authors wishes to thank Julia Pastor Bajo and Pilar Aguado Gime nez for their helpin the English translation.

References

Aguado, F., Rueda, F.M., Egea, M.A., Herna ndez, M.D., Faraco, F., Garc a Garca, B., 2001. Efecto de latemperatura sobre la supervivencia en el transporte, estabulacio n y engorde de Octopus vulgaris Cuvier (1797) en el Mediterraneo occidental. In: Fernandez-Palacios, H., Izquierdo, M. (Eds.), Convergencia entreInvestigacion y Empresa: Un reto para el Siglo XXI, Monograf as del ICCM no. 4. ICCM, Las Palmas deGran Canaria, pp. 174179.



11/12

Ballantyne, J.S., Hochachka, P.W., Mommsen, T.P., 1981. Studies on the metabolism of the migratory squid, Loligo opalescens : enzymes of tissues and heart mitochondria. Mar. Biol. Lett. 2, 7585.

Brett, J.R., Groves, T.D.D., 1979. Physiological energetics. In: Hoar, W.S., Randall, D.J., Brett, J.R. (Eds.), FishPhysiology Vol. VIII. Bioenergetics and Growth. Academic Press, New York, pp. 279352.

Cagnetta, P., Sublimi, A., 1999. Productive performance on the common octopus ( Octopus vulgaris C.) when fedon a monodiet. Seminar on Mediterranean Marine Aquaculture Finfish Species Diversification. CIHEAM-IAMZ and FAO, Zaragoza, pp. 1 3.

Cowey, C.B., Mackie, A.M., Bell, J.G., 1985. Nutrition and Feeding in Fish. Academic Press, London, 489 pp.Forsythe, J.W., Van Heukelem, W.F., 1987. Growth. In: Boyle, P.R. (Ed.), 1987. Cephalopod Life Cycles, vol. 2.

Academic Press, London, pp. 351365.Garca Garca, B., 1994. Factores que influyen sobre el consumo de ox geno, ingesta y crecimiento en la dorada

(Sparus aurata , L.): una aproximacion al establecimiento de modelos lineales. PhD Thesis. University of Murcia (Spain).

Goolish, E.M., Adelman, I.R., 1984. Effects of ration size and temperature on the growth of juvenile commoncarp (Cyprinus carpio L.). Aquaculture 36, 2735.

Guerra, A., 1978. Sobre la alimentacio n y el comportamiento alimentario de Octopus vulgaris . Invest. Pesq. 42,351364.Halver, J.E., 1989. Fish Nutrition, 2nd edn. Academic Press, San Diego, 789 pp.Hidalgo, F., Alliot, E., Thebault, H., 1987. Influence of water temperature of food intake, food efficiency and

gross composition of juvenile sea bass, Dicentrarchus labras . Aquaculture 64, 199207.Iglesias, J., Sa nchez, F.J., Otero, J.J., 1997. Primeras experiencias sobre el cultivo integral del pulpo ( Octopus

vulgaris , Cuvier) en el Instituto Espanol de Oceanografa. In: de Costa, J., Abella n, E., Garc a Garca, B.,Ortega, A., Zamora, S. (Eds.), Actas VI Congreso Nacional de Acuicultura, Cartagena 911 de Julio de 1997.Ministerio de Agricultura, Pesca y Alimentacio n, Madrid, pp. 221226.

Lee, P.G., 1994. Metabolic substrates in cephalopods. In: Portner, H.O., ODor, R.K., MacMillan, D.L. (Eds.),Physiology of Cephalopod Molluscs, Lifestyle and Performance Adaptations. Gordon & Breach, Switzerland, pp. 3551.

Luaces-Canosa, M., Rey-Me ndez, M., 1999. El engorde industrial de pulpo ( Octopus vulgaris ) en jaulas: ana lisisde dos an os de cultivo en la R a de Camarin as (Galicia). In: Ferna ndez-Palacios, H., Izquierdo, M. (Eds.),Convergencia Entre Investigacio n y Empresa: Un reto para el Siglo XXI, Monograf as del ICCM no. 4.ICCM, Las Palmas de Gran Canaria, pp. 184189.

Lupatsch, I., Kissil, G.W., 1998. Predicting aquaculture waste from gilthead sea bream ( Sparus aurata ) cultureusing a nutritional approach. Aquat. Livest. Res. 11 (4), 265268.

Mangold, K.M., 1983. Octopus vulgaris. In: Boyle, P.R. (Ed.), 1983. Cephalopod Life Cycles, vol. 1. AcademicPress, London, pp. 335364.

Mangold, K.M., von Boletzky, S.V., 1973. New data on reproductive biology and growth of Octopus vulgaris .Mar. Biol. 19, 712.

Miglavs, I., Jobling, M., 1989. The effects of feeding regime on proximate body composition and patterns of energy deposition in juvenile artic charr, Salvelinus alpinus . J. Fish Biol. 35, 111.

Mommsen, T.P., Hochachka, P.W., 1981. Respiratory and enzymatic properties of squid heart mitochondria. Eur.J. Biochem. 120, 345350.

Muller-Feuga, A., 1990. Mode lisation de la croissance des poissons en e levage. Rap. Sci. Tech. IFREMER 21,156.

National Research Council (NRC), 1983. Nutrient Requirements of Warmwater Fishes and Shellfishes. NationalAcademy Press, Washington, DC, 102 pp.

Nigmatullin, Ch.M., Ostapenko, A.A., 1976. Feeding of Octopus vulgaris from the North West African coast.ICES C.M. 1976/K 6, 115.

ODor, R.K., Wells, M.J., 1978. Reproduction versus somatic growth: hormonal control in Octopus vulgaris . J.Exp. Biol. 77, 1531.

ODor, R.K., Mangold, K., Boucher-Rodoni, R., Wells, M.J., Wells, J., 1984. Nutrient absorption, storage andremobilization in Octopus vulgaris . Mar. Behav. Physiol. 11, 239258.

Petridis, D., Rogdakis, I., 1996. The development of growth and feeding equations for sea bream, Sparus aurataL., culture. Aquacult. Res. 27, 413419.



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Rodr guez, C., Carrasco, J.F., 1999. Engorde de pulpo ( Octopus vulgaris Cuvier): resultados de crecimiento,supervivencia y reproduccio n. In: Ferna ndez-Palacios, H., Izquierdo, M. (Eds.), Actas del VIII Congreso Nacional de Acuicultura, Las Palmas de Gran Canaria, Espan a. p. 44.

Wells, M.J., 1978. Octopus. Physiology and Behaviour of an Advanced Invertebrate. Chapman & Hall, London,417 pp.

Xie, J.L., Sun, R., 1992. The bioenergetics of the southern catfish ( Silurus meridionalis , Chen): growth rate as afunction of ration level, body weight, and temperature. J. Fish Biol. 40, 719730.


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Influence of Diet on Ongrowing and Nutrient Utilization in the Common Octopus