Iglesias-Estévez, J. (José)

Lavens, P.

Peleteiro-Alonso, J.B. (José Benito)

Rodríguez-Ojea, G.

English

Peleteiro-Alonso, José Benito

Iglesias-Estévez, José

Digital.CSIC

Relationship between egg quality and fatty acid content of various turbot broodstocks (Scophthalmus maximus L.)

The paper presents the data relating to the spawning quality of 20 turbot females (Scophthalmus maximusL.) subjected to natural and controlled photoperiods and fed with two different types of food. A comparison is made between the data usually utilized in hatcheries for defining the spawning quality (number of viable eggs, fertilization and hatching rates, number of larvae produced) and the highly unsaturated fatty acid (HUFA) content of fertilized eggs at the two-cell stage. The results indicate that there is no correlation between the HUFA content of the eggs and any of the egg quality criteria examined. Nevertheless, significant differences (p<0,05) are found between the females fed with fresh trash fish (higher 18:3n-3, 20:4n-6, total lipid content and the ratio DHA/EPA) and those fed with commercial pellets

Peleteiro, J.B.

Rodríguez-Ojeja, G.

Iglesias, J.

Open Marine Archive

Relationship between egg quality and fatty acid content of various turbot broodstocks (<i>Scophthalmus maximus</i> L.)

Repositorio Institucional Digital del IEO

III. Endogenous nutritionICES mar. Sci. Symp., 201: 51-56.1995Relationship between egg quality and fatty acid content ofvarious turbot broodstocks (Scophthalmus maximus L.)J. B. Peleteiro, P. Lavens, G. Rodríguez-Ojea, and J. IglesiasPeleteiro, J. B., Lavens, P., Rodríguez-Ojea, G., and Iglesias, J. 1995. Relationshipbetween egg quality and fatty acid content of various turbot broodstocks iScophthaí-mus maximus L.). - ICES mar. Sci. Symp., 201: 51-56.The paper presents the data relating to the spawning quality of 20 turbot females(Scophthalmus maximus L.) subjected to natural and controlled photoperiods and fedwith two different types of food. A comparison is made between the data usuallyutilized in hatcheries for defining the spawning quality (number of viable eggs,fertilization and hatching rates, number of larvae produced) and the highly unsatur-ated fatty acid (HUFA) content of fertilized eggs at the two-cell stage. The resultsindicate that there is no correlation between the HUFA content of the eggs and any ofthe egg quality criteria examined. Nevertheless, significant differences (p <0.05) arefound between the females fed with fresh trash fish (higher 18:3n-3, 20:4n-6, totallipidcontent and the ratio DHA/EPA) and those fed with commercial pellets.J. B. Peleteiro, G. Rodríguez-Ojea, andJ. Iglesias: Instituto Español de Oceanografía,Apdo. 1552, 36280- Vigo, Spain [tel: (+34) 86 492IlI, fax: (+34) 86 492351j. P.Lavens: Laboratory of Aquaculture and Artemia Reference Center, University of Gent,Rozier 44, B-9000 Gent, Belgiurn [tel: (+32) 91643754, fax: (+32) 91644193f.IntroductionIn the last decade it has been demonstrated extensivelythat highly unsaturated fatty acids are an essential nutri-ent for early larval development (Fraser el al., 1987;Watanabe, 1993). Maternal nutrition affects the eggnutrient composition (Lavens and Sorgeloos, 1991) andconsequently egg and larval quality, since throughoutthis period they rely on the endogenous energy reserves(Watanabe, 1993).The sampling strategy applied in this work enabled usto check whether certain broodstock conditions affectthe nutrient content of the eggs. In particular, factorswhich are generally accepted to have an effect on eggquality were considered, e.g. photoperiod control vsnatural breeding conditions, part of the reproductiveperiod, ripe vs overripe eggs, etc. Egg quality was evalu-ated in accordance with the data usually utilized inhatcheries for this purpose. We therefore attempt in thiswork to find a correlation between any of these par-ameters and the egg nutrient composition.Materials and methodsTwo turbot broodstocks from the Spanish Oceano-graphic Institute in Vigo were kept under different feed-ing and light conditions. One group was fed twice a weekwith semi-dry pellets made with a mixture of fish oil, fishmeal, water, and a supplement of vitamins A, e, and E,giving a final composition of29.4% protein, 10.2% lipid,42.9% humidity, and 6.9% ash content.This broodstock was subjected to photoperiodcontrol. From June 1990 to January 1991 the light wasmaintained constant for 8 h day-I. In J anuary 1991 thephotoperiod was increased suddenly from 8 to16 h oay', and maintained at this level until spawningended. The first egg batches were obtained after about 2months.The second broodstock was also fed twice a week withfresh trash fish, with a basic composition of 25% bluefish and 75% white fish. This group was subjected tonatural photoperiod.The tWQ diets analysed in this experiment are those52 J. B. Peleteiro et al.usually utilized in our hatchery and in the commercialturbot farms in northern Spain.Eggs and milt were obtained by hand-stripping, andthe dry fertilization method was used (Forés et al.,1990). Sea water was added after 15 min, and thenumber of buoyant and non-buoyant eggs and thepercentage fertilization were calculated after 3-4 h,when eggs are in the two-cell stage. At this moment, asmall sample (200 mgdry wt.) of eggs was taken from theftoating layer of eggs for biochemical analysis.The rest of the buoyant eggs were then incubated in a150 litre cylindrical-conical incubator with open-watercirculation and mild aeration. The incubation tempera-ture was kept between 13 and 15°C. At the end ofincubation (4-5 days), the percentage hatch and numberof larvae were calculated.Eggs were c1assified in two groups of different quality(good and medium) according to the morphological cri-teria cited by Kjersvik et al. (1990), including the sym-metry of the early blastomeres, egg tansparency, andsize of perivitelline space.Buoyancy of the eggs after artificial fertilization wasthe only criterion used for c1assifying the eggs as ripe(buoyant) and overripe (non-buoyant).Egg samples were stored at -80°C until freeze-drying.Fatty acids were analysed by gas chromatography asdescribed by Léger el al. (1991).ResultsThe spawning characteristics and fatty acid compositionof all the analysed egg samples are presented in Table 1.The results show a high variation for most of the fattyacid c1asses among the egg samples. Calculation of thevariation coefficients gives values of 20% for EP A, andmore than 35% for DHA and the sum of n-3 HUFA.Even the total lipid content varies by more than 20%,which seems to be very high, since this is a major energyso urce as well as an essential component for the develop-ment of membrane structures during early larval de-velopment. The fatty acid concentrations, too, varytremendousl y.This table shows that there is no relationship betweenany of the criteria utilized to describe the spawningquality and the fatty acid content. For example, some ofthe lowest values in fertilization, hatching, and larvaeproduced (females 108, 52 and 58) correspond to highlevels in DHA, ¡ HUFA, and percentage total lipids,while high values in those three characteristics (females,17,55, and 2) correspond to low DHA and ¡ HUFAcontent. Even two different spawns of female 5, with avery different viable eggs rate, have similar fatty acidvalues.When trying to see if certain broodstock conditionsICES mar. Sci. Symp .. 201 (1995)interfere with the nutrient content of the eggs, Table 2shows that only in a very few cases are there differencesin fatty acid composition between any of the groupsselected. When comparing these parameters it is c1earthat no correlation can be drawn with the fatty acidcomposition or totallipid content of the eggs. However,when broodstock feeding conditions are investigated(see also Fig. 1) it can be noted that significant differ-ences (ANOV A P < 0.05) are detected between thesamples obtained from females fed with pellets andthose from females fed with fresh fish: the former have alower 18:3n-3, 20:4n-6, percentage total lipids andDHAJEPA ratio than the latter.Because of these differences in fatty acid content dueto the diet, we finally tried to see whether the broodstockfeeding conditions also affect spawning characteristicssuch as buoyancy, fertilization, and hatching percent-ages. No significant differences were found (p < 0.05ANOVA test).Discussion and conc1usionsIt is striking that a high variability in fatty acid compo-sition of the turbot eggs is detected. However, the aver-age values of HUFA content, more specifically EP A andDHA, and the ratios DHAJEPA and n-3/n-6 are com-parable to those reported by Witt el al. (1984) and evensubstantially higher than those given by Planas et al.(1989). Lavens and Sorgeloos (1991) compared severalbroodstocks, also finding higher levels for HUFA andDHA in French turbot eggs compared to our samples,which is in agreement with the data of Rubio Rincón(1986). Apparently, there is no c1ear reason for thesedifferences, especially since the same broodstock con-ditions result in a high variability, e.g., DHA rangesmaximally ± 12 mg.One would expect that the differences noted wouldalso interfere with the egg quality, since Planas el al.(1989) suggest that (n-3) HUFA play an important rolejust after hatching and that some fatty acids are the mainenergy source during embryogenesis. The strategy of thesampling campaign enabled us to check whether certainbroodstock conditions interfere with the nutrient con-tent of the eggs and, finally, egg and larval quality. Inparticular, factors which are generally accepted to havea possibly negative impact on egg quality (Kjersvik etal., 1990) were considered. lt can be concluded fromthese data that no correlation can be drawn between thefatty acid composition of the eggs, on the one hand, andthe production conditions examined or the egg and lar-val viability, on the other.However, there is one exception: significant(ANOVA p < 0.05) differences could be detected be-tween eggs obtained from stocks fed on artificial diet andñmV>~P!:{'3-o,~eTable l. Spawning characteristics and fatty acid cornposition of different egg batches (DHA = 22:6n-3; EPA = 20:5n-3; ¿ HUFA = 11-3highly unsaturatcd fattyacids >20:3n-3). The first 13 batches are frorn the broodstock fed with pellets, and the last 9 frorn the broodstock fed with trash fish.]Buoyant Sinkingeggs eggsBateh Fernale (x 10) (x 10) % Fert.RB-l 5 90 O 925 10 238 ORB-3 10 247 34 55RB-4 18 268 ORB-IO 67 162 O 60RB-12 17 112 13 92RB-Ió 39 112 99 65RB-19 55 247 49 97RB-24 99 112 144 97RB-30 53 90 18 87RB-36 9 157 49 9141 40 81RB-46 108 90 63 55S.N. 21RB-53 2 112 22 85RB-62 54 135 85 94RB-68 52-H 76 16 6758 67 25 37 151 87 28RB-70 lO4 45 135 65RB-72 16 117 211 72RB-73 77 45 I1 87% Hatch.2.1mglgDW TotallipidsLarvae (%hatched 18:211-6 18:3n-3 20:4n-6 20:5n-3 22:6n-3 HUFA D.W.) DHNEPA n-3/n-61875 4.1 l7 0.9 7.2 16.5 25.8 lO.37 2.29 3.934.2 1.5 0.9 70 17.2 26.3 15.09 2.46 3.92O 3.0 2.3 0.6 5.4 13.8 21.5 15.46 2.55 3.4530000 3.5 1.8 0.7 5.4 14.7 22.5 17.79 2.72 3.63 ~19400 3.8 1.5 0.7 6.9 15.7 24.6 12.21 2.27 3.84 ""59000 3.3 2.3 0.4 5.9 12.3 19.9 13.33 2.08 3.04~s::26200 3.1 1.8 0.6 5.2 12.9 19.7 12.68 2.48 3.36 ""164400 3.1 2.2 0.6 6.3 12.3 20.1 12.74 1.95 3.38 ~32500 3.3 13 0.7 6.9 15.1 23.8 12.37 2.19 4.48 "";::;29300 3.9 1.9 1.0 8.4 20.4 31.7 12.57 2.43 4.48 ~4.0 2.3 0.7 7.5 17.3 27.5 18.93 2.31 3.97 ?3.7 2.5 0.9 6.4 18.1 27.4 15.14 2.83 3.4 ~1000 4.7 3.0 0.8 7.5 16.8 26.6 21.48 2.24 2.82 ""r¡5.4 2.2 1.1 iU 16.6 27.6 2509 200 3.14 ES.:46500 3.4 3.2 2.4 5.2 13.3 20.5 37.28 2.56 2.14r¡o33300 1.8 1.7 09 5.4 16.0 24.0 14.73 2.96 4.36 ;::;~O 3.2 3.0 1.0 6.4 20.0 28.7 17.97 3.12 3.48 :?3.8 3.4 1.2 6.5 24.5 33.7 20.97 3.77 3.86 ~2.9 2.7 0.9 5.9 17.9 25.8 17.3 3.03 3.48 '"20000 2.2 3.6 2.3 6.3 18.3 27.6 15.25 2.90 2.74 ""...•6450 2.3 2.3 0.9 5.3 13.8 21.1 18.59 2.60 3.3 C3s::14300 1.5 2.3 2.0 5.1 13.6 21.6 13.6 2.67 2.66 ""~...•~~~...•oo~O-r¡;.,-""u.V-lO10.113.352.42970.728.960.644.923.8O406.638.4Table 2. Fatty acid cornposition of turbot cggs according to certain broodstock conditions. The results are presented as rncan values ±s.d. Significant differences(p < 0.05) werc only found where indicated in bold type (groups with lcss than thrce samples wcre not cornparcd).mglgDW Totallipids18:2n-6 IR:3n-3 20:4n-6 20:Sn-3 22:6n-3 HUFAS (%DW) DHA/EPA n-3/n-6 SarnplesFeed Pellcts 3.7 ± O.S 2.0±0.5 0.7 ± 0.2 6.6 ± 10 IS.6±2:4 24:4 ± 3.6 14.63 ±3.15 2.37 ± 0.24 3.67 ± 0.50 13Fresh fish 2.9 ± 1.2 2.7 ± 0.6 1.4 ± 0.6 6.0 ± 10 17.1 ± 3.6 25.6 ± 4.3 20.09 ± 7.33 2.85 ± 0.48 3.24 ± 0.67 9Brecding Beginning 3.6 ± Ol) 2.2±0.7 1.0 ± O.S 6:4 ± 1.0 16.R ± 3.3 25.S ± 3.9 IR.70 ± 7.77 2.67 ± 0.51 3.58 ± 0.60 10season Middlc 3.0 ± Ok 2.3 ± 0.6 1.0 ± 0.6 6.3 ± 1.0 IS.6±2.9 24.2 ± 4.0 14.77 ± 2:47 2.50 ± 0.35 3:48±0.61 11End 4.7 3.0 o.s 7.5 16.k 26.6 21 :4k 2.24 2.82 IFcmalc Early 3.3±0.9 2.2 ± 0.6 Ol)±O6 6.3 ± o.s 15.0±2.1 23.5 ± 3.0 14.78±3.18 2.38 ± 0.26 3.45 ± 0.55 13spawning Middlc 3.2 ± 07 2.5 ± 07 1.2 ± 0.6 6.1 ± 1.1 18.1 ±3.8 26.7 ± 4.9 19.80±8.15 2.94± 0.44 3.63±0.77 7cycle End 3.7 2.5 O.'! 6.4 IR.I 27.4 15.14 2.83 3.40 1Egg Good 3.2±0.9 2.0± 0.5 1.0 ± 0.6 6.4 ± 1.1 ISO ± 2.5 23.6 ± 3.R 17.6 ± 9.7 2.38 ± 0.28 3.60 ± 0.84 11quality Medium 3.3 ± 08 2.6± 0.7 1.0 ± 0.5 6.2 ± 0.7 17.5 ± 3.2 26.1 ± 3.R 17.5 ± 2.4 2.82 ± 0.43 3.42 ± 0.36 \OEgg Ripe 3.3 ± 0.9 2.3 ± 0.6 1.0 ± 0.6 6.4 ± 1.0 16.1 ± 3.1 24.7 ± 4.0 17.04 ± 6.07 2.56 ± 0.44 3.48 ± 0.62 20stage Overripc 4.0 ± 0.4 2.0 ± 0.7 0.9 ± 0.0 6.7 ± 0.4 17.7 ± 0.6 26.9 ± O.R 15.12±0.O4 2.65 ± 0.26 3.66 ± 0.37 2AII samples 3:4±0.9 2.3 ± 0.6 1.0 ± 0.5 6.4 ± 1.0 16.2 ± 2.9 24.9 ± 3.R 16.86 ± 5.67 2.56 ± 0:43 3.49 ± 0.58 22Vl~<....t!:i"¡¡~'"~:::;.el~~ñmV>~~V>'3"O]~g D.W. 3030 ....--------.---- ----- -- --------------r-- :I Ir 2!252015105%D.W.4 -,-- -----63~ 2015 210o o +- L.;.:..:i._L_. -----l~_. L~L __L ._--~DHAlEPA n-31n"18:2n-6 20-.50-3EPA22:6n-3DHAo +--LL1_~L-L.-J~-j -!..~:L-l_______I..:~.: ..L_-L __r_--LJ-- .L,TOTALUPlDS18:3n-3 20:4n-6-r+-t-HUFAIYu0J Fed wi th commercial pellets (13 samples)bd Fed wi th fresh trash fish (9 samples)Figure 1. Fatty acid composition of turbot eggs obtained from females submitted to different feeding conditions. There are significant differences (p < 0.05) in18:3n-3, 20:4n-6, percentage totallipids and DHNEPA ratio.ñm<J>3~<J>~.<J>-c3'O8~~O<¡,.¡:,l::;:,~§I:l..~~;:,'"'15.:8;::¡~~~'<::;:,...•o't;¡:;;.o....•<:J-aoa-s'"'~VIVI56 J. B. Peleteiro el al.on fresh trash fish. The first contain lower levels of18:3n-3, 20:4n-6 DHA, and total lipids. Broodstocknutrition therefore affects the biochemical compositionof the offspring, as was also demonstrated by Watanabe(1991) for red sea bream. However, using fatty acidcomposition as a criterion for egg or larval quality didnot show any correlation again.This implies that all observed minimum levels of theessential fatty acids EPA and DHA seem to be suf-ficiently high to meet the requirements for normal em-bryonic development. Labarta el al. (1989) report thatoptimal egg quality in turbot is achieved when 16:0,18:1n-9, and 22:6n-3 levels are respectively 1.8,1.4 and1.7% of the egg dry weight. Unfortunately, we do nothave sufficient data available on start-feeding success forany conclusions on overall larval quality to be drawn.Moreover, the data of the different broodstock feedingshould be interpreted with care, since also another cul-ture parameter is changing: natural or photoperiodicalcontrol of the reproduction cycle.Although some authors (Planas el al., 1991) reportthat a shift of the spawning period through photoperio-die control results in a decrease of n-3 PUF A and n-9fatty acids, Forés el al. (1990), working with the samebroodstock as in our experiment, found that a dramaticchange in the photoperiod produced eggs of good qual-ity with a similar percentage of fertilization and hatch tothose spawned by natural photoperiod. Because of this,we consider that it is the broodstock diet compositionand not the photoperiodic control which really affectsthe egg lipid content.ReferencesForés, R., Iglesias, L, Olmedo, M., Sánchez, F. L, and Pele-teiro, l. B. 1990. Induction of spawning in turbot (Scophthal-mus maximus L.) by a sudden change in the photoperiod.Aquacult. Engineering, 9: 357-366.Fraser, A. r.,Sargent, l. R., Gamble, l. c., and Maclachlan, P.1987. Lipid class and fatty acid composition as indicators ofthe nutritional condition oflarval Atlantic herring. Am. Fish.Soco Symp. 2: 129-143.ICES mar. Sci. Symp .. 201 (1995)Kjersvik , E., Mangor-Jensen, A., and Homefjord, I. 1990. Eggquality in fishes. In Adv. Mar. Bio!., 26: 71-113.Labarta, U., Planas, M., Ferreiro, M. L, Fernández-Reiriz, M.L, and Garrido, l. L. 1989. Biochemical factors affecting eggquality in turbot: a general approach. ICES Working Groupon Mass Rearing of Juvenile Marine Fish. Montpellier ,France , June 1989.Lavens, P., and Sorgeloos, P. 1991. Variation in egg and larvalquality in various fish and crustacean species. In Larvi '91 -Fish and Crustacen Larviculture Symposium. Eur. Aquacult.Soc., Spec. Pub!. No. 15: 221-222.Léger, P., Bengtson, D. A., and Sorgeloos, P. 1989. Analyticalvariation in the determination of the fatty acid compositionof standard preparations of brine shrimp Anemia: an inter-laboratory exercise , pp. 413-423. In Aquatic toxicology andhazard assessment: 12th volume, ASTM STP 1027, U. M.Cowgill and L. R. Williams (Eds.) American Society forTesting and Materials, Philadelphia, USA.Planas, M., Ferreiro, M. L, Fernández-Reiriz, M. L, andLabarta, U. 1989. Evolución de la composición bioquímica yactividades enzimáticas en huevos de rodaballo (Scophthal-mus maximus L.) durante la embriogénesis. In AcuaculturaInterrnareal, pp. 215-227. Ed. by M. Yúfera. Inst. Cien.Andalucía, Cádiz.Planas, M., Garrido, l. L., Labarta, U., Fernández-Reiriz,M. J., Rodríguez, J. L., and Otero, J. J. 1991. Biochemicalcharacteristics of the eggs of farmed turbot (Scophthalmusmaximus L.). In Larvi '91- Fish and Crustacen LarvicultureSymposium. Eur. Aquacult. Soc., Spec. Pub!. No. 15: 207-209.Rubio Rincón, E. A. 1986. Evolution de la composition enacides gras de l'ovocyte a la larve du turbot (Psetta maximaL.) en fonction du Régime alimentaire des reproducteurs etdes larves, ainsi que de la température d'incubation. PhDthesis, Université de Bretagne Occidentale. 183 pp.Watanabe, T. 1991. Axtaxanthin: an effective dietary compo-nent for red seabream broodstock. In Fish nutrition in prac-tice, book of abstracts. IV International Symposium on FishNutrition and Feeding. Biarritz, France.Watanabe, T. 1993. Importance of Docosahexaenoic acid inmarine larval fish. In Larvi '91- Fish and Crustacean Larvi-culture Symposium. Eur. Aquacult. Soc., Spec. Pub!. No.15: 19.Witt, U., Ouantz, G., Kuhlmann, D., and Kattner, G. 1984.Survival and growth of turbot larvae Scophthalmus maximusL. reared on different food organisms with special regard tolong-chain polyunsaturated fatty acids. Aquacult. Engineer-ing, 3: 177-190.

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Relationship between egg quality and fatty acid content of various turbot broodstocks (Scophthalmus maximus L.)

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