1
2
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Lipid and mineral distribution in different zones of
farmed and wild blackspot seabream (Pagellus
bogaraveo)
5
6
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9
10
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13
Victoria Álvareza, Isabel Medinaa, Ricardo Pregob, and Santiago
14
P. Aubourga,*
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26
a
(CSIC), C/ Eduardo Cabello 6, 36208-Vigo (Galicia, Spain)
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28
b
31
32
33
34
Department of Oceanography; Instituto de Investigaciones Marinas
(CSIC), C/ Eduardo Cabello 6, 36208-Vigo (Galicia, Spain)
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30
Department of Food Technology; Instituto de Investigaciones Marinas
*
Correspondent: Fax: +34 986 292762; e-mail: saubourg@iim.csic.es
1
SUMMARY
2
3
Lipid composition was studied in different white muscle zones (ventral, dorsal
4
and tail) of wild and farmed blackspot seabream (Pagellus bogaraveo). The study was
5
complemented by the moisture, trimethylamine oxide (TMAO) and trace mineral
6
determinations. Farmed fish muscle showed higher lipid and triglyceride contents, but
7
lower values for moisture, TMAO and α-tocopherol than its counterpart wild fish; no
8
differences could be observed between both kinds of fish for the phospholipid, sterol
9
and free fatty acid content. When compared to wild fish, a higher saturated (SFA),
10
monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acid content was obtained
11
in farmed fish, while lower values could be observed for the ω3/ ω6 and 22:6 ω3/ 20:5
12
ω3 fatty acid ratios. Most minerals analysed (Cu, Fe, Mn, Se and Zn) showed higher
13
mean values in farmed fish muscle, except for Ca and Mg that provided higher mean
14
contents in wild fish. Concerning muscle sites comparison, greater SFA, MUFA and
15
PUFA contents could be detected in the dorsal zone than in the two other locations both
16
for farmed and wild fish, according to a higher mean lipid content found in this site.
17
Finally, the tail zone showed higher TMAO values than the two other locations.
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Running Title: Lipid and mineral distribution in blackspot seabream
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Keywords: Blackspot seabream, muscle zones, farmed, wild, lipid classes, fatty acids,
22
trimethylamine oxide, minerals
2
1
1. INTRODUCTION
2
3
Marine species include relevant contents of different constituents such as
4
nutritional and digestible proteins, lipid-soluble vitamins, microelements, non-protein
5
nitrogen compounds and highly unsaturated fatty acids [1-3]. Most of these constituents
6
have shown to support an important role both in human diet and in quality changes
7
developed during processing and storage of the corresponding seafood product. Among
8
such constituents, the lipid fraction is now the subject of a great deal of attention due to
9
its high content on ω3 polyunsaturated fatty acids (PUFA), which has shown potential
10
benefits to human health [4, 5] and negative effects on quality changes during the
11
technological treatment [6].
12
Fish constituents have often been shown to be inhomogeneously distributed
13
along the body of a fish, probably affected by physiological and anatomical factors [7].
14
In this sense, the lipid matter has been recognised as the most highly affected, showing
15
wide differences in its content distribution in fatty [8, 9] and lean [10, 11] fish,
16
depending on the tissue considered. Further, fatty fish studies have reported notorious
17
differences concerning the lipid damages of different zones during processing [9, 12-
18
13].
19
In recent years, the fishing sector has suffered from dwindling stocks of
20
traditional species as a result of marked changes in their availability. This has prompted
21
fish technologists and the fish trade to pay more attention to aquaculture techniques as a
22
source of fish and other aquatic food products. Fish farming offers the possibility to
23
control the quality of the entire productions processes, being one of the most important
24
objectives to obtain a final product with sensory and nutritional quality attributes as
25
close as possible to those of wild fish [14-16].
3
1
One of such fish species is blackspot seabream (Pagellus bogaraveo). This high
2
value commercial species has long attracted a great interest because of its firm and
3
flavourful flesh, so that remarkable efforts have recently been focused on its
4
commercialisation as a farmed product [17]. Thus, most research concerning its
5
aquaculture production has been carried out on farming conditions [18] and genetic
6
differences [19]. However, previous information concerning its composition [20] and
7
chemical changes during processing [21] can be considered scarce.
8
The present work was focused on the lipid composition of blackspot seabream.
9
Its objective was to identify elements of differentiation that characterise wild and
10
farmed fish. Such differentiation is considered important if cultured blackspot seabream
11
is to be used as a replacement for the wild one in the seafood European marketing
12
system. In addition, this study was addressed to different edible sites of the fish body
13
and was complemented by the moisture, trimethylamine oxide and trace mineral
14
assessments.
15
16
17
2. MATERIALS AND METHODS
18
19
2.1. Fish material and sampling
20
Farmed blackspot seabream specimens (12 individuals; 0.65-0.85 kg weight; 32-
21
35 cm length) were obtained from a local aquaculture facility (La Coruña, Spain). Fish
22
were cultivated in a single tank by employing a sand-bed-filtered seawater (salinity
23
range 3.2-3.4 g/ 100 g). Feeding was carried out to satiety by employing the following
24
commercial diet: moisture (9.5%), protein (44.5%), fat (13.5%), carbohydrate (23.5%)
25
and ash (9.0%). Fish specimens were sacrificed in a water-ice mixture in the
4
1
aquaculture facility and then kept in ice for 10 h until they arrived at the laboratory. The
2
fish were distributed into six groups (two individuals per group). Each group was
3
studied independently in order to carry out the statistical analysis (n = 6).
4
Wild blackspot seabream (12 individuals; 0.65-0.80 kg weight; 34-37 cm length)
5
were caught near the Galician Atlantic coast and obtained in a local market 10 h after
6
being caught. From catching till arrival to laboratory the fish were kept in ice. The fish
7
were distributed into six groups (two individuals per group). Each group was studied
8
independently in order to carry out the statistical analysis (n = 6).
9
In all cases, individual gonads were at the 5th/6th stage of Maier’s scale of gonad
10
maturity. Both for farmed and wild fish groups, the white muscle of three different
11
zones (ventral, dorsal and tail; Figure 1) was considered, carefully separated and studied
12
independently in each fish group. The absence of bones, blood and dark muscle was
13
verified. Chemical analyses were carried out separately on each of the selected zones.
14
15
All solvents and chemical reagents used in the experiments were reagent grade
(Merck, Darmstadt, Germany).
16
17
2.2. Chemical analyses
18
Moisture content was determined by weight difference of the homogenised
19
muscle (1-2 g) before and after 4 h at 105 ºC; the results were calculated as g water/ 100
20
g muscle.
21
22
The lipid fraction was extracted by the Bligh and Dyer [22] method.
Quantification results were calculated as g lipid/ 100 g muscle.
23
Trimethylamine oxide (TMAO) content was determined by previous reduction
24
of a trichloracetic acid extract of the muscle with titanium (III) chloride [23] and further
5
1
assessment of trimethylamine (TMA) content by the spectrophotometric method
2
described by Tozawa et al. [24]. Results are expressed as g TMAO-N/ 100 g muscle.
3
Total phospholipids (PL) were quantified by measuring the organic phosphorus
4
on total lipid extracts according to the Raheja et al. [25] method based on a complex
5
formation with ammonium molybdate. Results are expressed as g PL/ kg muscle.
6
Total sterols (ST) were determined on total lipid extracts by the method of
7
Huang et al. [26] based on the Liebermann-Buchardt reaction. Results are expressed as
8
g ST/ kg muscle.
9
Free fatty acid (FFA) content was determined following the Lowry and Tinsley
10
[27] method, which is based on a complex formation with cupric acetate-pyridine. In
11
this study, benzene was replaced by toluene. Results are expressed as g FFA/ 10 kg
12
muscle.
13
To measure the triacylglycerol (TG) content, the lipid extract was first purified
14
by 20 x 20 cm thin-layer chromatography plates coated with a 0.5 mm-layer of silica gel
15
G from Merck (Darmstadt, Germany) using a mixture of hexane/ethyl ether/acetic acid
16
(90:10:1, vol/vol/vol; two developments) as eluent [9]. Once the TG fraction was
17
purified, the method of Vioque and Holman [28] was used for measuring the ester
18
linkage content, according to their conversion into hydroxamic acids and further
19
complexion with Fe (III). Results are expressed as g TG/ kg muscle.
20
Tocopherol isomers were analysed according to the Cabrini et al. [29] method.
21
For this, lipophilic antioxidants were extracted from the muscle with hexane, dried
22
under nitrogen flux, dissolved in isopropanol and injected into the HPLC system (ODS
23
column, 15 cm x 0.46 cm i.d.); detection was achieved at 280 nm. The presence of the
24
different tocopherol isomers was checked. Only the α-tocopherol isomer was detected,
25
and its content was expressed as mg α-tocopherol/ kg muscle.
6
1
Total lipid extracts were converted into fatty acid methyl esters (FAME) by
2
employing acetylchloride and then analysed by gas-liquid chromatography (Perkin-
3
Elmer 8700 chromatograph), according to previous procedure [13]. For it, a fused silica
4
capillary column SP-2330 (0.25 mm i.d. x 30 m, Supelco, Inc., Bellefonte, Pa, USA)
5
was employed. Peak areas were automatically integrated, 19:0 fatty acid being used as
6
internal standard for quantitative analysis. Content of each fatty acid is expressed as g/
7
kg muscle.
8
Seven essential minerals (Ca, Cu, Fe, Mg, Mn, Se and Zn) were chosen for the
9
present study as being included among the most abundant oligoelements [1] and
10
according to previous farmed/ wild fish comparative studies [15, 30].
11
Edible flesh samples were dried in a stove at 50º C until constant weight and
12
later ground in a mortar. Then, a fraction of ca. 500 mg of each sample was weighed in
13
a Teflon vessel of 40 ml and a mixture of 4 ml of 65 % HNO3 and 1 ml of H2O2 was
14
added to carry out the microwave digestion. To be digested, the different muscle
15
mixtures were introduced in a Milestone 1200 Mega microwave grouped in series of
16
seven samples plus one blank and one certified material reference (DORM-2, National
17
Research Council Canada) to verify the correct sample solution. Concentration values
18
(mg/ kg muscle) for the different minerals in the reference material (found and certified,
19
respectively) were as follows: Ca (1.08±0.07 and not certified), Cu (2.03±0.57 and
20
2.34±0.16), Fe (127±20 and 142±10), Mg (1.02±0.09 and 1.01±0.04), Mn (3.00±0.23
21
and 3.66±0.34), Se (1.49±0.05 and 1.40±0.09) and Zn (23.3±0.9 and 25.6±2.3).
22
Mineral contents of the digested samples were determined by atomic absorption
23
spectrometry (AAS). Ca, Fe, Mg and Zn were analysed by means of flame atomic
24
absorption spectrometry (FAAS) using a Varian 220 FS apparatus. Cu, Mn and Se were
25
analysed by means of electrothermal atomic absorption spectrometry (ETAAS) using a
7
1
Varian 220 apparatus equipped with Zeeman background correction. Quantification
2
results are expressed as mg/ kg muscle, except for Ca and Mg (g/ kg muscle).
3
4
2.3. Statistical analysis
5
Data (n = 6) obtained from the different chemical analyses were subjected to the
6
ANOVA method (p<0.05) to explore differences by two different ways: fish origin
7
(farmed/ wild comparison) and body zone (ventral/ dorsal/ tail comparison) (Statsoft
8
Inc., Statistica, version 6.0, 2001). Comparison of means was performed using a least-
9
squares difference (LSD) method. For parameters where a non-homogeneous variation
10
was detected, the non-parametric Kruskal-Wallis test was employed.
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12
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3. Results and Discussion
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15
3.1. General composition parameters
16
In all muscle zones studied, moisture content (Table 1) was found higher for
17
wild fish than for its counterpart obtained from farming conditions. However, no
18
significant differences could be concluded among muscle sites for both kinds of fish
19
material.
20
A higher lipid content (Table 1) was obtained in farmed fish than in wild one,
21
this according to the known inverse ratio between water and lipid constituent values [1].
22
This higher lipid content can be explained as a result of the different diet and live
23
conditions corresponding to both kinds of fish and agrees to previous comparative
24
research on other fish species such as turbot [14, 30], gilthead seabream [16] and
8
1
seabass [31]. As for moisture content, no differences could be observed among muscle
2
sites for both wild and farmed fish.
3
Water and lipid contents obtained for the white muscle of wild blackspot
4
seabream agree to those reported for other lean fish species [1, 11]. Contrary, contents
5
on such constituents for the farmed fish can be considered as belonging to a fattier-type
6
fish pattern than the wild one [21]. However, lipid content values for farmed fish
7
muscle can be considered low when compared to previous studies on related farmed fish
8
species such as seabass [15, 31] and sea bream [16, 31], where fattier diets were
9
employed. Such differences can be explained on the basis of the strong and direct
10
influence of lipid content in diet on lipid content of the farmed product [14, 32].
11
TMAO molecule has been recognised as an ubiquitous constituent of marine
12
species, supporting an important role in the osmoregulation during the live animal
13
period [2]. After the fish death, TMAO can develop different kinds of breakdown
14
damages during the processing/ storage process that lead to different spoilage molecule
15
formation such as TMA, dimethylamine and formaldehyde, this implying an important
16
effect on quality loss [33, 34].
17
In the present study, TMAO-N content (Table 1) for wild fish was found largely
18
higher than for its counterpart obtained from farming conditions. This result agrees to
19
previous comparative research on cod [35] and olive flounder [36] and may be related to
20
the different live conditions. Accordingly, a higher formation of the above mentioned
21
spoilage molecules is to be expected in wild fish muscle than in its counterpart from
22
farming condition when technological treatments are applied. When the comparative
23
zone study is considered, both kinds of fish showed higher mean values in the tail site
24
than in the two others, being this difference significant in the case of farmed fish. To
25
our knowledge, no previous research accounts for the distribution of TMAO in different
9
1
muscle zones of the fish body. The higher value obtained in the tail zone in the present
2
study may be explained as a result of a greater interchange surface with the live medium
3
in this zone; thus, in agreement to the osmoregulation role accorded to TMAO, a higher
4
TMAO content would be necessary in this zone to prevent dehydration.
5
Previous research has shown that the highest TMAO-N contents are described in
6
elasmobranches, squids and gadoid fish (750-2500 mg TMAO-N/ kg muscle) [2, 33,
7
34]. Present results prove that TMAO-N content in farmed blackspot seabream is
8
relatively low [21], being similar to that reported for flat and pelagic fish species [33,
9
34].
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11
12
13
3.2. Lipid composition
Table 2 shows the lipid group contents obtained in the three muscle locations of
wild and farmed blackspot seabream.
14
When PL, ST and FFA are considered, no differences between farmed and wild
15
fish are observed. Such lipid groups are considered as functional ones, so that their
16
content and presence in the muscle should not be specially influenced by external
17
factors such as water temperature, feeding availability and its composition [7].
18
Additionally, differences among muscle zones were not obtained in both kinds of fish in
19
the present work. Again, this result agrees to the fact that such kinds of lipid groups
20
develop a structural role in living bodies, so that its presence in the muscle is hardly
21
affected by internal factors such as anatomical and physiological aspects [7, 14]. This
22
difference lack among muscle sites agrees to previous research on PL [37] and
23
cholesterol [31] contents related to other fish species.
24
Free fatty acid content has been recognised as a good indicator of lipid
25
hydrolysis during processing and storage of fish species [38]. Value ranges found in the
10
1
present study correspond to a very low lipid hydrolysis development [11, 21], according
2
to the fact that fish was analysed immediately after catching/ slaughtering. Thus, values
3
obtained in the present research should correspond to the in vivo metabolic action of
4
lipases and phospholipases on high-molecular-weight lipids such as TG and PL,
5
respectively. According to data shown in Table 2, a different hydrolytic enzyme activity
6
in the different muscle zones was not observed for both kinds of fish.
7
Results are different when a depot lipid class like TG is concerned. In this case,
8
a higher content was obtained for farmed fish than for its counterpart from wild
9
condition. This higher level can be explained as a result of the diet and the live
10
conditions, and agrees to the higher lipid content mentioned in Table 1 for farmed fish.
11
As for the other lipid groups, no differences among zones could be detected for both
12
wild and farmed fish.
13
Alpha-tocopherol contents obtained in fish muscle are also expressed in Table 2.
14
Values were included in the range reported for most fish species [1, 39]. However,
15
higher values were obtained for wild fish than for its counterpart from farming
16
condition. This difference could be explained as a result of a different diet intake
17
between both kinds of blackspot seabream, according to previous comparative research
18
[40, 41]. Indeed, if the α-tocopherol/ total lipid ratio is considered, an even lower value
19
is observed in each zone in the farmed fish when compared with its corresponding site
20
in the wild one (30-43 and 120-180 mg/ 100 g lipids for farmed and wild fish,
21
respectively). Concerning the muscle zone comparison, lower mean values could be
22
detected for the tail site than in the two others; such differences were significant in the
23
case of wild fish between ventral and tail zones. Some different distribution of α-
24
tocopherol in muscle was also observed in higher-size farmed fish species such as turbot
25
(Scophthalmus maximus) and Atlantic halibut (Hippoglossus hippoglossus) [42].
11
1
Tocopherols are known lipid-soluble chain-breaking antioxidants, whose main
2
role is protecting the unsaturated fatty acids from oxidation [43]. Different isomers (α-,
3
β-, γ- and δ-) have been identified in plants and all have been found in most seaweeds
4
and unicellular algae. However, α-tocopherol has been reported to be the only
5
tocopherol which accumulates in higher marine animals from natural diets [44]. When
6
farmed fish is considered, deposition of different tocopherol molecules (primarily α and
7
γ isomers) as influenced by the diet has often been observed [45]. However, in the
8
present study only the α-tocopherol isomer was detected for both farmed and wild fish.
9
10
3.3. Fatty acid composition
11
Fatty acid content in the three muscle locations of wild and farmed fish is
12
exposed in Table 3. In the case of wild fish, most abundant fatty acids were 22:6 ω3
13
(DHA), 16:0 and 18:1 ω9, according to a wide number of previous studies carried out
14
on fish species obtained from wild conditions [1, 46]. For farmed fish, such three fatty
15
acids were still the most abundant in the present study, although some differences with
16
the wild fish pattern could be mentioned; thus, an important presence of 18:2 ω6 and
17
20:5 ω3 (EPA) fatty acids could be detected. Differences between farmed and wild fish
18
can be explained as a result of the different diet provided to both kinds of fish,
19
according to previous farmed/ wild comparison studies on other fish species [14-16].
20
Discussion concerning content differences between farmed and wild fish and
21
among the different sites will now be focused on fatty acid group contents and fatty acid
22
ratio values (Table 3). Thus, a higher saturated (SFA), monounsaturated (MUFA) and
23
PUFA content could be observed in farmed fish muscle than in its counterpart from
24
wild condition. This result agrees with the fact that a higher lipid content is present in
25
the muscle belonging to fish from farming condition (Table 1).
12
1
Among muscle locations, farmed fish showed higher SFA, MUFA and PUFA
2
contents in the dorsal zone than in the two other ones, this being in agreement with a
3
higher mean value for its lipid content (Table 1). Related to wild fish, a higher SFA and
4
MUFA was also detected in the dorsal muscle than in the two other zones, this again
5
according to a higher mean value for lipid content obtained for such body site (Table 1);
6
no zone differences were concluded for the PUFA content in wild fish.
7
A great interest has recently been accorded to the ω3/ ω6 ratio of foods included
8
in the human diet [4, 5]. In the present study (Table 3), both farmed and wild blackspot
9
seabream provided a profitable ω3/ ω6 ratio in order to maintain the recommended
10
value (1/6, ω3/ ω6) for the whole human diet [47]. However, a greater ω3/ ω6 ratio was
11
obtained for wild fish than for its counterpart from farming condition, this according to
12
previous comparative research on other fish species [14-16, 30]. Among muscle sites,
13
no differences could be detected both in farmed and wild fish for the ω3/ ω6 ratio.
14
In agreement to the recent interest on the ω3 fatty acids, a great attention has
15
been accorded to both most abundant components (DHA and EPA) of the series. Thus,
16
EPA has been recognised to be beneficial for human health by reducing the risk of
17
cardiovascular diseases [48], while DHA has been recognised to develop relevant
18
functions related to nervous system and visual functions in human beings [49].
19
According to this interest, the DHA/ EPA ratio distribution in the different sites and
20
kinds of blackspot seabream was studied (Table 3). In all cases, a value > 1 for this ratio
21
was obtained. In all muscle locations considered, a greater ratio was obtained for wild
22
fish than for its counterpart from farming conditions, this agreeing to previous
23
comparative research on other fish species [15, 30, 37]. Among muscle zones, no
24
differences could be detected both in farmed and wild fish.
25
13
1
3.4. Mineral composition
2
Marine organisms have shown to accumulate minerals from the diet and deposit
3
them in their skeletal tissues and organs, so as to be considered a good source of
4
essential minerals [1]. Several studies have indicated that the concentration of trace
5
minerals in fish muscle may be influenced not only by external factors (food source,
6
environment), but also by anatomical and physiological aspects [15, 50].
7
Trace mineral contents obtained in the actual study are expressed in Table 4.
8
Level ranges obtained for Ca and Mg were higher than for the five remaining minerals
9
according to common distribution in marine species flesh [1, 50]. Present research
10
showed some differences when comparing farmed and wild individuals, being the diet
11
provided responsible for such differences [15, 30]. Thus, Ca and Mg contents showed
12
higher mean values in wild fish than in its counterpart obtained from farming condition;
13
such differences were significant only in the case of the tail zone. Related to Fe, Mn, Se
14
and Zn, higher mean values were obtained in most cases for farmed fish than for its
15
counterpart from wild condition; such differences were found significant in all cases at
16
the ventral zone. No differences in Cu content could be observed between wild and
17
farmed fish. Comparison among the different zones provided some significant
18
differences, although a general pattern could not be established.
19
Previous research has accounted for the essential and toxic mineral assessment
20
on wild blackspot seabream [20]. In such experiment, fish was captured in the
21
Portuguese coast and no muscle zone study was achieved. Compared to the present
22
study, lower values were obtained for Ca and Se contents, being higher those from Zn.
23
When compared to previous comparative research on other farmed and wild fish species
24
[1, 37, 51], expected values were obtained in the actual study for most minerals (Ca, Fe,
25
Mg, Mn and Zn); however, such comparison showed that lower and higher values were
14
1
obtained for Cu and Se, respectively. Se values obtained can be considered interesting
2
since this mineral is actually reported to be a health-promoting ingredient in foods
3
because of a wide number of important biological functions that depend on the activity
4
of certain Se-containing proteins [52].
5
6
7
4. CONCLUDING REMARKS
8
9
Farmed and wild blackspot seabream muscle has shown to include valuable
10
components related to lipid fraction (PUFA, ω3 PUFA, ω3/ ω6 fatty ratio and α-
11
tocopherol values) and minerals (Se, especially).
12
Contrary to previous related research on other fish species, constituents
13
evaluated (lipid and non-lipid parameters) provided limited differences among the
14
muscle zones considered in both wild and farmed fish; most of such differences arose
15
from lipid content distribution in muscle. However, a marked non-homogeneous
16
distribution can not be concluded from the present study.
17
However, comparison between farmed and wild fish led to a wide number of
18
differences (general composition parameters, lipid groups and fatty acids), most of them
19
related to the different diet intake and to the different live conditions. A great attention
20
should be accorded to the lipid content and composition included in the diet provided,
21
so that farmed fish can maintain similar values found in wild specimens of blackspot
22
seabream, specially those related to ω3/ ω6 fatty ratio and endogenous antioxidants like
23
tocopherol isomers.
24
25
26
15
1
FIGURE LEGENDS
2
3
4
Figure 1: Position of the three white muscle zones (ventral, dorsal and tail) considered
5
in the present study
6
7
8
9
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1
REFERENCES
2
3
4
[1] G. Piclet: Le poisson aliment. Composition- intérêt nutritionnel. Cahiers Nutr Diet.
1987, XXII, 317-335.
5
[2] G. Finne: Non-protein nitrogen compounds in fish and shellfish. In: Advances in
6
Seafood Biochemistry. Eds. G. Flick, R. Martin, Technomic Publishing,
7
Lancaster (Pa, USA) 1992, pp. 393-399.
8
[3] A. Simopoulos: Nutritional aspects of fish. In: Seafood from producer to consumer,
9
Integrated approach to quality. Eds. J. Luten, T. Börrensen, J. Oehlenschläger,
10
Elsevier Science, London (UK) 1997, pp. 589-607.
11
[4] R. Ackman, W. Ratnayake: Chemical and analytical aspects of assuring an effective
12
supply of omega-3 fatty acids to the consumer. In: Omega-3 fatty acids in health
13
and disease. Eds. R. Lees, M. Karel, Marcel Dekker, New York (USA) and
14
Basel (Switzerland) 1990, pp. 215-233.
15
[5] P. Weber: Dietary fatty acids and eicosanoid Biochemistry. In: Advances in Seafood
16
Biochemistry. Ed. G. Flick, R. Martin, Technomic Publishing, Lancaster (Pa,
17
USA) 1992, pp. 181-184.
18
[6] A. Kolakowska: Lipid oxidation in food systems. In: Chemical and functional
19
properties of food lipids. Eds. Z. Sikorski, A. Kolakowska, CRC Press, London
20
(UK) 2003, pp. 133-165.
21
22
[7] A. Pearson, J. Love, F. Shorland: “Warmed-over” flavor in meat, poultry and fish.
Adv Food Res. 1977, 23, 2-61.
23
[8] D. Body, P. Vlieg: Distribution of the lipid classes and eicosapentaenoic (20:5) and
24
docosahexaenoic (22:6) acids in different sites in blue mackerel (Scomber
25
australasicus) fillets. J Food Sci. 1989, 54, 569-572.
17
1
[9] S. Aubourg, J. Gallardo, C. Sotelo: Distribution of triglycerides, phospholipids and
2
polyunsaturated fatty acids in different sites in raw albacore (Thunnus alalunga)
3
muscle: Changes after cooking. Can Inst Sci Technol J. 1991, 24, 287-291.
4
[10] T. Ingemansson, N. Olsson, B. Herslöf, B. Ekstrand: Lipids in light and dark
5
muscle of farmed rainbow trout (Oncorhynchus mykiss). J Sci Food Agric. 1991,
6
57, 443-447.
7
[11] S. Aubourg, M. Rey-Mansilla, C. Sotelo: Differential lipid damage in various
8
muscle zones of frozen hake (Merluccius merluccius). Z Lebensm Unters
9
Forsch. 1999, 208, 189-193.
10
11
[12] P. Ke, R. Ackman, B. Linke, D. Nash: Differential lipid oxidation in various parts
of frozen mackerel. J Food Technol. 1977, 12, 37-47.
12
[13] S. Aubourg, I. Medina, R. Pérez-Martín: Polyunsaturated fatty acids in tuna
13
phospholipids: Distribution in the sn-2 location and changes during cooking. J
14
Agric Food Chem. 1996, 44, 585-589.
15
16
[14] L. Sérot, G. Gandemer, M. Demaimay: Lipid and fatty acid compositions of
muscle from farmed and wild adult turbot. Aquac Int. 1998, 6, 331-343.
17
[15] C. Alasalvar, K. Taylor, E. Zubcov, F. Shahidi, M. Alexis: Differentiation of
18
cultured and wild sea bass (Dicentrarchus labrax): total lipid content, fatty acid
19
and trace mineral composition. Food Chem. 2002, 79, 145-150.
20
21
[16] K. Grigorakis, K. Taylor, M. Alexis: Seasonal patterns of spoilage of ice-stored
cultured gilthead sea bream (Sparus aurata). Food Chem. 2003, 81, 263-268.
22
[17] L. Genovese, G. Maricchiolo, V. Micale, M. Costanzo, M. Garaffo, G. Palmegiano,
23
S. Greco: Pagellus bogaraveo: an interesting species for aquaculture. Biol Mar
24
Mediterr. 2004, 11, 389-392.
18
1
[18] P. Silva, C. Andrade, V. Timóteo, E. Rocha, L. Valente: Dietary protein, growth,
2
nutrient utilisation and body composition of juvenile blackspot seabream,
3
Pagellus bogaraveo (Brunnich). Aquac Res. 2006, 37, 1007-1014.
4
[19] M. Ponce, C. Infante, R. Jiménez-Cantizano, L. Pérez, M. Manchado. Complete
5
mitochodrial genome of the blackspot seabream, Pagellus bogaraveo
6
(Perciformes: Sparidae), with high levels of length heteroplasmy in the
7
WANCY region. Gene. 2008, 409, 44-52.
8
[20] M. Carvalho, S. Santiago, L. Nunes: Assessment of the essential element and
9
heavy metal content of edible fish muscle. Anal Bioanal Chem. 2005, 382, 426-
10
432.
11
[21] V. Álvarez, X. Feás, J. Barros-Velázquez, S. Aubourg: Quality changes of farmed
12
blackspot seabream (Pagellus bogaraveo) subjected to slaughtering and storage
13
under flow ice and ozonised flow ice. Int J Food Sci Tecnol. 2009, in press. Ref:
14
ID IJFST-2008-03597.
15
16
[22] E. Bligh, W. Dyer: A rapid method of total extraction and purification. Can J
Biochem Physiol. 1959, 37, 911-917.
17
[23] K. Parkin, H. Hultin: Some facts influencing the production of dimethylamine and
18
formaldehyde in minced and intact red hake muscle. J Food Proc Pres. 1982, 6,
19
73-97.
20
[24] H. Tozawa, K. Erokibara, K. Amano: Proposed modification of Dyer’s method for
21
trimethylamine determination in codfish. In: Fish Inspection and Quality
22
Control. Ed. R. Kreuzer, Fishing News Books Ltd., London (UK) 1971, pp. 187-
23
190.
19
1
[25] R. Raheja, C. Kaur, A. Singh, A. Bhatia: New colorimetric method for the
2
quantitative determination of phospholipids without acid digestion. J Lipid Res.
3
1973, 14, 695-697.
4
5
6
7
8
9
[26] T. Huang, C. Chen, V. Wefler, A. Raftery: A stable reagent for the LiebermannBuchardt reaction. Anal Chem. 1961, 33, 1405-1407.
[27] R. Lowry, I. Tinsley: Rapid colorimetric determination of free fatty acids. J Am Oil
Chem Soc. 1976, 53, 470-472.
[28] E. Vioque, R. Holman: Quantitative estimation of esters by thin-layer
chromatography. J Am Oil Chem Soc. 1962, 39, 63-66.
10
[29] L. Cabrini, L. Landi, C. Stefanelli, V. Barzanti, A. Sechi: Extraction of lipid and
11
lipophilic antioxidants from fish tissues: A comparison among different
12
methods. Comp Biochem Physiol B Biochem Molec Biol. 1992, 101, 383-386.
13
[30] E. Sheehan, P. Sheehy, P. Morrisey, R. Fitzgerald: Compositional analysis on wild
14
and farmed turbot and fish feeds in Ireland. In: Turbot culture: Problems and
15
prospects. Ed. P. Lavens, R. Remmerswaal, European Aquaculture Society,
16
Special Publication No. 22, Gent (Belgium) 1994, pp. 302-311.
17
[31] E. Orban, T. Nevigato, G. Di Lena, I. Casini, A. Marzetti: Differentiation in the
18
lipid quality of wild and farmed seabass (Dicentrarchus labrax) and gilthead sea
19
bream (Sparus aurata). J Food Sci. 2003, 68, 128-132.
20
21
[32] B-S. Saether, M. Jobling: Fat content in turbot feed: influence on feed intake,
growth and body composition. Aquacult Res. 2001, 32, 451-458.
22
[33] J. Gallardo, R. Pérez-Martín, J. Franco, S. Aubourg, C. Sotelo: Changes in volatile
23
bases and trimethylamine oxide during the canning of albacore (Thunnus
24
alalunga). Int J Food Sci Technol. 1990, 25, 78-81.
20
1
[34] H. Huss: Chemical composition (principle constituents, lipids, proteins, N-
2
containing extractives and vitamins and minerals). In: Quality and quality
3
changes in fresh fish. Ed. H. Huss, FAO Fisheries Technical Paper No. 348,
4
Rome (Italy) 1995, pp. 20-34.
5
[35] H. Herland, M. Esaiassen, R. Olsen: Muscle quality and storage stability of farmed
6
cod (Gadus morhua L.) compared to wild cod. J Aquat Food Prod Technol.
7
2007, 16, 55-66.
8
[36] C. Park: Comparison of extractive nitrogenous constituents in cultured and wild
9
olive flounder (Paralichthys olivaceus) muscle. J Kor Soc Food Sci Nutr. 2000,
10
29, 174-179.
11
[37] S. Aubourg, V. Losada, R. Prego: Distribution of lipids and trace minerals in
12
different muscle sites of farmed and wild turbot (Psetta maxima). Int J Food Sci
13
Technol. 2007, 42, 1456-1464.
14
[38] Z. Sikorski, E. Kolakowski: Endogenous enzyme activity and seafood quality:
15
Influence of chilling, freezing, and other environmental factors. In: Seafood
16
enzymes. Eds. N. Haard, B. Simpson, Marcel Dekker, New York (USA) 2000,
17
pp. 451-487.
18
[39] N. Ruff, R. Fitzgerald, T. Cross, J. Kerry: Comparative composition and shelf-life
19
of fillets of wild and cultured turbot (Scophthalmus maximus) and Atlantic
20
halibut (Hippoglossus hippoglossus). Aquaculture International, 2002, 10, 241-
21
256.
22
[40] G. Stéphan, J. Guillaume, F. Lamour: Lipid peroxidation in turbot (Scophthalmus
23
maximus) tissue: effect of dietary vitamin E and dietary n-6 or n-3
24
polyunsaturated fatty acids. Aquaculture. 1995, 130, 251-268.
21
1
[41] S. Jittinandana, B. Kenney, S. Slider, N. Kamireddy, J. Hankins: High dietary
2
vitamin E affects storage stability of frozen-refrigerated trout fillets. J Food Sci.
3
2006, 71, C91-C95.
4
[42] N. Ruff, R. Fitzgerald, T. Cross, A. Lynch, J. Kerry: Distribution of alpha-
5
tocopherol in fillets of turbot (Scophthalmus maximus) and Atlantic halibut
6
(Hippoglossus hippoglossus), following dietary alpha-tocopheryl acetate
7
supplementation. Aquacult Nutr. 2004, 10, 75-81.
8
9
[43] A. Kamal-Eldin, L. Appelqvist: The chemistry and antioxidant properties of
tocopherols and tocotrienols. Lipids. 1996, 31, 671-701.
10
[44] S. Sigurgisladóttir, R. Ackman, S. O’Keefe: Selective deposition of alpha-
11
tocopherol in lipids of blue mussels (Mytilus edulis). J Food Lipids. 2003, 1, 97-
12
109
13
14
[45] M. Parazo, S. Lall, J. Castell, R. Ackman: Distribution of - and -tocopherols in
Atlantic salmon (Salmo salar) tissues. Lipids. 1998, 33, 697-704.
15
[46] H. Saito, R. Yamashiro, K. Ishihara, C. Xue: Lipids of three highly migratory
16
fishes: Euthynnus affinis, Sarda orientalis and Elagatis bipinnulata. Biosci
17
Biotechnol Biochem. 1999, 63, 2028-2030.
18
[47] A. Simopoulos: Fatty acids. In: Functional foods, designer foods, pharmafoods,
19
nutraceuticals. Ed. I. Goldberg, Chapman and Hall, New York (USA) 1994, pp.
20
355-392.
21
[48] W. Hall, K. Sanders, T. Sanders, P. Chowienczyk: A high-fat meal enriched with
22
eicosapentaenoic acid reduces postprandial arterial stiffness measured by digital
23
volume pulse analysis in healthy men. J Nutrit. 2008, 138, 287-291.
24
25
[49] Y. Linko, K. Hayakawa: Docosahexaenoic acid: A valuable nutraceutical ? Trends
Food Sci Technol. 1996, 7, 59-63.
22
1
[50] S. Lal: Macro and trace elements in fish and shellfish. In: Fish and fishery
2
products: composition, nutritive properties and stability. Ed. A. Ruiter, CAB
3
International, Wallingford, Connecticut (USA) 1995, pp. 187-214.
4
[51] J. Engman, L. Jorhem: Toxic and essential elements in fish from Nordic waters,
5
with the results seen from the perspective of analytical quality assurance. Food
6
Additives and Contaminants, 1998, 15, 884-892.
7
8
[52] C. Reilly: Selenium: A new entrant into the functional food arena. Trends Food Sci
Technol. 1998, 9, 114-118.
9
10
11
12
Acknowledgements
13
This work was supported through a project grant by the Secretaría Xeral de I+D from
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the Xunta de Galicia (Project PGIDIT 05 TAL 00701 CT). The authors thank Mr.
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Marcos Trigo, Mrs. Salomé Lois and Mrs. Ana García for their excellent technical
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assistance.
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