Comparative Analysis of Fatty Acid Profiles in Brains and Eyes of Five Economic Fish Species in Wint...

Huan Li, Jin-Pin Liu, Mei-Ling Zhang, Na Yu, Er-Chao Li, Li-Qiao Chen, Zhen-Yu Du

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Comparative Analysis of Fatty Acid Profiles in Brains and Eyes of Five Economic Fish Species in Winter and Summer

Huan Li1, Jin-Pin Liu1, Mei-Ling Zhang1, Na Yu1,, Er-Chao Li1, Li-Qiao Chen1, Zhen-Yu Du1,

1Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai 200241, P.R. China

Abstract

Fish brains and eyes are commonly consumed in China, however, their nutritional importance has not been evaluated. We investigated the fatty acid (FA) profiles in brains and eyes of five economically important fish species with different food habits (carnivorous, omnivorous, and herbivorous). The fatty acid profiles were also compared between winter and summer. The FA compositions of brains and eyes of carnivorous and marine fishes were similar, and differed from those of omnivorous and herbivorous freshwater fishes. In winter, there were higher proportions of n-3 polyunsaturated fatty acids in brains and eyes of carnivorous and marine fishes than in those of omnivorous and herbivorous freshwater fishes; the magnitude of this difference was smaller in summer. The FA compositions of brains and eyes of these five fishes were comparable to those reported for their fillets in previous studies. Therefore, fish brains and eyes are not more nutritious than fillets of the same species.

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Cite this article:

  • Li, Huan, et al. "Comparative Analysis of Fatty Acid Profiles in Brains and Eyes of Five Economic Fish Species in Winter and Summer." Journal of Food and Nutrition Research 2.10 (2014): 722-730.
  • Li, H. , Liu, J. , Zhang, M. , Yu, N. , Li, E. , Chen, L. , & Du, Z. (2014). Comparative Analysis of Fatty Acid Profiles in Brains and Eyes of Five Economic Fish Species in Winter and Summer. Journal of Food and Nutrition Research, 2(10), 722-730.
  • Li, Huan, Jin-Pin Liu, Mei-Ling Zhang, Na Yu, Er-Chao Li, Li-Qiao Chen, and Zhen-Yu Du. "Comparative Analysis of Fatty Acid Profiles in Brains and Eyes of Five Economic Fish Species in Winter and Summer." Journal of Food and Nutrition Research 2, no. 10 (2014): 722-730.

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1. Introduction

The potential health benefits of fish consumption are mainly attributed to n-3 highly unsaturated fatty acids (HUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids play roles in protection against cardiovascular disease (CVD), insulin resistance, and systemic inflammatory diseases [1]. Therefore, the fatty acid profiles of edible parts of fish are one of the main aspects of their nutritional value.

Most people consume fish fillets, rather than other parts of the fish. For most fish species, fatty acid composition data has been obtained for their fillet tissues. However, other fish organs are also consumed in some parts of the world. In China, fish brains and eyes are commonly consumed, especially by children. In Chinese culture, consumption of fish brains and eyes is believed to make children cleverer. If the proportion of n-3 HUFAs is higher in brain and eye tissues than in fillet tissues, then the traditional consumption of brains and eyes would be supported by modern nutritional theory that consumption of n-3 HUFA-rich tissues could benefit neural system development in young children. There is a higher proportion of n-3 HUFAs in neural tissues than in muscle in mammals and human [2]. However, it is unknown whether the fatty acid composition differs between neural tissues and muscle tissues in fishes.

Previous studies have indicated that the fatty acid profile in fish tissues varies depending on food habit and environmental factors, such as temperature and salinity [3, 4, 5]. Studies on mammals have shown that the fatty acid composition is more stable in neural tissues than in other organs [6], but this has not been fully investigated in fishes.

The aims of this study were to determine the fatty acid profile in brains and eyes of some commonly consumed fish species, and to determine whether these profiles are affected by the food habit and/or the environment of the fish. We selected five fish species with different food habits and environments for these analyses. We purchased the fish from local markets in Shanghai in winter and summer, and analyzed the fatty acid compositions of their eyes and brains.

2. Materials and Methods

2.1. Fish and Sampling

The five fish species selected in the present study are large yellow croaker (Pseudosciaena crocea) which is a marine carnivorous fish, silvery pomfret (Pampus argenteus) which is a marine carnivorous fish too, river eel (Anguilla japonica) which is a freshwater carnivorous fish, tilapia (Oreochromis mossambicus) which is a freshwater omnivorous fish, and grass carp (Ctenopharyngodon idellus) which is a freshwater herbivorous fish. Fishes were bought from three separated local markets at Minhang, Putuo and Huangpu Districts in Shanghai in January in winter and July in summer 2013, and the corresponding temperatures were between 1 to 9°C and 29 to 39°C, respectively. The basic biological characteristics of all collected fish are listed in Table 1.

Table 1. The basic biological and sampling information of five fish species

The fish samples were immediately transported to the lab at East China Normal University, and the eyes and brains from 9-12 fish were rapidly taken and stored at -80°C until analysis.

2.2. Lipid Extraction and Fatty Acid Analysis

Total lipids of eyes and brains were extracted according to Bligh & Dyer (1959) [7]. Fatty acids from lipid samples were methylated using 10% potassium hydroxide in methanol for 1 h at room temperature. FA methyl esters were then analyzed and quantified using a Hewlett-Packard HP-5890 gas chromatograph in a cross-linked 5% phenylmethyl silicone gum phase column (L=25m, ID=0.32mm, DF=0.25µm, HP-Ultra 2, with nitrogen as the carrier gas), with flame ionization detection. Injector and detector temperatures were 280 and 300°C, respectively. The column temperature set at 190°C was then risen to 260°C (2°C/min) and held for 5 min. Results are expressed as the percentage of each FA with respect to total FA.

2.3. Statistical Analysis

Statistical analyses were performed using SPSS 19.0 for Windows (SPSS Inc., Chicago, IL). All analytical determinations were performed in triplicate and the mean values were reported. The average results of peak area are offered as means ± SE. The percentages of fatty acid were firstly tested by analysis of variance (ANOVA) and the differences between means were evaluated using Duncan’s multiple test or T-test at p<0.05. Principal component analysis (PCA) was performed using the MATLAB environment.

3. Results

3.1. Fatty Acid Composition of Fish Brains in Winter and Summer

Table 2 shows the 18 main fatty acids in the brains of the five fish species in winter. A PCA analysis indicated that carnivorous fishes (large yellow croaker, silvery pomfret, and river eel) had a similar fatty acid composition pattern, which differed from that of omnivorous (tilapia) and herbivorous fishes (grass carp) (Figure 1a). Specifically, large yellow croaker, silvery pomfret, and river eel contained higher proportions of saturated fatty acids (SFA) (mean SFA, 38.39%, 48.14%, and 40.20%, respectively), higher proportions of n-3 polyunsaturated fatty acids (PUFAs) (mean n-3 PUFAs, 22.01%, 15.80%, and 16.82%, respectively), higher proportions of EPA+DHA (mean, 18.14%, 12.06%, and 13.38%, respectively), higher n-3/n-6 ratios (mean, 9.35, 35.63, and 27.03, respectively), and lower proportions of n-6 PUFAs (mean, 2.35%, 0.44%, and 0.62%, respectively), compared with their respective mean values in omnivorous (tilapia) and herbivorous (grass carp) fishes (SFA, 33.7% and 27.77%; n-3 PUFA, 8.26% and 7.25%; EPA+DHA, 3.94% and 2.71%; n-3/n-6 ratio, 0.44 and 0.41; n-6 PUFA, 18.73% and 17.52%, respectively). Of the three carnivorous fishes, large yellow croaker had the highest proportions of EPA, n-3 PUFA, and n-6 PUFA, and the lowest n-3/n-6 ratio.

Table 2. Fatty acid composition of fish brains in winter and summer

Figure 1. PCA analysis of fatty acid composition in brains and eyes of five economic fish species

In summer, the general differences in fatty acid composition between carnivorous fishes and non-carnivorous fishes still existed (Figure 1a). However, there were no significant differences in the proportions of most specific fatty acids, especially n-3 PUFAs and EPA+DHA, between carnivorous and non-carnivorous fishes (Table 2). In summer, yellow croaker, silvery pomfret, and river eel showed higher proportions of SFAs (50.92%, 59.14%, and 47.51%, respectively), higher n-3/n-6 ratios (3.5, 19.01, and 12.56, respectively) and lower proportions of n-6 PUFAs (1.68%, 0.44%, and 0.91%, respectively), compared with their corresponding values in tilapia and grass carp (SFA, 35.33% and 30.88%; n-3/n-6 ratio, 0.6 and 0.57; n-6 PUFAs, 15.26% and 16.87%, respectively). Of the three carnivorous fishes, large yellow croaker had the lowest n-3/n-6 ratio, because the proportion of n-3 PUFAs was relatively low and that of n-6 PUFAs was relatively high. Tilapia and grass carp showed similar fatty acid compositions.

We determined whether the main fatty acids were correlated with food habit (carnivorous, herbivorous, omnivorous) or environment (freshwater or sea water) (Table 4). The proportions of SFAs, MUFAs, n-3 PUFAs, n-6 PUFAs, and EPA+DHA in fish brains were significantly correlated with diet and with environment in winter. In summer, there were no significant correlations between MUFA and food habit or environment, between n-3 PUFAs and food habit, or between EPA+DHA and food habit or environment.

To compare the effects of season on the fatty acid composition of brains, we compared the fatty acid composition for the same fish species between winter and summer (see Table 2). There were significant differences between winter and summer in the proportions of seven fatty acids (16:0, 18:0, 18:1n-9c, 18:3n-3, 20:3n-3, 20:5n-3, 22:6n-3) in large yellow croaker, two fatty acids (14:0, 17:0) in silvery pomfret, one fatty acid (20:3n-3) in river eel, three fatty acids (14:0, 17:0, 18:3n-3) in tilapia, and three fatty acids (14:0, 16:1, 18:0) in grass carp. Figure 2 shows the trends in the differences in brain fatty acids between winter and summer. The proportion of SFAs tended to increase from winter to summer in carnivorous fishes, but was similar in winter and summer in omnivorous and herbivorous fishes. The proportion of MUFAs in the brain was significantly higher in summer than in winter for large yellow croaker, but lower in summer than in winter in the other fishes. The proportions of n-3 PUFA and EPA+DHA in brains were lower in summer than in winter in the three carnivorous fishes, but higher in summer than in winter in tilapia and grass carp.

Figure 2. Seasonal alteration of main fatty acids percentages in brains and eyes of five economic fish species. * or ** means significant (P < 0.05) or very significant (P < 0.01) difference between two seasons
3.2. Fatty Acid Composition of Fish Eyes in Winter and Summer

We determined the main fatty acids in the eyes of the five fish species in winter (Table 3). A PCA analysis showed that carnivorous fishes had a similar fatty acid composition pattern, which differed from that of omnivorous and herbivorous fishes (Figure 1b). Specifically, large yellow croaker, silvery pomfret, and river eel contained higher proportions of n-3 PUFAs (mean, 19.49%, 11.52%, and 9.2%, respectively), higher proportions of EPA+DHA (mean, 15.83%, 8.6%, and 7.56%, respectively), higher n-3/n-6 ratios (mean, 5.42, 5.44, and 1.82, respectively), and lower proportions of n-6 PUFAs (mean, 3.59%, 2.12%, and 5.04%, respectively), compared with their respective values in tilapia and grass carp (n-3 PUFAs, 4.35% and 2.79%; EPA+DHA, 0.86% and 0.42%; n-3/n-6 ratio, 0.21 and 0.13; n-6 PUFAs, 20.93% and 20.80%, respectively). Of the three carnivorous fishes, large yellow croaker had the highest proportions of EPA, DHA, and n-3 PUFAs.

Table 3. Fatty acid composition of fish eyes in winter and summer

In summer, the fatty acid composition of eyes was similar in river eel, tilapia, and grass carp (Figure 1b). The fatty acid composition in summer differed between the marine fishes (large yellow croaker and silvery pomfret) and freshwater fishes (river eel, tilapia and grass carp). Specifically, large yellow croaker and silvery pomfret had higher proportions of EPA+DHA (11.5% and 1.9%, respectively), higher n-3/n-6 ratios (3.29 and 1.84, respectively), and lower proportions of n-6 PUFA (2.95% and 2.11%, respectively), compared with those in river eel, tilapia, and grass carp (EPA+DHA, 0.65%, 0.85%, and 0.87%; n-3/n-6 ratio, 0.33, 0.16, and 0.19; n-6 PUFA, and 21.23%, 21.20%, and 23.87%, respectively). Of the five fishes, large yellow croaker had the highest proportions of n-3 PUFAs and EPA+DHA, and the highest n-3/n-6 ratio.

Table 4 shows the correlations between the main fatty acids of fish eyes and food habit (carnivorous, herbivorous, omnivorous) or environment (freshwater or sea water). The concentrations of SFA, MUFA, n-3 PUFA, n-6 PUFA and EPA+DHA in fish eyes were significantly correlated with food habit and environment in winter. There were no significant correlations between n-3 PUFA and food habit, EPA+DHA and food habit in summer.

Table 4. Correlation analysis of selected nutrient vs. living environment and food habit, in brain and eyes of fish in winter and summer

We determined the effects of season on the fatty acid composition of eyes of the five fish species (Table 3). The fatty acid composition of fish eyes in tilapia and grass carp was comparable between winter and summer (Figure 2). For the three carnivorous fishes, the proportions of most n-3 PUFAs were significantly higher in winter than in summer, but the proportion of n-6 PUFA in river eel eyes was significantly higher in summer than in winter (5.04% in winter vs. 21.23% in summer). Figure 2 shows the seasonal trends in the main fatty acids in the eyes. These trends were similar to those observed for fatty acids in the brains, except for the higher proportion of n-6 PUFAs in river eel eyes in summer than in winter.

4. Discussion

Fish fillets are the main edible parts of fish, and are an important dietary source of n-3 PUFAs for consumers. Therefore, most studies on the fatty acid composition of fish tissues have focused on fish fillets [8, 9, 10]. In contrast, few studies have evaluated the fatty acid composition of fish brains and eyes [11, 12]. The nutritional importance of consuming fish brains and eyes had not been evaluated previously.

Studies on mammals have indicated that neural tissues, including the brain and eye retina, contain higher concentrations of n-3 HUFAs than do other organs, and that n-3 HUFAs are specifically retained in these tissues even under dietary deprivation [13]. Mammals and human have a specific requirement for 18: 2n-6, and their muscles have low n-3 PUFA contents. The specific retention of high concentrations of n-3 HUFAs in mammalian neural tissues indicates that n-3 PUFAs are important components of neural tissues. Whereas n-6 fatty acids are essential for mammals, n-3 PUFAs are essential fatty acids for most fishes [14]. Fish fillets contain high proportions of n-3 PUFAs. Several studies have reported the n-3 PUFA composition of fillets for the five fish species that we studied. Those studies reported that the proportion of n-3 PUFAs was 19–24% in large yellow croaker [15], 15.37–25.26% in silvery pomfret [16], 15.22–19.64% in river eel [17, 18], 3.1–15.9% in tilapia [19], and 9.7–16.8% in grass carp [20]. Comparison of the data obtained in the present study with those data indicates that the n-3 PUFA content is not higher in brains and eyes than in fillets. Furthermore, considering the tiny mass of brains and eyes, the specific consumption of brains and eyes is more likely based on a cultural tradition, rather than the nutritional value of these tissues.

Marine fishes generally contain a higher proportion of n-3 HUFAs than do freshwater fish. This typical fatty acid composition of marine fish results from the fatty acid composition of the marine phytoplankton that they consume [21]. Higher salinity also increases the proportion of n-3 HUFA, even within the same fish species [22]. Our findings are consistent with those studies. That is, there were higher proportions of n-3 HUFAs in the two marine fishes (large yellow croaker and silvery pomfret) than in tilapia and grass carp. River eel, a freshwater fish, had a very similar fatty acid profile to that of marine fish, except for the fatty acid profile of eyes in summer. River eel is a catadromous fish; that is, it inhabits the sea during its early life stage (glass eel stage). Some studies have demonstrated that the capacity to biosynthesize long-chain PUFA (LCPUFA) in some fish, including salmon and Japanese eel, is more strongly affected by environmental and nutritional factors during their early life stage than during their adult stage [23, 24]. Therefore, the characteristic marine fish fatty acid composition of river eel may be because it is catadromous.

As well as food habit and salinity, temperature is a key factor affecting the fatty acid composition of fish fillets [25, 26]. However, the seasonal differences in the fatty acid profiles in fish brains and eyes had not been evaluated previously. In mammals, fatty acids are more stable in neural tissues than in other tissues [6]. This biochemical stability in the neural system could help to maintain a stable internal environment. The ability to maintain a stable environment is related to the homothermal mechanism in mammals and human. In contrast, fish are heterothermic organisms; that is, their body temperature fluctuates depending on the water temperature. This study is the first report that the n-3 PUFA content in brains and eyes of fishes, especially marine fishes, is higher in winter than in summer. However, the effects of season on the n-3 PUFA content in fish fillets vary depending on the species. In sardine and tilapia, the proportion of n-3 PUFAs in fillets negatively correlates with water temperature [5, 26], similar to our results for fish brains and eyes. However, in anchovy and picarel, the reverse trend has been reported; that is, higher n-3 PUFA content in fillets in summer than in winter [5]. In croaker, the n-3 PUFA composition of fillets was reported to be similar in winter and summer [26]. HUFAs are necessary to maintain the fluidity of cellular membranes, especially in cold environments [27, 28]. Therefore, fishes may need to synthesize more long-chain PUFA in neural tissues in winter than in summer to maintain sufficient membrane fluidity [29]. Our data show that the fatty acid composition of brains and eyes of tilapia and grass carp, which contained a high proportion of n-6 PUFAs, remained relatively stable regardless of the season. This suggests that in fishes, and especially in fish neural tissues, n-3 PUFAs, but not n-6 PUFAs, are more sensitive than other types of fatty acids to water temperature. This hypothesis should be tested in further studies.

5. Conclusion

We analyzed the fatty acid profiles in fish brains and eyes, and determined the effects of food habit and environment on the fatty acid profiles. The fatty acid profiles of brains and eyes were comparable to those reported for fillets of the same species. Therefore, specific consumption of fish brain and eyes will not confer any additional nutritional benefits compared with consuming fish fillets.

Acknowledgements

This work is funded by Shanghai National Natural Science Fund (12ZR4008800), National Basic Research Program of China (973 program 2014CB138600), the Special Fund for Agro-scientific Research in the Public Interest (No. 201203065), National Natural Science Fund (31272676/C190401), Program for New Century Excellent Talents in University, and Daxia Student Research Fund of ECNU.

Statement of Competing Interests

The authors have no competing interests.

Abbreviations

CVD, Cardiovascular disease; DHA, Docosahexaenoic acid; EPA, Eicosapentaenoic acid; FA, Fatty acid; HUFA, Highly unsaturated fatty acid; MUFA, Monounsaturated fatty acid; PUFA, Polyunsaturated fatty acid; PCA, Principal component analysis; SFA, Saturated fatty acid;

References

[1]  Connor, WE. Importance of n-3 fatty acids in health and disease. American Journal of Clinical Nutrtion 71 (suppl), 171S-175S, 2000.
In article      
 
[2]  Sastry, P.S. Lipids of nervous tissue: composition and metabolism. Progress of Lipid Research 24, 69-176, 1985.
In article      CrossRef
 
[3]  Kolanowski, W. Laufenberg, G. Enrichment of food products with polyunsaturated fatty acids by fish oil addition. European Food Research and Technology 222, 472-477, 2006.
In article      CrossRef
 
[4]  Ozogul, Y., Ozogul, F., Alagoz, S. Fatty acid profiles and fat contents of commercially important seawater and freshwater fish species of Turkey: A comparative study. Food Chemistry 103, 217-223, 2007.
In article      CrossRef
 
[5]  Zlatanos, S., Laskaridis, K. Seasonal variation in the fatty acid composition of three Mediterranean fish-sardine (Sardina pilchardus), anchovy (Engraulis encrasicholus) and picarel (Spicara smaris). Food Chemistry 103, 725-728, 2007.
In article      CrossRef
 
[6]  Menon, N.K., Dhopeshwarkar, G.A. Essential fatty acid deficiency and brain development. Progress of Lipid Research 21, 309-326, 1982.
In article      CrossRef
 
[7]  Bligh, E.C., Dyer, W.J. A rapid method of total lipid extraction and purification. Canadian Journal of Biochemistry and Physiology 37, 911-927, 1959.
In article      CrossRef
 
[8]  Jabeen, F., Chaudhry, A.S. Chemical compositions and fatty acid profiles of three freshwater fish species. Food Chemistry 125, 991-996. 2011,
In article      CrossRef
 
[9]  Zhao, F., Zhuang, P., Song, C., Shi, Z.H., Zhang, L.Z. Amino acid and fatty acid compositions and nutritional quality of muscle in the pomfret, Pampus punctatissimus. Food Chemistry 118, 224-227, 2010.
In article      CrossRef
 
[10]  Aggelousis, G., Lazos, E.S. Fatty acid composition of the lipids from eight freshwater fish species from Greece. Journal of Food Composition and Analysis 4, 68-76, 1991.
In article      CrossRef
 
[11]  Tocher, D.R., Harvie, D.G. Fatty acid compositions of the major phosphoglycerides from fish neural tissues: (n-3) and (n-6) polyunsaturated fatty acids in rainbow trout (Salmo gairdneri) and cod (Gadus morhua) brains and retinas. Fish Physiology and Biochemistry 5, 229-239, 1988.
In article      CrossRef
 
[12]  Kreps, E.M., Avrova, N.F., Chebotarëva, M.A., Chirkovskaya, E.V., Levitina, M.V., Omazanskaya, L.F., Pravdina, N.I. Some aspects of comparative biochemistry of brain lipids in teleost and elasmobranch fish. Comparative Biochemistry and Physiology 52, 293-299, 1975.
In article      
 
[13]  Tinoco, J. Dietary requirements and functions of alpha-linolenic acid in animals. Progress of Lipid Research 21, 1-46, 1982.
In article      CrossRef
 
[14]  Sargent, J.R., Bell, J.G., McEvoy, L., Tocher, D.R., Estevez, A. Recent developments in the essential fatty acid nutrition of fish. Aquaculture 177, 191-199, 1999.
In article      CrossRef
 
[15]  Tang, H.G., Chen, L.H., Xiao, C.G., Wu, T.X. Fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age. Journal of Zhejiang University Science B 10, 154-158, 2009.
In article      CrossRef
 
[16]  Shi, Z.H., Huang, X.X., Li, W.W., Peng, S.M., Pan, H., Feng, Z. Changes of body lipid content and fatty acid profile in cultured juvenile silver pomfret, Pampus argenteus. Journal of Shanghai Fisheries University 17, 435-439, 2008.
In article      
 
[17]  Prigge, E., Malzahn, A.M., Zumholz, K., Hanel, R. Dietary effects on fatty acid composition in muscle tissue of juvenile European eel, Anguilla Anguilla (L.). Helgoland Marine Research 66, 51-61, 2012.
In article      CrossRef
 
[18]  Yang, X.S., Xu, Z., Wang, J., Guo, Q.Y. Fatty acid composition and cholesterol content in Anguilla. Journal of Fishery Science of China 9, 382-384, 2002.
In article      
 
[19]  Ng, W.K., Lim, P.K., Sidek, H. The influence of a dietary lipid source on growth, muscle fatty acid composition and erythrocyte osmotic fragility of hybrid tilapia. Fish Physiology and Biochemistry 25, 301-310, 2001.
In article      CrossRef
 
[20]  Du, Z.Y., Clouet, P., Huang, L.M., Degrace, P., Zheng, W.H., He, J.G. Utilization of different dietary lipid sources at high level in herbivorous grass carp (Ctenopharyngodon idella): mechanism related to hepatic fatty acid oxidation. Aquaculture Nutrition 14, 77-92, 2008.
In article      CrossRef
 
[21]  Steffens, W. Effects of variation feeds on nutritive in essential fatty acids in fish value of freshwater fish for humans. Aquaculture 151, 97-119, 1997.
In article      CrossRef
 
[22]  Fallah, A.A., Nematollahi, A., Saei-Dehkordi, S.S. Proximate composition and fatty acid profile of edible tissues of Capoeta damascina (Valenciennes, 1842) reared in freshwater and brackish water. Journal of Food Composition and Analysis 32, 150-154, 2013.
In article      CrossRef
 
[23]  Tocher, D.R. Metabolism and function of lipids and fatty acids in teleost fish. Review of Fishery Science 11,107-184. 2003.
In article      CrossRef
 
[24]  Wang, S., Monroig, O., Tang, G., Zhang, L., You, C., Tocher, D.R., Li Y. Investigating long-chain polyunsaturated fatty acid biosynthesis in teleost fish: functional characterization of fatty acyl desaturate (Fads2) and Elovl5 elongase in the catadromous species, Japanese eel Anguilla japonica. Aquaculture (accepted).
In article      
 
[25]  Sushchik, N.N., Gladyshew, M.I., Kalachova, G.S. Seasonal dynamics of fatty acid content of a common food fish from the Yenisei river, Siberian grayling, Thymallus arcticus. Food Chemistry 104, 1353-1358, 2007.
In article      CrossRef
 
[26]  Luzia, L.A., Sampaio, G.R., Castellucci, C.M.N., Torres, E.A.F.S. The influence of season on the lipid profiles of five commercially important species of Brazilian fish. Food Chemistry 83, 93-97, 2003.
In article      CrossRef
 
[27]  Kelly, A.M., Kohler, C.C. Cold tolerance and fatty acid composition of striped bass, white bass, and their hybrids. North American Journal of Aquaculture 61, 278-285, 1999.
In article      CrossRef
 
[28]  Snyder, R.J., Hennessey, T.M. Cold tolerance and homeoviscous adaptation in freshwater alewives (Alosa pseudoharengus). Fish Physiology and Biochemistry 29, 117-126, 2003.
In article      CrossRef
 
[29]  Trushenski, J.T., Schwarz, M.H., Bowzer, J.C., Gause, B.R., Fenn, T., Delbos, B.C. Temperature Affects Growth and Tissue Fatty Acid Composition of Juvenile Atlantic Spadefish. North American Journal of Aquaculture 74, 338-346, 2012.
In article      CrossRef
 
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