Fatty Acid Composition of the Muscle Lipids of Five Fish Species in Işıklı and Karacaören Dam Lake, Turkey

Total fatty acid composition of muscle lipids in some fish species (Cyprinus carpio (Işıklı Dam Lake), Tinca tinca (Işıklı Dam Lake), Scardinius erythrophthalmus (Işıklı Dam Lake), Cyprinus carpio (Karacaören Dam Lake), and Carassius carassius (Karacaören Dam Lake)) was determined by gas chromatography. Polyunsaturated fatty acids (PUFAs) of Cyprinus carpio (Işıklı Dam Lake) were found higher than PUFA of other species. Palmitic acid was the highest saturated fatty acid (SFA) in Tinca tinca (24.64%). Oleic acid was the highest monounsaturated fatty acid (MUFAs) in Cyprinus carpio (Işıklı Dam Lake) (19.25%). The most abundant polyunsaturated fatty acid in Scardinius erythrophthalmus was docosahexaenoic acid (DHA) (17.94%). Total ω3 fatty acid composition was higher than the total ω6 fatty acids of Cyprinus carpio in both dam lakes. ω3/ω6 rates in Cyprinus carpio (Işıklı Dam Lake), Tinca tinca, Scardinius erythrophthalmus, Cyprinus carpio (Karacaören), and Carassius carassius were 2.12, 1.19, 2.15, 2.87, and 2.82, respectively.


Introduction
The composition of fat acids of sea and freshwater fish has distinct differences [1]. The difference of fat acids compositions of fats in seafood depends on some factors. Those factors can be considered as diet, geographic conditions, ambient temperature, and seasonal changes, according to the season of hunting, body length, sex, species, and fat content [2].
The lipid and the type of fatty acids vary mainly according to species, seasons (especially the breeding season), the feeding areas, food structure, water temperature, and pollution, whether species culture or wild forms, diet, geographic conditions, ambient temperature, and seasonal changes, according to the season of hunting, body length, sex, fat contents, and the body portions [3,4].
It has demonstrated that the consumption of food containing long-chain fatty acids undertakes role in reducing the risk of coronary heart disease, in treating hypertension and cardiac arrhythmia, in preventing sudden death, in reducing the incidence of diabetes, in the improvement of skin diseases, in reducing symptoms of rheumatoid arthritis, in preventing impaired vision, alzay, and schizophrenia, and in reducing problems such as hyperactivity in slowing disease, inhibitors to fight cancer. As a result, deficient nutrition of 3 has been identified as indeficient development vision and nerve tissue in babies [5].
Eicosapentaenoic acid (EPA) and DHA in fish are also important physiologically. For development of sea fish's brain and retina, those essential oils are also necessary [6]. After identification of therapeutic aspects of EPA and DHA, it has been understood that they protect the body against especially migraine headaches, heart attacks, depression, rheumatic fever, certain forms of cancer, diabetes seen in adults, high cholesterol, high blood pressure, cardiovascular diseases, and some allergies. As a result of this, the pills produced from fish oil are commercially marketed [7].
No reports have yet been published about the fatty acid composition of Cyprinus carpio (Işıklı Dam Lake), Tinca tinca (Işıklı Dam Lake), Scardinius erythrophthalmus (Işıklı Dam Lake), Cyprinus carpio (Karacaören Dam Lake), and Carassius carassius (Karacaören Dam Lake). Cyprinus carpio's fatty acid composition varies in the reservoir. The aim of 2 Veterinary Medicine International this study is to characterize and compare these species in terms of their fatty acid composition. In addition, another aim of study is to determine the differences between fatty acid compositions of Cyprinus Carpio's and other species.

Study Area.
Işıklı and Karacaören Dam Lakes are freshwater lakes in Isparta region of Turkey. It is a large lake in Isparta and situated in southwestern part of Turkey. It is located at around 37 ∘ N 30 ∘ E and has an area of 25-80 km 2 . Karacaören and Light Isparta and Burdur Lake Dam are located within the city borders. It is about 270 meters above sea level having average depth of 80 meters. The highest water level is 275.5 meters with catchment area of 5582 km 2 . The elevation from the sea level of Karacaören Lake Dam is about 2000 meters. Dam construction started in 1972 and was completed in 1989. Lake irrigates 9,500 hectares in downstream and serves purposes such as electricity generation and fishing [8]. Işıklı and Karacaören Dam Lake is also an important wetland for birds. Cyprinus carpio (Işıklı Dam Lake), Tinca tinca (Işıklı Dam Lake), Scardinius erythrophthalmus (Işıklı Dam Lake), Cyprinus carpio (Karacaören Dam Lake), and Carassius carassius (Karacaören Dam Lake) are the most common fish species in such lakes.

Sample Collection. Cyprinus carpio (Işıklı Dam Lake),
Tinca tinca (Işıklı Dam Lake), Scardinius erythrophthalmus (Işıklı Dam Lake), Cyprinus carpio (Karacaören Dam Lake), and Carassius carassius (Karacaören Dam Lake) were used in this study. They were obtained from local fishermen in both dam Lakes in July. The season chosen for analysis was summer (hot season). Nine individuals were sampled from all species for total lipid extraction and fatty acid analyses in this season. All fish had almost the same size (average weight 1.000 kg) and age (over 2-year-old). Fish were transported in ice to the laboratory. Dorsal muscle tissues of fish were taken as samples. The samples were frozen at −24 ∘ C until analyses. At the beginning of analysis, the samples were allowed to equilibrate at room temperature.

Fatty Acid Analysis.
Total lipids of fish were extracted with chloroform: methanol (2 : 1 v/v) according to Folch et al. [9]. The fatty acids in the total lipid were esterified into methyl esters by saponification with 0.5 N methanolic NaOH and transesterified with 14% BF 3 (v/v) in methanol [10].
Fatty acid methyl esters (FAMEs) were prepared from nine samples obtained from the 5 fish species in July. The FAMEs were analyzed on a HP (Hewlett Packard) Agilent 6890N model gas chromatograph (GC), equipped with a flame ionization detector (FID) and fitted with a DB-23 capillary column (60 m, 0.25 mm i.d, and 0.25 m). Injector and detector temperatures were 270 and 280 ∘ C, respectively. Column temperature program was 190 ∘ C for 35 min then increased at 30 ∘ C/min up to 220 ∘ C where it was maintained for 5 min. Total run time was 36 min. The used carrier gas was helium (1 mL/min). GC analysis of FAMEs was performed with 3 replications.

Statistical Analysis.
Nine items of fish samples were analysed in July and each sample in triplicate. The average results of peak area were offered as means ± SD. FID responses were corrected to weight percent automatically. The results were submitted to analysis of variance (ANOVA), at 0.05 significance level, using SPSS 19.0. The mean values were compared by Tukey's test.

Result and Discussion
The fatty acid composition in muscles of Cyprinus carpio (Işıklı Dam Lake), Tinca tinca (Işıklı Dam Lake), Scardinius erythrophthalmus (Işıklı Dam Lake), Cyprinus carpio (Karacaören Dam Lake), and Carassius carassius (Karacaören Dam Lake) are presented in Table 1. Thirty-two fatty acids were identified and evaluated in the fish samples.
The predominant MUFA was oleic acid and it was followed by palmitoleic acid in all the species except Cyprinus carpio. Similar results were observed by Cengiz et al. [16], for Liza abu, Kalyoncu et al. [18], for V. vimba, Ateş et al. [19], for Salmo trutta macrostigma, and Guler et al. [11], for S. lucioperca. Higher levels of palmitoleic acid have been described as a characteristic of C. carpio [12]. In our study, the oleic acid in C. carpio (19.25%) was significantly Veterinary Medicine International 3  [18], and 21.12-40.04% in Alburnus chalcoides [12]. In the present study, C. carpio was rich in PUFA, especially DHA, arachidonic acid, EPA, docosapentaenoic acid (DPA), and linoleic acid. These results matched with Guler et al. [20], who reported that EPA, DHA, and arachidonic acid are the most abundant PUFA in C. carpio muscle

Conclusion
In the current study, fatty acid compositions of five important fish species in Işıklı and Karacaören Lake were researched. The reservoirs of C. carpio's fatty acid composition obtained from Işıklı and Karacaören was different from each other. C. carpio (Karacaören) had more 3 fatty acids, important for human health, than other fish species. The percentages of total 3 fatty acids were higher than those of the total 6 fatty acids in all species. C. carpio may be a good dietary source of 3 PUFA.