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International Journal of Aquaculture, 2014, Vol.4, No.05
http://ija.sophiapublisher.com
30
2009). Even though these species have less demand in
fresh condition, there is considerable market for dry
fish and also as fishmeal especially in poultry
industry.
In this study we selected two marine fish; goat fish
and pony fish because they are trash fish in our
trawlers, also the world total catch of them is 2643
and 111448 ton respectively (FAO, 2010).
Fishery, distribution, biology and population dynamics
of them have been studied in detail (Rajkumar, 2006;
Shadi et al., 2011; Sparks, 2006; Kwak and
Klumpp,2004; Ra et al., 2005; Golani et al., 2011;
Murty, 1986; Abraham et al., 2011; Chakrabarty,2008;
Gholami and Zoriasatein, 2005) Since no detailed
information is available on fatty acid profile from
these species so the objective of this study was to
determine fatty acid profiles of goatfish and pony fish
and to compare their nutritional content in Fall and
Spring season in Mahshahr Port .
1 Method and Materials
1.1 Samples
Goat fish and pony fish were obtained from fishermen
at Mahshahr port randomly in spring and Fall season,
because in other season they didn’t catch in their net.
In every season, 30 fish have been collected from
every species. The fish were caught the night before
the procedure, kept in ice and transferred to the
laboratory for analyses. The fishes were weighed,
deheaded, eviscerated and cleaned prior to freezing. In
an attempt to obtain a homogeneous sample from each
species, their flesh were removed from their
backbones, minced, blended and immediately
extracted. The mean weights and total length of the
fishes were: 78.25±11.6 g and 17±0.8 cm for goat fish
and 13.25±5.7 gram 6.5±1.7 cm for pony fish.
1.2 Lipid Extraction
Lipid extractions were performed on minced fish
samples (25g each) using the extraction methods of
Folchet et al. (1957): chloroform-methanol. Methylene
chloride (100μL) and 1 mL 0.5M NaOH in methanol
were added to oil extracts in a test-tube and heated in
a water bath at 90
℃
for 10 min. The test tubes were
removed from the water bath and allowed to cool
before addition of 1 mL 14% BF
3
in methanol. The
test tubes are heated again in a water bath for 90
℃
for 10 min, and cooled to room temperature. One mL
distilled water and 200-500μL hexane was added to
the test tubes and then FAME (Fatty Acid Methyl
Ester) was extracted by vigorous shaking for about 1
min. Following centrifugation (2000rpm), the top
layer was transferred into a sample bottle for GC
analysis (Chukwuemwka et al., 2008).
1.3 Fatty Acids Analysis
Fatty acid analyses were carried out using the IUPAC
II.D.19 method (IUPAC, 1979). Fatty acids were
analyzed using a HP Agilent 5890 system Gas
Chromatograph equipped with SP-2330 and a flame
ionization detector (FID). Separation of fatty acid
methyl esters was achieved by using fused silica
capillary column (30m × 0.25mm × 0.20μm film
thickness). The oven temperature was set at 120
℃
for
2 min then reached to 220
℃
with a ramp rate of 5
℃
/min, and then held for 15 min. The injector and
detector temperatures were maintained at 155
℃
and
260
℃
, respectively. The carrier gas was helium 10psi
with a split ratio of 1/50. The air and hydrogen of
pressure were 338 ml/min and 45 ml/min respectively.
Fatty acids were identified by comparing the retention
times of fatty acid methyl esters(FAME) with a
standard
37
component
FAME
mixture
(Supelco-Catolog No: 18919-1Amp.).Results were
expressed as the percentage of each fatty acid with
respect to the total fatty acids. (Turan et al., 2007;
Kaya and Turan, 2008).
1.4 Indexes of Lipid Quality
The saturated/unsaturated fatty acids (SFA/UFA)
ratios were calculated including trans fatty acids in the
UFA group. The atherogenicity (AI) and
thrombogenicity (TI) indices were also calculated
according to the following equations (Larqué et al.,
2003).
From the data on the fatty-acid composition, the
following were calculated:
1) Index of atherogenicity (IA): indicating the
relationship between the sum of the main saturated
fatty acids and that of the main classes of unsaturated,
the former being considered pro-atherogenic (favoring
the adhesion of lipids to cells of the immunological
and circulatory system), and the latter anti atherogenic
(inhibiting the aggregation of plaque and diminishing
the levels of esterified fatty acid, cholesterol, and
phospholipids, there- by preventing the appearance of