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1.
In this study, we examine changes in fatty acid composition of polar and neutral lipids in gill, liver, and muscle of freshwater
alewives (Alosa pseudoharengus) after temperature challenges in the laboratory. Alewives experienced either a warm or cold challenge in which temperatures
were raised or lowered 0.5°C day−1 over 4–6 weeks. In alewives experiencing the cold challenge, gill polar lipids showed evidence of significant remodeling,
including decreases in palmitic acid and saturated fatty acids and increases in n-3 and n-6 highly unsaturated fatty acids including docosahexaenoic acid (DHA) and arachidonic acid. In alewives experiencing the
warm challenge, we observed significant increases in saturated fatty acids (due mainly to increased palmitic acid) and decreases
in polyunsaturated fatty acids in polar lipids of muscle and liver tissue. Fish that died during the cold challenge had significantly
higher levels of palmitic acid in muscle polar lipids compared to fish that survived; fish that died during the warm challenge
displayed complex changes in fatty acid composition. Based on theoretical considerations, the changes in polar lipids we observed
during thermal acclimation are likely to promote appropriate membrane fluidity under each thermal regime. The increased incorporation
of highly unsaturated fatty acids during cold acclimation could have significant physiological and ecological implications.
In particular, since highly unsaturated fatty acids are typically scarce in freshwater food webs, dietary deficiencies in
these essential fatty acids may be a significant factor in winter mortality of freshwater alewives. 相似文献
2.
Arzu Özlüer Hunt Ferbal Özkan Kenan Engin Nazmi Tekelioğlu 《Aquaculture International》2011,19(1):51-61
The purpose of this study was to investigate the effect of freshwater rearing on the fatty acid profiles of the whole body
and muscle tissue of the European sea bass (Dicentrarchus labrax). Half of initial fish were gradually acclimated to freshwater (FW) kept at the same temperature to salt water and grown
in same conditions as their counterparts in saltwater (SW). The decrease in salinity caused an increase in the percentages
of 18:1n − 9, 24:1n − 9, 18:3n − 3, 18:2n − 6 and decrease in the percentages of 14:0, 15:0, 20:0, 21:0, 20:5n − 3 and 22:6n − 3 both in the whole body and in the muscle tissue fatty acid profiles. The lipids of FW-reared fish contained significantly
(P < 0.01) higher percentages of 18:2n − 6 and 18:3n − 6 than that of SW-reared fish. However, percentages of 20:5n − 3 and 22:6n − 3 fatty acids decreased significantly (P < 0.05) compared with those of salt water-reared European sea bass. There was a clear trend of decrement in the percentages
of n − 3 PUFA fatty acids due to the decrease in water salinity. However, the percentages of n − 6 PUFA fatty acids were also increased with the decrease in water salinity. We concluded that the FW acclimation is followed
by changes in certain lipid classes of sea bass muscle tissue and whole body samples. n − 3/n − 6 PUFA ratios were characteristic to previously reported ratios for both FW- and SW-reared European sea bass. In addition,
EPA/DHA ratios were basically similar for the fish reared in both SW and FW indicating the equal nutritional value of the
final products in terms of providing PUFA’s for human nutrition. 相似文献
3.
Izquierdo MS Robaina L Juárez-Carrillo E Oliva V Hernández-Cruz CM Afonso JM 《Fish physiology and biochemistry》2008,34(2):117-127
The Δ6 and Δ5 desaturases and elongases show only very limited activity in marine fish, and little is known of the possibility
of enhancing Δ6 desaturase gene expression in these fish. The use of plant oils in marine fish diets is limited by their lack
of n−3 highly unsaturated fatty acids (HUFA) despite an abundant content of the 18C fatty acid precursor linoleic and α-linolenic
acids. The objective of the present study was to determine the ability of larval gilthead seabream to utilize vegetable oils
and assess the nutritional regulation of Δ6 desaturase gene expression. Seventeen-day-old gilthead seabream larvae were fed
during a 17-day period with one of four different microdiets formulated with either sardine fish oil (FO), soybean, rapeseed
or linseed oils, respectively, or a fifth diet containing defatted squid meal and linseed oil. Good larval survival and growth,
both in terms of total length and body weight, were obtained by feeding the larvae either rapeseed, soybean or linseed oils.
The presence of vegetable oils in the diet increased the levels of 20:2n−9 and 20:2n−6, 18:2n−9, 18:3n−6, 20:3n−6 and 20:4n−6, in larvae fed rapeseed and soybean oils in comparison to those fed FO. In addition, a sixfold increase in the relative
expression of Δ6 desaturase-like gene was found in larvae fed rapeseed and soybean oils, denoting the nutritional regulation
of desaturase activity through its gene expression in this fish species. However, feeding linseed oil did not increase the
expression of the Δ6 desaturase gene to such a high extent. 相似文献
4.
Fernando D. Brignol Vitor A. G. Fernandes Renata O. Nobrega Camila F. Corrêa Keith Filler James Pettigrew Dbora M. Fracalossi 《Aquaculture Research》2019,50(3):707-716
Nile tilapia juveniles (8.35 ± 0.80 g) were fed on four levels (0.0%; 0.5%; 1.0%; 2.0%, 4.0%) of Aurantiochytrium sp. meal (ALL‐G‐RICH?), a source of docosahexaenoic acid (DHA). The 1% Aurantiochytrium sp. meal diet was compared to a control diet, which contained the same amount of DHA as cod liver oil (CLO) at 1.7% diet. Groups of 25 fish were stocked in 100 L tanks and fed twice daily until apparent satiation, for 57 days, at 28°C. Increasing dietary Aurantiochytrium sp. meal reduced the body retention of DHA and n‐3 polyunsaturated fatty acids (n‐3 PUFA) but increased the body retention of alpha‐linolenic (α‐LNA), linoleic (LOA) and n‐6 polyunsaturated fatty acids (n‐6 PUFA). Fatty acid profile in tilapia muscle was affected by increasing dietary inclusions of Aurantiochytrium sp. meal, with an increase in DHA, α‐LNA, n‐3 PUFA and n‐3 long chain‐polyunsaturated fatty acids (n‐3 LC‐PUFA) but a decrease in monounsaturated fatty acids (MUFA), n‐6 PUFA and n‐6 long‐chain polyunsaturated fatty acids (n‐6 LC‐PUFA). There was a larger body retention of DHA, α‐LNA, LOA, n‐3 PUFA and n‐6 PUFA fatty acids and a higher percentage of DHA, n‐3 PUFA and n‐3 LC‐PUFA in muscle fatty acid profile in fish fed on CLO diets than in those fed on 1% Aurantiochytrium sp. Therefore, Aurantiochytrium sp. meal is an alternative source of DHA for Nile tilapia diets. 相似文献
5.
Lipids and essential fatty acids are determinants of the reproductive process in marine fish, affecting fecundity, egg quality,
hatching performance, pigmentation and larval malformation. We have analyzed and characterized the lipids of eggs and unfed
larvae of two wild caught scombroid fish, the Atlantic northern bluefin tuna (Thunnus thynnus) and Atlantic bonito (Sarda sarda). Dry matter and total lipid contents, polar and neutral lipid classes and total lipid fatty acid contents were determined
in the eggs of bluefin tuna and eggs and unfed larvae during the development of Atlantic bonito. Bluefin tuna eggs had slightly
but significantly more dry mass than bonito eggs but very similar lipid content. However, bluefin tuna eggs presented a higher
polar lipid content due to increased proportions of phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol
(PI). Bonito eggs and larvae showed increasing dry mass and decreasing lipid content with development. The proportion of polar
lipids increased due to increased PE, PS and PI, whereas choline-containing polar lipids (phosphatidylcholine and sphingomyelin)
remained relatively constant. Free cholesterol also increased, whereas the levels of other neutral lipids, especially triacylglycerol
and steryl ester fractions, decreased, presumably due to utilization for energy to drive development. Bluefin tuna eggs had
higher levels of n − 3 and n − 6 highly unsaturated fatty acids due to higher docosahexaenoic and arachidonic acid contents, respectively, than bonito eggs.
The results are discussed in relation to the lipid and fatty acid requirements of larval scombroid fish in comparison to those
of other larval marine finfish species under culture conditions. 相似文献
6.
Rolf Erik Olsen Bjørn Tore Dragnes Reidar Myklebust Einar Ringø 《Fish physiology and biochemistry》2003,29(3):181-192
Rainbow trout (Oncorhynchus mykiss Walbaum) were fed purified diets containing fish oil for six weeks and then soybean lecithin or soybean oil for 25 days.
The gastrointestinal tract segments, stomach, midgut and hindgut were then sampled for lipid and fatty acid composition and
electron microscopy. Membrane lipid class composition was fairly similar in all three segments of trout fed fish oil. Hindgut
contained slightly more phosphatidylserine than stomach and midgut, while midgut contained more phosphatidylcholine and less
lysophospatidylcholine/sphingomyelin. Feeding soybean products appeared to marginally decrease free cholesterol. The fatty
acid compositions of the main lipid classes showed significant regional differences. In control fish, stomach had higher levels
of arachidonic acid (20:4n-6) and n-6 polyunsaturated fatty acids than midgut and hindgut, and lower content of docosahexaenoic
acid (22:6n-3) and n-3 polyunsaturated fatty acids. Midgut phosphatidylethanolamine also had higher levels of saturated fatty
acids and less n-3 polyunsaturated fatty acids than the other tissues. Feeding soybean products decreased the n-3/n-6 ratio
mainly due to increases in linoleic (18:2n-6) and 20:4n-6 and decreases in 22:6n-3 and eicosapentaenoic acid (20:5n-3). Phosphatidylcholine
and to a lesser extent phosphatidylethanolamine adapted more readily to dietary changes by major increases in 18:2n-6 and
C20−22 n-6 polyunsaturated fatty acids. The composition of phosphatidyl-serine and -inositol appeared to be under more strict metabolic
control. Linoleic acid hardly increased at all while the increase in other n-6 polyunsaturated fatty acids was less pronounced
than for the other lipid classes. Regardless of lipid class, stomach resisted dietary changes more strongly than midgut and
hindgut. Increases in n-6 polyunsaturated fatty acids were minor as were the loss of n-3 polyunsaturated fatty acids. The
dead-end product 20:2n-6 accumulated to a higher degree in hindgut phosphatidyl-ethanolamine and -coline compared to midgut
and stomach, suggesting that the activity of Δ6 desaturation is higher in the anterior part of the intestine where most of the lipid is absorbed. Feeding soybean oil caused
massive accumulation of free lipid droplets in midgut enterocytes while little lipid droplets were observed in trout fed fish
oil or soybean lecithin. Since both soybean products influenced intestinal composition to the same degree, altered fatty acid
profiles in membranes is not responsible for the observed lipid accumulation. This supports previous observations in Arctic
charr (Salvelinus alpinus L.), suggesting that fish may require exogenous phospholipids in order to sustain a sufficient rate of lipoprotein synthesis.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Fish oil (FO) substitution has been studied in many marine carnivorous fish, but seldom in marine herbivorous or omnivorous species. To evaluate the feasibility of using soybean oil (SO) as a dietary lipid and confirm its capability of converting C18 polyunsaturated fatty acid (PUFA) into long chain polyunsaturated fatty acid (LC‐PUFA) in the marine herbivorous teleost Siganus canaliculatus, juvenile fish were fed with four formulated diets differing in lipid composition, with SO accounting for 0.76% (SO0), 23% (SO23), 45% (SO45) and 67% (SO67) of total dietary lipid respectively. After feeding for 8 weeks, growth performance including weight gain, specific growth rate, feed conversion ratio and protein efficiency rate were better in the SO23 and, especially, SO45 groups than in the SO0 and SO67 groups (P < 0.05). Tissue fatty acid compositions were affected by diet, with the liver contents of eicosapentaenoic (EPA), docosapentaenoic (DPA), docosahexaenoic (DHA) acids and total n‐3 PUFA displaying parallel changes with the corresponding dietary fatty acids. While the muscle contents of EPA, DPA and total n‐3 PUFA between SO0 and SO23 groups, and the liver contents of arachidonic acid (ARA) and 20:4n‐3, as well as the muscle content of 20:3n‐6 between SO0 and SO45 groups showed no difference, confirming the biosynthesis of LC‐PUFA from C18 precursors in vivo as the contents of corresponding fatty acids in diets SO23/SO45 were much lower than those in diet SO0 (P < 0.05). The results indicate that SO may be a suitable dietary lipid source for S. canaliculatus, and can replace up to 67% or 45% of total dietary FO without negatively compromising growth performance or nutritional quality of fish respectively. Moreover, the study increases our knowledge of FO substitution in marine herbivorous fish. 相似文献
8.
N. Chaitanawisuti S. Sangsawangchote S. Piyatiratitivorakul 《Aquaculture International》2011,19(1):23-31
This study is the first attempt to condition broodstock Babylonia areolata using formulated diets under hatchery conditions. Samples of spotted babylon egg capsules from broodstock fed either a formulated
diet or a local trash fish, carangid fish (Seleroides
leptolepis) for 120 days were analyzed for proximate composition and fatty acid composition. The formulated diet contained significantly
higher levels of arachidonic acid (20:4n − 6; ARA), eicosapentaenoic acid (20:5n − 3; EPA) and docosahexaenoic acid (22:6n − 3; DHA) than those of the local trash fish. The formulated diet also had significantly higher ratios of DHA/EPA and (n − 3)/(n − 6) PUFA than those of local trash fish but not for the ARA/EPA ratio. The compositions of egg capsules produced from broodstock
fed formulated diet contained significantly more ARA, EPA and DHA compared to broodstock fed the local trash fish. The ARA/EPA
and DHA/EPA ratios in egg capsules were significantly higher in the trash fish—fed group compared to those fed the formulated
diet. However, (n − 3)/(n − 6) PUFA ratios in egg capsules produced from broodstock fed the formulated diet did not differ significantly compared to
those from broodstock fed the local trash fish. The relatively low DHA/EPA, ARA/EPA and (n − 3)/(n − 6) ratios in the egg capsules produced from the formulated diet—fed broodstock B. areolata suggested that this diet is inferior, when compared to the traditional food of trash fish. 相似文献
9.
The influence of feed oils on fatty acid compositions of cod liver oils was examined to investigate how fatty acid profiles
are modified, and to provide estimates of feed oil compositions needed to give liver oils meeting production guidelines [3–11%
18:2n−6, 7–16% 20:5n−3 (EPA) and 6–18% 22:6n−3 (DHA)]. Attention was directed to examination of cod liver oil contents of n−6 and n−3 fatty acids, the essential fatty acids. Data, mostly taken from published work, were subjected to regression analysis to
investigate the relationships between the percentages of fatty acids (18:2n−6, total n−6 fatty acids, 18:3n−3, 20:5n−3, 22:6n−3 and total n−3 fatty acids) in feed oils and their percentages in liver oils. 相似文献
10.
Adrian A. Bischoff Patrick Fink Uwe Waller 《Aquaculture (Amsterdam, Netherlands)》2009,296(3-4):271-276
The potential of solid waste originating from a recirculated fish culture system, i.e. faecal material, uneaten food pellets and bacterial biofilms was examined as food source for the marine polychaete Nereis diversicolor. These polychaetes could be a valuable food for fish if they provide essential fatty acids to the fish. Therefore, we analysed the fatty acid profiles from feed and faecal materials, the sediment as well as the cultured organisms — fish and several batches of N. diversicolor — from an integrated recirculating aquaculture system.The major fatty acids (saturated, monounsaturated and polyunsaturated) for all analysed fish feed, fish and faeces samples were C16:0, C18:1 and C22:6 (n − 3), accounting for 48% to 57% of the fatty acids in the samples. The major fatty acids within the sediment were C16:0, C18:1 and C18:3 (n − 3), accounting for 61% of the total fatty acids. The samples of N. diversicolor revealed C16:0, C18:1 and C20:5 (n − 3) as the major fatty acids. Combined, they accounted for 56% of the total fatty acids detected within the worm samples.The results indicate that a recycling or even an upgrade of excreted feed nutrients such as fatty acids, which were otherwise discharged, can be achieved through integrated aquaculture combining fish and worm culture. 相似文献
11.
Molecular cloning and functional characterization of a putative Elovl4 gene and its expression in response to dietary fatty acid profiles in orange‐spotted grouper Epinephelus coioides 下载免费PDF全文
Songlin Li Óscar Monroig Juan Carlos Navarro Yuhui Yuan Wei Xu Kangsen Mai Douglas R Tocher Qinghui Ai 《Aquaculture Research》2017,48(2):537-552
12.
Retentions of total n-3 and n-6 essential fatty acids (EFAs) were assessed in Atlantic salmon (Salmo salar L.) parr held at 8 °C and 2 °C until they increased in weight from ca. 19 g to 38 g. Feeds contained sandeel oil or a rapeseed:linseed
oil blend at 21 and 34% dietary fat. EFA retention efficiencies [(g EFA gained g EFA ingested-1) × 100] were estimated by
the 'mass balance method' from measurements of feed intake, changes in biomass for each tank of fish, and fatty acid compositions
of the feeds and fish. The n-3 EFA retentions were higher (overall mean 71%) across feed treatments and temperatures than
the n-6 EFA retentions (overall mean 63%). Retentions of the n-3 fatty acids were higher in the fish given the feeds with
the lower fat content (77% vs. 65%), implying improved retention with reduced n-3 EFA availability. n-3 EFA retention tended
to be higher at 2 °C than at 8 °C, although this was not consistent across feeds. At low temperature there was very high retention
of the n-3 EFAs in feeds containing sandeel oil (80%). Such high retention may represent an adaptation response to low temperature.
Lower n-6 EFA retentions imply that more n-6 fatty acids were metabolized than n-3 EFAs. Feed oil influenced retention of
the n-6 fatty acids, retention being lower for the salmon parr given the feeds containing sandeel oil (56% vs. 71%). This
could indicate a higher tissue deposition of n-6 fatty acids when they are freely available via the diet. Abbreviations: AA – arachidonic acid (C20:4 n-6); DHA – docosahexaenoic acid (C22:6 n-3); EFA – essential fatty acid; EPA – eicosapentaenoic
acid (C20:5 n-3); HUFA – highly-unsaturated fatty acid (\ge4 double bonds); MUFA – monounsaturated fatty acid (1 double bond); PL – phospholipid; PUFA – poly-unsaturated fatty acids
(\ge2 double bonds); SFA – saturated fatty acid (no double bond); TAG – triacylglycerol.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
13.
Zhi Luo Xiao‐Ying Tan Cai‐Xia Liu Xiao‐Dong Li Xiang‐Jiang Liu Wen‐Qiu Xi 《Aquaculture Research》2012,43(9):1392-1403
An 8‐week feeding trial was conducted to determine the effect of dietary conjugated linoleic acid (CLA) on growth performance, muscle fatty acid profile, hepatic intermediary metabolism and antioxidant responses in genetically improved farmed Tilapia (GIFT) strain of Oreochromis niloticus (initial body weight: 42.6 ± 0.4 g, mean ± standard deviation). Three replicated groups of GIFT strain of Nile tilapia were hand‐fed to satiation, twice a day, with the diets in which CLA oil, containing mainly the bioactive cis‐9, trans‐11 and trans‐10, cis‐12 isomers, was included at 0 (control), 0.5%, 1%, 1.5%, 2% and 2.5%, respectively, at the expense of fish oil to maintain the constant lipid and energy levels. Growth performance and feed utilization showed no significant differences among the treatments (P > 0.05). The dietary inclusion of CLA modified total percentages of the main groups of fatty acids. Increasing saturated fatty acid content and reduced mono‐unsaturated fatty acid contents in muscle were observed with increasing dietary CLA inclusion (P < 0.05). Total n‐3 fatty acids and total polyunsaturated fatty acids tended to decline with increasing dietary CLA levels (P < 0.05), but n‐6 fatty acids showed no significant differences among the treatments (P > 0.05). Dietary CLA supplementation resulted in the significant increase in the trans‐10, cis‐12 and cis‐9, trans‐11 CLA isomers in muscle (P < 0.05) and also significantly influenced several hepatic enzymatic activities, such as succinate dehydrogenase, lactate dehydrogenase, malic dehydrogenase, lipoprotein lipase and hepatic lipase activities (P < 0.05). Reduced superoxide dismutase and glutathione peroxidase activities, and the decline in malondialdehyde levels were observed in fish fed the CLA‐supplemented diets (P < 0.05), indicating that dietary CLA supplementation showed a powerful antioxidant effect for this fish species. Our study was the first report involved in the effect of dietary CLA inclusion on hepatic intermediary metabolism and antioxidant responses in fish, which could be used as indicators of nutritional and physiological status of the fish species. 相似文献
14.
The effects of irradiance and photoperiod on the biomass and fatty acid (FA) composition of Chlorella vulgaris were examined in the exponential growth phase. Results indicated significant differences in biomass and FA at different intensities
and photoperiods. Maximum biomass (2.05 ± 0.1 g l−1) was at 62.5 μmol photons m−2 s−1 and 16:8 h light/dark photoperiod. FA composition changed considerably in different light regimes; the maximum percentage
of total saturated (SFA) (33.38%) was recorded at 100 μmol photons m−2 s−1 and 16:8 h photoperiod, while monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids decreased with increasing irradiance
and light duration. The maximum percentage of total MUFA (15.93%) and PUFA (27.40%) was recorded at 37.5 μmol photons m−2 s−1 and 8:16 h photoperiod. 相似文献
15.
Y. Durmaz M. Donato M. Monteiro L. Gouveia M. L. Nunes T. Gama Pereira Ş. Gökpınar N. M. Bandarra 《Aquaculture International》2009,17(4):391-399
Diacronema vlkianum was grown in polyethylene bags at two different temperatures (18 and 26°C) in the laboratory. The biochemical composition
level decreased when the temperature increased from 18 to 26°C. The maximum cell number at 18°C was 11.9 × 106 cells ml−1, while maximum cell number at 26°C was 1.6 × 106 cells ml−1. The maximum level of α-tocopherol was 257.7 ± 21.6 μg g−1 dry weight (DW) at 18°C. The highest total carotenoids and chlorophylls were 6.5 mg g−1 DW and 4.3 mg g−1 DW, respectively, and the main pigments were determined as astaxanthin and lutein. Polyunsaturated fatty acids were found
to be the predominant group, reaching 39.5% of the total fatty acids at 18°C. This comprised 20:5(n − 3) as the main polyunsaturated
fatty acids (20.4%, at 18°C) followed by 22:6(n − 3) (4.8%, at 18°C). The results suggest that D. vlkianum can be successfully used as feed in shellfish hatcheries or aquaculture hatcheries, either as a substitute or in association
with other microalgae, when this algae is cultured at 18°C. 相似文献
16.
Vishwanath Patil Torsten Källqvist Elisabeth Olsen Gjermund Vogt Hans R. Gislerød 《Aquaculture International》2007,15(1):1-9
Twelve algal strains representing the classes Cyanophyceae, Prymnesiophyceae, Bacillariophyceae, Rhodophyceae, Cryptophyceae,
Chlorophyceae, Xantophyceae and Eustigmatophyceae were selected mainly from the culture collection of the Norwegian Institute
for Water Research (NIVA). The algae were grown as continuous cultures in a 1.8 l. reactor, internally illuminated with an
11 W fluorescent tube. The retention time was adjusted in the range 2–4 days to fit the growth rate of the algae. The growth
responses and fatty acid composition were analysed. The maximum production rate was obtained with Pseudokirchneriella subcapitata (0.63 g 1−1 day−1) and the lowest with Porphyridium cruentum 0.13 g 1−1 day−1. Arachidonic acid (AA) and eicosapentaenoic acid (EPA) were the dominating polyunsaturated fatty acids (PUFAs) in P. cruentum, while only EPA accumulated in Phaeodactylum tricornutum. Docosahexaenoic acid (DHA) was the major PUFA in Isochrysis galbana, while Pavlova sp. had both EPA and DHA. This is the first report on the fatty acid profiles of Nannochloropsis oceanica, Chroococcus sp., Synechococcus sp. and Tribonema sp. 相似文献
17.
Positional distribution of fatty acids in triacyl-sn-glycerols (TAG) of the flathead flounder Hippoglossoides dubius has been reinvestigated in order to accurately determine the contents of tetracosahexaenoic acid (24:6n-3) in the sn-1, sn-2, and sn-3 positions. Flesh TAG obtained from three flounders were subjected to stereospecific analysis using a suitable procedure
for fish TAG analysis. The 24:6n-3 acid was found in the three positions at the concentrations of 0.3–5.5 mole% (the sn-1 position), 1.6–23.3 mole% (the sn-2 position), and 0.6–8.9 mole% (the sn-3 position). In contrast to a previous analysis, the present analysis revealed that 24:6n-3 is preferentially esterified
in the sn-2 position followed by the sn-3 and sn-1 positions. Other polyunsaturated fatty acids, docosahexaenoic acid (22:6n-3; DHA) and docosapentaenoic acid (22:5n-3; DPA),
showed a similar distribution pattern. These results indicate that the general tendency observed for long-chain polyunsaturated
fatty acids in marine fish TAG can be extended to the distribution of 24:6n-3 in flathead flounder TAG. Because the use of
flathead flounders is entirely for human food, we thus intake 24:6n-3 concentrated in the sn-2 position of their TAG. 相似文献
18.
Vineeta Joshi M. S. Akhtar Prakash Sharma Sarika Singh Kushwaha Deepjyoti Baruah A. Ciji 《Journal Of Aquatic Food Product Technology》2017,26(7):843-855
Five species of snow trout (Schizothorax spp.) were investigated for their inherent nutritional value. Proximate composition, total fat, total cholesterol, triglyceride, fatty acids (FAs) profile, and mineral profiles were analyzed. Protein percentage in all five fish was found to be the same (P > 0.05), ranging from 15% to 18%. Moisture (75–82%) and lipid (1.5–8%) values were found to differ prominently (P < 0.05) in an inverse manner. Total fat (%), total cholesterol (mg/100 g), and triglyceride (mg/100 g) contents were found in the range of 2.73–6.54, 21.31–25.76, and 298.89–342.22, respectively. The trend of FAs in decreasing order was saturated > mono-unsaturated > polyunsaturated (n–6 > n–3). The sum of n–6 FAs value was higher than that of n–3, and the major n–6 and n–3 long chain polyunsaturated FAs (PUFAs) were arachidonic acid and docosahexaenoic acid, respectively. In most of these fish, the profile of macrominerals was phosphorus > potassium > calcium > sodium > magnesium, while the trend for microminerals was iron > zinc > copper > manganese. The snow trout species with best contribution potential to the daily requirement of n–3 long chain PUFAs was found in S. esocinus and S. niger, calcium and phosphorus in S. plagiostomus, and iron and copper in S. progastus. 相似文献
19.
Osama M. El–Husseiny Galal M. Abdul-Aziz Ashraf M. A. -S. Goda Ashraf Suloma 《Aquaculture International》2010,18(6):1105-1119
This experiment was conducted to study the effect of altering the linoleic acid (LA) and linolenic acid (LNA) levels and ratios
in the diet of Nile tilapia (Oreochromis niloticus) on fry performance. Twelve diets were formulated to be isonitrogenous, isocaloric, and differed only in their main lipid
source. An oil rich in n-3 fatty acids [linseed oil (L)] and two oils rich in n-6 fatty acids [soybean oil (S) and corn oil (C)] were added at 6% of the basal diet either separately or in equal combinations
(L1:S1 or L1:C1 or S1:C1) or at ratio 2:1 (L2:S1 or L2:C1 or C2:L1 or C2:S1 or S2:L1 or S2:C1). The fish were fed twice daily
(09 and 16 h) to apparent satiation throughout the duration of the trial (16 weeks). Survival rates increased in a linear
pattern with increasing the LA level in the diets (R
2 = 0.764). Final body weight was significantly higher in fish fed S, S2:L1, and L2:C1 diets, being 14.29, 14.14, and 14.09 g/fish,
respectively. However, tilapia fed C, S1:C1, and C2:S1 diets exhibited low final body weight (11.41, 11.60, and 11.76 g/fish,
respectively). The final body weight was negatively affected by increasing the LA/LNA ratios (R
2 = 0.647). Either LA or arachidonic acid (%) in the whole body of fish increased in a linear patterns (R
2 = 0.641 and 0.746, respectively) with increasing dietary LA. Besides, LNA, eicosapentaenoic, acid and docosahexaenoic acid
(%) in the whole body increased in a linear pattern (R
2 = 0.777, 0.501, and 0.8148, respectively) the increasing dietary LNA level. The present study indicated that LA/LNA ratio
less than 13 is recommended for nutrition of tilapia fry. 相似文献
20.
During cold winters, freshwater populations of alewives (Alosa pseudoharengus) are prone to massive die-offs, the physiological causes of which are poorly understood. We analyzed fatty acid composition
before and after a laboratory cold challenge to examine the potential loss of cell membrane fluidity as a factor in winter
mortality of these fish. Fish that died during the cold challenge displayed lower levels of polyunsaturated fatty acids, lower
indices of unsaturation, and higher levels of monounsaturated fatty acids in membrane lipids compared to controls and survivors.
Fatty acids associated with storage lipids were largely unaffected by the cold challenge. Differences in diet (Artemia versus Daphnia) had little effect on the fatty acid composition of these fish. Reduced activity of Δ5 desaturase enzymes may explain the
decreased levels of polyunsaturated fatty acids (specifically arachidonic acid and docosahexaenoic acid) we observed in the
cold temperature mortalities. Our results indicate that a loss of homeoviscous adaptation may play a role in low temperature
mortality of freshwater alewives, and an analysis of alewife diets may improve our ability to predict winter die-offs of these
fishes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献