Marine Fish Oil Research Articles

Fatty acid requirements in ontogeny of marine and freshwater fish

Essential fatty acid (EFA) requirements vary qualitatively and quantitatively with both species and during ontogeny of fish, with early developmental stages and broodstock being critical periods. Environment and/or trophic level are major factors, with freshwater/diadromous species generally requiring C18 polyunsaturated fatty acids (PUFA) whereas marine fish have a strict requirement for long-chain PUFA, eicosapentaenoic, docosahexaenoic and arachidonic acids. Other than marine fish larvae, defining precise quantitative or semi-quantitative EFA requirements in fish have received less attention in recent years. However, the changes to feed formulations being forced upon the aquaculture industry by the pressing need for sustainable development, namely the replacement of marine fish meal and oils with plant-derived products, have reintroduced EFA into the research agenda. It is particularly important to note that the physiological requirements of the fish to prevent deficiency pathologies and produce optimal growth may not parallel the requirements for maintaining nutritional quality. For instance, salmonids can be successfully cultured on vegetable oils devoid of long-chain n-3 PUFA but not without potentially compromising their health benefits to the human consumer. Solving this problem will require detailed knowledge of the biochemical and molecular basis of EFA requirements and metabolism.

Effects of phosphorus and vitamin C deficiency, vitamin A toxicity, and lipid peroxidation on skeletal abnormalities in Atlantic halibut (Hippoglossus hippoglossus)

Summary Dietary nutrients play an important role in skeletal tissue metabolism of fish. Deficiency and toxicity of certain nutrients have been linked to bone deformities in larval and juvenile fish. The pathogenesis of skeletal disorders in larval and juvenile fish from the same genetic stock, cultured under similar environment conditions is often difficult to distinguish when marginal deficiencies of multiple nutrients are involved. A study was conducted to characterize the skeletal deformities linked to the deficiency of phosphorus and ascorbic acid, vitamin A toxicity and lipid peroxidation in juvenile halibut. Five experimental diets containing a low level of phosphorus (0.5% dry matter basis), no vitamin C supplement, high level of vitamin A (80 000 IU kg−1) and oxidized marine fish oil (peroxide value, 7.53 meq kg−1) and a control diet based on cod fillet and vitamin free casein were fed to juvenile Atlantic halibut for 14 weeks in an attempt to characterize the skeletal deformities. Phosphorus, ascorbic acid, retinol, and α-tocopherol concentrations of liver and kidney were measured at 0 and 14 weeks. Reduced vertebral ash and phosphorus content were observed in fish fed the low phosphorus diet. Skeletal abnormalities included abnormal hemal and neural spines in the hemal region and scoliosis in the cephalic and hemal regions of the vertebral column. Hepatic and kidney ascorbic acid concentrations were significantly lower in the group fed no ascorbic acid supplement. Skeletal abnormalities were scoliosis and lordosis primarily in the hemal region of the vertebral column. High levels of vitamin A in the diet caused increased hepatic retinol content and scoliosis spanning the cephalic/prehemal and anterior hemal regions of the vertebral column. Fish fed the oxidized oil diet showed increased thiobarbituric acid (TBA) value in the liver and muscle tissue with no significant decrease in hepatic vitamin E concentration. The most frequent skeletal deformity observed was scoliosis, spanning the cephalic/prehemal regions as well as the anterior hemal region of the vertebral column. The pattern and type of abnormalities observed in fish fed these experimental diets were similar to those observed in a commercial halibut hatchery.

Toward Improved Public Confidence in Farmed Fish Quality: A Canadian Perspective on the Consequences of Diet Selection

Marine fish oils (MFO) are used in salmon diets to mimic the natural diet, to ensure that essential fatty acid requirements for good fish growth and health are met, and to provide salmon flesh with an omega-3 highly unsaturated fatty acid content that can benefit human health. However, an extensive use of MFO in formulated salmonid diets is perceived as an unsustainable use of wild marine fish stocks. In addition, MFOs have a background level of persistent organic pollutants (POPs) unrelated to aquaculture practices. This review considers recently completed studies using alternative lipid sources of terrestrial origin as replacements for MFO and shows that the composition of conventional finfish diets can be altered to reduce the reliance on MFO while concurrently maintaining fish health as well as reducing background levels of POPs. A challenge still ahead is the need for a concerted and sustained outreach to ensure that the public is aware of such improvements to seafood quality so that the preoccupation of the news media with presenting negative images of fish culture to the public is combated.

Performance and Emission Characteristics of a DI Compression Ignition Engine Operated on Marine Fish- Oil Biodiesel

The high viscosity of vegetable oils leads to problem in pumping and spray characteristics. Biodiesel is recognized as a clean alternative fuel or as a fuel additive to reduce pollutant emissions from combustion equipment. Because cultivated land is too limited to grow seed- oil plants sufficient to produce both food and biodiesel, non-landbased oleaginous materials have been considered important sources for the production of the latter. In this study, fish-oil biodiesel blends are used as fuel. Marine fish oil was extracted from the discarded parts of mixed marine fish and refined. The refined marine fish oil was then transesterified with methyl alcohol to produce biodiesel, which was used thereafter as engine fuel to investigate its engine performance and emission characteristics. This paper presents the results of investigations carried out on a single-cylinder, four stroke, direct-injection, CI engine operated with methyl ester of fish-oil. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 10, 20, 40, 60, 80, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured. The maximum thermal efficiency for B20 (32.28%) was higher than that of diesel at rated load. The experimental results show that the engine performance are close to the values obtained from diesel fuel and the amount of exhaust emissions are lower than those of diesel fuel.

Omega-3 fatty acids and heart failure

During the past three decades, the protective role of omega (n)-3 polyunsaturated fatty acids (PUFA), mainly eicosapentaenoic acid and docosahexaenoic acid, in patients with coronary heart disease has been widely reported. The Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-Heart Failure (GISSI-HF) study, a large-scale clinical trial, recently showed that n-3 PUFA (850-882 mg/d) reduced mortality and admission to the hospital for cardiovascular reasons in patients with chronic heart failure (HF) who were already receiving recommended therapies. The favorable effects of n-3 PUFA in GISSI-HF suggest that marine fish oils could confer protection in HF mainly through their antiarrhythmic action and in part by influencing the mechanisms related to HF progression. This article reviews recent clinical and experimental evidence on the effect of n-3 PUFA in coronary heart disease, with particular attention on HF and its pathophysiologic mechanisms.

Use of commercial fermentation products as a highly unsaturated fatty acid source in practical diets for the Pacific white shrimpLitopenaeus vannamei

Removal or reduction of marine ingredients (MI) from feed formulations is critical to the sustainability of the aquaculture industry. By removing MI, diets may become limiting in several nutrients including highly unsaturated fatty acids (HUFA) such as docosahexaenoic acid (DHA) and arachidonic acid (ArA). To reduce reliance on MI in shrimp diets, two trials were conducted with Litopenaeus vannamei juveniles to determine the feasibility of using fermentation meals rich in DHA and ArA as the primary source for HUFA. A practical diet with no MI was formulated with/without DHA and ArA supplements and fed in the first trial. A diet with menhaden fish oil or a combination of plant oil with/without DHA and ArA supplements was used in the second trial. To determine whether HUFA is only needed in the early growth stages, we also fed one group a HUFA-supplemented diet to 5 g and then switched them to a HUFA-supplement-free diet. In both trials, the weights were reduced when HUFA supplements were not provided either throughout the trial or from 5 g to harvest (<16 g). These results suggest that supplementation of plant oils with DHA- and ArA-rich oils from fermented products is a viable option to replace marine fish oil for L. vannamei.

Engine performance and emission characteristics of marine fish-oil biodiesel produced from the discarded parts of marine fish

Biodiesel is recognized as a clean alternative fuel or as a fuel additive to reduce pollutant emissions from combustion equipment. Because cultivated land is too limited to grow seed-oil plants sufficient to produce both food and biodiesel, non-land-based oleaginous materials have been considered important sources for the production of the latter. In this study, the discarded parts of mixed marine fish species were used as the raw material to produce biodiesel. Marine fish oil was extracted from the discarded parts of mixed marine fish and refined through a series of pretreatment processes. The refined marine fish oil was then transesterified with methyl alcohol to produce biodiesel, which was used thereafter as engine fuel to investigate its engine performance and emission characteristics. The experimental results show that, compared with commercial biodiesel from waste cooking oil, marine fish-oil biodiesel has a larger gross heating value, elemental carbon and hydrogen content, cetane index, exhaust gas temperature, brake fuel conversion efficiency, NO x and O 2 emissions, and black smoke opacity and a lower elemental oxygen content, fuel consumption rate, brake-specific fuel consumption rate, equivalence ratio, and CO emission. Compared with ASTM No. 2D diesel, both marine fish-oil and waste cooking-oil biodiesels appear to have a lower gross heating value, cetane index, exhaust gas temperature, equivalence ratio, black smoke opacity, elemental carbon content, and CO emission and a higher fuel consumption rate and elemental oxygen content.

PUFAs in Fish: Extraction, Fractionation, Importance in Health

ABSTRACT: Polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are currently in demand in the pure form and actively being studied to understand their potential roles in human health. Arachidonic acid, 20:4 (n‐6), and DHA, 22:6 (n‐3), are important in normal neurodevelopment and visual function. Infants fed formula often have low blood lipid 20:4 (n‐6) and 22:6 (n‐3). Consumption of fish oils may increase the 20:5 (n‐3) (EPA) and 22:6 (n‐3) (DHA) in human blood. Some marine fish oils contain higher amounts of arachidonic acid, EPA, and DHA. PUFA contents in different marine fishes and methods for their extraction and fractionation, in terms of fatty acid constituents in the form of methyl esters, are covered in this review. Emphasis is given to the fractionations of EPA and DHA by means of supercritical fluid extractions (SFE). The advantages of SFE compared to conventional methods are discussed in this review. PUFAs are usually extracted at about 10 to 30 MPa and at 40 to 80 °C. SFE is a promising and currently the best technique to extract PUFAs, especially EPA and DHA, from marine and freshwater fish.

Fuel properties of biodiesel produced from the crude fish oil from the soapstock of marine fish

The soapstock of a mixture of marine fish was used as the raw material to produce the biodiesel in this study. The soapstock was collected from discarded fish products. Crude fish oil was squeezed from the soapstock of the fish and refined by a series of processes. The refined fish oil was transesterified to produce biodiesel. The fuel properties of the biodiesel were analyzed. The experimental results showed that oleic acid (C18:1) and palmitic acid (C16:0) were the two major components of the marine fish-oil biodiesel. The biodiesel from the mixed marine fish oil contained a significantly greater amount of polyunsaturated fatty acids than did the biodiesel from waste cooking oil. In addition, the marine fish-oil biodiesel contained as high as 37.07 wt.% saturated fatty acids and 37.3 wt.% long chain fatty acids in the range between C20 and C22. Moreover, the marine fish-oil biodiesel appeared to have a larger acid number, a greater increase in the rate of peroxidization with the increase in the time that it was stored, greater kinematic viscosity, higher heating value, higher cetane index, more carbon residue, and a lower peroxide value, flash point, and distillation temperature than those of waste cooking-oil biodiesel.

Essential fatty acids influence metabolic rate and tolerance of hypoxia in Dover sole (Solea solea) larvae and juveniles

Dover sole (Solea solea, Linneaus 1758) were raised from first feeding on brine shrimp (Artemia sp.) with different contents and compositions of the essential fatty acids (EFA) arachidonic acid (ARA, 20:4n − 6); eicosapentaenoic acid (EPA, 20:5n − 3), and docosahexaenoic acid (DHA, 22:6n − 3), and their metabolic rate and tolerance to hypoxia measured prior to and following metamorphosis and settlement. Four dietary Artemia preparations were compared: (1) un-enriched; (2) enriched with a commercial EFA mixture (Easy DHA SELCO Emulsion); (3) enriched with a marine fish oil combination (VEVODAR and Incromega DHA) to provide a high ratio of ARA to DHA, and (4) enriched with these fish oils to provide a low ratio of ARA to DHA. Sole fed un-enriched Artemia were significantly less tolerant to hypoxia than the other dietary groups. Larvae from this group had significantly higher routine metabolic rate (RMR) in normoxia, and significantly higher O2 partial pressure (PO2) thresholds in progressive hypoxia for their regulation of RMR (Pcrit) and for the onset of agitation, respiratory distress and loss of equilibrium. Metamorphosis was associated with an overall decline in RMR and increase in Pcrit, but juveniles fed on un-enriched Artemia still exhibited higher Pcrit and agitation thresholds than the other groups. Sole fed un-enriched Artemia had significantly lower contents of EFA in their tissues, both before and after settlement. Thus, enriching live feeds with EFA has significant effects on the respiratory physiology of sole early life stages and improves their in vivo tolerance to hypoxia. We found no evidence, however, for any effect of the ratio of ARA to DHA.

Formation of Highly Reactive Cyclopentenone Isoprostane Compounds (A3/J3-Isoprostanes) in Vivo from Eicosapentaenoic Acid

Omega-3 (omega-3) polyunsaturated fatty acids (PUFAs) found in marine fish oils are known to suppress inflammation associated with a wide variety of diseases. Eicosapentaenoic acid (EPA) is one of the most abundant omega-3 fatty acids in fish oil, but the mechanism(s) by which EPA exerts its beneficial effects is unknown. Recent studies, however, have demonstrated that oxidized EPA, rather than native EPA, possesses anti-atherosclerotic, anti-inflammatory, and anti-proliferative effects. Very few studies to date have investigated which EPA oxidation products are responsible for this bioactivity. Our research group has previously reported that anti-inflammatory prostaglandin A(2)-like and prostaglandin J(2)-like compounds, termed A(2)/J(2)-isoprostanes (IsoPs), are produced in vivo by the free radical-catalyzed peroxidation of arachidonic acid and represent one of the major products resulting from the oxidation of this PUFA. Based on these observations, we questioned whether cyclopentenone-IsoP compounds are formed from the oxidation of EPA in vivo. Herein, we report the formation of cyclopentenone-IsoP molecules, termed A(3)/J(3)-IsoPs, formed in abundance in vitro and in vivo from EPA peroxidation. Chemical approaches coupled with gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) were used to structurally characterize these compounds as A(3)/J(3)-IsoPs. We found that levels of these molecules increase approximately 200-fold with oxidation of EPA in vitro from a basal level of 0.8 +/- 0.4 ng/mg EPA to 196 +/- 23 ng/mg EPA after 36 h. We also detected these compounds in significant amounts in fresh liver tissue from EPA-fed rats at basal levels of 19 +/- 2 ng/g tissue. Amounts increased to 102 +/- 15 ng/g tissue in vivo in settings of oxidative stress. These studies have, for the first time, definitively characterized novel, highly reactive A/J-ring IsoP compounds that form in abundance from the oxidation of EPA in vivo.

Use of Terrestrial Based Lipids in Aquaculture Feeds and the Effects on Flesh Organohalogen and Fatty Acid Concentrations in Farmed Atlantic Salmon

Consumption of salmon, wild or farmed, has been encouraged by many scientists and by national and international health organizations due to the potential health benefits associated with their high contents of omega-3 (n-3) highly unsaturated fatty acids (n-3 HUFAs). In 2004, there was increased public concern regarding the safety of farmed Atlantic salmon following the publication of several studies that indicated higher levels of organohalogens in their flesh relative to those noted in the flesh of wild Pacific salmon. Farmed salmon obtain most of these contaminants from the consumption of marine fish oil (MFO) present in salmon feed. In both a laboratory feeding trial and an on-farm field study, partial replacement of MFO in aquaculture feeds with economical and abundant lipids of terrestrial origin resulted in farmed Atlantic salmon with reduced flesh polychlorinated biphenyl and polychlorinated dibenzodioxin and furan concentrations. Flesh levels of n-3 HUFAs (g/(100 g serving)) were lower in farmed Atlantic salmon fed diets with alternative lipids relative to farmed salmon fed more traditional MFO-based diets. However, the former salmon were found to have higher flesh levels of n-3 HUFAs and also similar or lower flesh levels of organic contaminants than some species of market-size wild Pacific salmon. These findings showthat consumption of either farmed Atlantic salmon or wild Pacific salmon can meet recommended weekly n-3 HUFA levels with minimal concurrent intake of flesh organohalogens.

Comparison of Soy and Fish Oils in Practical Diets for Fingerling Walleyes

AbstractA 63‐d feeding trial was conducted to compare growth and other performance variables of feed‐trained juvenile walleyes Sander vitreus fed an open‐formula diet containing 10% soy oil (SO) as a replacement for 11.75% Atlantic menhaden Brevoortia tyrannus oil that is used in the commercially manufactured walleye grower diet (WG). The SO diet was formulated to be identical to the WG formulation except for the oil. The feeds contained 46% crude protein and similar gross energy (SO: 1,121 J/g; WG: 1,192 J/g). Fish were stocked (209 fish; 5.1 g/L) into triplicate 1,000‐L tanks. Fish were fed 7% body weight/d during a 16‐h light period with in‐tank lighting. Juvenile walleyes were 157 d old, 124 ± 1.0 mm in total length (mean ± SE), and 24.4 ± 0.71 g at the start of the trial. Differences between treatment in relative growth, specific growth rate, survival, final mean length, and mean weight between treatments were not statistically significant. Although derived from a short‐term trial, the findings suggest that SO at 10% is a suitable replacement for nearly 12% marine fish oil in a feed for juvenile walleyes. In 2007, the cost of Atlantic menhaden oil in the WG formulation was 1.6‐fold greater (US.39/0.454 kg) than that of the SO (.29/0.454 kg) used in the diets.

Effects of dietary fish oil replacement with vegetable oils on growth and tissue fatty acid composition of humpback grouper, Cromileptes altivelis (Valenciennes)

The replacement of dietary marine fish oil with vegetable oils was examined in fingerling humpback grouper, Cromileptes altivelis, over the course of an 8-week growth trial. Five isolipidic (10%) and isoproteic (50%) fish meal-based practical diets were formulated to contain iso-ingredients but with different sources of lipids [crude palm oil (CPO), refined, bleached and deodorized, palm olein (RBDPO), soybean oil (SBO) or canola oil (CNO)], and their performance was compared with the control diet, which contained cod liver oil (CLO) as the added lipid source. The experimental diets were fed close to apparent satiation twice a day to triplicate groups of fish (10.6 ± 2.2 g). The grouper fingerlings were randomly distributed into groups of 12 fish in cylindrical cages (61 cm depth and 43 cm diameter) that were placed in a 150 tonne polyethylene seawater tank. There were no significant differences (P>0.05) in terms of growth, survival, feed conversion ratio, protein efficiency ratio, net protein utilization, hepatosomatic index and condition factor among fish fed the various dietary treatments. Similarly, the dietary lipid source did not significantly affect the whole body proximate composition of the fish. Muscle and liver fatty acid composition of fish was influenced by the experimental diets. Replacement of dietary CLO with CPO, RBDPO, SBO or CNO produced fish with lower n-3 highly unsaturated fatty acids and increased levels of 18:2n-6 in the muscle and liver. The n-3:n-6 fatty acid ratio in the muscle of fish fed the CLO-based diet was 3.0 compared with 0.5-0.8 in the muscle of fish fed the various vegetable oil-based diets. The present study demonstrated that various vegetable oils can be used in fish meal-based dietary formulations for humpback grouper without compromising growth or feed utilization efficiency. © 2008 The Authors.

Artificial rearing with docosahexaenoic acid and n-6 docosapentaenoic acid alters rat tissue fatty acid composition

Docosahexaenoic acid (DHA; 22:6n-3) and n-6 docosapentaenoic acid (DPAn-6; 22:5n-6) are components of enriched animal feed and oil derived from Schizochytrium species microalgae. A one generation, artificial rearing model from day 2 after birth onward (AR) and a dam-reared control group (DAM) were used to examine DPAn-6 feeding on the fatty acid composition of various rat tissues at 15 weeks of age. Four AR diets were based on an n-3 fatty acid-deficient, 18:2n-6-based artificial milk with 22:6n-3 and/or 22:5n-6 added: AR-LA, AR-DHA, AR-DPAn-6, and AR-DHA+DPAn-6. The 22:6n-3 levels for the DAM, AR-DHA, and AR-DHA+DPAn-6 groups tended to be similar and higher than in the AR-LA and AR-DPAn-6 groups. The levels of 22:5n-6 tended to be higher only in the absence of dietary 22:6n-3. Adipose levels of 22:5n-6 was the only exception, as 22:5n-6 was significantly higher in AR-DHA+DPAn-6 than was observed in either the DAM or the AR-DHA group. There were no differences in 20:4n-6 levels within the tissues examined. In conclusion, 22:5n-6 replaces 22:6n-3 in the absence of 22:6n-3 only and does not appear to compete with 22:6n-3 in the presence of dietary 22:6n-3, suggesting that oils containing 22:5n-6 and 22:6n-3 may be a good dietary source of 22:6n-3.

Effects of Diets with or without Menhaden Fish Meal and Oil on Egg Size, Hatchability, and Fry Size for Rosy Red Fathead Minnow

AbstractFathead minnow Pimephales promelas represent 20% of total baitfish sales in the USA. Fathead minnow spawn in captivity, but the effects of diet on reproduction are virtually unknown. The objective of this study was to determine the main and interactive effects of dietary protein sources (plant versus animal) and lipid sources (poultry versus fish oil) on fathead minnow broodstock and egg and larval quality. Broodstock of the rosy red variety of fathead minnow were stocked into 24 outdoor pools and fed practical diets containing 10% lipid as poultry fat or menhaden fish oil in combination with animal proteins (poultry and fish meal) or plant proteins. Fish received the diets for 2 months before spawning, which began in late February. Eggs were collected from spawning substrates seven times during the spawning season and egg diameter was determined each time. Hatching percentage and larval length were determined during three of the sampling periods, and fatty acid composition was determined once (May sample). There were no differences in egg diameter, hatching percentage, or larval length due to diet, despite pronounced differences in the fatty acid composition of the eggs from adults fed diets with different lipids. The eggs reflected the fatty acid composition of the dietary lipids and the ability of fathead minnow to elongate and desaturate the fatty acids 18:2(n‐6) and 18:3(n‐3) into the highly unsaturated fatty acids 20:5(n‐3), 22:6(n‐3), and 20:4(n‐6). Adult female fathead minnow fed diets with vegetable proteins also had a higher condition index than those fed diets with animal proteins. These results indicate that poultry fat and vegetable proteins are suitable feed ingredients for broodstock diets of fathead minnow in outdoor systems because no improvements in the quantity or quality of eggs and fry were observed in fish fed diets with animal proteins or marine fish oil.

Effect of the combined supplementation of diets with increasing levels of fish and linseed oils on yolk fat composition and sensorial quality of eggs in laying hens

Yolk fatty acid (FA) concentrations and egg quality were evaluated with respect to the inclusion of different levels of marine fish oil (MFO) and linseed oil (LO) in a basal diet. Ten diets were arranged factorially with two levels of MFO addition (15 and 17 g/kg) and five levels of linseed oil (1, 2, 3, 4 and 5 g/kg). Two commercial feeds with no n-3 FA sources added, or containing 15 g MFO/kg served as controls for egg sensorial quality traits. Type of diet did not affect egg production traits, nor total fat content in yolk or saturated and monounsaturated FA concentration in yolk fat. An increase in the inclusion of MFO from 15 to 17 g/kg increased (P<0.05) egg yolk content of total n-3 FA, C 20:5 n-3 and C 22:6 n-3 by 3.3, 9.8 and 3.5%, respectively. Linseed oil addition increased linearly (P<0.001) the level of total n-3 FA and the proportion of C 18:3 n-3, C 20:5 n-3, C 22:5 n-3 and C 22:6 n-3 retained in yolk fat by respectively 131, 12.0, 6.9 and 20.7% between extreme diets. Efficiency of retention of n-3 FA decreased (P<0.001) with dietary level of n-3 FA, and with the dietary ratio of MFO to LO. Both MFO and LO addition decreased (P<0.001) C 20:4 n-6 to C 18:2 n-6 ratio in yolk. Sensorial quality of eggs was not affected by treatments and did not differ with respect of that obtained in commercial n-3 FA enriched eggs. No interaction was found between LO and MFO addition for any of the traits studied. Regression equations have been calculated in order to predict efficiency of retention and yolk fat content of LC n-3 and n-6 FA from dietary characteristics.

Effect of dietary source of very long chain n-3 polyunsaturated fatty acids on their concentrations in the edible tissues of the chicken

The benefits to human health from consuming the very long chain n-3 polyunsaturated fatty acids (VLC n-3 PUFA) 20:5 (EPA) and 22:6 (DHA) are well known. In the human diet, oil-rich fish is a key source of VLC n-3 PUFA but fish consumption is so low that VLC n-3 PUFA intake is well below the minimum recommended. Other vehicles for increasing dietary supply have been explored and chicken meat is a potentially important contributor to human intakes if it is enriched with VLC n-3 PUFA, as it is responsive to dietary manipulation and is widely consumed. Enrichment of chicken meat can be achieved by supplementing the diets of growing birds with fish oil. However, reliance upon fish oil for this purpose is potentially unsustainable and the meat that is produced is more susceptible to constraints associated with its oxidative stability and organoleptic properties. Alternative sources of these fatty acids include marine algae (the primary producers of VLC n-3 PUFA) and fish oil encapsulated in a gelatin capsule. Both of these alternatives may increase the VLC n-3 PUFA content of the meat and also enhance its oxidative stability compared with meat that has been enriched by the inclusion of fish oil in the broiler diet. The objective of this study was to compare different sources of VLC n-3 PUFA in the broiler diet in relation to their effects on EPA and DHA concentration of the white and dark meat of the chicken.

The use of palm oil in aquaculture feeds for salmonid species

AbstractIn this overview, our current knowledge and research being conducted on the use of palm oil in the commercial feeds for cold‐water salmonid species such as Atlantic salmon and rainbow trout will be highlighted. Salmonid diets have a high lipid content to provide a source of easily available energy and also n‐3 polyunsaturated fatty acids (PUFA) which is used to maintain membrane fluidity in a cold‐water environment. The culture of salmonid fishes has traditionally depended on marine fish oils for this purpose, but with limited supplies and the rapid increase in salmon production, alternatives to fish oils must be investigated. Research has shown that crude palm oil can be used to replace 100% of added fish oils in salmonid diets without compromising growth performance and feed utilization efficiency, despite reductions in lipid and fatty acid digestibilities that occur during low water temperatures over the winter rearing period. Fatty acid desaturation and elongation activities increased with increasing dietary palm oil and, to a certain extent, decreasing water temperatures. The effects of palm oil on fish health requires further research, but the use of this more saturated vegetable oil may reduce oxidative stress in fish, thereby reducing pathological conditions associated with this physiological state. It is generally known that the fish fillet fatty acid composition directly reflects that of the dietary oil used. Extrapolating from work done with other vegetable oils, the supply of beneficial n‐3 PUFA in salmon fillets to the human consumer can be maintained by using a finishing diet strategy just prior to harvesting, despite significant reductions in these fatty acids when high levels of dietary palm oil are used in grower feeds. Compared to vegetable oils such as soybean or rapeseed oil, palm oil has several advantages in terms of high oil productivity, lower cost, less deposition of undesirable fatty acids such as 18:2(n‐6), superior energy source in the form of saturated and monounsaturated fatty acids, and a high content of natural antioxidants (carotenes and vitamin E). Fillet texture and color were not affected by feeding salmon palm oil‐based diets.

Effect of Combination Lipid-Modifying Therapy on the Triglyceride Lowering Effect of Fish Oil

Marine fish oil supplements are frequently administered with other lipid medications for treatment of hypertriglyceridemia. The efficacy of fish oil may be reduced in the presence of other lipid agents, particularly fibrates that also act as PPARalpha agonists. We therefore sought to determine the efficacy of fish-oil supplements when coadministered with other lipid-modifying agents. Patients receiving fish oil supplements were identified from the computer database of a large governmental HMO. Change in plasma lipoprotein levels after administration of fish oil was compared between patients receiving fish oil as their only treatment and those for whom fish oil was added to other drugs. A total of 166 evaluable records were identified, 66 from patients treated with fish oil alone and 100 from patients for whom fish oil was added to another agent or other agents. Fish oil effectively reduced triglyceride levels to an equal extent in the fish oil only and fish oil added groups (-30% versus -27% respectively; P = 0.84). Fish oil effectively reduces plasma triglyceride levels when administered with concomitant lipid medications. These findings suggest the presence of additional and even complementary mechanisms of action of fish oil to lower triglyceride when added to other lipid drugs. These findings validate the common clinical practice of combining fish oil supplements with other lipid-lowering medications in patients with hypertriglyceridemia.