Dogfish Liver Oil Research Articles

Asymmetric Synthesis of Methoxylated Ether Lipids: Total Synthesis of Polyunsaturated C18:3 Omega-3 and Omega-6 MEL Triene Derivatives.

The asymmetric synthesis of polyunsaturated triene C18:3 n-3 and C18:3 n-6 methoxylated ether lipids (MEL) of the 1-O-alkyl-sn-glycerol type is described as possible structural candidates for a triene C18:3 MEL of an unknown identity found in a mixture of shark and dogfish liver oil. Their C18:3 hydrocarbon chains constitute an all-cis methylene skipped n-3 or n-6 triene framework, along with a methoxyl group at the 2'-position and R-configuration of the resulting stereogenic center. The methoxylated polyenes are attached by an ether linkage to the pro-S hydroxymethyl group of the glycerol backbone. The syntheses were based on the polyacetylene approach that involves a semi-hydrogenation of the resulting triynes. Both syntheses were started from our previously described enantio- and diastereomerically pure isopropylidene-protected glyceryl glycidyl ether, a double-C3 building block that was designed as a head group synthon for the synthesis of various types of MELs.

Using Compound-Specific Carbon Stable Isotope Analysis of Squalene to Establish Provenance and Ensure Sustainability for the Deep-Water Shark Liver Oil Industry

Deep-water dogfish (sharks) are caught on Australia’s continental shelf as by-products to other deep-water species with revenue derived from fillets for human consumption and from the livers which are sold for their oil content. Deep-water dogfish utilise a large oil-rich liver for buoyancy, which may account for 20–25% of their body weight. An important constituent of certain dogfish liver oil is squalene, a highly unsaturated triterpenoid (C30H50) hydrocarbon which in some species can be up to 90% of the oil, though in the Australian commercial species it is typically around 50%. Squalene (and deep-water dogfish liver oil in general) has a long-standing high value in products, such as cosmetics and nutraceuticals. Manufacturers are increasingly required to demonstrate the sustainability of products, and this is integral to the importance of demonstrating product provenance. Australia’s mid-slope deep-water dogfish fishery is recognised globally as well managed and sustainable; therefore, it is important to be able to distinguish products derived from these regions from other unregulated, unsustainable and cheaper sources in order to protect Australia’s competitive advantages and ensure sustainability. In this study, we have sourced deep-water dogfish liver oil samples originating from Southeast Australia, New Zealand, India, Northeast Africa and the Arabian Sea. The squalene was isolated by commercial or laboratory processing. A compound-specific carbon stable isotope analysis of the derived squalene was then used to determine isotopic resolution and assign the likely origins of a variety of commonly available off-the-shelf nutraceuticals in Australian outlets. Squalene sourced and produced from Southeast Australian and New Zealand dogfish liver oils showed δ13C values in the range of −22.1 to −24.2‰, with all other squalene samples distinguishable at −19.9 to −20.7‰. Many of the off-the-shelf squalene products claiming to be of Australian origin showed δ13C values very distinct from the range of the genuine Southeast Australian- and New Zealand-produced squalene.

Effect of antioxidant compounds from seaweeds on storage stability of C20-22 polyunsaturated fatty acid concentrate prepared from dogfish liver oil

Ethyl acetate extracts of seaweeds were chromatographically fractionated to yield 14-methyl pentyl tetrahydro-8-hydroxy-10-methylnaphthalene–8-carboxylate (1) and tetrahydro-4-isopropyl-9-(9, 14-dimethyldec-9-enyl)-pyran-1-one (2) from Sargassum ilicifolium, whereas Padina gymnospora afforded dihydro-2-(10-(hydroxymethyl)-7,15-dimethyl-9-oxoundec-11-enyl)-2-methyl-2H-pyran-1(4H)-one (3) and 1-(decahydro-1-hydroxy-7-methyl-8-vinylnaphthalen-2-yl)ethanone (4) as major constituents. Compound 1 displayed significantly higher antioxidant activity (IC50 < 1 mg/mL, p < 0.05) comparable to other analogues (IC50 > 1 mg/mL). The C20-22 polyunsaturated fatty acid (C20-22 PUFA) concentrate (CFA) prepared from the deep-sea dogfish liver oil was added with the studied compounds and physiochemical properties and fatty acid composition during an accelerated storage were evaluated. No significant reduction in C20-22 PUFAs (∼6%) in the CFA treated with 1 as compared to that with the control (∼35%) was recorded. A greater induction time was observed for the CFA supplemented with 1 (6.8 h) than other compounds (≤6 h) and control (∼1.6 h), maintaining the oxidation indices of the CFA within desirable limits.

Evaluation of cleaning of dogfish liver Oil

Integrated and rational processing of raw materials involves the most complete use of organs and tissues of hydrobionts, which ensures the first generation of food products, as well as forage, technical and special purpose. In many countries, вщпашір is a promising raw material for the food industry. However, the expediency of using the domestic Black Sea dogfish for food production requires the necessity of systematic studies of dimensional-mass characteristics, morphological characteristics, chemical composition, structural-mechanical, physical, and rheological properties, etc. The purpose of the study is to assess the survival of the dogfish liver Oil through the determination of the basic physical and physicochemical indices of the Oil of the Black Sea dogfish, which characterize its biological efficiency and quality changes during storage. The subject of the study is the Oil from the liver of dogfish, comparing with the Oils from the cod and salmon liver. The technology of obtaining the Oils from the cod and salmon liver involves the application of the cold pressing method we developed with the addition of the kitchen salt. The investigated product meets the established requirements for the content of free fatty acids of fat, which is characterized by an acid number. The method of gas chromatography was used to determine the fatty acid composition of the Oils from the cod and salmon liver. The analysis of the fatty acid composition shows that in the selected Oils from the cod and salmon liver is dominated by monounsaturated fatty acids that act as a source of energy. By calculation, the molar mass of Oils from the cod and salmon liver is 285,8326 g / mol. Molar mass is an important characteristic that should be taken into account when modeling the storage, transport or processing of fish oil. Thus, it has been established that the lowest density of the molecule has fat from the shark of a low-temperature storage catrrane. The mass of a drop of all fats in the range of 0,0225-0,0226 х10-3 kg.

Similarities in the lipid class profiles of oils from Atlantic and Pacific dogfish livers

AbstractLiver oils from Atlantic and Pacific dogfish (Squalus acanthias) have been compared for lipid classes, fatty acids of the total oil and of important lipid classes, and details of the alkyl chains in the 1‐O‐alkyl‐2,3‐diacylglycerol ethers (DAGE). In general there were few striking differences, confirming the view of biologists that these sharks are one species. The Pacific dogfish liver oil had a higher content (41.2%) of DAGE than the oil from Atlantic dogfish (18.2%). Both oils had all common and expected fatty acids in the proportions usual for marine oils, but they differed in the eicosenoic chains of the glycerol ethers (GE). The Pacific oil was unusual in having low but similar proportions of two alkyl chain isomers, 20:1n‐11 and 20:1n‐9. The Atlantic oil was very high in the 20:1n‐11 isomer, which is usually lower than 20:1n‐9 in the fatty acids of most regional marine oils. Unexpectedly, the DAGE of both oils had further unusual 20:1 isomer proportion in the GE chain, with 20:1n‐7 &gt;20:1n‐9. Minor oddities in the fatty acids may reflect different basic food sources.

Solubility of Fish Oil Components in Supercritical CO2 and CO2 + Ethanol Mixtures

Solubility measurements for squalene, vitamin A palmitate, orange roughy oil, spiny dogfish liver oil, and commercial cod liver oil in supercritical carbon dioxide are reported over the temperature range 313−333 K and pressure range 200−300 bar. Solubility measurements are also reported for squalene, orange roughy oil, spiny dogfish liver oil, and cod liver oil in supercritical carbon dioxide + ethanol mixtures over the pressure range 200−300 bar at 333 K, and ethanol mass concentrations up to 12% by mass on a solute free basis. The use of ethanol as an entrainer substantially increased the solubility of all fish oil components. The increase in solubility, S, with ethanol concentration at fixed temperature and pressure was correlated by the empirical equation S = S0 exp(kX), where S0 is the solubility in pure CO2 at given temperature and pressure, k is a fitted constant, and X is the mass fraction of ethanol on a solute-free basis.

Preparation of polyunsaturated fatty acid concentrates from the liver oil of dogfish (&lt;i&gt;Squalus acanthias&lt;/i&gt;) from the Black Sea.

The fatty acid composition of the liver oil from the Black Sea dogfish Squalus acanthias , as well as its seasonal variations were determined. A scheme for concentration of polyunsaturated fatty acids from the dogfish liver oil by urea complexation was proposed. From 360g of free fatty acids a 48g concentrate was obtained, containing 7,8% C 20:4 , 16,4% C 20:5 . 9,2% C 22:5 and 49,7% C 22:6 .

Digestion of the 1-O-alkyl diacylglycerol ethers of Atlantic dogfish liver oils by Atlantic salmon Salmo salar.

Dogfish (Squalus acanthias) liver poses a waste disposal problem in Canada because it is not utilized for any commercial purpose. The liver of Atlantic dogfish, which is often up to 20% of the weight of the fish, contains 40-70% oil. The oil contains about 30-40% 1-O-alkyl diacylglycerol ethers (DAGE) which render it unacceptable for human use, and it has also not been considered satisfactory for animal feed use. Polyunsaturated fatty acids (20:5n-3 and 22:6n-3) are present in dogfish liver oils at levels comparable to those in herring oil. Dogfish liver oil could be a source of essential fatty acids for Atlantic salmon (Salmo salar), but their ability to hydrolyze DAGE from dogfish oil has not been examined. Experiments were designed to measure the digestibility of fatty acids of DAGE in salmon. The fatty acid moieties were liberated by the digestive enzymes of the fish and made readily available as a source of energy. The 1-O-alkylglycerol ether moiety was absorbed to a small extent but should not constitute a health problem in either the fish or the human fish consumer. The long-chain polyunsaturated fatty acids were particularly well absorbed, with an apparent digestibility in salmon of 87-95% when feeding on dogfish liver oil. The total fatty acids and other lipids were in fact both absorbed to the extent of approximately 85%.

Methods of extraction composition and stability of vitamin A and other components in dogfish ( Squalus acanthias) liver oil

Oil was extracted from dog fish ( Squalus acanthias) livers by the Bligh and Dyer, Soxhlet and steaming extraction methods. Oil yields using the steaming method (22% w w ) were lower than from the solvent extraction methods (68% w w ). The vitamin A content of the oil produced by steaming was 54 mg retinol/100 g oil, and slightly higher (62–68 mg/100 g) contents were recorded in the solvent extracted oils. The Bligh and Dyer extraction produced an oil containing 12% phospholipid, much higher than the 4% via the Soxhlet and 1 % in the steaming extractions. The level of squalene (40 mg/100 g) in the oil produced by steaming was higher than in the other oils (28 and 32 mg). Concentrations of vitamin E and cholesterol were similar in all three oils at approximately 25 mg tocopherol/100 g and 1.1 g cholesterol/100 g, respectively. Oils were stored under air at room temperature in half filled dark coloured bottles. Although highest PVs were observed in the stored Bligh and Dyer-extracted oils, the highest apparent loss of vitamin A (30% in 3 weeks) occurred in the oil extracted by steaming.

Hydrocarbons of dogfish and cod livers and herring oil.

AbstractDogfish and cod liver oils and the oil from the whole herring were saponified and the hydrocarbons concentrated by chromatography of the unsaponifiable portion over alumina followed by silica gel treatment of the resulting fractions. Temperature programmed gas chromatography employing a 3% SE‐30 packing was applied to the analysis of hydrocarbons of C14 to C32.5. The paraffins comprised two or more groups. Dogfish liver oil gave rise to 7.62% unsaponifiables and pristane, other saturated types, squalene and an additional group, high in unsaturated components, were 193, 325, 308 and 200 mg% in this portion or 15.7, 24.8, 23.5 and 15.3 mg%, respectively, in the oil. Cod liver oil yielded 1.0% unsaponifiables of which the above hydrocarbons in the order stated amounted to 0.30%, 1.15%, 3.29% and 2.27% or 3.0, 11.5, 32.9 and 22.7 mg% in the liver oil. The unsaponifiable material of herring oil (1.35%) was prominent in paraffinic hydrocarbons, the levels of the above specified components being 16.34%, 3.51%, 0.99% and 1.41% as stated or 221, 47.4, 13.4 and 19.1 mg% in the oil. The sterol and alcoholic contents were ascertained for the three marine oils and the glyceryl ether levels found to be highest for dogfish liver oil.

Studies on the preparation and analysis of glyceryl ether derivatives and the isolation and reductive ozonolysis of unsaturated glyceryl ethers

Glyceryl ethers were identified and quantified by the GLC analysis of their alkyl iodide (special conditions described), acetonide and allyl alkyl ether derivatives. The acetoxy-mercuri-methoxy derivatives of unsaturated glyceryl ether swere separated from saturated glyceryl ethers by TLC and the fractions were analyzed as alkyl iodides. Monoiodides from saturated glyceryl ethers and diiodides from unsaturated glyceryl ethers were also separated by TLC and then analyzed. Allyl alkyl ethers had small retention volumes and these derivatives were separated into pure fractions by preparative GLC. Ozonides were reduced either to alcohols with lithium aluminum hydrodie or to aldehydes with dimethyl sulfide. The alcohols were converted to mono- and diiodides which were separated by TLC and analyzed by GLC. The recovery of n-C(6) and n-C(7) monoiodides was not quantitative. Diiodides and aldehydes were both identified and quantified by GLC. Ozonolysis data suggest that the 16ratio1 glyceryl ethers from dogfish liver oil contain 7,8 and 9,10 isomers and the 18ratio1 glyceryl ethers contain 9,10 and 11,12 isomers.

Chemical synthesis of 1- O-(D)- and 3- O-(L)-glyceryl monoethers, diethers and derivatives: Glycerides, monoester phospholipids and diether phospholipids

1. 1. A convenient route to the synthesis of 1- O-glyceryl ether from 3- O-glyceryl ether is reported. This technique, which is based on the procedure of Lands and Zschocke 35 for conversion of 3- O-benzylglycerol to 1- O-benzylglycerol, utilized either 3- O-hexadecylglycerol or 3- O-octadecylglycerol as the starting material. The ether was converted to its ditosylate and this latter group was displaced with freshly fused potassium acetate in anhydrous ethanol. Alkaline hydrolysis yielded the desired 1- O-alkyl glycerol, with an equal but opposite optical rotation to the starting material, in good yields. 2. 2. 1- O- cis-9'-Octadecenyl-2- O-octadecanoylglycerol (2-stearoyl selachyl al-cohol) was synthesized by borate replacement of 1- O- cis-9'-octadecenyl-2- O-octade-canoyl-3- O-tritylglycerol in triethyl borate and boric acid, followed by column chromatography on neutral silicic acid. Catalytic amounts of HClO 4 isomerizes 2-stearoyl selachyl alcohol completely to its positional isomer 3-stearoyl selachyl alcohol. Acylation of 1- O-cis-9'-octadecenylglycerol in the presence of up to 2 M excess of acyl chloride, was found to occur preferentially at the primary hydroxyl group forming 3-stearoyl selachyl alcohol and the diacyl derivatives (dipalmitoyl, dioleoyl and distearoyl selachyl alcohol) formed in good yield only when a 4–6 M excess of acyl chloride was used. The properties of the synthetic diacyl-glyceryl derivatives correlated closely with the natural diacyl-glyceryl monoether isolated from dog fish liver oil. 3. 3. 1,2-Di- O- cis-9'-octadecenylglycerol which was synthesized by acid hydrolysis of its trityl derivative was converted to the corresponding phosphorylethanolamine and phosphorylcholine derivatives; 2- and 3-stearoyl selachyl alcohol were converted to their phosphoryl ethanolamine and phosphorylcholine derivatives. The physical properties of the monoethers, monoacyl monoethers, diethers and their corresponding phospholipids are tabulated and discussed. Comparable results in properties between the synthetic 1- O- cis-9'-octadecenyl-2- O-octadecanoyl-3-glycerophosphorylethanolamine and the natural monoether monoacyl glycerophosphorylethanolamine isolated from bovine erythrocytes were found.

Studies of the distributions of lipids in hypercholesteremic rats: 3. Changes in hypercholesteremia and tissue fatty acids induced by dietary fats and marine oil fractions

The hypocholesteremic activities of dogfish liver oil and tuna and menhaden oils were duplicated by feeding rats proportionate amounts of the fatty acid components of the oils; neither selachyl alcohol nor the unsaponifiable components of the oils affected the hypercholesteremia of the rats. The relative hypocholesteremic activities of menhaden oil fatty acid ester fractions (I.V. of 48.6–353) were not predictable on the basis of such criteria as their total unsaturation, contents of polyunsaturated fatty acids (PUFA), or contents of more saturated acids. The hypocholesteremic activity of the fraction with an iodine value of 48.6 was similar to that of corn oil (I.V. = 124). Only minor amounts of the linolenate homologues were required to promote significant reductions in the cholesterol contents of the livers in these rats. Rats fed tallow-PUFA mixtures incorporated little of the available PUFA into the cholesterol esters of their tissues. However, a homeostatic mechanism appeared to regulate the incorporation of appreciable and uniform amounts of available PUFA into the plasma phospholipids and myocardia of the rats. The PUFA patterns in the plasma and liver suggested that the preconditioned animals had a partial depletion of the essential fatty acid (EFA) reserves for these tissues. However, a very adequate supply of EFA was apparently available for the myocardial tissues of these same rats. The fractionation of marine oils and some modified methods for lipid analyses are discussed.

The Effect of Excessive Amounts of Dietary Vitamin A on Egg Production in White Leghorn Hens

ALTHOUGH adequate amounts of vitamin A are necessary for the normal metabolism of animals, and humans, it is well known that excessive quantities of the vitamin can prove harmful. Giroud and Martinet (1954) reported that large amounts of dietary vitamin A adversely affected the reproductive ability of the rat and a similar conclusion was reached by Friend and Crampton (1961) in their studies with mink. During the course of an investigation in these laboratories on cholesterol metabolism in White Leghorn chickens (Wood, Biely and Topliff, 1961) it was observed that the presence of dogfish liver oil in the diet resulted in a cessation of egg production. Since the oil was rich in vitamin A it was thought that perhaps this was due to the massive doses of vitamin A ingested by the birds. The present investigation was carried out to ascertain whether vitamin A did interfere with egg production, and …

水産動物内臓油利用に関する研究-IX

From the viewpoint of opening the use of residual oil brought forth in preparing a concentrated product of vitamin A by molecular distillation, a few investigations were advanced into the technique of obtaining from molecular distillation residue of dogfish liver oil a concentrated preparation of glyceryl ether as well as into the surface-active properties of the preparation thus obtained. In the first part of the present work, a sample of dogfish liver oil as starting material was hydrolyzed by following the routine saponification procedure, unsaponifiable matters were separated and these matters were then collectively submitted to molecular distillation (see Table 1). From the sum of distillate fractions 2, 3 and 4, there was thus obtained through the trial of taking out glyceryl ether from said kind of residual oil in which the ether had been known to be present as resistive to molecular distillation a concentrated preparation of glyceryl ether containing selachyl alcohol as main constituent and having an acetyl value of 246-257.6 and an iodine value of 82.1-87.9 with an yield of 5.36% based upon the amount of starting material. Then, by hydrogenating the preparation of glyceryl ether and recrystallizing the hydrogenation product in ethyl ether, a refined preparation as fine crystals was obtained, which had a melting point of 67.5°C and was proved by elemental analysis to contain C of 73.28% and H of 12.71%. These data may be looked upon to be in a close approximation to those for batyl alcohol appearing in literature. In the second part of the present work, measuring the interfacial tension between a kerosene solution of the concentrated preparation of selachyl alcohol and water (see Table 6 and Figs. I and 2), said preparation obtained as above from a molecular distillation residue of dogfish liver oil was examined in its aspect of surface-activity (see Tables 2, 3, 4 and 5). As seen from the values thus obtained, the interfacil tension between kerosene and water is strongly minimized by adding the former with selachyl alcohol as said type of concentrated preparation in an amount of 0.25-1%. It was found also that, with kerosene solution containing said preparation in amounts not in excess of 1%, selachyl alcohol exerts the greater ability of lowering the interfacil tension between kerosene and water at the lower temperature, insofar as the temperature concerned is in the range of 20-60°C. Further, to estimate the emulsifying power of said concentrated preparation of selachyl alcohol, two similar series of samples were prepared, which consisted of refined coconut oil added with said selachyl alcohol preparation, on the one hand, and mono fatty acid glyceryl ester, on the other, up to various concentrations ranging from 0.5 to 4%, and these samples were compared with one another in respect of the emulsifying effect they developed in water. According to the result obtained (see Table 7), the two substances examined were both found to be fairly good in emulsifying power. As to the state of emulsion they produce, however, these substances used as emulsifyer were observed to behave somewhat differently from each other. Thus, when the breakdown of emulsion commences, while the emulsion prepared with mono fatty acid glyceryl ester begins to separate an aqueous layer, that prepared with the concentrated preparation of selachyl alcohol does so an oily layer.

The effect of diet, age, and sex on cholesterol metabolism in white leghorn chickens.

The cholesterol metabolism of chickens differed in birds of different age and sex. The normal serum cholesterol levels were higher in females than in males and higher in 1-week-old chicks than in mature birds of the same sex. Laying hens were less susceptible to hypercholesterolemia induced by dietary cholesterol than were mature cockerels or young chicks of either sex. Corn oil tended to increase the degree of hypercholesterolemia in all cholesterol-fed birds except young cockerels. A vitamin-A-rich oil, dogfish liver oil, decreased the rise in serum cholesterol level in cholesterol-fed chicks of both sexes, but in mature birds it produced the opposite effect. The addition of 1% cholesterol to the control diet of hens increased the yolk cholesterol concentration of eggs laid by the birds and this increase in concentration was greatly enhanced if 10% corn oil was also present in the diet.

Monoenoic fatty acids in dogfish livers: isomers of the C16, C18, C20, and C22 series.

SummaryStructural isomers of monoenoic fatty acids in dogfish (Squalus acanthias) liver oil were determined. These fatty acids comprised 58% of total fatty acids and 87% of unsaturated fatty acids of the oil. Although it is known that polyunsaturated C20 and C22 fatty acids are present in quantity in most fish oils, dogfish-liver oil was found to contain substantial amounts of C20 and C22 monoenoic fatty acids as well. The following isomers were found in the oil: cis-9-hexadecenoic acid (6.1%), cis-9-octadecenoic acid (24.7%), cis-11-octadecenoic acid (9.8%), cis-9-eicosenoic acid (4.0%), cis-11-eicosenoic acid (5.1%), cis-11-docosenoic acid (6.7%), and cis-13-docosenoic acid (1.8%). It is suggested that most of the monoenoic fatty acids of dogfish-liver oil may be formed by addition of acetate units to oleic acid and other fatty acids having a Δ9 double bond.

Fatty Alcohols from Marine Oils and Segregated Esters

Fatty alcohols were prepared by lithium aluminium hydride reduction of the three main methyl ester fractions obtained by countercurrent extraction of methyl esters from herring oil.Alcohols were also prepared by the same method from commercially important Canadian marine oils, e.g. cod oil, cod liver oil, seal oil, herring oil and dogfish liver oil, and their properties tabulated.A comparison was made between the sodium reduction method and the lithium aluminium hydride method in the reduction of methyl esters from herring oil and their effect on producing conjugation of the ethylenic double bonds.

A Substance in Lingcod Liver Oil which prevents Hypercholesterolæmia in Cholesterol-fed Chickens

THE serum cholesterol-level in some animals is elevated above the normal value by the addition of cholesterol to the diet. In certain species, such as the chicken, cholesterol by itself brings about this increase; but in other species, exemplified by the rat, the presence of cholic acid is also required. The degree of hypercholesterolaemia is altered when certain vegetable and fish oils are added to the diet; but the observed effect of any one oil is dependent on the species of animal under investigation. De Groot and Reed1 showed that cod liver oil and corn oil prevented the increase in plasma cholesterol in rats due to dietary cholesterol and cholic acid. Dam et al. 2 investigated the effect of dietary cod liver oil and linseed oil in cholesterol-fed chickens, and found that both oils increased the hypercholesterolaemia caused by the dietary cholesterol. Similar experiments on chickens were performed by Wood and Biely3 using corn oil, tallow and various fish oils. Corn oil, tallow and herring oil were observed to increase the hypercholesterolaemia; but lingcod liver oil and halibut liver oil completely prevented the appearance of hypercholesterolaemia. Ratfish liver oil, dogfish liver oil and basking shark liver oil were intermediate in effect. In view of the diverse effects of the oils observed in the chicken studies, further investigations were carried out to obtain additional information about the mode of action of the oils. Corn oil, herring oil and lingcod liver oil were chosen for the investigation.

THE EFFECT OF DIETARY MARINE FISH OILS ON THE SERUM CHOLESTEROL LEVELS IN HYPERCHOLESTEROLEMIC CHICKENS

An investigation was carried out into the effect of marine fish oils on the serum cholesterol levels in hypercholesterolemic chickens. The oils were fed at the 10% level in the diet. Lingcod liver oil and halibut liver oil prevented the hypercholesterolemic effect of supplementary cholesterol, whereas crude herring oil increased the hypercholesterolemia to the same extent as did corn oil and tallow. Ratfish liver oil, dogfish liver oil, and basking shark liver oil had less noticeable effects on the cholesterol levels. No clear explanation could be given for the observed behavior but there seemed to be a difference in the effects on serum cholesterol of liver oils from teleostei fish and from selachii fish, the former class of liver oils being much more potent in preventing the increase in serum cholesterol concentration in chickens caused by the addition of cholesterol to the diet.