Shark Liver Oil Research Articles

English

Shark liver oil (SLO) has been widely used as a food supplement to boost human immunity. The extraction method of shark liver oil is immature. In this study, four different extraction methods of shark liver oil were tried, the effect of the solid-liquid ratio, quality of the enzyme, reaction pH and temperature on SLO extraction rate have been discussed. Infrared spectroscopy, gas chromatography and high performance liquid chromatography was used to detect the main composition of SLO, and U14 tumor bearing mice were used to explore anti-tumor effect of SLO. Our results show that alkaline protease extraction method was the best with an extraction rate of 30.15%, and the solid-liquid ratio, quality of the enzyme, reaction pH and temperature was 1:2, 2% of the liver quality, 9, 3.5 h, 48°C respectively. Characteristic peak of alkoxy glycerol, squalene and vitamin A was presented in the IR spectra of SLO, the proportion of alkoxy glycerol, squalene content and vitamin was 35.3, 40.4 and 7.8% determined by gas chromatography (GC) and high performance liquid chromatography (HPLC). The inhibition rate was 54.56. Key words: Shark liver oil, extraction, characterization, gas chromatography, high performance liquid chromatography (HPLC).

Alkylglycerols reduce serum complement and plasma vascular endothelial growth factor in obese individuals.

Alkylglycerols (AKGs), isolated or present in shark liver oil have anti-inflammatory properties. Complement 3 (C3) and 4 (C4) participate in lipid metabolism and in obesity, contributing to the metabolic syndrome and to the low-grade inflammation associated with obesity. In a randomized, controlled, crossover study, 26 non-diabetes obese individuals were assigned two preparations with low (LAC, 10mg AKGs) and high (HAC, 20mg AKGs) AKG content. Intervention periods were of 3weeks preceded by 2-week washout periods in which shark liver oil was avoided. Cholesterol, C3, C4, and vascular endothelial growth factor (VEGF) decreased in a linear trend (P<0.01) from baseline (control) to LAC and HAC. Values after HAC were significantly lower (P<0.05) versus both baseline and after LAC. No adverse effects were observed or reported. Data from this pilot study open a promising field for the study of the beneficial effects of AKGs on cardiovascular risk factors in obese individuals.

Does shark liver oil have a potent antithrombotic effect in spontaneously hypertensive rats?

The present study was conducted with the aim to investigate the favorable effect of dose‐dependent effect of shark liver oil (SLO) on the improvement of blood circulation by enhancing endothelial function and antithrombotic effects against spontaneously hypertensive rats (SHRs). Rats were randomized into 5 groups (n=10/group): Wistar Kyoto (WKY) rat control; SHR control; SLO1 (45% squalene; 400mg/kg body weight); SLO2 (98% squalene; 400 and 1,020mg/kg). The test materials were administered orally on a daily basis with a normal diet for 8 weeks. 6‐week‐old male SHRs were given test materials by gavage feeding and blood pressure was recorded on a weekly basis. Blood pressure was significantly reduced in SHRs fed the 98% squalene high dose (1,020 mg/kg B.W) group compared to vehicle group (p&lt;0.05). Platelet aggregation induced by thrombin and adenosine diphosphate was significantly reduced in SHRs fed the 98% squalene low dose (400 mg/kg B.W) group compared to vehicle group. However, prothrombin time and activated partial thromboplastin time had no significant differences. Plasma prostaglandin‐I2 and thromboxane‐B2 levels were significantly different between WKY and SHR, however, there was no significant different between SHR and SLO‐treated SHRs. These finding suggests that SLO might have a favorable effect for improving blood pressure control and platelet aggregation regardless of dose dependency. In further study, phosphatidylinositol 3‐kinase‐Akt‐eNOS signaling pathway will be observed to elucidate the mechanism of the blood pressure response to SLO.Support or Funding Information* This work was supported by the Ministry of Science, ICT &amp; Future Planning (Bio‐synergy Research Project NRF2012M3A9C4048761) and BK21 PLUS through the National Research Foundation.

Selective cytotoxic effect of 1-O-undecylglycerol in human melanoma cells

Context: 1-O-alkylglycerols are ether-linked glycerols derived from shark liver oil and found in small amounts in human milk. Previous studies showed antineoplastic activity for this family of compounds, structurally related to alkylphospholipids, but the activity of linear chain synthetic alkylglycerols in cancer cell lines is less documented. Melanoma is a high incidence cancer, highly resistant to potential treatments. Finding new anti-cancer compounds to improve melanoma prognosis is a relevant research issue. Aims: To study the cytotoxic effect of 1-O-undecylglycerol in primary cultured normal fibroblasts and A375 human melanoma cell line. Methods: Cells were treated with different concentrations of 1-O-undecylglycerol and viability assessed by MTT assay. Morphological changes were visualized by DAPI and acridine orange-ethidium bromide staining. Mitochondrial membrane potential was evaluated, and gene expression of P53 and BcL-2 was semi-quantified. Results: 1-O-undecylglycerol decreased viability of A375 cells and exerted very low cytotoxicity on primary cultured normal fibroblasts. Necrosis appeared in A375 cells but not in fibroblasts, and no apoptotic changes were visualized in DAPI staining experiments. After 24 h fibroblasts and melanoma cells developed mitochondrial potential changes similar to valinomycin. The gene expression of P53 and BcL-2 decreased in treated cells. Conclusions: 1-O-undecylglycerol exhibited selective cytotoxic activity in A375 melanoma cells when compared with primary cultured fibroblast. Its toxicity is mediated by necrosis that may be related with mitochondrial events and decrease in P53 and BcL-2 expression. The results suggest that UDG could be a useful strategy to combine with other chemotherapeutic agents in melanoma treatment.

Advances in Biochemistry and Microbial Production of Squalene and Its Derivatives.

Squalene is a linear triterpene formed via the MVA or MEP biosynthetic pathway and is widely distributed in bacteria, fungi, algae, plants, and animals. Metabolically, squalene is used not only as a precursor in the synthesis of complex secondary metabolites such as sterols, hormones, and vitamins, but also as a carbon source in aerobic and anaerobic fermentation in microorganisms. Owing to the increasing roles of squalene as an antioxidant, anticancer, and anti-inflammatory agent, the demand for this chemical is highly urgent. As a result, with the exception of traditional methods of the isolation of squalene from animals (shark liver oil) and plants, biotechnological methods using microorganisms as producers have afforded increased yield and productivity, but a reduction in progress. In this paper, we first review the biosynthetic routes of squalene and its typical derivatives, particularly the squalene synthase route. Second, typical biotechnological methods for the enhanced production of squalene using microbial cell factories are summarized and classified. Finally, the outline and discussion of the novel trend in the production of squalene with several updated events to 2015 are presented.

Rapid Quantitative Determination of Squalene in Shark Liver Oils by Raman and IR Spectroscopy.

Squalene is sourced predominantly from shark liver oils and to a lesser extent from plants such as olives. It is used for the production of surfactants, dyes, sunscreen, and cosmetics. The economic value of shark liver oil is directly related to the squalene content, which in turn is highly variable and species-dependent. Presented here is a validated gas chromatography-mass spectrometry analysis method for the quantitation of squalene in shark liver oils, with an accuracy of 99.0 %, precision of 0.23 % (standard deviation), and linearity of >0.999. The method has been used to measure the squalene concentration of 16 commercial shark liver oils. These reference squalene concentrations were related to infrared (IR) and Raman spectra of the same oils using partial least squares regression. The resultant models were suitable for the rapid quantitation of squalene in shark liver oils, with cross-validation r (2) values of >0.98 and root mean square errors of validation of ≤4.3 % w/w. Independent test set validation of these models found mean absolute deviations of the 4.9 and 1.0 % w/w for the IR and Raman models, respectively. Both techniques were more accurate than results obtained by an industrial refractive index analysis method, which is used for rapid, cheap quantitation of squalene in shark liver oils. In particular, the Raman partial least squares regression was suited to quantitative squalene analysis. The intense and highly characteristic Raman bands of squalene made quantitative analysis possible irrespective of the lipid matrix.

Vascular effects and safety of supplementation with shark liver oil in middle-aged and elderly males.

Shark liver oil (SLO) has long been used as a traditional health food, with a particular benefit for vascular health, in Japan. The aim of this study was to assess the effect of dietary supplementation with SLO on arterial stiffness and peripheral microvascular function in otherwise healthy middle-aged and older males with slightly increased arterial stiffness. A randomized, double-blind, placebo-controlled, parallel study design was used to assign 41 healthy males with a mean age of 59.0±4.0 years (range, 45-69 years) to either SLO (n=21) or placebo (n=20) treatment for eight weeks. The effects on arterial stiffness and peripheral microvascular function were assessed by the cardio-ankle vascular index (CAVI) and by measurement of hand blood flow to cutaneous tissues using a laser Doppler perfusion imaging (LDPI) technique, respectively. Although the magnitude of the changes in the CAVI value during the eight-week intervention for the SLO group did not significantly differ from that for the placebo group, the changes in the CAVI value for the former group were significantly associated (r=0.575, P<0.01) with age. It was also found that the LDPI values at week 8 were significantly lowered (P<0.05) compared with the baseline values in the placebo group, while no change was observed in the SLO group, resulting in a significant difference in the changes between the two groups (P=0.002). Neither SLO supplementation-related adverse side-effects nor any abnormal changes in routine laboratory tests, including lipid profiles and anthropometric and haemodynamic parameters, were observed throughout the intervention. SLO may have the potential to safely improve vascular health in middle-aged and elderly males.

健常男女成人における唾液の分泌型免疫グロブリン A 濃度に対する深海鮫肝油含有食品の効果

唾液中の分泌型免疫グロブリン A (s-IgA) は，病原体の生体内侵入に対する第一線の防御機構として働き，粘膜免疫に重要な役割を担っている．深海鮫肝油 (SLO) 含有食品の健常男女成人における唾液中 s-IgA 濃度に対する効果を検討することを目的として，42 人の被験者に 1 日当り 2,400 mg（SLO として 1,500 mg）の SLO 含有食品またはプラセボを 6 週間摂取させる無作為化，二重盲検，プラセボ対照，平行群間比較試験によって有効性並びに安全性の評価を行った．介入開始前（ベースライン）と比較して，摂取 6 週目の SLO 群では s-IgA 濃度の有意な上昇 (P = 0.033) が認められたが，プラセボ群では認められなかった．またベースラインからの変化量も SLO 群のほうがプラセボ群よりも有意に高い値を示した (P = 0.030)．試験期間を通して介入に関連する有害事象または一般臨床検査値の異常変動はみられなかった．以上の結果から，SLO 含有食品は，唾液中の s-IgA 濃度を上昇させる効果をもつことが示唆された．

SHARK FISHERIES EXPLOITATION, TRADE, CONSERVATION AND MANAGEMENTIN THE BAY OF BENGAL OF BANGLADESH REGION

The study was conducted during July, 2003 to June, 2013 about landing volumes of shark fishery (sharks and rays) in artisanal and industrial fishing sector only in group- wise not in species wise. In these periods, in artisanal fisheries gill nets (shark nets), set bag nets, long lines and trammel nets exploiting data were analyzed. But from 2012-13 periods in industrial fisheries harvesting data of sharks and rays by trawl fishing were started to record keeping in group wise. During 2012-13 total sharks and rays landing volume contributes only 0.85% (5017 MT) of total the marine fish production of Bangladesh.8&#x0D; During 2010-11 to 2012-13 no sharks and rays product items had been traded from Bangladesh due to international market ban But from 2003-04 to 2009-10 period sharks and rays product with fish maws export to the Myanmar, India, Singapore, Thailand, Hong Kong, China, USA and other countries. Dried and iced sliced meat of shark and rays, its sun-dried hide, bones, fins, tails, teeth and shark liver oil all are sold for local consumers, but only sets of fins (2 pectoral, 2 pelvic, 1 dorsal, 2 anal and 1 caudal fin) and skins were exporting to the foreign markets, which has been stopped now. In the year 2009-10 total 955 MT of sharks and rays product (with fish maws) were exporting and earning (app.) USD 1.60 million. For the conservation and management of shark fishery need National Plan of Action, which exploiting in the MSY and help to banning of critically endangered sharks and rays species. Appropriate law in the Fish Act (at present Fish Act has no forms of restriction for harvesting sharks, while Forestry Act restricts it in Sundarbans area) for sustainable harvesting and conservation of the elasmobranchs. Such law should include how many boats (motorized- and non-motorized) and industrial trawlers could be allowed to harvest sharks from which area, in which season and the allowable limit of harvests; in every case proper ways of fishing methods should strictly be followed. Coastal areas around Saint Martin’s Island and Sundarbans proposed by the Bay of Bengal should be declared as Marine Protected Area as most sharks use these areas as their nursing grounds.

Jurassic surgery and immunity enhancement by alkyglycerols of shark liver oil.

BackgroundShark liver oil (SLO) contains both alkylglycerols (AKG) and squalene and is an ancient remedy among the fishermen on the west coast of Norway and Sweden. Literature reports showed that alkyglycerols enhance Fc–receptor mediated phagocytosis, increase humoral immune response and delay hypersensitivity reactions.MethodsOn this background we performed an open spontaneous study on 40 very old aged surgical patients preoperatively treated with alkyglycerols (500 mg twice a day for 4 weeks), in order to reduce the risks of operation, counteracting the postoperative inflammatory and anergic conditions thus achieving quick and plain recovery. To better understand the possible therapeutic impact of alkyglycerols we compared on a case/control basis treated versus untreated patients submitted contemporarily to the identical operation and exposed to the same environmental and seasonal risks.ResultsThe onset of complications was reduced in the alkyglycerols treated group and the compliance to the natural treatment was excellent without any serious adverse effect. WBC count and IgG significant increase (respectively p <0.05 and p <0.001) might explain some sort of protection against infectious agents and wound repair adverse events. Also lymphocytes concentration significantly increased in the AKG treated group (p <0.001) whereas a slight decrease was observed in the control group. Conversely neutrophils significantly decreased in the AKG treated group (p <0.001) meaning that patients have no more infections and have re-established their physiologic state. However a significant increase was observed in the control group (p <0.05). CRP significantly decreased in the group receiving AKG (p <0.05), thus evidencing a slight antiinflammtory effect of the product. Also ESR decreased from a baseline in the group receiving AKG.ConclusionsIn conclusion we suggest the opportunity to introduce this nutraceutical product in dosages of 500 mg twice a day to very old people before surgical treatment for an effective modulation of leukocytes and soluble immune reactivity according with the shark liver oil consumption trend in the northern Europe countries folk medicine. For this reason it might be advisable a wider study on a substantially bigger patients cohort focused on the complication rate prevention or control.

Shark liver oil

Shark liver oil

Alkylglycerols modulate the proliferation and differentiation of non-specific agonist and specific antigen-stimulated splenic lymphocytes.

Alkylglycerols (AKGs) are ether-linked glycerols derived from shark liver oil and found in small amounts in human milk. Previous studies showed that oral AKGs administration significantly increased the immune response in mice. The aim of the present study was to investigate the in vitro immunomodulatory effect of AKGs on stimulating splenic lymphocyte responses. C57BL/6 mice were immunized with hepatitis B surface antigen (HBsAg). Splenic B cells were purified and stimulated with anti-BCR and anti-CD38. Meanwhile, splenic CD4+ T cells were purified and stimulated with anti-CD3 and anti-CD28. For antigen specific stimulation, the purified CD4+ T cells were cocultured with HBsAg -pulsed dendritic cells. The stimulated lymphocytes were treated with different concentrations of AKGs. The cell proliferation was assessed by [3H]-thymidine incorporation assay. The maturation of B cells was assessed by examining the germline (GL) transcription of IgG (γ1) mRNA expression, and the surface expressions of CD80/CD86 markers were examined by flow cytometry analysis. Th1/Th2 polarity was assessed by T-BET (Th1)/GATA-3 (Th2) flow cytometry assay and by characteristic cytokines ELISA assay (TNF-α and IFN-γ for Th1; IL-4 and IL-10 for Th2). It was found that AKGs significantly increased the BCR/CD38 -stimulated B cell proliferation. The T cell proliferation in response to CD3/CD28 or specific antigen stimulation was also increased by AKGs. The transcriptional level of IgG (γ1) and the expressions of CD80/CD86 molecules were markedly increased by AKGs in BCR/CD38 -stimulated B cells. Meanwhile, the results showed that AKGs increased the expression of T-BET transcriptional factor and the production of Th1 cytokines (TNF-α and IFN-γ) upon CD3/CD28 stimulation; whereas, levels of Th2 cytokines (IL-4 and IL-10) were decreased by AKGs. Our study demonstrated that AKGs can modulate immune responses by boosting the proliferation and maturation of murine lymphocytes in vitro.

Anti-ulcer Property of Shark Liver Oil on Water Immersion Restraint Stress Induced Gastric Ulcer in Rats

Shark liver oil is one of the sources of cellular energy and provides repair and restoration of damaged cells, and supports in protection of the body from the emergence of tumorous conditions. The Shark liver oil was tested orally at the dose of 1g/kg body weight, on gastric ulceration experimentally induced by water immersion (Swimming). The parameters considered to assess the anti-ulcer activity were percentage of ulcer, ulcer index, percentage of inhibition, pH, free acidity and total acidity. Pretreatment with the Shark liver oil resulted in a significant decreased of the ulcerated area and reduced pH, free acidity and total acidity.

Exercise and Shark Liver Oil Supplementation Reduce Tumor Growth and Cancer Cachexia in Walker 256 Tumor Bearing Rats

This study investigated whether exercise associated to shark liver oil supplementation (1 g/kg b.w./day) affects tumor growth, cachexia, lipid peroxidation and proteins expression involved in cell death in Walker 256 tumorbearing rats. Animals were divided into 4 groups: sedentary tumor-bearing (W), sedentary tumor-bearing shark liver oil supplemented (WSL), exercised tumor-bearing (EW) and exercised tumor-bearing shark liver oil supplemented (EWSL). Training sessions consisted of 6 bouts, 30 seconds each with 50% body-weight load attached to the trunk followed by 1 minute of resting (jump training). Five minutes after the finish jump training the exercise groups were subjected to 30 minutes of continuous swimming with a load equivalent to 6% of body weight, 4 times a week during 8 weeks. Tumor cells were injected at the 6th training week and all groups were killed 15 days post inoculation. Tumor weight (g) in W group was of 26.50 ± 1.79 and in the WSL, EW and EWSL was of 14.08 ± 0.91, 15.60 ± 0.55 and 12.60 ± 1.07, respectively. The group W showed hypoglycemia (68.67 ± 2.12 mg/dl), hyperlactacidemia (1.49 ± 0.06 mmol/L), hypertriacylglycerolemia (161.4 ± 9.4 mg/dl) and body weight reduction (13.21 ± 2.25 g) characterizing cachexia state. The groups WSL, EW and EWSL presented reduction of tumor cells proliferation ex vivo, and the production of hydroperoxide and apoptosis was increased. Bax/Bcl-2 expression ratio was increased only in the exercised groups. Shark liver oil supplementation and exercise alone were able in to avoid the installation of cachexia state and also reduced tumor growth, but the association of both cause further effect only in the tumor growth.

Transforming Yeast from Moonshiners into Oil Barons

Amyris has transformed ethanologenic baker's yeast into farnesene oil producers. Farnesene is a 15-carbon hydrocarbon derived from the sterol synthesis pathway (the same root pathway that make cholesterol). Its branched structure makes it ideal for processing into base-oils for cosmetics (replacing shark liver oil), synthetic engine lubricants, diesel fuel, and high-performing polymers for tires. In four years, Amyris has improved its yeast from producing only a single microliter in a test tube, to making thousands of liters in a full-scale fermentations at unprecedented yields and productivities. I will share lessons learned from the challenges of strain development and scale-up at Amyris, and how those lessons might be applied to accelerate and empower research in Industrial Biotechnology.

Squalene: a multi-task link in the crossroads of cancer and aging

Since its discovery in the beginning of the XXth century, squalene has been recognized as an important link in metabolic pathways. More recently, it has been further recognized as an intermediate step in the biosynthesis of cholesterol. Its well known antioxidant capability, together with its ability to protect skin, improve the immune system, and modulate the lipid profile, confer a high potential to this natural substance, which is spread all across the body structure, though mainly in the epithelial tissues, and in particular the skin sebum. This review will focus mainly on its major properties, which are related to anticancer properties, the maintenance of the oxidation/antioxidation balance, and its antiaging capabilities. Although the substance was originally obtained from shark liver oil, it is currently possible to obtain useful amounts from vegetable sources like extra virgin olive oil, therefore avoiding the dependence on capturing the aforementioned animal species. Recognized as one of the key components of the Mediterranean dietary style, squalene is necessary to adequately manage oxygen and its derivatives in every cell of the body. Key words: aging, antioxidants, cancer, cholesterol, diet, olive oil, squalene

Antitumor and anti-cachectic effects of shark liver oil and fish oil: comparison between independent or associative chronic supplementation in Walker 256 tumor-bearing rats

BackgroundShark liver oil (SLOil) and fish oil (FOil), which are respectively rich in alkylglycerols (AKGs) and n-3 polyunsaturated fatty acids (PUFAs), are able to reduce the growth of some tumors and the burden of cachexia. It is known that FOil is able to reduce proliferation rate and increase apoptotic cells and lipid peroxidation of tumor cells efficiently. However, there are few reports revealing the influence of SLOil on these parameters. In the current study, effects of FOil chronic supplementation on tumor growth and cachexia were taken as reference to compare the results obtained with SLOil supplementation. Also, we evaluated if the association of SLOil and FOil was able to promote additive effects.MethodsWeanling male Wistar rats were divided into 4 groups: fed regular chow (C), supplemented (1 g/kg body weight) with SLOil (CSLO), FOil (CFO) and both (CSLO + FO). After 8 weeks half of each group was inoculated with Walker 256 cells originating new groups (W, WSLO, WFO and WSLO + FO). Biochemical parameters of cachexia, tumor weight, hydroperoxide content, proliferation rate and percentage of apoptotic tumor cells were analysed. Fatty acids and AKG composition of tumor and oils were obtained by high performance liquid chromatography and gas chromatography – mass spectrometry, respectively. Statistical analysis was performed by unpaired t-test and one-way ANOVA followed by a post hoc Tukey test.ResultsFourteen days after inoculation, SLOil was able to restore cachexia parameters to control levels, similarly to FOil. WSLO rats presented significantly lower tumor weight (40%), greater tumor cell apoptosis (~3-fold), decreased tumor cell proliferation (35%), and higher tumor content of lipid hydroperoxides (40%) than observed in W rats, but FOil showed more potent effects. Supplementation with SLOil + FOil did not promote additive effects. Additionally, chromatographic results suggested a potential incorporation competition between the n-3 fatty acids and the AKGs in the tumor cells’ membranes.ConclusionsSLOil is another marine source of lipids with similar FOil anti-cachectic capacity. Furthermore, despite being less potent than FOil, SLOil presented significant in vivo antitumor effects. These results suggest that the chronic supplementation with SLOil may be adjuvant of the anti-cancer therapy.

Oral Administration of Alkylglycerols Differentially Modulates High-Fat Diet-Induced Obesity and Insulin Resistance in Mice

Alkylglycerols (AKGs) from shark liver oil (SLO) were demonstrated to have strong potency to stimulate immune response. However, no study has been conducted on the effects of AKGs on diet-induced obesity and metabolic inflammatory disorder. The purpose of the present study was to investigate the effect of two AKGs isoforms on obesity and insulin resistance in mice fed high-fat (HF) diet. Forty-eight C57BL/6 mice were divided into normal, HF, HF + 20 mg/kg selachyl alcohol (SA), HF + 200 mg/kg SA, HF + 20 mg/kg batyl alcohol (BA), and HF + 200 mg/kg BA groups. Body weight, fasting glucose, lipids, insulin and leptin levels, serum IL-1β, and TNF-α levels were compared among different groups. Our results showed that high-dose SA decreased body weight, serum triglyceride, cholesterol, fasting glucose level, insulin level, and serum leptin level of the HF fed mice, while high-dose BA increased fasting insulin level of the HF fed mice. Pretreatment of primary adipocytes with 10 μM SA or BA differentially modulates LPS-mediated MAPK and NF-κB signaling. Our study demonstrated that oral administration of AKGs has differential effects on HF-induced obesity and metabolic inflammatory disorder in mice.

Discrimination against diacylglycerol ethers in lipase-catalysed ethanolysis of shark liver oil

Lipase-catalysed ethanolysis of squalene-free shark liver oil was investigated. The mentioned shark liver oil was comprised mainly of diacylglycerol ether and triacylglycerols. In order to test discrimination against diacylglycerol ether, up to 10 different lipases were compared. The ratio of oil to ethanol and lipase stability were also evaluated. Surprisingly, lipase from Pseudomonas stutzeri was the fastest biocatalyst among all assayed, although poor discrimination against diacylglycerol ether was observed. The best results in terms of selectivity and stability were obtained with immobilised lipase from Candida antarctica (Novozym 435). Ethanolysis reaction after 24h in the presence of Novozym 435 produced total disappearance of triacylglycerol and a final reaction mixture comprised mainly of diacylglycerol ethers (10.6%), monoacylglycerol ethers (32.9%) and fatty acid ethyl esters (46.0%). In addition, when an excess of ethanol was used, diacylglycerol ethers completely disappeared after 15h, giving a final product mainly composed of monoacylglycerol ethers (36.6%) and fatty acid ethyl esters (46.4%).

Regiospecific Analysis of Shark Liver Triacylglycerols

AbstractThe liver oils of six shallow‐water shark species, silky (Carcharhinus falciformis), thresher (Alopias superciliosus), oceanic whitetip (Carcharhinus longimanus), blue (Prionace glauca), hammerhead (Sphyrna lewini) and salmon (Lamna ditropis) were analyzed with particular attention to the regioisomeric composition of triacylglycerols (TAG). The TAG compositions were analyzed by using an HPLC‐evaporative light scattering detector and each molecular species identified by HPLC‐atmospheric pressure chemical ionization/mass spectrometry. Major lipid components of all sharks’ oils were TAG (~80 %) made up of omega‐3 polyunsaturated fatty acids at 26–40 % and 20–25 % docosahexaenoic acid (DHA). Forty different molecular species were detected in the TAG fractions. TAG consisting of one palmitic acid, one DHA and one oleic acid (12.5–19.9 %) and TAG consisting of two palmitic acids and one DHA (8.4–15.4 %) were the predominant form while 30–50 % TAG molecular species were bound to one or more DHA. Distribution of fatty acids in the primary (sn‐1 and sn‐3) and secondary (sn‐2) position of the glycerol backbones was examined by regiospecific analysis by using pancreatic lipase and it was found that DHA was preferentially positioned at sn‐2. These findings greatly extend the utilization of shark liver oils in food productions and may have a significant impact on the future development of the fish oil industry.