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In this study, α-lactalbumin-chitosan (ALA-CHI) colloidal nanoparticles were spontaneously formed mainly through electrostatic interactions for stabilizing Pickering emulsion loaded with health-beneficial but unstable menhaden oil. The oxidative stability of menhaden oil was supposed to be significantly enhanced with Pickering emulsion-based delivery systems with ALA-CHI colloidal particles. The film of ALA-CHI colloidal nanoparticles had higher surface hydrophobicity than ALA at pH 5.0, and 6.5. A near-neutral wettability (89.6°) of ALA-CHI nanoparticles was observed at pH 5.0. Stable Pickering emulsions (60% menhaden oil fraction, w/w) were successfully fabricated with only 0.12% (w/w) of ALA-CHI nanoparticles. Pickering emulsions exhibited superior storage, heat, and centrifugation stability. The formation of gel-like structures was confirmed by rheological results. The viscosity and storage modulus in the frequency range of 0.1 to 10 Hz with a 1.0% strain exhibited remarkable increases with increasing colloidal particle concentration or oil fraction. Increasing oil fractions from 20% to 60% (w/w) or colloidal particle concentrations 0.12% to 2.40% (w/w) can pronouncedly facilitate the inhibition of lipid oxidation, as confirmed by detecting the formation of primary and secondary oxidation products.

Oleogels were produced using a phytosterol blend of β-sitosterol/γ-oryzanol or a blend of sucrose stearate/ascorbyl palmitate (SSAP) as oleogelators. Four lipid phases were compared in oleogel formation for each oleogelator blend: menhaden oil, structured lipid (SL) of menhaden oil and 30 mol% caprylic acid (SL-C), SL of menhaden oil and 20 mol% stearic acid (SL-S), and SL of menhaden oil and 14 mol% each of caprylic and stearic acid (SL-CS). All SLs were produced enzymatically using a recombinant lipase from Candida antarctica as the biocatalyst. Menhaden oil, SL, phytosterol, or SSAP oleogels were evaluated as alternatives to shortening in the preparation of yellow cake in terms of batter and cake physicochemical properties. The shortening, phytosterol, and SSAP oleogel batters exhibited statistically similar specific gravities (0.85). The shortening, and menhaden oil phytosterol and SSAP oleogel batters, exhibited similar Power-Law values (n: 0.78, k: 31 Pa sn ), while all SL (and respective oleogels) batters typically had lower flow index values (n: 0.68 to 0.72), and higher consistency index values (k: 45 to 79 Pa sn ). All SL (and respective oleogels) cakes exhibited lower hardness (5 to 8 N) and chewiness (4 to 6 N) than the shortening cake (12 N, 9 N). Menhaden oil and SL-S phytosterol oleogel cakes, and SL-CS SSAP oleogel cake, showed similar textural properties to the shortening cake. Both phytosterol and SSAP oleogels were acceptable as zero trans-fat substitutes for shortening in yellow cake. PRACTICAL APPLICATION: The oleogels in this study may be a suitable replacement for shortening in yellow cake. These oleogels, which contain health beneficial omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have the potential to lower consumer consumption of total saturated fat when used in foods.

To rigorously explore the role of omega-3 polyunsaturated fatty acids (PUFA) in the treatment of diabetic peripheral neuropathy (DPN), we have created a transgenic mouse utilizing a Cre-lox promoter to control overexpression of human 15-lipoxygenase-1 (15-LOX-1). In this study, we sought to determine the effect of treating type 2 diabetic wild-type mice and transgenic mice ubiquitously overexpressing 15-LOX-1 with menhaden oil on endpoints related to DPN. Wild-type and transgenic mice on a C57Bl/6J background were divided into three groups. Two of each of these groups were used to create a high-fat diet/streptozotocin model for type 2 diabetes. The remaining mice were control groups. Four weeks later, one set of diabetic mice from each group was treated with menhaden oil for twelve weeks and then evaluated using DPN-related endpoints. Studies were also performed using dorsal root ganglion neurons isolated from wild-type and transgenic mice. Wild-type and transgenic diabetic mice developed DPN as determined by slowing of nerve conduction velocity, decreased sensory nerve fibers in the skin and cornea, and impairment of thermal and mechanical sensitivity of the hindpaw compared to their respective control mice. Although not significant, there was a trend for the severity of these DPN-related deficits to be less in the diabetic transgenic mice compared to the diabetic wild-type mice. Treating diabetic wild-type and transgenic mice with menhaden oil improved the DPN-related endpoints with a trend for greater improvement or protection by menhaden oil observed in the diabetic transgenic mice. Treating dorsal root ganglion neurons with docosahexanoic acid but not eicosapentaenoic acid significantly increased neurite outgrowth with greater efficacy observed with neurons isolated from transgenic mice. Targeting pathways that will increase the production of the anti-inflammatory metabolites of omega-3 PUFA may be an efficacious approach to developing an effective treatment for DPN.

The goal of this study was to improve the chemical stability of menhaden oil and control the lipolysis in emulsions with whey protein during in vitro digestion through EGCG conjugation and genipin-mediated interfacial cross-linking (CL). WPI-EGCG conjugate was successfully synthesized, confirmed by SDS-PAGE, ESI-MS, and phenolic group quantifications (125.3 mg/g), and characterized with far UV CD and ATR-FTIR. Emulsion particle diameter with WPI-EGCG is lower than with WPI. Compared to the native emulsion, WPI CL increased particle diameter and physical stability. Higher oxidative stability was observed for emulsions stabilized with WPI-EGCG conjugate than that with interfacial cross-linking due to the great antioxidant activity. Whereas, WPI CL is more effective than WPI-EGCG conjugate in hindering the rate and extent of lipolysis. The combination of EGCG conjugation and interfacial CL showed both the highest protection of menhaden oil against degradation and highest inhibition on the rate and extent of lipolysis of menhaden oil.

In this study, we wanted to extend our investigation of the efficacy of fish oil with or without salsalate on vascular and neural complications using a type 2 diabetic rat model. Four weeks after the onset of hyperglycemia, diabetic rats were treated via the diet with 3 different amounts of menhaden oil with or without salsalate for 12 weeks. Afterwards, vascular reactivity of epineurial arterioles and neuropathy-related endpoints were examined. The addition of salsalate to high-fat diets enriched with 10% or 25% kcal of menhaden oil protected vascular reactivity to acetylcholine and calcium gene-related peptide, motor and sensory nerve conduction velocity, thermal nociception, intraepidermal nerve fiber density, and cornea sensitivity to a greater extent than 10% or 25% menhaden oil alone. Vascular and neural function was maximally protected with diet containing 45% kcal as menhaden oil, and adding salsalate did not provide any additional benefit. Salsalate alone in the high-fat diet of diabetic rats provided minimal protection/improvement of vascular and neural dysfunction. These studies imply that dietary salsalate in combination with lower amounts of menhaden oil can provide greater benefit toward diabetes-induced vascular and neural impairment than menhaden oil alone.

This study investigated the efficacy of monotherapy versus combination of menhaden oil, α-lipoic acid, and enalapril on corneal sensation and morphometry and other neuropathy-related endpoints in a rat model of type 2 diabetes.Male Sprague-Dawley rats (aged 12 weeks) were fed a high-fat diet for 8 weeks followed by 30 mg/kg streptozotocin. After 16 weeks of hyperglycemia, 12-week treatments consisting of menhaden oil, α-lipoic acid, enalapril, or their combination were initiated. Before and after treatments, we performed analyses of multiple neural and vascular endpoints including corneal sensitivity, corneal nerve density, vascular reactivity of epineurial arterioles, motor and sensory nerve conduction velocity, intraepidermal nerve fiber density, and thermal nociception.Before treatment, all the neural and vascular endpoints in diabetic rats were impaired. Treating diabetic rats with monotherapy was effective in improving neural and vascular deficits with menhaden oil being most efficacious. However, the combination therapy provided the greatest benefit and improved/reversed all nerve and vascular deficits. The effect of combination therapy on corneal relative sensitivity and structure (in mm/mm), primary endpoints for this study, for control, diabetic, and diabetic treated rats was 4.2 ± 1.4 and 7.5 ± 0.5, 12.1 ± 1.3* and 3.8 ± 0.2*, and 6.6 ± 2.3 and 7.3 ± 0.5, respectively (*P0.05 compared with control rats; P0.05 compared with diabetic rats).These studies suggest that a combination therapeutic approach may be most effective for treating vascular and neural complications of type 2 diabetes.

In sows, n-3 fatty acids increase litter sizes, however, effects on gilt reproductive development have not been adequately studied. Moreover, not determined are effects of feeding n-3 fatty acids to sows on reproduction in offspring. The objective here was to determine effects of 4% dietary menhaden oil on growth and puberty in gilts farrowed by sows fed menhaden oil. Sows (n = 44) were assigned to: (1) control gestation and lactation diets, or (2) diets including menhaden oil. For primiparous sows only, total litter size and born alive were greater (P < 0.05) in females fed menhaden oil. Conversely, pigs from primiparous controls were heavier (P < 0.05) than pigs from primiparous sows fed menhaden oil (parity by diet interactions, P < 0.01). Diet did not affect (P > 0.20) other sow and litter characteristics. At weaning, 84 gilts from control- or menhaden oil sows were placed three gilts per pen and provided control diets or diets containing menhaden oil. Nursery and grow-finish feed intake and feed efficiency were similar (P > 0.21) for gilts from the different sows and weight gain was similar (P > 0.24) for gilts fed control or menhaden diets. Gilts fed menhaden oil tended to eat less in the nursery (1.18±0.08 kg v. 0.98±0.08 kg; P = 0.09) and overall (1.83±0.04 kg v. 1.72±0.04 kg; P = 0.06). Thus, overall feed to gain was greater (2.52±0.03 v. 2.33±0.03; P < 0.01) and nursery (2.12±0.04 v. 1.80±0.04; P = 0.10) and grow-finish (3.07±0.19 v. 2.58±0.19; P = 0.08) feed to gain tended to be greater, for control gilts. Age at puberty was greater (P = 0.02) for gilts from menhaden oil-fed sows (205.1±3.2 days) compared to gilts from controls (193.9±3.2 days) and tended to be greater (P = 0.09), for controls (203.5±3.2 days) compared to gilts fed menhaden oil (195.5±3.2 days). A tendency existed (P = 0.09) for greater follicular fluid in gilts fed menhaden oil, however, ovulation rate and ovarian, luteal and uterine weights were not affected by sow diet, gilt diet or the interaction (P > 0.23). Feeding gilts menhaden oil enhanced feed efficiency and hastened puberty onset. Gilts from sows consuming menhaden oil exhibited delayed puberty and retaining females from sows fed this feedstuff may be ill advised.

The purpose of this research was to produce organogels using two different organogelator blends and two different oil substrates and compare their physicochemical properties. A medium-long-medium (MLM)-type structured lipid (SL) containing 37.44 mol% MLM-type triacylglycerols (TAG) was produced by enzymatic modification of menhaden oil with ethyl caprate. Menhaden oil and SL were used as oil substrates to form organogels. One organogel was formed using a phytosterol blend of β-sitosterol and γ-oryzanol (molar ratios of 2 : 1, 1 : 1, and 1 : 2 at 4, 6, and 8% (w/w) in oil), and another was formed with a blend of sucrose stearate (HLB value: 2) and ascorbyl palmitate (SSAP) (molar ratios of 3 : 1, 1 : 1, and 1 : 3 at 8, 10, and 12% (w/w) in oil). Organogels were formed for all ratios except 2 : 1 and 3 : 1 for the phytosterol and SSAP blend, respectively. For both organogels, the 1 : 1 molar ratio was optimal. This ratio produced organogels with higher melting completion temperatures than menhaden oil and SL (13.6 and 14.3 °C). The SSAP blend had higher melting completion temperatures (72.3 and 72.4 °C) than the phytosterol blend (69.2 and 68.4 °C) for organogels formed using menhaden oil and SL, respectively. All 1 : 1 molar ratio blends exhibited β′ polymorphic form with short spacing peaks at 4.20, 3.97, and 3.71 A. All organogels improved the oxidative stability of the menhaden oil and SL. These organogels have the potential for use as nutraceuticals or health beneficial low saturated fat alternatives to saturated and/or trans-fats.

Phenolic compounds, including propyl gallate, 1-o-galloylglycerol, ferulic, gallic, caffeic, rosmarinic, and carnosic acids, tocopherols, and butylated hydroxytoluene (BHT), were investigated as antioxidants to improve the oxidative stability of a structured lipid (SL) produced by the enzymatic acidolysis of menhaden oil with caprylic and stearic acids. SL had similar physical properties to butterfat but was more susceptible to oxidation. The above phenolic compounds were each added to SL as antioxidants. SL with 1-o-galloylglycerol, rosmarinic acid, or BHT showed the highest oxidative stability during an accelerated oxidation test with the total oxidation (TOTOX) value around 250 after 18 days. Oxidation induction time (OIT) using differential scanning calorimetry showed a good correlation with the accelerated oxidation test. A mixture of 1-o-galloylglycerol and tocopherols at 50:50 ppm had the strongest protective effect on SL (OIT = 115.1 min) compared to the other tested compounds or combinations at the same concentration (OIT 100 min).

The omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are recognized for their health-promoting qualities. Marine fish and fish oil currently provide the main sources of EPA and DHA for human consumption. An alternative plant-based source of EPA and DHA is provided by EPA + DHA canola event LBFLFK (LBFLFK). A comparative analysis and a 28-day toxicity study assessed the safety of LBFLFK refined, bleached, and deodorized (RBD) oil. Thirty-one different commercially-obtained fat and oil samples were tested, and principal component analysis showed that the overall fatty acid profile of LBFLFK RBD oil was most similar to Mortierella alpina oil and salmon flesh. Samples with the fewest differences in the presence or absence of individual fatty acids compared to LBFLFK RBD oil were menhaden oil and some other fish oils. In a 28-day toxicity study, LBFLFK RBD oil was administered by oral gavage to male and female Wistar rats. No signs of toxicity were evident and no adverse effects were noted in clinical observations, clinical pathology, or histopathology. Overall, these studies support the safety of LBFLFK RBD oil as a source of EPA and DHA for human consumption.

The purpose of this study was to determine the effect of supplementing the diet of a mouse model of type 2 diabetes with menhaden (fish) oil or daily treatment with resolvin D1 on diabetic neuropathy. The end points evaluated included motor and sensory nerve conduction velocity, thermal sensitivity, innervation of sensory nerves in the cornea and skin, and the retinal ganglion cell complex thickness. Menhaden oil is a natural source for n-3 polyunsaturated fatty acids, which have been shown to have beneficial effects in other diseases. Resolvin D1 is a metabolite of docosahexaenoic acid and is known to have anti-inflammatory and neuroprotective properties. To model type 2 diabetes, mice were fed a high-fat diet for 8 wk followed by a low dosage of streptozotocin. After 8 wk of hyperglycemia, mice in experimental groups were treated for 6 wk with menhaden oil in the diet or daily injections of 1 ng/g body wt resolvin D1. Our findings show that menhaden oil or resolvin D1 did not improve elevated blood glucose, HbA1C, or glucose utilization. Untreated diabetic mice were thermal hypoalgesic, had reduced motor and sensory nerve conduction velocities, had decreased innervation of the cornea and skin, and had thinner retinal ganglion cell complex. These end points were significantly improved with menhaden oil or resolvin D1 treatment. Exogenously, resolvin D1 stimulated neurite outgrowth from primary cultures of dorsal root ganglion neurons from normal mice. These studies suggest that n-3 polyunsaturated fatty acids derived from fish oil could be an effective treatment for diabetic neuropathy.

Renal necrosis can be induced in weanling rats due to choline deficient diet. Menhaden oil has a protective effect against the development of renal necrosis in choline deficient weanling rats. The aim of this work was to determine the effects of menhaden oil in a model of acute kidney injury due to ischemia reperfusion. Wistar rats were divided into two groups and fed vegetable oils or menhaden oil as lipids. Unilateral renal ischemia was performed for 30 minutes and animals were sacrificed 48 hours later. Histopathological examination showed no significant differences between groups. Menhaden oil did not prevent histopathological lesions. Fil: Ossani, Georgina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Alemán. Laboratorio de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina Fil: Marcotegui, Ariel R.. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina Fil: Uceda, Ana Margarita. Hospital Alemán. Laboratorio de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina Fil: Monserrat, Alberto Juan. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina Fil: Lago, Néstor Rubén. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina Fil: Perazzo, Juan C.. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina

Background After massive small bowel resection (SBR), a postoperative diet high in fat is associated with enhanced villus growth. The purpose of this study was to further elucidate the quantity and composition of enteral fat in structural and metabolic changes after SBR. Methods C57/Bl6 mice underwent a 50% proximal SBR. Mice were then randomized to receive a low-fat diet (12% kcal fat), medium-fat diet (44% kcal fat), or high-fat diet (HFD; 71% kcal fat) ad libitum. In a separate experiment, mice underwent 50% proximal SBR and then were randomized to liquid diets of 42% kcal of fat in which the fat was composed of menhaden oil, milk fat, or olive oil. After 2 weeks, mice underwent body composition analysis and the small intestine was harvested. Results Mice that ingested the greatest amount of enteral fat (HFD) had the greatest percent lean mass. When the effects of the different kinds of enteral fat were analyzed, mice that consumed menhaden oil had the greatest percent lean mass with the greatest overall retention of preoperative weight. Conclusion These findings suggest that enteral fat enriched in omega-3 fatty acids may offer clinically relevant metabolic advantages for patients with short gut syndrome.

International audience; The in vitro digestion of beta-lactoglobulin stabilized emulsions rich in the n-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), was studied using several physicochemical techniques. Artificial media for the mouth, stomach and small intestine were used in a sequential static in vitro digestion method. Different sizing techniques were compared to follow the droplet size during the digestion steps, including diffusing wave spectroscopy (DWS) which allowed direct measurements on undiluted emulsions. Titration of fatty acids confirmed that the digestion of such emulsified fish oils is partial. The study of the digestion at the oil-water interface using tensiometry revealed specific affinities between lipids and proteins. These could explain the emulsion and the single droplet lipolysis. Nevertheless, by comparing our results to a previous study on fish oil lipolysis, we identified two other important factors. Those were the aqueous solubility and the rate of hydrolysis of the individual fatty acids, the emulsion with the most soluble and hydrolysable ones being digested more quickly.

Higher intakes of polyunsaturated fatty acids (PUFA) are associated with benefits at several skeletal sites in postmenopausal women and in rodent models, but the effect of PUFA-containing oils on tooth-supporting alveolar bone of the mandible has not been studied. Moreover, direct comparison of the effect of flaxseed oil (a source of alpha-linolenic acid (ALA)) and menhaden oil (a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) is unknown. One-month old female Sprague-Dawley rats (n = 48) were randomized to and fed a diet containing flaxseed oil or menhaden oil from one to six months of age. At three months of age, rats were randomized to receive SHAM or ovariectomy (OVX) surgery (n = 12/diet). The inter-radicular septum below the first molar of the mandible was imaged at 6 months of age (study endpoint) using micro-computed tomography (μCT) at a resolution of 9 μm. As expected, OVX significantly reduced percent bone volume (BV/TV), connectivity density (Conn. D.), trabecular number (Tb. N.), and increased trabecular separation (Tb. Sp.) compared to SHAM rats (p < 0.001). However, post hoc analysis revealed these differences were present in rats fed menhaden oil but not those fed flaxseed oil. These results suggest that providing flaxseed oil, possibly through its high ALA content, provides protection against the OVX-induced alveolar bone loss in rats.

To examine the effects of n-3 and n-6 polyunsaturated fatty acids (n-3 and n-6 PUFAs) in a murine model of herpetic chorioretinitis.BALB/c mice were fed on three high fat diets, which contained: Menhaden oil (rich in n-3 PUFAs); Safflower oil (rich in n-6 PUFAs); or Corn oil (rich in saturated fatty acids) as control group, 14 days previously and until 12 days following anterior chamber (AC) HSV-1 inoculation.Mice fed on Menhaden oil present an early development of contralateral chorioretinitis by day 6 post-AC HSV-1 inoculation and also significant increase of RNA HSV-1 expression compared with Safflower and Corn oil groups. Furthermore, mice fed on Menhaden oil showed a significant decrease secretion of TNF-α, IFN-γ, IL-2 and IL-10 in splenic cells and both retinas.Our results showed that mice fed on Menhaden oil (n-3 PUFAs) presented an early development of contralateral chorioretinitis by day 6 post-AC HSV-1 inoculation and also a significant increase in RNA HSV-1 expression compared with animals fed on Safflower and Corn oils. This increase of HSV-1 could be associated with the higher development of chorioretinitis.

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) or menhaden oil may reduce inflammatory eicosanoids (prostaglandin E₂, thromboxane B₂, leukotriene B₄, and 11-dehydro thromboxane B₂), matrix metalloproteinases (MMPs), and blood lactate in dogs with nasal carcinomas receiving radiation therapy. We hypothesized that menhaden oil would reduce inflammation from radiation damage and lower blood lactate levels in dogs with nasal carcinoma. In a randomized, double-blind, placebo-controlled clinical study, 12 dogs with malignant carcinomas of the nasal cavity were given dietary menhaden oil (DHA and EPA) or soybean oil (control) and then received radiation therapy. Megavoltage radiation was delivered in 18 fractions to a total dose of 56 Gy. Blood levels of DHA, EPA, insulin, glucose, lactic acid, and MMPs 2 and 9; resting energy expenditure; and inflammatory eicosanoids from nasal biopsies were measured throughout radiation therapy. Samples were obtained from each patient 1 week before the start of radiation therapy, at start of radiation, and 7, 18 (end of radiation therapy), and 42 days after radiation was initiated. Dogs that are fed with menhaden oil had significantly (P.05) higher plasma concentration of DHA by 500% and EPA by 200% and had significantly lower tissue inflammatory eicosanoids and decreased resting energy expenditure by 20% when compared with controls. Increased plasma DHA was significantly associated (P.05) with decreased plasma lactic acid and MMPs. These data may suggest that dietary fish oil could reduce some detrimental inflammatory eicosanoids and metabolic consequences of radiation therapy.

In an effort to investigate the effect of positional distribution on oxidative stability of menhaden and seal blubber oils, Novozyme 435 was used as a random biocatalyst. Positional distribution of fatty acids was determined using gas chromatography. As some of the α-tocopherol was lost during randomization, its content was adjusted to the level prior to the process to eliminate this effect on oxidative stability of oils tested. Conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) were used as indicators of oxidative stability. The results showed that the polyunsaturated fatty acids were distributed predominantly at terminal positions in randomized menhaden oil, whereas they were distributed more evenly among all positions in enzymatically randomized seal blubber oil, compared to their unrandomized counterparts. Results of CD and TBARS values indicated that randomized menhaden oil was more stable than the original oil, whereas randomized seal blubber oil was more vulnerable to oxidation compared to its counterpart. Changes of oxidative stability after randomization were mainly due to positional redistribution of fatty acids, especially those of the polyunsaturated types.

Unrefined menhaden oil was evaluated for thermal and rheological properties and its temperature-dependent viscosity and lipid oxidation rate were determined. Peroxide value, free fatty acids, density, specific gravity, water activity, moisture content, and enthalpy of the unrefined menhaden oil were 5.70 meq/kg, 3.80%, 0.93 g/mL, 0.93%, 0.52%, 0.15%, and 20.2 kJ/kg, respectively. The melting point range of unrefined menhaden oil was found to be -69.5 to 27.21 degrees C. The menhaden oil exhibited non-Newtonian fluid behavior at lower temperatures (5 to 25 degrees C), while it behaved like a Newtonian fluid at 30 degrees C. The oil apparent viscosity at 5 degrees C (0.22 Pa.s) was significantly higher (P < 0.05) than that at 30 degrees C (0.033 Pa.s). The average magnitude of activation energy for viscosity of the unrefined menhaden oil was 50.37 kJ/mol. The predicted apparent viscosity agreed (R(2)= 0.9837) satisfactorily with the experimental apparent viscosity. The minimal lipid oxidation rate of the oil was found at 25 and 35 degrees C for 6 h, higher lipid oxidation rates were observed when the oil was heated for 6 h at 45 to 85 degrees C. The rate of lipid oxidation for unrefined menhaden oil was temperature dependent (R(2)= 0.9425). This study showed that the magnitude of the apparent viscosity and oxidation rate of the unrefined menhaden oil was greatly influenced by temperature.

Menhaden oil-in-water emulsions (20%, v/v) were stabilized by 2 wt% whey protein isolate (WPI) with 0.2 wt% xanthan gum (XG) in the presence of 10 mM CaCl(2) and 200 microM EDTA at pH 7. Droplet size, lipid oxidation, and rheological properties of the emulsions were investigated as a function of heating temperature and time. During heating, droplet size reached a maximum at 70 degrees C and then decreased at 90 degrees C, which can be attributed to both heating effect on increased hydrophobic attractions and the influence of CaCl(2) on decreased electrostatic repulsions. Combination of effects of EDTA and heat treatment contributed to oxidative stability of the heated emulsions. The rheological data indicate that the WPI/XG-stabilized emulsions undergo a state transition from being viscous like to an elastic like upon substantial thermal treatment. Heating below 70 degrees C or for less than 10 min at 70 degrees C favors droplet aggregation while heating at 90 degrees C or for 15 min or longer at 70 degrees C facilitates WPI adsorption and rearrangement. WPI adsorption leads to the formation of protein network around the droplet surface, which promotes oxidative stability of menhaden oil. Heating also aggravates thermodynamic incompatibility between XG and WPI, which contributes to droplet aggregation and the accumulation of more WPI around the droplet surfaces as well.

Antarctic krill, also known as Euphausia superba, is a marine crustacean rich in both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We tested the hypothesis that krill oil would increase plasma concentrations of EPA and DHA without adversely affecting indicators of safety, tolerability, or selected metabolic parameters. In this randomized, double-blind parallel arm trial, overweight and obese men and women (N = 76) were randomly assigned to receive double-blind capsules containing 2 g/d of krill oil, menhaden oil, or control (olive) oil for 4 weeks. Results showed that plasma EPA and DHA concentrations increased significantly more (P < .001) in the krill oil (178.4 +/- 38.7 and 90.2 +/- 40.3 micromol/L, respectively) and menhaden oil (131.8 +/- 28.0 and 149.9 +/- 30.4 micromol/L, respectively) groups than in the control group (2.9 +/- 13.8 and -1.1 +/- 32.4 micromol/L, respectively). Systolic blood pressure declined significantly more (P < .05) in the menhaden oil (-2.2 +/- 2.0 mm Hg) group than in the control group (3.3 +/- 1.5 mm Hg), and the response in the krill oil group (-0.8 +/- 1.4 mm Hg) did not differ from the other 2 treatments. Blood urea nitrogen declined in the krill oil group as compared with the menhaden oil group (P < .006). No significant differences for other safety variables were noted, including adverse events. In conclusion, 4 weeks of krill oil supplementation increased plasma EPA and DHA and was well tolerated, with no indication of adverse effects on safety parameters.

Capabilities of methanol extracts from oregano and rosemary in retarding oxidation of long-chain polyunsaturated fatty acids, docosahexaenoic acid C22:6 (DHA) and eicosapentaenoic acid C20:5 (EPA), in menhaden oil were investigated. The fish oils after mixing with the extracts at different concentrations were oxidized in an accelerated study by heating at 150 degrees C for 30 min or incubating at 60 degrees C for 5 d. After heating at 150 degrees C, only 15.9% of DHA and 18.5% of EPA remained in the fish oil without extract, while 38.8% to 65.9% of DHA and 44.7% to 69.0% of EPA were retained in the fish oil mixed with 1% to 5% of oregano extract. The highest retained DHA (56.9%) and EPA (58.0%) in the fish oils mixed with rosemary extract were observed at 2.5% addition. Increasing rosemary extract to 5% lowered its capability of inhibiting DHA and EPA oxidation. After incubation at 60 degrees C for 5 d, the highest inhibition capability was also found at 2.5% of added rosemary extract, and the oil retained 88.2% DHA and 88.3% EPA. However, only 18.8% DHA and 23.6% EPA were retained in the fish oil mixed with 5% of oregano extract and no DHA and EPA were detected in the fish oil without extract after 5-d incubation at 60 degrees C. Thus, antioxidant activity of the rosemary extract was greater than that of oregano extract, but was sensitive to heat. The rosemary extract also demonstrated higher DPPH (2,2'-diphenyl-1-picrylhydrazyl) free radical scavenging capability, which was approximately 3 times higher than oregano extract, although there was no significant difference in the total phenolic contents between both extracts.

An organic solvent-stable lipase from Proteus vulgaris K80 was used to produce the omega-3 polyunsaturated fatty acid ethyl esters (ω-3 PUFA EEs). First, the lyophilized recombinant lipase K80 (LyoK80) was used to perform the transesterification reaction of menhaden oil and ethanol. LyoK80 produced the ω-3 PUFA EEs with a conversion yield of 82 % in the presence of 20 % water content via a three-step ethanol-feeding process; however, in a non-aqueous condition, LyoK80 produced only a slight amount of the ω-3 PUFA EEs. To enhance its reaction properties, the lipase K80 was immobilized on a hydrophobic bead to derive ImmK80; the biochemical properties and substrate specificity of ImmK80 are similar to those of LyoK80. ImmK80 was then used to produce ω-3 PUFA EEs in accordance with the same transesterification reaction. Unlike LyoK80, ImmK80 achieved a high ω-3 PUFA EE conversion yield of 86 % under a non-aqueous system via a one-step ethanol-feeding reaction. The ω-3 PUFA EEs were purified up to 92 % using a urea complexation method.

Weanling male Wistar rats fed a choline-deficient diet develop acute kidney injury. Menhaden oil, which is a very important source of omega-3 fatty acids, has a notorious protective effect. The mechanism of this protection is unknown; one possibility could be that menhaden oil changes renal lipid profile, with an impact on the functions of biological membranes. The aim of this work was to study the renal lipid profile in rats fed a choline-deficient diet with menhaden oil or vegetable oil as lipids. Rats were divided into 4 groups and fed four different diets for 7 days: choline-deficient or choline-supplemented diets with corn and hydrogenated oils or menhaden oil. Serum homocysteine, vitamin B12, and folic acid were analyzed. Renal lipid profile, as well as the fatty acid composition of the three oils, was measured. Choline-deficient rats fed vegetable oils showed renal cortical necrosis. Renal omega-6 fatty acids were higher in rats fed a choline-deficient diet and a choline-supplemented diet with vegetable oils, while renal omega-3 fatty acids were higher in rats fed a choline-deficient diet and a choline-supplemented diet with menhaden oil. Rats fed menhaden oil diets had higher levels of renal eicosapentaenoic and docosahexaenoic acids. Renal myristic acid was increased in rats fed menhaden oil. The lipid renal profile varied quickly according to the type of oil contented in the diet. Fil: Ossani, Georgina Paula. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Denninghoff, Valeria Cecilia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; Argentina Fil: Uceda, Ana Margarita. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina Fil: Díaz, Maria L.. Hospital Británico de Buenos Aires; Argentina Fil: Uicich, Raúl. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina Fil: Monserrat, Alberto Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología. Centro de Patología Experimental; Argentina

Fish oil made from menhaden (Brevoortia tyrannus) can be used as a dietary supplement for the presence of high levels of the long-chained omega-3 fatty acids, viz. epentaenoic and docosahexanoic. In this work, for the first time, two different multidimensional approaches were developed and compared, in terms of peak capacity, for triacylglycerol characterization. In particular, silver ion chromatography with a silver-ion column and non-aqueous reverse-phase liquid chromatography with a C18 column were tested in both comprehensive (stop-flow) and off-line modes. The use of mass spectra attained by atmospheric pressure chemical ionization for both LC approaches, and the fatty acids methyl esters profile of menhaden oil obtained by gas chromatography analysis, greatly supported the elucidation of the triacylglycerol content in menhaden oil. The off-line approach afforded a better separation and, thus, higher peak capacity to allow identifying and semiquantifying more than 250 triacylglycerols. Such a huge number has never been reported for a menhaden oil sample.The main disadvantage of such an approach over the stop-flow one was the longer analysis time, mainly attributable to solvent exchange between the two dimensions.

The kinetics of the lipase-catalyzed (Pseudomonas cepacia) ethanolysis of fish oil has been studied in a batch reactor using menhaden oil, tuna oil, and acylglycerol mixtures derived from menhaden oil. Multi-response models derived from a generalized Michaelis-Menten mechanism were developed to describe the rates of formation of ethyl esters of the primary fatty acids present in the precursor oil. A first-order model for deactivation of the lipase was fit simultaneously to one of the data sets.

The effects of maternal and starter diet polyunsaturated fatty acid (PUFA) composition on the tocopherol (TOC) status of posthatch chicks were investigated. Fertile eggs enriched with long chain n-3, 18:3 n-3 or 18:2 n-6 PUFA were incubated. The eggs were collected from hens fed diets containing 3.5% menhaden oil (MO), linseed oil (LO), or sunflower oil (SO) and a vitamin E mix containing 400 microg/g total TOC. Posthatch chicks from MO, LO, or SO were fed starter diets containing 3.5% MO, LO, or SO along with vitamin E mix containing 48 microg/g total TOC. Tissues (liver, blood, brain) were collected on d 0 (day of hatch), 7, 14, and 21 posthatch. On d 0, MO chicks had the lowest liver and plasma TOC (P0.05). A rapid depletion of liver and plasma TOC was observed on d 7 and 14 posthatch (P0.001) and was lower in MO chicks (P0.05) than LO. When compared with d 0, a 98% decrease of tocopherol on d 7 was observed for chicks from all treatments. No changes due to age or diet PUFA was observed in the brain TOC status. Data showed that maternal and starter diet PUFA could alter the TOC status of chicks in early life.

We investigated the effect of dietary conjugated linoleic acid (CLA) along with n-3 polyunsaturated fatty acid (n-3 PUFA) on yolk fatty acid composition and volatile compounds in eggs that were raw (RA), hard-boiled (HB), or hard-boiled, irradiated (HBI, 2.5 kGy). Single Comb White Leghorn laying hens (n = 40) were randomly assigned to one of the four experimental diets containing 0, 0.5, 1.0, or 2.0% CLA. Menhaden oil was used as the source of n-3 PUFA. Eggs collected after 6 wk of feeding were analyzed for fatty acids and volatile compounds. The content of docosahexaenoic acid (C22:6 n-3) was reduced (P0.05) in eggs from hens fed the 2.0% CLA diet. Eggs from hens fed 0.5% CLA incorporated the highest concentration of docosahexaenoic acid (P0.05) with a concomitant reduction in arachidonic acid (P0.05). The yolk contents of cis-9 trans-11 CLA and trans-10 cis-12 CLA increased linearly (P0.05) as the dietary CLA supply increased. Total monounsaturates were reduced (P0.05) with an increase in saturates in yolk. No difference was observed in the total PUFA content of eggs. Total volatiles were reduced in RA eggs from 1.0 and 2.0% CLA diets. 2-Propanone, hexane, and methyl cyclopentane were the major volatiles in RA eggs and were reduced by dietary CLA at 1.0 and 2.0%. Acetaldehyde, pentane, propanol, acetic acid methyl ester, acetic acid ethyl ester, propionic acid methyl ester, 2-methylmethyl propionic acid, 2-propanone, and octane were the major volatiles in HB eggs and were reduced by 2.0% CLA (P0.05). No difference was observed in the acetaldehyde, pentane, propanol, acetic acid ethyl ester, octane, or total volatile content of HBI eggs.

Hemoglobin-mediated lipid oxidation in washed, minced cod muscle was related to the triacylglycerol to membrane lipid ratio. The same rapid development of thiobarbituric acid reactive substances (TBARS) and painty odor occurred with and without the presence of up to 15% menhaden oil. Without hemoglobin, development of TBARS and painty odor was slow, despite a high amount of hydroperoxides in samples with oil added (1135 micromol/kg muscle). This suggested that hemoglobin reacted by cleaving preformed hydroperoxides into secondary oxidation products. Nearly doubling the hemoglobin concentration approximately doubled the extent of lipid oxidation with and without added oil. This indicated that hemoglobin was limiting for the oxidation reaction. The noneffect of added oil suggests that membrane lipids and/or preformed membrane lipid hydroperoxides provided sufficient substrate in hemoglobin-catalyzed oxidation of washed minced cod muscle. Fe(2+-)ADP did not induce any oxidation of washed minced cod with/without added oil. Results suggest that lipid oxidation in fatty fish may be more related to the quantity and type of the aqueous pro-oxidant and the membrane lipids than to variations in total fat contents.

Feeding menhaden oil, high in n-3 fatty acids, or a mixture of lard and corn oil with a polyunsaturated-to-monounsaturated fatty acid ratio of 1:1 was hypothesized to inhibit promotion of hepatocarcinogenesis in rats by decreasing hepatic prostaglandin (PG) levels. Ten-day-old female Sprague-Dawley rats were injected with diethylnitrosamine (DEN, 15 mg/kg body wt ip). At 4 wk of age, rats were fed fumonisin B1(50 mg/kg diet) for 5 wk in diets containing 14% lard + 6% corn oil, 10% lard + 10% corn oil, 14% menhaden oil + 6% corn oil, and 7% menhaden oil + 13% corn oil. Plasma alanine aminotransferase activity was 20% lower in rats fed 10% lard than in rats fed the other diets (P0.05). In menhaden oil-fed rats, total plasma cholesterol concentrations decreased 26% (P0.05) and hepatic phospholipid C20:5n-3, C22:5n-3, and C22:6n-3 fatty acid concentrations increased compared with lard-fed rats. Hepatic n-3 fatty acids were threefold greater in rats fed 10% lard than in rats fed 14% lard. The liver-associated natural killer cell activity in rats fed menhaden oil was 58% lower than in rats fed lard (P0.03). Rats fed lard had threefold (P0.05) greater area of _-glutamyltransferase-positive altered hepatic foci (AHF) than did rats fed menhaden oil. There was no significant difference in placental glutathione S-transferase-positive AHF among the groups. Hepatic PGF2alpha production was 60-80% greater in rats fed 14% lard than in rats fed the other diets (P0.05). Hepatic PGE2 was 48% less in rats fed 14%; menhaden oil than in rats fed 14% lard (P0.05). Although gamma-glutamyltransferase-positive focal area was inhibited by menhaden oil, only 14% menhaden oil inhibited PGE2. Feeding 10% lard inhibited PGF2alpha, but not the development of AHF. Therefore, decreased hepatic PGs did not explain the inhibition of carcinogenesis.

The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids in the regulation of triglyceridemia in rats. Male Sprague-Dawley rats (n = 56) were subjected to 28-d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14% w/w): (i) casein-menhaden oil, (ii) casein-beef tallow, (iii) soy protein-menhaden oil, and (iv) soy protein-beef tallow. Significant protein-lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect on post-heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil.

The effect of the water content on the lipase-catalyzed (Candida rugosa) interesterification (acidolysis) of menhaden oil with conjugated linoleic acid was studied for amounts of added water ranging from 0-4% (w/w). The rate of the acidolysis reaction increased with increasing water content, but the corresponding percentage of n-3 fatty acids liberated also increased. The implications of water content for minimization of the release of n-3 fatty acid residues while maximizing incorporation of CLA are discussed.

cope : Skeletal health is a lifelong process impacted by environmental factors, including nutrient intake. The n-3 source and PUFA ratio affect bone health in growing rats, or following ovariectomy (OVX), but no study has investigated the longitudinal effect of PUFA-supplementation throughout these periods of bone development. Methods and results : One month old, Sprague-Dawley rats (n = 98) were randomized to receive 1 of 4 diets from 1 through 6 months of age. Diets were modified from AIN-93G to contain a varying amount and source of n-3 (flaxseed versus menhaden oil) to provide an n-6 to n-3 ratio of 10:1 or 5:1. At 3 (prior to SHAM or OVX) and 6 months of age, bone microarchitecture of the tibia was quantified using in vivo micro-computed tomography (SkyScan 1176, Bruker microCT). Providing 5:1 (flaxseed) resulted in lower trabecular thickness and medullary area and greater cortical area fraction during growth compared to diets with a 10:1 PUFA ratio, but many of these differences were not apparent following OVX. Conclusion : PUFA-supplementation at levels attainable in human diet modulates some bone structure outcomes during periods of growth, but is not an adequate strategy for the prevention of OVX-induced bone loss in rats This article is protected by copyright. All rights reserved

The purpose of this study was to determine the effect of supplementing the diet of type 1 diabetic rats with menhaden oil on diabetic neuropathy. Menhaden oil is a natural source for n-3 fatty acids, which have been shown to have beneficial effects in cardiovascular disease and other morbidities. Streptozotocin-induced diabetic rats were used to examine the influence of supplementing their diet with 25% menhaden oil on diabetic neuropathy. Both prevention and intervention protocols were used. Endpoints included motor and sensory nerve conduction velocity, thermal and mechanical sensitivity, and innervation and sensitivity of the cornea and hindpaw. Diabetic neuropathy as evaluated by the stated endpoints was found to be progressive. Menhaden oil did not improve elevated HbA1C levels or serum lipid levels. Diabetic rats at 16-wk duration were thermal hypoalgesic and had reduced motor and sensory nerve conduction velocities, and innervation and sensitivity of the cornea and skin were impaired. These endpoints were significantly improved with menhaden oil treatment following the prevention or intervention protocol. We found that supplementing the diet of type 1 diabetic rats with menhaden oil improved a variety of endpoints associated with diabetic neuropathy. These results suggest that enriching the diet with n-3 fatty acids may be a good treatment strategy for diabetic neuropathy.

A study was conducted to examine the effects of dietary conjugated linoleic acids (CLA; 0, 0.5 or 1.0 g/100 g total CLA) and lipid source (menhaden oil, soybean oil or a 1:1 mixture of menhaden:soybean oil) on growth rates and fatty acid composition of yellow perch. Dietary treatments were fed to apparent satiation to triplicate groups of fish initially weighing 37.9 g/fish. At the end of the 9-wk feeding trial, no significant differences were detected in weight gain or feed intake among fish fed any of the dietary treatments. Dietary CLA, lipid source and/or their interaction significantly affected feed efficiency, total liver lipid concentration, and muscle and liver fatty acid concentrations. Feed efficiency (g gain/g feed) was significantly lower in fish fed diets containing soybean oil (0.51) compared with fish fed menhaden oil (0.58) or menhaden:soybean oil (0.60). Liver total lipid concentrations were significantly reduced in fish fed 0.5 and 1.0 g/100 g CLA compared with fish fed the diets containing no CLA and in fish fed menhaden oil compared with those fed soybean oil or a 1:1 mixture of menhaden:soybean oil. Total CLA levels increased in both liver and muscle as dietary CLA concentration increased, irrespective of lipid source. However, total CLA concentrations were significantly lower in liver and muscle of fish fed soybean oil. Total muscle CLA concentrations were 0, 1.26 and 2.92 g/100 g fatty acids in fish fed diets containing menhaden oil and 0, 0.5 and 1.0 g/100 g CLA, respectively. Mono- and polyunsaturated fatty acid (PUFA) concentrations were significantly lower in muscle and liver of fish fed CLA compared with fish fed the diets containing no CLA. In contrast, liver concentrations of saturated fatty acids, 14:0, 16:0 and 18:0, were significantly higher in fish fed 1.0 g/100 g CLA.

Lipase-catalyzed acidolysis of p-coumaric acid with seal blubber oil (SBO) and menhaden oil (MHO) was carried out, followed by identification of major phenolipids in the resultant acidolysis mixture using high-performance liquid chromatography/mass spectrometry. Separation of phenolipid components from the resultant acidolysis mixture was achieved using flash column chromatography. The antioxidant activities of the phenolipids were examined in in vitro assays and biological model systems. The major phenolipids identified from acidolysis mixtures with both SBO and MHO included eight phenolic monoacylglycerols and eight phenolic diacylglycerols. Phenolipids derived from SBO and MHO generally showed good antioxidant potential in the systems tested. The prepared phenolipids exhibited high scavenging capacity toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) and peroxyl radicals and displayed reducing power, strong inhibitory effect on bleaching of β-carotene, human low-density lipoprotein (LDL) cholesterol oxidation, as well as radical-induced DNA cleavage, thus suggesting that phenolipids derived from omega-3 oils may be used as potential stable products for health promotion and disease risk reduction.

Sprague-Dawley rats were fed purified diets varying in both protein (20%) and lipid (11%) content for 28 d to verify the independent and interactive effects of dietary proteins and lipids on serum and hepatic lipids, and on tissue lipoprotein lipase (LPL) activity in both fasted and postprandial states. These diets consisted of either casein-menhaden oil, casein-coconut oil, soy protein-menhaden oil (SPMO), soy protein-coconut oil, cod protein-menhaden oil, or cod protein-coconut oil. A randomized 3 x 2 factorial design was used. A significant protein-lipid interaction was seen on serum triglyceride levels: menhaden oil, compared with coconut oil, induced a decrease in serum triglyceride levels when combined with soy protein but not when combined with cod protein and casein. The lower serum triglyceride concentrations observed in the SPMO-fed rats could be the result of decreased hepatic triglycerides when soy protein was compared with casein and when menhaden oil was compared with coconut oil. Total LPL activity in the heart was higher in menhaden oil-fed rats than in coconut oil-fed rats in the postprandial state. The higher LPL activity in the heart could, however, explain only 10% of the reduction of serum triglycerides, contributing slightly to the lowering effects of SPMO diet on serum triglycerides. Therefore, the present results indicate that dietary proteins can modulate the effects of fish oil on triglyceridemia in the rat, and that could be mainly related to specific alterations in hepatic lipid concentrations.

Although fish oil supplementation may prevent the onset of diet-induced insulin resistance in rats, it appears to worsen glycemic control in humans with existing insulin resistance. In the present study, the euglycemic, hyperinsulinemic (4× basal) clamp technique with [3-3H]glucose and 2-deoxy-[1-14C]glucose was used to directly compare the ability of fish oil to prevent and reverse sucrose-induced insulin resistance. In study 1 (prevention study), male Wistar rats were fed a purified high-starch diet (68% of total energy), high-sucrose diet (68% of total energy), or high-sucrose diet in which 6% of the fat content was replaced by menhaden oil for 5 wk. In study 2 (reversal study), animals were fed the high-starch or high-sucrose diets for 5 wk and then the sucrose animals were assigned to one of the following groups for an additional 5 wk: high starch, high sucrose, or high sucrose with 6% menhaden oil. Rats fed the high-starch diet for 10 wk served as controls. In study 3 (2nd reversal study), animals followed a similar diet protocol as in study 2; however, the reversal period was extended to 15 wk. In study 1, the presence of the fish oil in the high-sucrose diet prevented the development of insulin resistance. Glucose infusion rates (GIR, mg ⋅ kg−1⋅ min−1) were 17.0 ± 0.9 in starch, 10.6 ± 1.7 in sucrose, and 15.1 ± 1.5 in sucrose with fish oil animals. However, in study 2, this same diet was unable to reverse sucrose-induced insulin resistance (GIR, 16.7 ± 1.4 in starch, 7.1 ± 1.5 in sucrose, and 4.8 ± 0.9 in sucrose with fish oil animals). Sucrose-induced insulin resistance was reversed in rats that were switched back to the starch diet (GIR, 18.6 ± 3.0). Results from study 3 were similar to those observed in study 2. In summary, fish oil was effective in preventing diet-induced insulin resistance but not able to reverse it. A preexisting insulin-resistant environment interferes with the positive effects of menhaden oil on insulin action.

We investigated the effects of dietary menhaden oil on cyclophosphamide (CP) antineoplastic activity and its protective effect against CP toxicity. We found that dietary menhaden oil (HMO, 20% menhaden oil + 5% corn oil) enhanced the CP antitumor effect at the lowest dose tested (50 mg/kg) compared with the control group (LCO, 5% corn oil). Dietary HMO and CP treatment had a significant effect on the activities of tumor and liver microsomal cytochrome P-450 (CYP) over the controls. Activity of one of the key CP activating enzymes, CYP2B1 (which is similar to human CYP2B6), was significantly enhanced in the liver and tumor by the HMO diet, which could result in the formation of more pharmacologically active CP metabolites and, therefore, increased CP antitumor response. Moreover, the HMO diet exhibited a very significant protective effect against CP acute toxicity. The activity of the CP detoxifying enzyme aldehyde dehydrogenase (ADH) was significantly increased in the liver after HMO feeding; thus the observed protective effect of HMO feeding against CP toxicity may be partially the result of induction of ADH activity in the liver. In summary, our findings suggested that dietary menhaden oil can modulate ADH and CYP activities in a manner that may alter the metabolism of CP and, therefore, improve its therapeutic index by increasing its therapeutic effect and decreasing its toxicity.

The purpose of Study 1 was to examine the effect of dietary soy on the progression of MDA-MB-435 human breast cancer cell solid tumors in nude mice. When toasted soy chips were fed at levels of 5%, 10%, or 20% (wt/wt) in a high-fat, linoleic acid-rich diet for 12 weeks, there was a trend for larger mammary fat pad tumors to occur with increasing soy intake. However, compared with the controls the severity of macroscopic lung metastasis was reduced significantly in the groups fed 10% and 20% soy. Study 2 compared the effects of diets containing 23% corn oil (CO), 18% menhaden oil (MO) + 5% CO, 18% MO + 5% CO + 10% soy chips, and MO or soy-supplemented diets + indomethacin treatment in the same animal model. Feeding the 18% MO diet without soy or indomethacin reduced primary tumor growth; statistically significant effects were not observed in any of the other groups. All three of the groups with MO supplementation showed a reduction in the occurrence and severity of macroscopic lung metastases, together with the expected decreases in tumor prostaglandin E levels. These effects were most pronounced when MO was combined with indomethacin treatment. When indomethacin was given with dietary soy, the previously reported suppressive effect of the cyclooxygenase inhibitor on MDA-MB-435 cell tumor progression was lost, despite reductions in tumor prostaglandin E concentrations.