Menhaden Oil Diet Research Articles

Dietary n-3 polyunsaturated fatty acids alter lipid composition and decrease prostaglandin synthesis in rat spleen

Three groups of rats were fed a semisynthetic diet containing 10% olive oil, 10% corn oil, or 10% menhaden oil for three weeks. Olive oil was used as a control and corn and menhaden oils as sources of n-6 and n-3 fatty acids, respectively. The spleen phospholipids were enriched with eicosapentaenoic (20:5 n-3) and docosahexaenoic acids (22:6 n-3) in rats on menhaden oil diets. The enrichment of these n-3 fatty acids was accompanied by a decrease in the arachidonic acid content (20:4 n-6) of spleen phospholipids. The syntheses of prostaglandin E 2 (PGE 2), 6-keto prostaglandin F 1α (6 keto PGF 1α) and thromboxane B 2 (TXB 2) from endogenous substrates in n-3 fatty acid enriched spleens were decreased by 50, 57 and 80% respectively. These studies indicate that dietary n-3 fatty acids can effectively displace arachidonic acid from phospholipids and decrease prostaglandin synthesis in rat spleen.

Effect of dietary fish oil on myocardial phospholipids and myocardial ischemic damage.

The effect of dietary fish oil on myocardial phospholipids and ischemic damage to the heart was studied in the rat. Four weeks of feeding 5% (i.e., 12 energy percent) menhaden oil (MO) produced both profound changes in the fatty acyl composition of phospholipids in myocardial membranes and a significant reduction in the loss of creatine kinase following coronary artery ligation compared with feeding 5% (i.e., 12 energy percent) corn oil (CO). The MO diet did not change the content of either phospholipids or cholesterol in the heart. However, dietary MO resulted in significant elevations in the percent of fatty acids in the total phospholipids that were saturated, the n-3/n-6 ratio and the double-bond index. The changes in total phospholipids were not uniform for all phospholipid classes. Although the n-3/n-6 ratio was increased in each of the individual phospholipids examined, the predominant n-3 fatty acid incorporated (i.e., 20:5, 22:5, 22:6) differed among the major phospholipid classes. Also, the percent saturation was elevated in phosphatidylcholine with no change in double-bond index, whereas both the percent saturation and double-bond index were elevated in phosphatidylethanolamine. Thus dietary MO resulted in selective alterations in individual myocardial phospholipids. These membrane changes may be involved in the observed reduction of ischemic damage in the heart.

Phenobarbital depression of hepatic microsomal benzo[a]pyrene hydroxylation in rats starved and refed a diet containing menhaden fish oil: substrate and fat level dependency.

The influence of phenobarbital on the activity of hepatic mixed function oxidases responsible for benzo[a]pyrene hydroxylation was studied in rats fed diets containing menhaden fish oil (rich in n-3 fatty acids). Male rats were starved for 2 days and refed diet devoid of fat or containing 0.5, 10, or 20% menhaden oil for 4 days. Phenobarbital increased the apparent Km value as well as Vmax for benzo[a]pyrene hydroxylase in microsomes from rats fed the 20% menhaden oil diet. The increased Km was due to a progressive decrease in benzo[a]pyrene metabolism at the lower substrate concentrations, even in the presence of increased cytochrome P-450 content. The phenobarbital-induced increase in Km and the decreases in benzo[a]pyrene hydroxylation were not observed in rats fed 0.5% menhaden oil or a diet devoid of fat.

BP metabolism and the in vivo binding to hepatic DNA of rats fed diets containing menhaden fish oil.

It is well established that dietary polyunsaturated omega-6 fatty acids promote tumorigenesis and support the activity of mixed-function oxidases (MFO), which are responsible for carcinogen activation. This study was undertaken to determine if increased levels of dietary menhaden fish oil (rich in omega-3 fatty acids) would affect in vivo binding of [3H]benzo[a]pyrene (BP) to rat liver DNA. The effects of dietary menhaden oil on the activities of phase I and phase II drug-metabolizing enzymes were also studied to determine the possible relationships between the activity of these enzymes and the binding of [3H]BP metabolites to liver DNA. Following a single intraperitoneal injection of [3H]BP, more BP was bound to liver DNA recovered from rats fed diet containing 20% menhaden oil for 11 days at all time intervals tested (16, 24, 48, and 192 hours) than was bound from rats fed 0.5% menhaden oil. The increased binding of [3H]BP to liver DNA of rats fed the high level of menhaden oil may be due, in part, to increases in the MFO responsible for BP activation (as suggested by increased cytochrome P-450 level and total BP hydroxylase activity). The higher concentrations of radioactivity extracted from blood of rats fed 20% menhaden oil diet at the initial time periods (16 and 24 hours) may be a reflection of the greater capacity of the liver to metabolize BP to more water-soluble metabolites. The maximum velocity (Vmax) for ethoxycoumarin O-dealkylase, expressed as nanomoles per milligram protein or per gram liver, was increased three- to fourfold by feeding the high level of menhaden oil. The differences in these enzymatic responses suggest that certain form(s) of cytochrome P-450 are preferentially increased by feeding the omega-3 fatty acids of menhaden oil.

Dietary n-3 Polyunsaturated Fatty Acids: Modification of Rat Cardiac Lipids and Fatty Acid Composition

The effects of 5, 10 and 20% dietary menhaden oil (MO) on the composition of heart lipid classes and fatty acids were studied. Male Sprague-Dawley rats were fed ad libitum 0, 5, 10 and 20% MO for 3 wk. The heart phosphoglyceride content and composition and cholesterol were unchanged by dietary MO. A nonlinear dose-response relationship was observed between dietary MO levels and fatty acid compositional changes. Cardiolipin, choline (PC), ethanolamine (PE) and serine/inositol (PS/PI) phosphoglycerides showed an incorporation of n-3 fatty acids, eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3), between the control and 5% MO group, a plateau between the 5 and 10% MO groups and a further increase at the 20% MO level. The initial reduction in 20:4n-6 content remained unchanged as dietary MO increased except in PE where a further reduction was found at the 20% MO level. Dietary MO did not significantly change the 20:4n-6 content in neutral lipids. Linoleic acid content was most resistant to dietary MO removal. The level of 18:2n-6 was significantly lowered in heart PC when rats were fed 10% MO. No significant differences were found in PS/PI. In PE and NL significant differences occurred only when rats were fed 20% MO. The significant fatty acid modifications of heart lipid and PL found between the control and lowest level of dietary MO (5%) suggest that dietary fish oil supplementation in human diets may not be required for this effect.

Growth Response of Blue Tilapias to Selected Levels of Dietary Menhaden and Catfish Oils

Abstract Blue tilapia (Tilapia aurea) fingerlings were fed a series of nine semipurified diets containing 0, 2.5, 5.0, 7.5 or 10% lipid in the form of menhaden oil or catfish oil over a 10-week experimental period. The study, conducted in flow-through aquaria, demonstrated that best growth and food conversions were obtained from fish fed the 10% menhaden oil diet. Total levels of the linolenic family (ω-3) of fatty acids were highest in the menhaden oil diets (up to 2.5%). In no instance did linolenic acid reach 1.0% of the total diet. That result supports the conclusion that growth reductions observed in tilapia and other fish species fed diets approaching 1% dietary linolenic acid are due to that specific fatty acid, and are not caused by the addictive effect of dietary ω-3 fatty acids.

Dietary fish oil reduces progression of established renal disease in (NZB x NZW)F1 mice and delays renal disease in BXSB and MRL/1 strains.

Previous studies have shown that dietary marine lipids containing large quantities of n-3 polyunsaturated fatty acids, administered to (New Zealand black X New Zealand white)F1 and MRL-lpr/lpr mice before the development of renal disease, reduce the severity of glomerulonephritis in mice of these strains. The present study demonstrated that delayed administration of a marine lipid diet, 25% menhaden oil (MO) by weight, until after the onset of overt renal disease, also resulted in significant improvement in rates of mortality, proteinuria, and histologic evidence of glomerular injury, compared with control animals fed a diet that contained mostly saturated fatty acids, 25% beef tallow. The MO diet also reduced the histologic severity of renal disease in male BXSB/MpJ and male MRL-lpr/lpr mice. In contrast, necrotizing vasculitis was more frequent in small and medium-sized renal arteries of the MRL-lpr/lpr mice fed MO than in those fed beef tallow (33.4% versus 7.6%, respectively).

The effect of a menhaden oil-containing diet on hemostatic and lipid parameters of nonhuman primates with atherosclerosis

Three species of nonhuman primates were fed an atherogenic diet for 6 months (baseline period) and a menhaden oil (EPA)-containing diet for 8 weeks (test period) during which various hemostatic and lipid parameters were compared. The EPA-rich diet prolonged bleeding times, inhibited platelet aggregation response to ADP and collagen, and increased mean platelet lifespan. This diet elicited an increase in the polyunsaturated fatty acids C20 : 5 (EPA) and C22 : 6 (docosahexaenoic acid) at the expense of C18 : 2 (linoleic acid) and C20 : 4 (arachidonic acid) in pooled samples of platelet membranes, creating an increase in the ratio of n-3/n-6 polyunsuturated fatty acids. The serum lipid response to a menhaden oil diet comprised a nonsignificant decrease in total serum cholesterol and a significant decrease in HDL cholesterol.

The protective effect of dietary fish oil on murine lupus

Dietary marine lipids markedly reduce the severity of glomerulonephritis and its associated mortality in inbred strains of mice developing autoimmune disease, a model for human systemic lupus erythematosus. We report here the influence of varying the dose of menhaden oil and the timing of its administration on the mortality of female (NZB x NZW) F 1 mice. After ingesting 25 wt% menhaden oil (MO) for periods of 1.5 weeks to 12 months, there was a stable content of tissue n-3 fatty acids, with total n-3 fatty acids of 28% and 35% in spleen and liver, respectively. The extent of protection from mortality was dependent on the dose of MO with marked protection at doses of 11 to 25%, marginal protection at 5.5% and no protection at 2.5% MO. Delay in the institution of MO until ages 5 or 7 months still resulted in large reductions of mortality. Conversely, institution of a MO diet from 6 weeks until ages 5 to 7 months followed by a change to beef tallow resulted in little protection. Serum levels of 4 cyclooxygenase products were reduced ranging from 26 to 76% in mice fed MO diets, compared to mice fed beef tallow, based on radioimmunoassay. The degree of reduction of mortality on different doses of MO was correlated best with tissue levels of C22:5, and levels of C20:5 and C22:6 were similar at high and low doses of MO, suggesting that levels of 22:5 may be related to the protective effects of marine lipids on autoimmune disease.

Dietary Effects of Menhaden Oil on the Growth and Membrane Lipid Composition of Rat Mammary Tumors234

The objective of this study was to evaluate the effect of quantitative differences in dietary menhaden oil, an n-3 polyunsaturated marine oil, on mammary tumor development and to compare these results with those produced by corn oil, an n-6 polyunsaturated vegetable oil. Inbred female BUF rats were treated with the carcinogen N-methyl-N-nitrosourea (CAS: 684-93-5) and maintained on diets containing graded levels of each of the respective oils. Our results indicated that diets containing 20% menhaden oil produced a reduction in tumor incidence and a prolongation of the tumor latent period. This finding contrasted sharply with the enhanced tumor development and shortened latent period observed in the animals fed the equivalent dietary level of corn oil. Fatty acid analyses performed on the lipids extracted from the tumor and hepatic microsomes of the animals on the menhaden oil diets demonstrated that the proportion of eicosapentaenoic acid (No. of C-atoms:No. of double bonds = 20:5) present in these microsomal lipids was related inversely to mammary tumor development.

Effects of pair-feeding and a menhaden oil diet on survival to endotoxin in guinea pigs : E.A. Mascioli, Y. Iwasa, S. Trimbo, B.R. Bistrian, G.L. Blackburn. (Department of Medicine and Surgery, Harvard Medical School, and Travenol Laboratories, Boston, MA, USA)

Effects of pair-feeding and a menhaden oil diet on survival to endotoxin in guinea pigs : E.A. Mascioli, Y. Iwasa, S. Trimbo, B.R. Bistrian, G.L. Blackburn. (Department of Medicine and Surgery, Harvard Medical School, and Travenol Laboratories, Boston, MA, USA)

Dietary menhaden oil lowers plasma prostaglandins and calcium in mice bearing the prostaglandin-producing HSDM1 fibrosarcoma.

The omega 3 class of polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA, 20:5), has been shown to alter the patterns of arachidonic acid (20:4) metabolism in both in vitro and in vivo systems. To examine further the role of arachidonic acid conversion to prostaglandins (PG) in hypercalcemic mice bearing the PG-producing HSDM1 fibrosarcoma, we have performed experiments in which control and tumor-bearing animals were fed diets either low (0.1-0.2% of total fatty acid) or high (17%) in EPA. In all five experiments performed, tumor-bearing mice eating control diets had markedly elevated (average sixfold above control) plasma concentrations of 13,14-dihydro-15-keto-PGE2 (PGE2-M), while in mice bearing HSDM1 tumors and eating the EPA-enriched menhaden oil diet, the elevation was reduced to only twice control values. The increase in plasma calcium concentration (approximately 2.5 mg/dl above control) in tumor-bearing animals was also reduced significantly (P less than 0.05) to only 1.3 mg/dl above control in mice eating the diet enriched in EPA. Plasma immunoreactive hydroxy fatty acids (i12-HETE) and sulfidopeptide leukotrienes (iSRS) were not elevated in tumor-bearing mice and were unaffected by diet. The contents of PGE2, PGF2 alpha, and 6-keto-PGF1 alpha were lower in tumor tissue from animals eating the diet high in EPA, whereas the tissue contents of i12-HETE and iSRS were not altered by diet. Fatty acid analysis of liver and tumor tissue revealed marked increases in certain omega 3 fatty acids (20:5, 22:5, and 22:6) from animals eating the enriched diet. Body weights, tumor weights, and tumor histology were not significantly altered by diet. To determine whether dietary calcium played a role in the elevation of plasma calcium in mice bearing the HSDM1 tumor and the reduction of plasma calcium in animals fed EPA, we compared results in mice fed diets containing 0.80% (normal) and 0.015% (deficient) calcium. The increases in plasma calcium and PGE2-M observed in tumor-bearing mice were the same on both normal and very low calcium intakes. We conclude, in mice of the Swiss albino strain bearing the HSDM1 fibrosarcoma, that consumption of a diet enriched in EPA reduces the production of cyclooxygenase products of arachidonic acid metabolism and thereby reduces the elevation of plasma calcium concentration. Dietary enrichment with EPA did not alter the production of serologically determined lipoxygenase products of arachidonic acid.

Reduction in thromboxane formation by n-3 fatty acids enriched lung microsomes from rat and guinea pig following the ingestion of dietary menhaden oil

Feeding rats and guinea pigs on a diet containing 5% menhaden oil altered the fatty acid composition of lung microsomes. The lung microsomal phospholipids contained increased amounts of n-3 fatty acids, eicosapentaenoic (20:5) and docosahexaenoic acid (20:6), following the ingestion of menhaden oil. There was a concomitant decrease in arachidonic acid (20:4) levels in rat lung microsomes, but no significant change of this fatty acid was observed in the microsomes from guinea pigs. The ability of lung microsomes to convert 14C-arachidonic acid. into thromboxane (TXB) was reduced by the enrichment of n-3 fatty acids in the microsomal lipids.

Effects of dietary enrichment with eicosapentaenoic acid upon autoimmune nephritis in female NZB X NZW/F1 mice.

A menhaden oil diet, rich in eicosapentaenoic acid, protected female NZB X NZW/F1 mice from autoimmune nephritis. Only 15% of mice treated with the diet from weaning had died with severe renal disease at 19 months, versus 98% of controls on a beef tallow diet. The menhaden oil also protected these mice from renal disease when instituted at 4 and 5 months of age and, under these conditions, levels of anti-native DNA antibodies were similar in both dietary groups. Our data suggest that the menhaden oil diet may act primarily to reduce inflammation via the ability of eicosapentaenoic acid to alter the production of prostaglandins and leukotrienes.

Production of prostaglandins in homogenates of kidney medullae and cortices of spontaneously hypertensive rats fed menhaden oil.

Menhaden oil (MO), whose polyunsaturated fatty acids consist mainly of (n-3) fatty acids, was fed to spontaneously hypertensive rats to determine the effect of (n-3) fatty acid on the in vitro production of prostaglandins produced from arachidonic acid (20:4[n-6]). Capacity to form PGE2 and PGF2 alpha was impaired in homogenates of kidney medullae and cortices from rats fed the MO diet compared to rats fed the control diet. The lower amounts of diene prostaglandins produced corresponded to the decrease in the amount of 20:4 (n-6) in the tissue. Possibly changes produced in tissue lipids by dietary fatty acids affect prostaglandin production by reducing the availability of substrate in tissue lipids.

The Effects of Varying Levels of Hydrolyzed Animal and Vegetable Fat Upon Growth and Carcass Characteristics of Broilers

DURING recent years the use of animal and vegetable fats in broiler rations has increased. Marion and Woodroof (1965) reported that body weights and feed efficiency were greater at higher levels of protein when fat was added to the diets. They also reported that the degree of rancidity, measured as “TBA Numbers,” was higher in tissues from birds reared on Menhaden oil diets. Essary et al. (1965) reported that different levels of added fat (2, 4, 6, and 8%) and protein fed to broilers did not appreciably influence dressing percentages but did significantly influence live weight. Stephenson et al. (1960) reported that added dietary fat at levels from 0 to 10 percent did not affect the breast blister condition of broilers. In this study the factors which appeared to significantly affect the breast blisters were market age, sex and breed. Gyles et al. (1957) reported that differences in incidence of .

Fish Oil and Fishy Flavor of Eggs and Carcasses of Hens

IN THE United States as well as in many other countries, there is some concern about the use of fish products in the rations of broilers and laying hens because of possible off-flavors. Much disputed is the so-called fishy flavor in broiler meat and in eggs as a result of feeding of fish meals and oils. Recently Edwards and May (1965) investigated the effects of feeding of menhaden fish oil on the flavor of broiler meat. They determined that the addition of as little as 2 percent menhaden fish oil to the ration imparted off-flavors to the meat of chickens fed this ration. Carlson et al. (1957) and Hardin et al. (1964) reported similar results except that lower levels of menhaden fish oil were detected (1.5 and 1.8% dietary menhaden oil respectively) in broiler meat.Relatively few authors have investigated the effects of feeding of fish products on the flavor …

Influence of Dietary Oils on Reproduction in the Hen

A study was conducted to determine the effect of safflower or menhaden oil on the reproductive performance of essential fatty acid-deficient hens. Single Comb White Leghorn pullets were reared from hatching with an essential fatty acid (EFA)-deficient diet. At 32 weeks of age the pullets were distributed into 6 groups of 15 birds each. Groups 1 through 4 received safflower oil (calculated to supply zero, 20, 80, and 1600 mg of linoleic acid (18:2)/hen/day, respectively. Groups 5 and 6 received menhaden oil calculated to supply 20 and 80 mg of 18:2/hen/day, respectively. Increasing the levels of dietary 18:2 supplied by safflower oil had a significant stimulatory effect on the reproductive characteristics of the EFA-deficient hen. Dietary menhaden oil fed to EFA-deficient hens promoted a significant increase in egg production, hatchability, and, to some extent, egg size that could not be assigned to its 18:2 content. The data indicated that the polyunsaturated fatty acids (PUFA) present in menhaden oil were responsible for this stimulation. The amount of 20:3 in the tissues of the EFA-deficient hen was found to bear a definite negative relationship to the expression of the reproductive characteristics of the chicken. The results of this study suggested that the PUFA of menhaden oil depressed the synthesis of 20:3 and may have also substituted, at least in part, for 18:2 or 20:4, or both.

Influence of Dietary Menhaden Oil on Growth Rate and Tissue Fatty Acids of the Chick

Using purified diets containing 2 sources of protein, an essential fatty acid deficiency was produced in chicks that was characterized by poor growth and a high quantity of eicosatrienoic acid in the liver lipid. The feeding of corn oil caused an increase in the eicosatetraenoic acid and a decrease in the eicosatrienoic acid content of the liver. The feeding of menhaden oil did not change the eicosatetrenoic acid content of the liver lipid, but caused a complete disappearance of eicosatrienoic acid. Eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid were present in the liver only when menhaden oil was fed. The data indicate that the feeding of fish oil with its high content of long-chain polyunsaturated fatty acids inhibits the synthesis of eicosatrienoic acid in the chicken. When menhaden oil was fed with corn oil, the level of arachidonic acid present in the liver and heart fat was decreased from levels resulting when corn oil is fed alone. Some interpretations of these observations are discussed.

The effect of diet on the fatty acid composition of several species of fresh water fish

SummaryFour kinds of fresh water fish were captured in the young stage, maintained on a low‐fat diet for about two months, and either continued on that diet or transferred to test diets containing 10% cottonseed or menhaden oil for about five weeks. The fish were then sacrificed, and their total body fatty acids were examined for relative amounts of 2, 3, 4, 5 and 6 double bonds. It was found that no significant change from the natural diet occurred in the fatty acids on the low‐fat or cottonseed oil diets while on the menhaden oil diet the fatty acid composition changed to resemble the composition of that oil.These changes differed from those of the marine mullet in that the body fat of the latter lost much of its naturally occurring polyunsaturated acids, when placed on the low‐fat regimen, and regained it on the menhaden oil diet.