Low Polyunsaturated Fatty Acids Research Articles

Finishing diets stimulate compensatory growth: results of a study on Murray cod, Maccullochella peelii peelii

The effective implementation of a finishing strategy (wash-out) following a grow-out phase on a vegetable oil-based diet requires a period of several weeks. However, fish performance during this final stage has received little attention. As such, in the present study the growth performance during both, the initial grow-out and the final wash-out phases, were evaluated in Murray cod (Maccullochella peelii peelii). Prior to finishing on a fish oil-based diet, fish were fed one of three diets that differed in the lipid source: fish oil, a low polyunsaturated fatty acid (PUFA) vegetable oil mix, and a high PUFA vegetable oil mix. At the end of the grow-out period the fatty acid composition of Murray cod fillets were reflective of the respective diets; whilst, during the finishing period, those differences decreased in degree and occurrence. The restoration of original fatty acid make up was more rapid in fish previously fed with the low PUFA vegetable oil diet. During the final wash-out period, fish previously fed the vegetable oil-based diets grew significantly (P

Alternative Oxidase Involvement in Cold Stress Response of Arabidopsis thaliana fad2 and FAD3+ Cell Suspensions Altered in Membrane Lipid Composition

To investigate how the fatty acid composition of membrane lipids influences cell growth and mitochondrial respiration, in particular the expression and capacity of alternative oxidase (AOX), under cold stress, we used the Arabidopsis thaliana fad2 knockout and FAD3+ -overexpressing cultured cells lines affected in extrachloroplastic fatty acid desaturation activities. At 22 degrees C, fad2 mitochondria exhibited a low polyunsaturated fatty acid content and low protein to lipid ratio, while mitochondria from FAD3+ were enriched in linolenic acid and in total membrane protein. As a consequence, both mutants showed a higher membrane microviscosity than the wild type. After exposure to 9 degrees C, FAD3+ mitochondria exhibited lower microviscosity and lower rigidification upon a temperature downshift than fad2. Furthermore, the extent of reduction of cell growth and respiratiory rates in the phosphorylating state was positively related to the cold sensitivity of each cell line, being more pronounced in fad2 that in the wild type, whereas the stability of those parameters reflected the cold resistance of FAD3+. In contrast, an increase in AOX capacity was observed in the three cell lines at 9 degrees C. These inductions were correlated to AOX protein amounts and seem to result from an accumulation of AOX1c transcripts in the three cell lines and of AOX1a transcripts in wild-type and fad2 cells. The fact that there is no direct relationship between the degree of cold tolerance of each cell line and their ability to enhance their AOX capacity suggests that the participation of AOX in the response of Arabidopsis cells to cold stress does not necessarily favor cold tolerance.

Effects of Conservation Treatment and Cooking on the Chemical Composition and Antioxidant Activity of Portuguese Wild Edible Mushrooms

The effects of processing and cooking practices on the chemical composition and antioxidant activity of Portuguese wild edible mushroom species (Lactarius deliciosus, Macrolepiota mastoidea, Macrolepiota procera, and Sarcodon imbricatus) were investigated. Dried, frozen, and cooked samples were analyzed for proximate constituents (moisture, fat, crude protein, ash, and carbohydrates) and nutritional value. Fatty acid and sugar profiles were also obtained by gas-liquid chromatography/flame ionization detection and high-performance liquid chromatography/refraction index, respectively. The antioxidant properties were evaluated by several biochemical assays: 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, reducing power, inhibition of beta-carotene bleaching, and inhibition of lipid peroxidation in brain tissue using thiobarbituric acid reactive substances. Results of this study show that mushroom species and processing and cooking practices are all effective determinants for either chemical composition or antioxidant properties. Cooked samples proved to have lower nutrient concentrations and lower antioxidant activities than either dried or frozen samples. In what concerns fatty acids and sugar individual profiles, only cooking proved to be relevant: The cooked samples presented higher monounsaturated fatty acid and lower polyunsaturated fatty acid and sugars contents.

Lipid composition of retailed organic, free‐range and conventional chicken breasts

SummaryLipid fractions of 20 retailed chicken breasts were correlated with production system: organic, corn‐fed, free‐range and conventional. Neutral lipid (NL), phospholipid (PL) and free fatty acids (FFA) were examined separately. Influence of production systems was found more pronounced in PL composition than NLs. Corn‐fed and free‐range NLs had higher contents of nutritionally beneficial eicosapentanoic acid (C20:5 n‐3) and docosahexanoic acid (C22:6 n‐3) than organic and conventional. Lower polyunsaturated fatty acids in organic and free‐range PLs could be beneficial for tissue stability. Principal component product space for PLs showed clear clustering related to product category. In contrast, this was not observed with FFA except in the partial least square regression product space suggesting influences on NLs and PLs and FFA. PLs had lower contents of arachidonic acid than in earlier studies. Advantages were observed in lipid fractionation using advanced sorbent extraction matrices.

Arachidonic and docosahexaenoic acids reduce the growth of A549 human lung-tumor cells increasing lipid peroxidation and PPARs

Polyunsaturated fatty acids (PUFAs) play an important role in both induction and prevention of carcinogenic process. It is well known that several types of neoplastic cells show decreased total PUFA content, contributing to their resistance to chemotherapy and lipid peroxidation. In the light of this, human lung cancer A549 cells, with low PUFA content, were exposed to arachidonic or docosahexaenoic acid to investigate the effect of n-6 and n-3 PUFAs on growth and elucidate underlying mechanisms. The bulk of the results showed that both n-6 PUFAs and n-3 PUFAs decrease human lung-tumor cell growth in a concentration-dependent manner, inducing cell death mainly evident at 100microM concentration. The mechanism underlying the antiproliferative effect of n-6 and n-3 PUFAs appeared to be the same, involving changes in fatty acid composition of biomembranes, production of cytostatic aldehydes derived from lipid peroxidation and able to affect DNA-binding activity of AP-1, and induction of PPAR. From these results it may be hypothesized that n-6 PUFAs, like n-3 PUFAs, are able to inhibit tumor growth.

ω−3 Fatty acid deficiency in major depressive disorder is caused by the interaction between diet and a genetically determined abnormality in phospholipid metabolism

Omega-3 fatty acids are a type of polyunsaturated fatty acid (PUFA). A growing body of evidence suggests that this form PUFA is a useful and well tolerated treatment for major depressive disorder, a common and serious mental illness. The efficacy of omega-3 PUFA is routinely explained as being due to a deficiency caused by inadequate dietary intake of this class of fatty acid. The hypothesis considered states that low omega-3 PUFA abundance in patients with major depressive and related disorders is due to an underlying genetically determined abnormality. The hypothesis can explain why although a specific and consistent deficit in omega-3, but not omega-6, PUFA occurs in major depressive and related disorders, the literature does not consistently support the notion that this is due to deficient dietary intake. Specifically it is hypothesized that having genetically determined low activity of fatty acid CoA ligase 4 and/or Type IV phospholipase A(2) combined with the low dietary availability of omega-3 PUFA results in reduced cellular uptake of omega-3 PUFA and constitutes a risk factor for depression. The hypothesis also has important consequences for the pharmacological treatment of depression in that it predicts that administering agents which enhance phospholipid synthesis, particularly those containing ethanolamine such as CDP-ethanolamine, should be effective antidepressants especially when co-administered with omega-3 PUFA.

Development of a method predicting the oxidative stability of edible oils using 2,2-diphenyl-1-picrylhydrazyl (DPPH)

The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to predict the oxidative stability of edible oils. The principle of DPPH method is to measure the free radicals generated from oxidized oils directly. The absorbance of DPPH from oils before thermal oxidation decreased proportionally to the concentration of free radical scavenging compounds such as butylated hydroxytoluene (BHT). Oxidized oils with high polyunsaturated fatty acid (PUFA) contents showed high changes in DPPH absorbance or free radical formation rates than those with low PUFA. Oxidized oils with high BHT content were more stable and showed slower pattern change of DPPH absorbance from positive to negative slopes than those with low BHT content. Oxidative stability of oils could be predicted considering the initial values of DPPH absorbance, the free radical formation rates, and the oxidation period for pattern changes. The results from DPPH method on the oxidative stability of vegetable oils agreed with conventional methods such as p-anisidine value ( p-AV), conjugated dienoic acids (CDA), or total polar matter (TPM).

Enhancing pork flavor and fat quality with swine raised in sylvan systems: Potential niche-market application for the Ossabaw hog

Our global food supply becomes more vulnerable as we continue to lose diverse genetic resources. The Ossabaw hog is a feral breed that is unique to North America, a distant relative to the renowned Iberian hog and is considered an endangered swine breed. The objective of our farmer participatory project was to examine the meat and fat characteristics of Ossabaw hogs raised in alternative management systems for niche-market application. At one farm, eight Ossabaw pigs were randomly assigned to a grass pasture and fed a free choice corn–soy (CS) ration or placed in a mixed hardwood forest plot and provided free choice peanuts in the shells (P), alfalfa pellets (A) and mast from the mixed hardwoods (diet collectively referred to as PAM). The two diets had no effect on Ossabaw production data or pork quality characteristics; however, fat profiles were altered. Ossabaws weighed approximately 70 kg when harvested at 400 days and produced chops with small loin eyes (21–23 cm2) and minimal evidence of intramuscular fat deposits (1%). The unsaturated fatty acid (USFA) to saturated fatty acid (SFA) ratio improved from 1.6 to 2.6 (P<0.01) as a result of feeding the PAM diet. Forest-finished Ossabaw pork was considered more flavorful by food critics and renowned chefs than that of conventionally fed animals. Mast from hardwoods offers the possibility of enhancing pork flavor for niche markets and using a renewable forest resource as a food source. For farm two, eight Ossabaw gilts and eight crossbred progeny (from European breeds) were randomly assigned to one of the two dirt-lots and fed free choice a CS ration or PA diet (same ration as mentioned above with no mast). Ossabaw hogs grew nearly one-third as fast as the crosses and weighed approximately 80% of the crosses' harvest weight at twice their age. Loin eye areas of the crosses were nearly twice as large as the Ossabaws while the subcutaneous back fat deposition was nearly half. Compared to the CS diet, the PA ration decreased SFA by 23% while polyunsaturated fatty acids (PUFA) increased by 60%. The USFA to SFA ratios improved from 1.5 to 2.2 (P<0.01) when PA diets were fed. Differences (P<0.05) in USFA profiles were observed for breed effects; Ossabaws had 8% higher levels of monounsaturated fatty acids and 18% lower PUFA levels than the crosses. When adjusted for breed effects, no differences in sensory characteristics for the CS versus PA diets were detected by a trained panel. Ossabaws were more flavorful than the crosses (2.3 versus 1.6); (P<0.05).

Adipose Tissue Proadipogenic Redox Changes in Obesity

The role of inflammation and oxidative stress in the development of obesity and associated metabolic disorders is under debate. We investigated the redox metabolism in a non-diabetic obesity model, i.e. 11-week-old obese Zucker rats. Antioxidant enzyme activities, lipophilic antioxidant (alpha-tocopherol, coenzymes Q) and hydrophilic antioxidant (glutathione, vitamin C) contents and their redox state (% oxidized form), were studied in inguinal white fat and compared with blood and liver. The adipose tissues of obese animals showed a specific higher content of hydrophilic molecules in a lower redox state than those of lean animals, which were associated with lower lipophilic molecule content and lipid peroxidation. Conversely and as expected, glutathione content decreased and its redox state increased in adipose tissues of rats subjected to lipopolysaccharide-induced systemic oxidative stress. In these in vivo models, oxidative stress and obesity thus had opposite effects on adipose tissue redox state. Moreover, the increase in glutathione content and the decrease of its redox state by antioxidant treatment promoted in vitro the accumulation of triglycerides in preadipocytes. Taken together and contrary to the emergent view, our results suggest that obesity is associated with an intracellular reduced redox state that promotes on its own the development of a deleterious proadipogenic process.

The predominance of polyunsaturated fatty acids in the butterfly Morpho peleides before and after metamorphosis

We hypothesized that the polyunsaturated fatty acids of the butterfly were probably derived from the diet and that there might be a great loss of body fat during metamorphosis. To substantiate these hypotheses, we analyzed the fatty acid composition and content of the diet, the larva, and the butterfly Morpho peleides. Both the diet and the tissues of the larva and butterfly had a high concentration of polyunsaturated fatty acids. In the diet, linolenic acid accounted for 19% and linoleic acid for 8% of total fatty acids. In the larva, almost 60% of the total fatty acids were polyunsaturated: linolenic acid predominated at 42% of total fatty acids, and linoleic acid was at 17%. In the butterfly, linolenic acid represented 36% and linoleic acid represented 11% of total fatty acids. The larva had a much higher total fatty acid content than the butterfly (20.2 vs. 6.9 mg). Our data indicate that the transformation from larva to butterfly during metamorphosis drastically decreased the total fatty acid content. There was bioenhancement of polyunsaturated fatty acids from the diet to the larva and butterfly. This polyunsaturation of membranes may have functional importance in providing membrane fluidity useful in flight.

Composition and estimation of intramuscular and subcutaneous fatty acid composition in Spanish young bulls

Sixty Pirenaica yearling intact bulls were raised and slaughtered at 519 ± 50 kg live weight and 371 ± 18 days of age. Fatty acid composition of intramuscular lipids in longissimus dorsi muscle and subcutaneous fat were determined by capillary gas chromatography. Carcass conformation and fatness, carcass weight, ether extractable intramuscular fat percentage, marbling, dorsal fat thickness, and ultrasonic parameters were recorded to study the relationship between these traits and fatty acid profile. Lipids of subcutaneous adipose tissue had higher monounsaturated fatty acids (MUFA) percentage (49% vs. 33%) but lower saturated fatty acids (SFA) (51% vs. 46%) and polyunsaturated fatty acids (PUFA) (16% vs. 5%) percentages than intramuscular fat depots ( p < 0.001). Fatter carcasses had higher MUFA percentage and lower PUFA percentage ( p < 0.01) in intramuscular fat. Carcass weight and conformation would contribute to explain the fatty acid profile of subcutaneous fat ( p < 0.05). Ultrasound readings reflected the effect of fatness on fat composition.

Plasma lipid levels and nutritional intake in childhood- and adolescence-onset young type 1 diabetic patients in Japan

In recent years, the diet of the young Japanese has changed to westernized diet with high fat content. Childhood-onset type 1 diabetic patients have had good diet training since onset of the disease, but adolescence-onset type 1 diabetic patients have already established westernized diet habit at onset of the disease, which may not be easily improved. We hypothesized that a difference of the age at onset of the disease may affect nutritional status and plasma lipid levels in Japanese type 1 diabetic patients. Plasma lipid levels and nutritional intake were compared between childhood- and adolescence-onset young type 1 diabetic patients. Our research involved 9 childhood-onset type 1 diabetic patients (childhood group), 11 adolescence-onset type 1 diabetic patients (adolescent group), and 24 age-matched non-diabetic control subjects. There were no significant differences in age and body mass index (BMI), daily energy intake among the childhood group, the adolescent group, and the non-diabetic control group. There was no significant difference in HbA1c level between the childhood group and the adolescent group. The adolescent group had significantly higher plasma levels of total cholesterol, triglyceride, and low-density lipoprotein (LDL)-cholesterol than the childhood group ( p < 0.01, <0.05, and <0.001, respectively) or the control group ( p < 0.001, <0.001, and <00.001, respectively). The adolescent group had significantly lower plasma level of high-density lipoprotein (HDL)-cholesterol than the childhood group ( p < 0.05). The adolescent group had significantly higher percentage energy intake from fat (31.7%, p < 0.001), higher saturated fatty acids intake (19.0 g/day, p < 0.01), and higher cholesterol intake (428 mg/day, p < 0.05), and significantly lower polyunsaturated fatty acids intake (13.4 g/day, p < 0.05) and lower fiber intake (9.5 g/day, p < 0.01) than the childhood group. It is concluded that young Japanese type 1 diabetic patients with onset of adolescence have lipid abnormalities, which may be mainly caused by westernized dietary habits.

Low essential fatty acid and B-vitamin status in a subgroup of patients with schizophrenia and its response to dietary supplementation

We assessed essential fatty acid (EFA) and B-vitamin status, together with their determinants, in 61 patients with schizophrenia and established whether those with poor status responded biochemically to the appropriate dietary supplements. As a group, the patients had high erythrocyte saturated fatty acids (FAs), monounsaturated FA and low polyunsaturated FA of the ω3 and ω6 series. Patients reporting not to take vitamin supplements had low vitamin B 12 and high homocysteine. Homocysteine variance proved best explained by folate in both the total group and male patients, and by vitamins B 12 and B 6 in females. Alcohol consumption and duration of illness are risk factors for low polyunsaturated FA status (<P2.5 of reference range), while male gender and absence of fish consumption predict hyperhomocysteinemia (>P97.5 of reference range). Two patients exhibited biochemical EFA deficiency and seven showed biochemical signs of ω3/docosahexaenoic acid (DHA) marginality. Four patients exhibited moderate hyperhomocysteinemia with plasma values ranging from 57.5 to 74.8 μmol/L. None of the five patients with either moderate hyperhomocysteinemia, biochemical EFA deficiency, or both, was predicted by their clinicians to have poor diets. That diet was nevertheless at the basis of these abnormalities became confirmed after supplementing 4 of them with B vitamins and with soybean and fish oils. We conclude that a subgroup of patients with schizophrenia has biochemical EFA deficiency, ω3/DHA marginality, moderate hyperhomocysteinemia, or combinations. Correction seems indicated in view of the possible relation of poor EFA and B-vitamin status with some of their psychiatric symptoms, but notably to reduce their high risk of cardiovascular disease.

Characteristics and Fatty Acid Compositions of Rhus coriaria Cultivars from Southeast Turkey

Rhus coriaria L., commonly known as sumac (also spelled sumach), grows wild in the region extending from the Canary Island over the Mediterranean coastline to Iran and Afghanistan. It is native to the Mediterranean and southeast Anatolian region of Turkey [1, 2]. The name is derived from “sumaga”, meaning red in Syriac [3]. The name sumac is given also to the commercial preparation of the dried and ground leaves of the Sicilian or tenners sumac ( Rhus coriaria) of Southern Europe, long used in making leather [4]. The spice, produced by grinding the dried fruit with salt, is used as a condiment and sprinkled over kebabs and grilled meat as well as over the salad often accompanying these dishes [5‐8]. There were different studies conducted on various sumac such as mineral content and antimicrobial and antioxidant effects [9‐16], but a study on the oil of sumac has not been previously reported. Sumac oil might be a good product for the food industry to use in salad and meals, especially when it is mixed with olive oil, and also seeds of sumac might be used in the different oil industries in the world. The objective of this study was the preliminary investigation of fatty acid composition and proximate composition of different sumac cultivars grown in the region of southeast Turkey. Four different cultivars of sumac samples were obtained from native producers in southeast Anatolia (Birecik, Darende, Kahramanmaras, Sanliurfa). The oil was extracted from the samples using cold ether extraction. For chemical analysis, each group of sumac was homogenized and then analyzed to determine moisture, oil, and protein using standard methods [17]. Fatty acid (FA) compositions of the oils were determined by preparing methyl esters of the FA [18]. The gas chromatography equipment used was a Shimadzu GC 40 A (Shimadzu, Kyoto, Japan) fitted with a 2.1 m spiral steel (SS) column of inner diameter 3.2 mm. The total oil, protein, moisture, and ash contents of the sumac ranged from 10.00 to 15.00 %, 3.36 to 3.74 %, 6.35 to 8.32 %, and 2.82 to 3.32 %, respectively (Table 1). The protein content of Rhus copallina was 6.3 % in the literature [19]. As seen from Table 1, the oleic acid contents of the oils ranged from 34.00 to 40.35 % while the linoleic and linolenic acid conte nts ranged from 33.31 to 35.83 % and 1.53 to 2.99 %, respectively. However, the palmitic acid content changed between 20.75 % and 25.60 %. In this study, it was seen that the major fatty acids in the sumac were oleic (C 18:1 ), linoleic (C 18:2 ), and palmitic (C 16:0 ) acids. The polyunsaturated fatty acid contents (18:2 +18:3) of the total fatty acids ranged from 34.84 to 37.36 %. Storage capabilities were also dependent on the polyunsaturated fatty acid level because polyunsaturated fatty acids are more susceptible to oxidative degradation [20‐22]. As sumac oil contains a lower polyunsaturated fatty acid content, it can probably be stored over a long time and contribute to the shelf life of the olive oil. McNeil et al. [23] pointed out that the consumer taste pref erence for certain cultivars varied from year to year. Especially, a mixture of sumac and olive oil may be a new product for different salad formulations and fast foods. Finally, the results indicate that some of the cultivars of sumac grown at southeast Anatolia are different from each other in terms of individual fatty acids. Since research on sumac oil is very limited in the literature, we suggest that furthe r research should be conducted on it and its chemical properties.

Effect of diet on fatty acid compositions in Sciaenops ocellatus

The role of dietary polyunsaturated fatty acids (PUFAs) on the fatty acid composition of juvenile red drum Sciaenops ocellatus was investigated. Individuals (n = 435) were fed three natural diets (Gulf menhaden Brevoortia patronus, brown shrimp Farfantapenaeus aztecus and Atlantic brief squid Lolliguncula brevis) that had significantly different proximate composition, energy density and PUFA compositions for 40 days. Diets were characterized as containing: high lipid, high protein, high energy and low PUFA (fish‐based), low lipid, low protein, low energy, moderate PUFA (shrimp‐based), and low lipid, high protein, moderate energy and high PUFA levels (squid‐based), respectively. Specimens were collected at days 0, 5, 10, 20 and 40 to evaluate rate of dietary fatty acid composition in tissues. Two‐source mixing models were used to calculate dietary fatty acid accumulation in consumer tissues. Results indicated that juvenile red drum incorporated an average of 35% dietary PUFAs after 5 days. Although relative biomass and dietary proximate composition had an effect upon the dietary fatty acid contribution, red drum averaged 91% incorporation of the five most prevalent PUFAs [18 : 2 (n − 6), 20 : 4 (n − 6), 20 : 5 (n − 3), 22 : 5 (n − 3) and 22 : 6 (n − 3)] across all diets after 40 days. Growth varied as a function of diet and rates were higher for individuals fed the squid diet than those fed shrimp or fish diets primarily due to increased levels of protein and PUFAs [including 22 : 6 (n − 3); 25·8%] in the diet. Red drum fed squid exhibited the greatest increase in average dietary fatty acid contribution by day 5, a trend that continued for the duration of the experiment. Since PUFA composition in red drum was significantly influenced by diet in as few as 5 days and almost completely incorporated into body tissues after 40 days, results from this study support the premise that fatty acids (especially PUFAs) are promising dietary indicators and may be useful for future studies examining trophic relationships of estuarine and marine fishes.

A Diet Enriched with the Omega-3 Fatty Acid Docosahexaenoic Acid Reduces Amyloid Burden in an Aged Alzheimer Mouse Model

Epidemiological studies suggest that increased intake of the omega-3 (n-3) polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) is associated with reduced risk of Alzheimer's disease (AD). DHA levels are lower in serum and brains of AD patients, which could result from low dietary intake and/or PUFA oxidation. Because effects of DHA on Alzheimer pathogenesis, particularly on amyloidosis, are unknown, we used the APPsw (Tg2576) transgenic mouse model to evaluate the impact of dietary DHA on amyloid precursor protein (APP) processing and amyloid burden. Aged animals (17-19 months old) were placed in one of three groups until 22.5 months of age: control (0.09% DHA), low-DHA (0%), or high-DHA (0.6%) chow. beta-Amyloid (Abeta) ELISA of the detergent-insoluble extract of cortical homogenates showed that DHA-enriched diets significantly reduced total Abeta by >70% when compared with low-DHA or control chow diets. Dietary DHA also decreased Abeta42 levels below those seen with control chow. Image analysis of brain sections with an antibody against Abeta (amino acids 1-13) revealed that overall plaque burden was significantly reduced by 40.3%, with the largest reductions (40-50%) in the hippocampus and parietal cortex. DHA modulated APP processing by decreasing both alpha- and beta-APP C-terminal fragment products and full-length APP. BACE1 (beta-secretase activity of the beta-site APP-cleaving enzyme), ApoE (apolipoprotein E), and transthyretin gene expression were unchanged with the high-DHA diet. Together, these results suggest that dietary DHA could be protective against beta-amyloid production, accumulation, and potential downstream toxicity.

Growth, survival, lipid and fatty acid profile of juvenile monaco shrimp Lysmata seticaudata fed on different diets

The present work evaluated the effect of three inexpensive diets (frozen minced mussel and edible cockle (MMC), frozen minced squid (MS) and gilthead seabream feed (GSF)) on growth, survival, sex reversal, lipid classes and fatty acid (FA) profile of juvenile ornamental shrimp Lysmata seticaudata. Shrimp fed GSF displayed the highest survival rate (±SD) (85.2±1.8%) and the highest percentage (±SD) of shrimp changing from male to simultaneous hermaphrodite (SH) phase (25.2±2.2%). All diets promoted growth rates superior to those reported in the wild, with SH shrimp displaying higher total lengths (TL). Shrimp in SH phase fed GSF displayed the highest TL (±SD) (40.6±1.2 mm). Cultured shrimp reflected the lipid content of experimental diets, with shrimp fed GSF displaying the highest triacylglycerols and sterols (ST) contents. The higher rearing density induced by lower mortality rates of shrimp fed GSF, and the high ST levels present in the diet, may explain the higher proportion of shrimp in SH phase. The higher levels of highly unsaturated fatty acids (HUFA) displayed by MS did not promote higher survival or growth rates. The low polyunsaturated fatty acids and HUFA content of MMC was not reflected in cultured shrimp, probably because of a selective retention of these FA.

Lipids in the food of a terrestrial snail

Summary Animals depend on a large set of essential compounds in their food. A reduced supply of specific lipid compounds has been shown to be critical for growth, reproduction and survival of aquatic molluscs and might also be critical for terrestrial gastropods. The effects were investigated of different fatty acid and cholesterol supplies on the growth, reproduction, and survival of the land snail Arianta arbustorum. Surprisingly, differences in diet did not affect shell growth, time to reach adulthood, and reproductive traits such as the number of eggs, dry mass and volume of spermatophores. However, snails reared on low cholesterol diets and low polyunsaturated fatty acid (PUFA) diets decreased their consumption rates and had a higher mortality. Snails fed a PUFA-rich diet showed higher mating activity than snails fed a diet deficient in PUFAs. A depletion of internal PUFA reserves may affect the regulation of mating behaviour because PUFAs play an important role as precursors for signal-transduction involved in the regulation of mating and reproduction. In contrast, when the diets were deficient in cholesterol, mating activity was not affected.

Lipid [corrected] classes, fatty acids, and sterols in seafood from Gilbert Bay, southern labrador.

Seafood from Gilbert Bay, southern Labrador, was sampled for lipid classes, fatty acid, and sterol composition. Gilbert Bay is a proposed Marine Protected Area, and the composition of seafood from this region is interesting from both human health and ecological perspectives. Analyses included four species of bivalves and flesh and liver samples from four fish species. Lipids from a locally isolated population of northern cod (Gadus morhua) were also compared to lipids from other cod populations. Lipid classes were analyzed by Chromarod/Iatroscan TLC-FID, fatty acids by GC, and sterols by GC-MS. Three cod populations had similar levels of total lipid per wet weight (0.6%) with triacylglycerols (TAG), sterols, and phospholipids comprising on average 13, 11, and 51%, respectively, of their total lipids. Fatty fish such as capelin and herring contained on average 8.4% lipid with 86% present as TAG. Fish livers from cod and herring showed opposite trends, with cod having elevated lipid (27%) and TAG (63%) and herring containing only 3.8% lipid and 20% TAG. Shellfish averaged 0.6% lipid; however, significant lipid class differences existed among species. Fatty acid analysis showed few significant differences in cod populations with on average 57% polyunsaturated fatty acids (PUFA), 18% monounsaturated fatty acids (MUFA), and 24% saturated fatty acids (SFA). Cod livers had lower PUFA (34%) and elevated MUFA (44%) relative to flesh. Bivalves averaged 25% SFA, 18% MUFA, and 57% PUFA, whereas scallop adductor muscle had the highest PUFA levels (63%). Bivalves contained 20 different sterols with cholesterol present as the major sterol (19-39%). trans-22-Dehydrocholesterol, brassicasterol, 24-methylenecholesterol, and campesterol individually accounted for >10% in at least one species. High levels of PUFA and non-cholesterol sterols observed in Gilbert Bay seafood demonstrate their positive attributes for human nutrition.

The role of polyunsaturated fatty acids in the expression of torpor by mammals: a review

Heterothermic mammals increase the proportion of polyunsaturated fatty acids (PUFA) in their body fats prior to entering torpor. Because PUFA have low melting points, it is thought that they play an important role in maintaining the fluidity of depot fats and membrane phospholipids at low body temperatures. However, PUFA are more prone to autoxidation when exposed to reactive oxygen species (ROS) during torpor and during the periodic arousals that characterize hibernation. A lack of PUFA or an excess of PUFA may constrain the use of torpor by heterothermic mammals. We performed a mixed model meta-analysis of 17 controlled-feeding studies to test the effect of dietary PUFA on the depth and expression of torpor by daily heterotherms and hibernators. We also reviewed the literature on the PUFA content of the diet and depot fats of heterothermic mammals to address two principal topics: (1) Do low dietary levels of PUFA reduce the expression of torpor under laboratory conditions and, if so, are free-ranging animals constrained by a lack of PUFA? (2) Do high dietary levels of PUFA result in a reduction in the use, depth, and duration of torpor and, if so, do free-ranging animals seek to optimize rather than maximize PUFA intake? Low-PUFA diets consistently increase the lower setpoint for body temperature and minimum metabolic rate for both hibernators and daily heterotherms. Above the lower setpoint, low-PUFA diets usually increase body temperature and metabolic rate and decrease the duration of torpor bouts and this effect is similar for hibernators and daily heterotherms. Free-ranging rodent hibernators have dietary PUFA intakes that are far higher than those of the low-PUFA diets offered in controlled-feeding experiments, so these hibernators may never experience the constraints associated with a lack of PUFA. Diets of free-ranging insectivorous bats and echidnas have PUFA levels that are less than half as high as those offered in experimental low-PUFA diets, yet they exhibit deep and extended bouts of torpor. We argue that alternate mechanisms exist for maintaining the fluidity of body fats and that high-PUFA intake may not be a prerequisite for deep and extended bouts of torpor. Four studies indicate that animals that were fed high-PUFA diets are reluctant to enter torpor and show shallower and shorter torpor bouts. Although authors attribute this response to autoxidation, these animals did not have a higher PUFA content in their depot fats than animals where PUFA was shown to enhance torpor. We suggest that these contradictory results indicate inter-specific or inter-individual variation in the ability to control ROS and limit autoxidation of PUFA. High dietary levels of PUFA will constrain the expression of torpor only when the oxidative challenge exceeds the capacity of the antioxidant defence system. Studies of diet selection indicate that insectivorous species with low dietary PUFA levels seek to maximize PUFA intake. However, herbivorous species that have access to plants and plant parts of high-PUFA content do not appear to maximize PUFA intake. These data suggest that animals attempt to optimize rather than maximize PUFA intake. The effect of PUFA should be viewed in the light of a cost–benefit trade-off, where the benefit of high-PUFA intake is an easier access to low body temperatures and the cost is increased risk of autoxidation.