Higher Levels Of C18 Research Articles

Fatty acid composition in chronic heart failure: low circulating levels of eicosatetraenoic acid and high levels of vaccenic acid are associated with disease severity and mortality

Free fatty acids (FFAs) are the major energy sources of the heart, and fatty acids (FAs) are active components of biological membranes. Data indicate that levels of FAs and their composition may influence myocardial function and inflammation. The aim of this study was to investigate whether total levels and composition of FAs and FFAs in plasma are altered in clinical heart failure (HF) and whether any alterations in these parameters are correlated with the severity of HF. Plasma from 183 patients with stable HF was compared with plasma from 44 healthy control subjects. Our main findings are as follows: (i) patients with HF had decreased levels of several lipid parameters and increased levels of FFAs in plasma, compared with controls, which were significantly correlated with clinical disease severity. (ii) Patients with HF also had a decreased proportion in the plasma of several n-3 polyunsaturated FAs, an increased proportion of several monounsaturated FAs, and a decreased proportion of some readily oxidized long-chain saturated FAs. (iii) These changes in FA composition were significantly associated with functional class, impaired cardiac function (i.e., decreased cardiac index and increased plasma N-terminal pro-B-type natriuretic peptide levels) and enhanced systemic inflammation (i.e., increased high-sensitivity C-reactive protein levels). (iv) Low levels of C20:4n-3 (eicosatetraenoic acid) and in particular high levels of C18:1n-7 (vaccenic acid) were significantly associated with total mortality in this HF population. Our data demonstrate that patients with HF are characterized by a certain FA phenotype and may support a link between disturbed FA composition and the progression of HF.

Dietary conjugated linoleic acid (CLA) for finishing Nile tilapia

A 8-week feeding trial was conducted to evaluate the nutritional value of dietary conjugated linoleic acid (CLA) for finishing Nile tilapia evaluating its effects on growth performance, whole body and filet compositions, fatty acid composition, plasma lipid parameters, filet texture, liquid loss and holding capacity. Triplicate groups of Nile tilapia were hand-fed until apparent satiation on diets in which CLA oil was supplemented at 0 (control), 5 or 10 g kg−1. No differences were observed on weight gain, feed intake, feed/gain ratio, protein efficiency ratio, hepatosomatic index, visceral fat, filet yield and survival between treatments. Fish-fed CLA diets had increased whole body crude protein and reduced filet lipid content. The total plasma cholesterol and triacylglycerol decreased with CLA supplementation. Neither 5 nor 10 g kg−1 dietary CLA improved liquid-holding capacity and filet texture when compared with fish fed the control diet. Fish-fed dietary CLA showed lower whole body and filet C18:3(n-6), C18:3(n-3) and C20:2(n-6) levels and higher levels of C18:0. CLA deposition in filet and whole body (16 mg–235 mg g−1 of tissue) are higher than presented in natural sources of CLA, proving to be a great product to increase CLA consumption by humans.

AP2-Cre-mediated inactivation of acetyl-CoA carboxylase 1 causes growth retardation and reduced lipid accumulation in adipose tissues

Adipose tissue is one of the major sites for fatty acid synthesis and lipid storage. We generated adipose (fat)-specific ACC1 knockout (FACC1KO) mice using the aP2-Cre/loxP system. FACC1KO mice showed prenatal growth retardation; after weaning, however, their weight gain was comparable to that of wild-type (WT) mice on a normal diet. Under lipogenic conditions of fasting/re-feeding a fat-free diet, lipid accumulation in adipose tissues of FACC1KO mice was significantly decreased; this is consistent with a 50-66% reduction in the ACC activity in these tissues compared with that of WT mice. Surprisingly, FACC1KO mice manifested skeletal growth retardation phenotype accompanied by decreased chondrocyte proliferation in the growth plate and lower trabecular bone density. In addition, there was about a 30% decrease in serum insulin-like growth factor I (IGF1), and while the serum leptin level was decreased by about 50%, it did not counteract the osteopenic effects of IGF1 on the bone. Fatty acid analyses of mutant bone lipids revealed relatively higher levels of C18:2n-6 and C18:3n-3 and lower levels of their elongation C20 homologs than that of WT cohorts, leading to lower levels of C20 homologs and bone development. Moreover, aP2-Cre-mediated ACC1 inactivation in bone tissue led to a decreased number of osteoblasts but not of osteoclasts. The downregulation of ACC1 on osteoblastogenesis may be the cause for the osteopenia phenotype of FACC1KO bone homeostasis.

Improving the fatty acid composition of ‘Chemlali’ virgin olive oil through clonal selection

SUMMARYSfax Province is one of the most important olive oil-producing regions in Tunisia, where plantations consist entirely of the cultivar ‘Chemlali’. The fatty acid composition of ‘Chemlali’ olive oil is characterised by having relatively low levels of C18:1. A selection programme to obtain ‘Chemlali’ olive clones with improved fatty acid compositions was initiated in 1994. Principal component analysis was applied to our chemical analysis data to reveal fatty acids present at the highest levels, in order to discriminate between the 36 clones studied. C18:1 and C18:2 fatty acids, and the mono-unsaturated:polyunsaturated fatty acids ratio were the most useful variables with which to classify the clones into four groups. One of these groups contained ten ‘Chemlali’ clones characterised by having high levels of C18:1 and relatively low levels of C16:1 and C18:2 compared with the cultivar ‘Chemlali’. We have extended this selection by including other discriminatory criteria such as stability against oxidation, and related anti-oxidant levels, to obtain six ‘Chemlali’ clones with improved chemical compositions for virgin olive oil production.

A comparison between red clover silage and grass silage feeding on fatty acid composition, meat stability and sensory quality of the M. Longissimus muscle of dairy cull cows

Sixteen Holstein–Friesian dairy cull cows were offered either ad libitum grass (G) or red clover (RC) silage for 12 weeks. Dry matter (DM), total nitrogen, and pH was higher for the RC than the G silage and organic matter, water-soluble carbohydrate, fibre, DM digestibility, ammonia-N, vitamin E and acetic acid higher for the G silage ( P < 0.05). Fatty acid compositions were different ( P < 0.05) with G silage having higher levels of C12:0, C14:0, C16:1 cis−9, C18:3 n−3 and total fatty acids whereas RC had higher levels of C18:0, C18:2 n−6 and C20:0. Daily liveweight gain was high and not different between groups (average 1.22 kg/d). Body condition score and back fat thickness at slaughter along with conformation, fat grade and slaughter weight were not different between groups. Animals offered the G silage produced larger M. longissimus length ( P < 0.01) and a trend ( P < 0.1) for width. RC fed animals had higher proportions of C18:3 n−3 ( P < 0.001), total n−3 fatty acids ( P < 0.01) and total PUFA compared to animals offered the G silage despite greater intakes of these fatty acids on G ( P < 0.001). Vitamin E concentration and stability of aged meat during simulated retail display, were lower ( P < 0.05) from animals offered RC than animals offered G. Shear force and ultimate pH, however were not different in steaks and sensory attributes were similar; the only difference being a higher score ( P < 0.01) for fishy in the RC steaks. The results suggest that feeding high DMD silage to dairy cull cows can result in a high standard of finish and liveweight gain. Furthermore RC silage as opposed to G silage can increase the beneficial fatty acid profile of the resultant meat.

A comparison of fatty acid composition and quality aspects of eggs and larvae from cultured and wild broodstock of common sole (Solea soleaL.)

Eggs from a F1 cultured broodstock of sole were compared with eggs from wild-caught breeders throughout one spawning season, to evaluate if egg quality may be affected by culture-related conditions. Fourteen batches of eggs from cultured broodstock and 17 batches from wild-caught sole were compared with respect to fatty acid (FA) composition, egg size, fertilization rate and hatching rate. Based on a multivariate analysis of the FA profiles, it was possible to discriminate between culture and wild inheritance. Eggs from cultured broodstock had high levels of C20:1(n-9), C18:2(n-6) and C18:3(n-3), whereas eggs from wild fish had high levels of C16:1(n-7), C20:4(n-6) and C20:5(n-3). Differences in FA profiles were most likely related to dietary differences. Fertilization and hatching rates were generally low and lowest in eggs from cultured broodstock, but not related to FA composition. Larval growth of one batch from each group was compared. Larval growth was not correlated to broodstock origin, FA composition or egg or larval size. However, larval survival was significantly lower for larvae from cultured broodstock.

Differential expression of (dihydro)ceramide synthases in mouse brain: oligodendrocyte-specific expression of CerS2/Lass2

Synthesis of dihydroceramide is catalyzed by a family of (dihydro)ceramide synthases (CerS), first identified in yeast as longevity-assurance genes. Six members (CerS1-6; Lass1-6) of this gene family have been identified in mammals. We examined expression of CerS genes during postnatal development in mouse brain by means of Northern blot analysis, real-time RT-PCR, and in situ-hybridization. In situ-hybridization experiments showed that CerS1 was the predominant CerS in neurons throughout the brain. This observation is in line with the high levels of C18:0-ceramide in neurons and the substrate specificity of CerS1. A similar distribution, but lower expression levels, were found for CerS4 and CerS6. Only low or undetectable amounts of CerS1, CerS4 and CerS6 were, however, present in white matter. In contrast, CerS5 mRNA was detected in most cells within gray and white matter of all brain regions, suggesting ubiquitous expression of this palmitoyl-CoA specific CerS. Expression of CerS2 was transiently increased during the period of active myelination. Furthermore, expression of CerS2 was specifically localized to white matter tracts of the brain. Furthermore, CerS2 was the predominant CerS in Schwann cells of sciatic nerves. These data suggest that CerS2 is important for the synthesis of dihydroceramide used for synthesis of myelin sphingolipids.

Effect of storage temperature on the quality of eggs from conjugated linoleic acid-fed laying hens

This study was designed to investigate the effects of storage temperature on the quality of eggs from conjugated linoleic acid (CLA)-fed laying hens. For 40 days laying hens (20 per group) were fed a diet containing either 0.5% maize oil (Group A, Control) or 0.5% CLA (Group B). For fatty acid analysis, three eggs were collected after the eighth day of feeding. After two days of feeding, eggs were collected and stored for 28 days at 4°C, 15°C or 24°C for colour quality assessment. For pH measurements, 30 eggs from each group were stored at 4 C or room temperature (21-24°C) for one, two or three weeks. Dietary CLA caused higher levels of C16:0 and C18:0 and lower levels of C16:1(n-7) and C18:1(n-9) compared to the control group. Egg yolk from Group B had higher levels of c-9, t-11 and t-10, c-12 CLA than the control group. The ratio of total saturated to unsaturated fatty acids (SFA/UFA) increased 2.4-fold in the eggs from CLA-fed hens. CLA eggs stored at 4°C had higher pH values in yolk and lower pH values in albumen compared to those from the control group. However, pH values of yolk or albumen in eggs stored at 21-24°C were similar in the control and treatment groups. Dietary CLA caused significant colour changes in yolk and albumen of the eggs stored at 4°C and 15°C. No colour changes were observed in the yolk and albumen of CLA eggs at 21-24°C. Results indicated that dietary CLA influenced fatty acid composition of eggs and had negative effects on the quality of eggs stored at 4°C or 15°C, but not at room temperature (21-24°C). It is suggested that CLA probably changed the permeability of the vitelline membrane during cold storage. South African Journal of Animal Science Vol. 36(1) 2006: 13-19

Comparative fatty acid profiling ofMucor rouxiiunder different stress conditions

To understand the relationship between fatty acid metabolism and the growth morphology of Mucor rouxii, fatty acid profiling was studied comparatively in cells grown under conditions which included different atmospheric conditions or the addition of phenethyl alcohol (PEA). The significant difference in fatty acid profiles from M. rouxii grown under aerobic or anaerobic conditions was not found to be directly related to morphological growth. Oxygen limitation, which induced the formation of pure multipolar budding yeasts, led to a decrease in long-chain fatty acids-- particularly unsaturated fatty acids-- and an increase in medium-chain saturated fatty acids, a finding which contrasted with the aerobic cultures, including mycelia and PEA-induced bipolar budding cells. High levels of C18 : 1Delta(9) were found in aerobic yeast cultures with additional PEA when compared to that in the aerobically grown mycelia. The identification of unusual fatty acids in Mucor in response to alcoholic and hypoxic stresses - including odd-numbered fatty acids and 7-hydroxy dodecanoic acid (7-OH C12 : 0) in addition to the more common fatty acids - implied that an important role existed for these unusual fatty acids.

Trophic ecology of Sargassum-associated fishes in the Gulf of Mexico determined from stable isotopes and fatty acids

Natural dietary markers (stable isotopes and fatty acids) were used to determine the trophic structure and characterize carbon source(s) of juvenile and adult fishes associated with float- ing Sargassum in mid-shelf waters of the Gulf of Mexico. Stable carbon isotope ratios (δ 13 C) of 4 autotrophs (Cladophora sp., phytoplankton (based on particulate organic matter, POM), S. fluitans, S. natans) were distinct (range -16.3 to -21.0‰), with S. fluitans and S. natans enriched by 2 to 5‰ rel- ative to Cladophora sp. and POM. Stable nitrogen isotope ratios (δ 15 N) of both S. fluitans and S. natans were depleted by 5 to 7‰ compared to Cladophora sp. and POM. The majority of δ 13 C values of consumers were between -16 and -18‰, and δ 13 C values were most depleted for juvenile shrimps, juvenile crabs and certain juvenile fishes (e.g. Aluterus heudeloti, Monacanthus hispidus, Abudefduf saxatilis, Histrio histrio, Seriola dumerili). Stable carbon isotope ratios of adult fishes varied from -16.1 to -17.5‰. Enrichment of δ 15 N occurred with increasing trophic position, and the lowest values were observed for juvenile crustaceans, which ranged from 6.0 to 8.7‰. The majority of juvenile fishes were secondary heterotrophs (δ 15 N values ca. 8.0 to 11.0‰), while most adult fishes were ter- tiary consumers with δ 15 N values ranging from 11.9 to 14.3‰. Carbon source estimates from a 2-source mixing model indicated that the 78% of organic matter supplied to consumers (pooled across taxa) in the Sargassum complex was derived from POM. Fatty acid signatures of the primary producers were significantly different, and were used to further evaluate organic matter contribution to Sargassum-associated consumers. C22 polyunsaturated fatty acids (PUFAs) (22:6n-3, 22:5n-3) were most abundant in POM, while high levels of C18 and C20 PUFAs were observed for Cladophora sp. and Sargassum spp. (18:2n-6 and 20:4n-6, respectively). Consumer signatures were dominated by 22:6n-3, and principal component analysis indicated that fatty acid signatures of each of the 6 juve- nile and 6 adult fish species were highly similar to POM and distinct from the other producers within the Sargassum complex.

Assessment of erythrocyte phospholipid fatty acid composition as a biomarker for dietary MUFA, PUFA or saturated fatty acid intake in a controlled cross-over intervention trial

BackgroundDietary intervention trials rely on self-reported measures of intake for assessment of energy and macronutrient composition. Dietary fat intake is of particular interest due to strong associations with pathophysiology. In epidemiological trials phospholipid fatty acid composition may reflect composition of habitual diet, although strong correlations have been identified only for essential polyunsaturated fatty acids (PUFAs). Preliminary evidence shows that saturated fatty acids (SFA) C15:0 and C17:0 may be acceptable biomarkers. This study measured changes in erythrocyte membrane fatty acids during a period of strictly controlled fat feeding to investigate their use as a short-term marker of compliance, particularly for intake of SFAs.ResultsThis was a randomised cross-over trial in which diet was provided and strictly controlled. 20 healthy, male subjects were given a 40 energy % (en%) fat diet, high in saturated (high-SFA, 20 en%) or unsaturated (high-USFA, 24 en%) fatty acids for 2 periods of 3 weeks. Subjects were residential during intervention with all food and beverages provided. Dietary composition was verified by direct chemical analysis. Blood samples were collected on days 1,7,14, 21 and analysed for red blood cell (RBC) membrane fatty acid composition. Pearson correlation showed RBC fatty acid composition to mimic dietary composition by 3 weeks, but the relationships were weak. Of the SFAs only RBC C16:0 decreased in response to decreased dietary content on high-USFA treatment (ANOVA, diet, P < 0.05). Of the USFAs, higher levels of C18:1 MUFA, C20:4 and C22:6 long chain PUFA on high-USFA diet lead to higher C18:1, C20:4 and C22:6 within RBCs (ANOVA, time*diet, P < 0.05). Pearson's correlation was significant between dietary and RBC fatty acids during the 21d dietary manipulation for C18:1, and C20:5, C22:6 only (P < 0.05).ConclusionRBC membrane fatty acids cannot reliably be used as an independent measure of compliance for dietary SFA intake in short-term studies. The MUFA oleic acid and PUFAs EPA and DHA may be more useful as markers of compliance during short term intervention trials.

SerumTrans-Fatty Acids Are Associated with Risk of Prostate Cancer in β-Carotene and Retinol Efficacy Trial

Biomarkers of trans-fatty acid consumption have been associated with increased risks of breast and colon cancer, although no studies have examined their associations with prostate cancer risk. Using data from the beta-Carotene and Retinol Efficacy Trial, this nested case-control study examined the relationships between serum phospholipid trans-fatty acids and prostate cancer incidence in 272 case and 426 control men. Trans-fatty acids were measured using organic extraction followed by separations with TLC and gas chromatography. Adjusted odds ratios for risk of prostate cancer with increasing levels of trans-fatty acids were calculated using logistic regression. There were consistent trends for increasing prostate cancer risk with higher levels of C18 but not C16 trans-fatty acids, although only trends for Delta11t 18:1 trans-vaccenic and Delta9c,12t 18:2 fatty acids reached statistical significance. Odds ratios (95% confidence interval) contrasting low versus high quartiles for these fatty acids were 1.69 (1.03-2.77) and 1.79 (1.02-3.15), respectively. There were no consistent differences in associations between low-grade and high-grade cancer among the subset of 209 cases with information on tumor grade. Additional studies are needed to confirm these findings and better control for factors, such as use of prostate-specific antigen screening, which may confound this association.

Effect of dietary linseed oil and α-tocopherol on selected properties of pig fat

The effect of linseed oil and α-tocopheryl acetate on the fatty acid composition, the susceptibility to oxidation of pig adipose tissue and the subcutaneous fat consistency was studied. Fifty female pigs were penned individually at approximately 25 kg and fed a conventional diet until 48.1 ± 3.5 kg. Pigs were then randomly assigned to one of five diets including: C, control (3% sunflower oil); L and LE (3% linseed oil) and LO and LOE (1.5% of linseed oil plus 1.5% of olive oil). LE and LOE had 200 mg α-tocopheryl acetate added per kilogram of diet whereas C, L and LO had 20 mg α-tocopheryl acetate added per kilogram of diet. Animals were slaughtered at 100.1 ± 7.1 kg. In the lard of the control diet animals the concentration of n-6 fatty acids rose markedly during the first 4 wk, and then stabilised. The concentrations of these fatty acids in the lard of L and LE group were not modified over time. In the lard of animals fed on LO and LOE diets, a moderate linear rise in the concentration of n-6 fatty acids was found. The addition of linseed oil to pig diets either as the only source of dietary fat or in combination with olive oil produced a higher (P &lt; 0.0001) C18:3n–3 and total n-3 fatty acids concentration in adipose tissue lipids. The n6/n3 ratio was sharply reduced (from 9.88 in the control batch to at least 2.48) when pigs were fed diets enriched in linseed oil. It was concluded that the higher the dietary concentration of n-3 fatty acids the greater and faster the response of pig tissue. The α-tocopherol content of adipose tissue from pigs fed diets enriched with α-tocopheryl acetate (200 mg kg-1 feed) was significantly greater (P &lt; 0.001) that those from pigs receiving a basal diet of 20 mg kg-1 feed. Adipose tissue from pigs fed diets enriched in C18:3n-3 showed higher susceptibility to oxidation than that from pigs fed diets containing high levels of C18:2n-6, but dietary supplementation with α-tocopheryl acetate markedly reduced the pig fat oxidation in groups fed diets enriched in n-3 fatty acids, eliminating the difference in the oxidative status between the two treatment groups. No effect of dietary treatment on lard rheological parameters (hardness, adhesiveness, springginess, gumminess and chewiness) of fat was observed. Conclusively, the diet enrichment in both linseed and α-tocopherol is a very effective approach to produce a healthier fat and to prevent the lipid oxidative deterioration. Key words: Pig, adipose tissue, linseed oil, fatty acid, α-tocopherol

Age-related changes in fatty acids in obese offspring of streptozotocin-induced diabetic rats.

The long-term effects of fetal hyperinsulinemia, time course of changes in liver and very-low-density lipoprotein (VLDL) lipid levels and fatty acid compositions were investigated in obese offspring of streptozotocin-induced mildly diabetic rats. Mild hyperglycemia in pregnant rats was induced by intraperitoneal injection of streptozotocin on day 5 of gestation. Control pregnant rats were injected with citrate buffer. Liver and VLDL lipids and fatty acids were analyzed in offspring at different ages. At birth, obese pups had higher VLDL triglyceride levels, saturated fatty acids, and C20:4n-6. They also had lower C18:2n-6 proportions in VLDL triglycerides, phospholipids, and cholesteryl esters than controls pups. In 1-month-old male and female obese rats, VLDL and liver lipid amounts were similar to those in their respective controls; however, high levels of C18:2n-6 and C20:4n-6 were noted in liver and VLDL lipids. At the age of 2 months, liver and VLDL triglyceride levels were higher in obese females than in control females. Fatty acid abnormalities seen in obese rats included low C18:3n-3 and high C22:6n-3 proportions in liver triglycerides and phospholipids. At the age of 3 months, obese rats, both males and females, compared with control animals, had higher VLDL and hepatic lipids with reduced C20:4n-6 levels and polyunsaturated/saturated fatty acids ratios in hepatic and VLDL triglycerides and phospholipids. Fetal obesity, associated with alterations in VLDL lipid fatty acid composition, represents an important risk factor for adult obesity and diabetes.

Effects of various dietary n-3 / n-6 fatty acid ratios on the performance and body composition of broilers

Different combinations of saturated and unsaturated fatty acids were fed to broilers to establish their effect on the fatty acid composition of the broiler carcass and the abdominal fat pad. Six combinations of Canola acid oil (CAO, high levels of C18:3n-3 and monounsaturated fatty acids) and Famarol acid oil (FAO, high levels of C18:2n-6 and saturated fatty acids) were included in the broiler diets from one day of age to six weeks of age, viz. 100% FAO, 80% FAO-20% CAO, 60% FAO-40% CAO, 40% FAO-60% CAO, 20% FAO-80% CAO, 100% CAO. There were no statistically significant differences between dietary groups in weight gain (1.71 ± 0.059 kg) or feed conversion ratios (1.97 ± 0.051 g feed/g gain). No significant differences between treatments were found in the moisture (66.20 ± 0.112%), protein (17.63 ± 0.484%), lipid (15.92 ± 1.507%) and ash (0.95 ± 0.115%) concentration of the carcasses, nor in the moisture (28.77 ± 0.112%), protein (3.03 ± 0.484%), lipid (63.32 ± 9.789%) and ash (0.45 ± 0.135%) concentrations of the abdominal fat pads. With the increase in dietary CAO levels, the mean percentages of C18:2n-6 and C20:4n-6 in the carcasses decreased respectively with 1.78% units from 20.88% and 0.35% units from 1.05%, whilst C18:3n-3 and longer chain n-3 fatty acids such as C20:5n-3 and C22:6n-3 increased respectively with 2.25% units from 1%, 0.1% units from 0.1% and 0.67% units from 0.2%. The same tendency was seen in the abdominal fat pads where C18:2n-6 and C20:4n-6 decreased respectively with 1.55% units from 20.75% and 0.98% units from 1.2% with an increase in dietary CAO, whilst C18:3n-3, C20:5n-3 and C22:6n-3 increased respectively with 2.13% units from 1.15%, 0.45% units from 0.03% and 0.95% units from 0.05%. The n-3 / n-6 ratio in the carcasses and abdominal fat pads increased respectively with 0.16% units from 0.06% and 0.19% units from 0.06% with an increase in dietary CAO. These results clearly indicate that dietary CAO enriched with á-linolenic acid lowered the saturated fatty acid concentrations in broiler carcasses and abdominal fat pads with 4.88% units and 10.63% units respectively, and increased the monounsaturated fatty acid concentrations with 3.87% units and 7.25% units, respectively and polyunsaturated fatty acid concentrations with 1.02% units and 2.38% units, respectively. The results of this experiment showed that substitution of Famarol oil with Canola oil in broiler diets can increase the ratio of n-6 to n-3 fatty acids in broiler carcasses and abdominal fat pads to 5:1, a ratio more suitable for human health. Increasing the level of n-3 fatty acids in the diets was also effective in reducing the level of saturated fatty acids in the carcasses and abdominal fat pads of broiler chickens resulting in ";healthier"; chickens. South African Journal of Animal Science Vol.32(3) 2002: 175-184

Effect of rearing system on muscle lipids of gilts and castrated male pigs

The objective of this study was to investigate the polar and neutral lipid fatty acid composition of pig muscle as influenced by rearing conditions and sex. A total of 120 Hampshire crossbreeds were divided in two groups, one reared free-range in a strip grazing fashion and one reared indoors in a large pen (120 m2). Free-range rearing produced a more unsaturated fatty acid composition (M. biceps femoris) in the neutral lipids, although the effect was small. In the polar lipids the effect of rearing condition was sex dependent. In the muscle of free-range gilts, there was a higher level of C18:2 n-6, compared with indoor gilts, indoor castrates, and free-range castrates. Moreover, muscle of gilts irrespective of rearing condition, had a higher level of the C⩾20 polyunsaturated fatty acids in the polar lipids (16.75 and 14.60, respectively). Thus, we suggest that the difference between castrates and gilts with respect to fatty acid composition in the polar lipids, might be affected by rearing condition.

Influence of species, cutting date and cutting interval on the fatty acid composition of grasses

Two experiments were conducted to evaluate the effects of species, cutting date and cutting interval on the concentration of fatty acids in temperate grasses. The first experiment compared eight species, harvested in late autumn and summer. Levels of individual fatty acids were distinctive for some species, with low levels of C18:1 in Dactylis glomerata L. and high levels of C18:2 in Phleum pratense L. Differences in individual fatty acids could not be used to differentiate fescues and ryegrasses. However, fatty acid profiles could be used to differentiate species when material was managed similarly (i.e. at the same cut). There were large species × cut interaction effects, showing that management factors will be as important as plant breeding in manipulating fatty acid levels. Cultivars belonging to one Lolium perenne L. gene pool were identified as having significantly higher α‐linolenic acid and total fatty acids in late‐season (November) material.The second experiment compared three ryegrass species over a growing season, with three or five cuts. All species had high concentrations of fatty acids and a high proportion of α‐linolenic acid during vegetative growth (late April). Fatty acid levels declined markedly in all species after this date, recovering by autumn. Kunth Lolium multiflorum Lam. and Lolium × boucheanum had higher levels of total fatty acids and α‐linolenic acid in the early and late season when compared with perennial ryegrass. Fatty acid levels (particularly C18:2 and C18:3) declined when the regrowth interval was extended from 20 to 38 d.These studies demonstrate opportunities to change the composition of ruminant products through breeding and management of grasses for altered levels of fatty acids.

Effect of feeding diets high in monounsaturated fatty acids and α-tocopheryl acetate to rabbits on resulting carcass fatty acid profile and lipid oxidation

AbstractThe effects of olive (MONO) or sunflower (POLY) oil-enriched (30 g/kg) diets with either a basal (10 mg/kg food) or supplemented (200 mg/kg) level of a-tocopheryl acetate on some measures of production, fatty acid composition of animal tissues and susceptibility to oxidation of rabbit meat and membrane extracts have been studied. MONO diet produced higher levels of C18:1 in animal tissues. Animals that received POLY diet had a higher level of C18:2 in perirenal and neutral fraction of intramuscular fat and higher levels of C18:2, C20:4, C22:4 and C22:5 in phospholipid, reaching a higher overall unsaturation (P = 0·001). Muscle samples from rabbits given the POLY diet were more susceptible to lipid oxidation (P = 0·0001). Differences in membrane lipid oxidation, between groups followed a similar pattern to that of meat. Diets rich in C18:2 resulted in increases in concentration of pentanal (P &lt; 0·001), hexanal (P = 0·0001) and total volatile aldehydes (P = 0·0001) in meat as monitored by headspace gas liquid chromatography. Dietary supplementation with α-tocopheryl acetate reduced the overall concentration of volatile aldehydes (P &lt; 0·05), particularly hexanal (P &lt; 0·05). Dietary administration of monounsaturated fatty acids not only reduces membrane and meat lipid oxidation but also modifies the relative proportion of volatile aldehydes generated upon heating, with a specific decrease in those generally related to rancidity and off-flavour of meats.

Fatty acid composition of Streptomyces hygroscopicus strains producing antibiotics.

The fatty acid composition from mycelia of Streptomyces hygroscopicus strains was studied. A significant proportion of C18:2 was found in cultures. High levels of C16:0, iso-C18:0 and C18:1 were also detected in all S. hygroscopicus strains. The different representatives of S. hygroscopicus had almost the same proportion of unsaturated fatty acids. Certain shifts in the amount of iso, anteiso and straight-chain fatty acids in some cultures were revealed. This might be explained by the adaptation capability of strains belonging to one species to form a variety of available fatty acids determined by particular cell membrane composition favouring certain antibiotic biosynthesis.

Fatty Acid Composition of Ulva pertusa Kjellman (Chlorophyta) and Gracilaria incurvata Okamura (Rhodophyta) in Japanese Coastal Waters

Crude lipid content and total fatty acid composition of 2 macrophytes, Ulva pertusa Kjellman (Chlorophyta) and Gracilaria incurvata Okamura (Rhodophyta) were monitored using material from the wild from March to July 1992. Ulva pertusa contained high levels of C16 (16: 4 n - 3) and C18 (18: 1, 18: 2 n-6, 18: 3 n - 3 and 18: 4 n - 3) unsaturated fatty acids (36 - 54% of total fatty acids), while the only unsaturated fatty acid occurring at high levels in G. incurvata was arachidonic acid (20: 4, 26 -46% of total fatty acids). Both seaweeds contained high levels of palmitic acid (16: 0, 19-33%). Temperature and daylength were not regarded as completely distinct environmental factors because of their highly significant correlation during the period of study (r 2 = 0.91, p < 0.003)