Lipid and fatty acid composition of muscle and internal organs from Ruvettus pretiosus

The lipid composition of different muscular areas (dorsal, ventral, subcutaneous, periosteum) and organs (liver, gall bladder, testes) of a gempylid fish Ruvettus pretiosus was examined. Waxes were the main lipid fraction in muscular areas, while the liver and testes were quite enriched in triglycerides and phospholipids. Oleic acid and fatty acids of n-3 family were the most frequently found in total lipids.     

Effect of dietary enrichment with either n-3 or n-6 fatty acids on systemic metabolite and hormone concentration and ovarian function in heifers

The objective of this experiment was to examine the effects of dietary n-3 or n-6 fatty acid (FA) supplementation on blood FA, metabolite and hormone concentrations, follicle size and dynamics and corpus luteum (CL) size. Reproductively normal heifers (n = 24) were individually fed diets of chopped straw and concentrate containing either (i) no added lipid (CON; n = 8); (ii) 2% added fat as whole raw soya beans (WSB, n-6; n = 8); or (iii) 2% added fat as fish oil (FO, n-3; n = 8). Following oestrous cycle synchronisation, blood samples were collected at appropriate times and intervals for the measurement of hormones, FAs and metabolites. On days 15 and 16 of the cycle, animals were subjected to an intravenous oxytocin challenge and prostaglandin F2α (PGF2α) response, measured as venous concentrations of 13,14-dihydro-15-keto PGF2α (PGFM). Dry matter intake and average daily gain were similar among treatments (P > 0.05). Plasma concentration of linoleic acid was highest on WSB (P < 0.05), while eicosapentaenoic (EPA, n-3; P < 0.0001) and docosahexaenoic acid (DHA, n-3; P < 0.0001) were greatest in the FO group. Plasma concentrations of arachidonic acid were higher on FO (P < 0.05) compared with CON and WSB. Plasma triglyceride concentrations increased, while β-hydroxybutyrate (BHBA) decreased with time on all diets (P < 0.05). There was a diet × time interaction (P < 0.01) for non-esterified fatty acid (NEFA) concentrations. Plasma cholesterol was higher on WSB and FO (P < 0.01) compared with CON. Progesterone (P4) and oestradiol (E2) concentrations, as well as follicle growth rate and CL diameter were similar across diets (P > 0.05). There was a diet × day interaction for PGFM (P < 0.01). When corrected for systemic E2 : P4 ratio, day 15 concentrations of PGFM were higher in the WSB group at 15 and 30 min (P < 0.01) post oxytocin administration compared with CON and FO, which were similar (P > 0.05). Concentrations of PGFM on day 16 were similar for WSB and FO and were greater than CON at 15 (P < 0.01) and 45 min (P < 0.05) post oxytocin administration, and at 30 min for FO (P < 0.05). With the exception of PGFM, dietary lipid source did not affect the reproductive variables measured.     

The lipid composition of two species of serrasalmid fish in relation to dietary polyunsaturated fatty acids

The lipid composition of two species of Serrasalmid fish with different natural feeding habits were compared in relation to the polyunsaturated fatty acids (PUFA) supplied in their diets. Mylossoma aureum , a herbivorous piranha, was maintained on oatmeal flakes in which : 2(n-6) and : 3(n-3) were the only PUFA and accounted for 40–8 and 1.2%, respectively of dietary fatty acids. Serrasalmus nattereri , the carnivorous red piranha, was fed mosquito larvae containing .0-33.4% of their total fatty acids as : 2(n-6)+18 : 3(n-3) and 4.9-8.5% as 20 : 4(n-6)+20 : 5(n-3). The two species had similar lipid class compositions in liver, brain, viscera and carcass, except that lipids from M. aureum were generally richer in triacylglycerols. In both species, visceral and carcass lipid contained high levels of triacylglycerols whose principal PUFA was : 2(n-6). In M. aureum the major PUFA in liver total lipid and triacylglycerols was : 2(n-6) whilst the major PUFA in liver phospholipids were : 4(n-6) and : 5(n-6), with : 6(n-3) being a minor component. The level of : 6(n-3) in ethanolamine glycerophospholipids was significantly greater in brain than liver of M. aureum. Although absent from dietary lipid, : 6(n-3) was the major PUFA in phosphatidylcholine and ethanolamine glycerophospholipids from both the liver and brain of S, nattereri . In both species, the ratio of (n-6)/(n-3)PUFA was consistently lower in tissue lipids than in dietary lipids. The results are consistent with (i) the herbivorous M. aureum converting dietary C18 PUFA to their C20 and C22 homologues, (ii) the carnivorous S, nattereri forming : 6(n-3) from either 18:3(n-3) or 20: 5(n-3) and (iii) both species selectively desaturating and elongating (n-3) rather than (n-6) PUFA.     

Effects of dam breed and dietary source of n-3 polyunsaturated fatty acids on the growth and carcass characteristics of lambs sourced from hill sheep flocks

The objectives of this study were to investigate the effect of dietary lipid source on the growth and carcass characteristics of lambs sourced from a range of crossbred hill ewes. Over a 2-year period, 466 lambs representing the progeny of Scottish Blackface (BF × BF), Swaledale (SW) × BF, North Country Cheviot (CH) × BF, Lleyn (LL) × BF and Texel (T) × BF ewes were sourced from six commercial hill flocks and finished on one of four diets: grass pellets (GP), cereal-based concentrate (CC), CC enriched with oilseed rape (CR) and CC enriched with fish oil (CF). Dry matter intake (DMI) was highest (P < 0.001) in lambs offered GP; however, carcass weight gain (CWG) and feed conversion efficiency were higher (P < 0.001) in lambs fed concentrate-based diets. For lambs offered concentrate-based diets, DMI and live weight gain were lower (P < 0.001) for CF than CC or CR. Lambs with T × BF dams achieved a higher (P < 0.05) daily CWG and CWG/kg DMI than BF × BF, SW × BF or LL × BF dams. When lambs were slaughtered at fat score 3, CH × BF, LL × BF and T × BF dams increased carcass weight by 0.8 to 1.4 kg (P < 0.001) and conformation score (CS) by 0.2 to 0.4 units (P < 0.001) compared with BF × BF or SW × BF dams. However, breed effects on carcass conformation were reduced by 50% when lambs were slaughtered at a constant carcass weight. Diets CC and CR increased carcass weight by 0.8 to 1.6 kg (P < 0.001) and CS by 0.1 to 0.3 units (P < 0.001) compared with GP and CF. Both, dam breed and dietary effects on carcass conformation were associated with an increase (P < 0.001) in shoulder width of the lambs. Lambs fed CF and slaughtered at a constant carcass weight had more subcutaneous fat over the Longissumus dorsi (P < 0.05), Iliocostalis thoracis (P < 0.001) and Obliquus internus abdominis (P < 0.001) compared with those fed CC. However, these effects were removed when lambs were slaughtered at a constant fat score. At both endpoints, lambs from T × BF dams contained less (P < 0.05) perinephric and retroperitoneal fat than SW × BF or LL × BF dams fed GP or CC, respectively. The results from this study show that using crossbred ewes sired by CH, LL or T sires will increase carcass weight and improve carcass conformation of lambs sourced from hill flocks. Inclusion of oilseed rape in lamb finishing diets had only minor effects on performance compared with a standard CC but feeding fish oil or GP impacted negatively on lamb growth and carcass quality.     

Effect of n-3 and n-6 fatty acids on hepatic microsomal lipid metabolism: a time course study

The present study examines the time dependent effects of n-6 and n-3 polyunsaturated fatty acids on liver microsomal lipid metabolism in FVB mice fed a diet supplemented with a mixture of free fatty acids (mainly 18:3n-6 and 20:5n-3) at 25 mg/g diet. Significant changes in the fatty acid composition of total liver and microsomal lipids were observed after 7 days on the diets. Thereafter, some animals remained on the same diet while others were fed a diet supplemented with hydrogenated coconut oil (HCO). With the exception of 20:5n-3 which showed a slower recovery, establishment of the HCO pattern was rapid indicating that the diet-induced changes could be easily reversed. The unsaturation index, the cholesterol/phospholipid ratio and the microviscosity of the microsomal membranes were not affected by these dietary manipulations. Unsaturated fatty acid supplementation reduced the activity of ⁹ desaturase by 50%. Feeding the HCO diet to mice previously fed the EPA/GLA diet led to a progressive increase in ⁹ desaturase activity, reaching 80% of the day zero values after 14 days. The monoene content of hepatic total lipids reflected, in most cases, the changes in enzyme activity. This study shows that a low dose of a n-3 and n-6 free fatty acid mixture increases the quantities of members of the n-3 family, without loss of n-6 fatty acids in microsomal membranes and modifies the activity of ⁹ desaturase without altering the microsome physicochemical parameters.     

不同饵料对卤虫生长、总脂含量及脂肪酸组成的影响

为了提高养殖卤虫的饵料营养价值,了解其不同生长阶段营养成分变化情况,采用单因子试验研究了8种饵料（三角褐指藻、小球藻、微绿球藻、酵母液、三角褐指藻＋小球藻＋微绿球藻、三角褐指藻＋酵母液、小球藻＋酵母液和微绿球藻＋酵母液）对卤虫生长、总脂含量及脂肪酸组成的影响,结果表明：不同饵料种类对卤虫生长、总脂含量及脂肪酸组成的影响显著（P＜0.05）,增长率,以三角褐指藻＋酵母液最优;总脂含量、以三角褐指藻最优（19.67%）,除酵母液外,与其它饵料相差不显著（P＞0.05）;脂肪酸组成效果,以微绿球藻组最优（EPA：18.01%,DNA：0.55%,（n-3）HUFA：19.08%）,与三角褐指藻组相差不大（P＞0.05）,显著高于其它各组（P＞0.05）.同时以三角褐指藻为饵料,研究了卤虫不同生长阶段（体长2、4、6、8、10 mm）总脂含量、脂肪酸组成变化,结果表明：卤虫体长2～10 mm总脂含量为14.27%～20.93%,随体长的增长降低;EPA、DHA及（n-3）HUFA的含量,均随体长的增长降低,EPA含量为：10.47%～20.77%,DNA含量为：0～0.70%,（n-3）HUFA含量为：10.85%～22.01%.结论认为,卤虫以三角褐指藻或三角褐指藻＋酵母液为饵料培养营养价值最佳,其体长小于6 mm营养价值较佳.     

Double enrichment of chicken eggs with conjugated linoleic acid and n-3 fatty acids through dietary fat supplementation

Yolk fat fatty acid (FA) concentrations, sensory quality and firmness of eggs and laying hen performance were evaluated with respect to the combined inclusion in the diet of conjugated linoleic acid (CLA), high n-3 oil sources and high-oleic sunflower oil (HOSO). Nine diets were arranged factorially, with three levels of n-3 FA supplementation (2.9, 3.7 and 4.5 g/kg) from three different sources (two fish oils highly concentrated in eicosapentanoic (EPA) or docosahexanoic acid (DHA) and one algae oil with a very high-DHA content) in diets added with fixed amounts of CLA (2.5 g/kg) and HOSO (30 g/kg). A commercial feed with no CLA, n-3 or HOSO added, and another one containing 4.5 g/kg of high-DHA fish oil but not CLA or HOSO were also formulated. An increase in n-3 FA supplementation had little effect on proportions of CLA, monounsaturated FA, saturated FA or total polyunsaturated FA in yolk fat, but increased (P<0.005) long-chain n-3 FA and decreased (P<0.001) long-chain n-6 FA. An increment of dietary n-3 FA also impaired linearly (P<0.001) egg acceptability by consumers. An increment in the proportion of DHA with respect to total n-3 FA from 0.28 to 0.96 increased yolk concentrations of DHA (P<0.001) and total n-3 FA (P<0.01), but decreased (P<0.001) concentrations of EPA and docosapentanoic acid FA. Current data indicate that addition of HOSO to diets supplemented with moderate amounts of CLA and n-3 FA allows the production of double enriched eggs while maintaining sensory quality for consumers at acceptable levels.     

Effects of intraperitoneally administered ubiquinone on the level of total lipid and fatty acids in rat liver

The purpose of the present study was to evaluate the effect of ubiquinone (coenzyme Q-10) on total lipid and fatty acid composition of liver tissues in rats. Twenty male wistar rats were randomly divided into two groups. The first group was used as a control. The second group received ubiquinone (8 mg/every other day) intraperitoneally. This administration was done for a period of 38 days. Body weight increases in animals fed diets for 38 days were on average 35 g in control group (C), and only 11 g in the ubiquinone group. Total lipid content of liver tissues in the ubiquinone group (UB) decreased significantly (p < 0.0001) compared to the control group (C). The ratio of 22:6 and total omega3 fatty acid in the UB increased (p < 0.01) compared to C. While the level of oleic acid (18:1), palmitoleic acid (16:1) and total monounsaturated fatty acid (MUFA) in UB significantly decreased (p < 0.01, p < 0.001, p < 0.001, respectively), the level of stearic acid (18:0) in liver tissue increased (p < 0.05) in the same group when compared to C. Stearoyl-CoA desaturase (SCD) is the rate-limiting enzyme catalyzing the synthesis of monounsaturated fatty acid mainly oleate (18:1). We speculate that ubiquinone inhibits SCD activity. SCD is an important metabolic control point in body weight regulation. Our results indicate that ubiquinone supplementation may have an inhibitory effect on obesity and it seems that the level of 22:6 in liver increased due to ubiquinone.     

Effects of dietary lead,fish oil,and ethoxyquin on hepatic fatty acid composition in chicks

Three experiments were conducted with day-old broiler chicks reared to 18 or 19 d of age. The objective was to examine the effects of dietary oil (cottonseed oil vs fish oil), dietary antioxidant (0 vs 75 ppm ethoxyquin), and dietary lead (0 vs 1000 ppm Pb as lead acetate trihydrate) on hepatic fatty acid composition. A 2×2 factorial arrangement was used in all experiments. In Experiment 1, the factors were oil (4% of each) and Pb. In Experiments 2 and 3, the factors were ethoxyquin and Pb in diets containing 3.5% cottonseed oil (Experiment 2) or 3.5% fish oil (Experiment 3). Hepatic fatty acid profiles were measured by gas-liquid chromatography in 10 chicks/treatment (Experiment 1) or 4 chicks/treatment (Experiments 2 and 3). Dietary oils altered the profiles, with cottonseed oil producing the higher values for linoleic acid (18∶2) and arachidonic acid (20∶4). With fish oil, in addition to the lower levels of 18∶2 and 20∶4, there were significant levels of eicosapentaenoic acid (20∶5) and docosahexaenoic acid (22∶6). Pb enhanced the levels of 20∶4, but the effect was greater with cottonseed oil diets compared with fish oil diets. The enhanced 20∶4 levels resulted in lower ratios of 18∶2/20∶4. Ethoxyquin enhanced the level of 18∶2 with the cottonseed oil diet, and of 20∶5 and 22∶6 with the fish oil diet. Ethoxyquin decreased the level of hepatic 20∶4 when fish oil was fed. The results clearly show that all three factors (oil type, Pb level, and ethoxyquin level) after hepatic fatty acid composition. Both oil source and Pb level appeared to exert an effect on the metabolic conversion of 18∶2 and 20∶4. The primary effect of ethoxyquin was to enhance the levels of polyunsaturated fatty acids in liver. The data do not allow the partitioning of possible ethoxyquin effects to protection of polyunsaturated acids in feed vs protection of polyunsaturated acids in liver tissue. Use of trade names implies neither approval by the North Carolina Agricultural Research Service of products named nor criticism of products not named.     

Metabolism of n-6 fatty acids by NIH-3T3 cells transfected with the ras oncogene

N-6 fatty acid metabolism was compared in NIH-3T3 cells and DT cells, which differ only in the presence of the v-Ki-ras oncogene. Non-dividing cells were incubated with [1-¹⁴C]-labelled fatty acids (18:2n-6, 18:3n-6, 20:3n-6 and 20:4n-6) at different time intervals (2–24 h) and concentration (0–120 M). In both cells lines, the uptake of different fatty acids from the medium was similar and reached a maximum at 6–8 h. All fatty acids reached the same maximum level in DT cells, whereas, the relative uptake of added fatty acids by NIH-3T3 cells was different: 20:4n-6>20:2n-6>18:2n-6=18:3n-6. Throughout the incubation (2–24 h), desaturation and elongation of n-6 fatty acids was more active in DT cells than in NIH-3T3 cells. However, in both cell lines, incubated with different n-6 fatty acid precursors, the levels of radiolabelled 20:4n-6 were relatively constant. In DT cells, phosphatidylcholine was found to be the major fraction labelled with n-6 fatty acids precursors and those of endogenous synthesis, whereas, in NIH-3T3 cells the neutral lipid fraction, particularly triglycerides, was also strongly labelled. In concentration dependent studies, phospholipid labelling by fatty acids was saturable. At lower concentrations, especially in DT cells, phospholipids were labelled predominantly. As the concentration increased there was an overflow into the triglyceride fraction. Since the differences in fatty acid metabolism between the two cell lines cannot be related to the growth rate, it is suggested that they were a consequence of the expression of the v-Ki-ras oncogene.Abbreviations BSA bovine serum albumin - CE cholesterol ester - DG diglyceride - DMEM Dulbecco's modification of Eagle's medium - EL ether lipids (glyceryl ether diesters) - FAME fatty acid methyl ester - FCS fetal calf serum - FFA free fatty acids - HEPES N-2-(hydroxyethyl)piperazine-N-2-ethanesulphonic acid - MG monoglyceride - NL neutral lipid - PC phosphatidylcholine - PE phosphatidylethanolamine - PI phosphatidylinositol - PL phospholipid - s.a specific activity - TG triglyceride - TLC thin layer chromatography     

Predicting duodenal flows and absorption of fatty acids from dietary characteristics in ovine and bovine species: a meta-analysis approach

Dietary and ruminal factors modify the ruminal biohydrogenation (RBH) of polyunsaturated fatty acids (FA), with duodenal FA flows being quantitatively and qualitatively different from FA intake. Using a meta-analysis approach from a database on duodenal flows of FA in ruminants, this study aimed to determine predictive equations for duodenal and absorbed flows of saturated FA, C18:1, C18:2 and C18:3 isomers, odd- and branched-chain FA (OBCFA), C20:5n-3, C22:5n-3 and C22:6n-3 and to quantify the effects of dietary and digestive factors on those equations. The database was divided into four subsets: forage, seed, vegetable oils or animal fats (oil/fat), and fish products (fish) subsets. Models of duodenal and absorbed FA flows were obtained through variance–covariance analysis. Effects of potential interfering factors (conservation mode and botanical families of forages, lipid source, technological processing of lipid supplements, diet composition and animal characteristics) were analysed. We obtained 83 models for duodenal FA flows as a function of FA intake for saturated FA (C14:0, C16:0 and C18:0), C18:1, C18:2 and C18:3 isomers and seven other models for OBCFA. For the seed/oil/fat subset, intakes of total C18:3, C18:2 and starch content increased the duodenal t11-C18:1 flow with 0.08, 0.16 and 0.005 g/kg of dry matter intake (DMI), respectively, whereas intake level [(DMI×100)/BW] decreased it. The c9c12c15-C18:3 RBH was higher for oil/fat than seed (96.7% v. 94.8%) and a protective effect of Leguminosae v. Gramineae against RBH for that FA appeared in the forage subset. The duodenal C17:0 flow increased with starch content and decreased with ruminal pH, respectively, whereas duodenal iso-C16:0 flow decreased with dietary NDF content for the seed/oil/fat subset. The duodenal C20:5n-3, C22:5n-3 and C22:6n-3 flows depended on their respective intake and the inhibitory effect of C22:6n-3 on duodenal C18:0 flow was quantified. Thirteen models of absorbed FA flows were performed depending on their respective duodenal flows. This study determined the effects of different qualitative and quantitative dietary and digestive factors, allowing for improved predictions of duodenal and absorbed FA flows.     

Effects of metabolic rate and sperm competition on the fatty‐acid composition of mammalian sperm

The sperm membrane is a key structure affecting sperm function and thus reproductive success. Spermatozoa are highly specialized and differentiated cells that undergo a long series of processes in the male and female reproductive tracts until they reach the site of fertilization. During this transit, the sperm membrane is prone to damage such as lipid peroxidation. The characteristics and performance of the sperm membrane are strongly determined by the fatty‐acid composition of membrane phospholipids. Polyunsaturated fatty‐acids (PUFAs) are the most prone to lipid peroxidation. Lipid peroxidation and other types of oxidative damage increase with higher metabolism and with higher levels of sperm competition due to the increased ATP production to fuel higher sperm velocities. Consequently, we hypothesized that, in order to avoid oxidative damage, and the ensuing impairment of sperm function, sperm cells exhibit a negative relationship between PUFA content and mass‐specific metabolic rate (MSMR). We also hypothesized that higher sperm competition leads to a reduction in the proportion of sperm PUFAs. We performed a comparative study in mammals and found that high MSMR and high levels of sperm competition both promote a decrease in the proportion of PUFAs that are more prone to lipid peroxidation. The negative relationship between MSMR and these PUFAs in sperm cells is surprising, because a positive relationship is found in all other cell types so far investigated. Our results support the idea that the effects of MSMR and sperm competition on sperm function can operate at very different levels.     

Changes in fatty acid composition of lipid classes in developing mustard seed

Maturation of mustard (Sinapis alba) seed proceeds with a sharp decrease in the amounts of palmitic and linoleic acids in the total lipids up to 6 weeks after flowering (WAF). Concomitantly, the concentration of oleic acid increases, reaching a plateau at 4 WAF, which is followed by chain elongation of oleic acid to gadoleic and erucic acids. Compositional changes in constituent fatty acids of individual lipid classes indicate that the very long-chain monounsaturated fatty acids (C₂₀ and C₂₂), as opposed to common long-chain fatty acids (C₁₆ and C₁₈), are metabolized to triacylglycerols mainly by esterification to preformed diacylglycerols and monoacylglycerols, rather than via esterification to glycerol-3-phosphate or lysophosphatidic acids.     

Maternal dietary n-3 fatty acids alter cardiac ventricle fatty acid composition, prostaglandin and thromboxane production in growing chicks

The effects of feeding n-6 and n-3 fatty acids to broiler hens on cardiac ventricle fatty acid composition, and prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) production of hatched chicks were investigated. Fertile eggs obtained from hens fed diets supplemented with 3.5% sunflower oil (Low n-3), 1.75% sunflower+1.75% fish oil (Medium n-3), or 3.5% fish oil (High n-3) were incubated. The hatched chicks were fed a diet containing 18:3 n-3, but devoid of longer chain n-6 and n-3 fatty acids for 42 days. Arachidonic acid content was lower in the cardiac ventricle of High n-3 and Medium n-3 compared to Low n-3 birds for up to 2 weeks (P<0.002). Long chain n-3 fatty acids were higher in the cardiac ventricle of chicks from hens fed High and Medium n-3 diets when compared to chicks from hens fed the Low n-3 diet. Differences in long chain n-3 fatty acids persisted up to four weeks of age (P<0.001). Peripheral blood mononuclear cells (PBMNC) of 7-day-old High n-3 broilers produced significantly lower PGE2 and TXA2 than PBMNC from Low n-3 and Medium n-3 birds. These results indicate that maternal dietary n-3 fatty acids increases cardiac ventricle n-3 fatty acids while reducing arachidonic acid and ex vivo PGE2 and TXA2 production during growth in broiler chickens.     

Effect of n-6 and n-3 polyunsaturated fatty acids ingestion on rat liver membrane-associated enzymes and fluidity

The influences of diets having different fatty acid compositions on the fatty-acid content, desaturase activities, and membrane fluidity of rat liver microsomes have been analyzed. Weanling male rats (35–45 g) were fed a fat-free semisynthetic diet supplemented with 10% (by weight) marine fish oil (FO, 12.7% docosahexaenoic acid and 13.8% eicosapentaenoic acid), evening primrose oil (EPO, 7.8% γ-linolenic acid and 70.8% linoleic acid) or a mixture of 5% FO-5% EPO. After 12 weeks on the respective diets, animals fed higher proportions of (n-3) polyunsaturated fatty acids (FO group) consistently contained higher levels of 20:3(n-6), 20:5(n-3), 22:5(n-3), and 22:6(n-3), and lower levels of 18:2(n-6) and 20:4(n-6), than those of the EPO (a rich source of (n-6) polyunsaturated fatty acids) or the FO + EPO groups. Membrane fluidity, as estimated by the reciprocal of the order parameter S_DPH, was higher in the FO than in the EPO or the FO + EPO groups, and the n-6 fatty-acid desaturation system was markedly affected.     

Effects of temperature and growth phase on lipid and biochemical composition of Isochrysis galbana TK1

The lipid and biochemical composition of the haptophyte Isochrysis galbana TK1 was examined. Cultures were grown at 15 °C and 30 °C, and harvested in the exponential and early stationary growth phases. Carbohydrate and protein content varied at the two culture temperatures and growth phases. The highest protein content was found at the exponential growth phase at 15 °C, and the highest carbohydrate content was found at the stationary phase at the same culture temperature. Lipid accumulated in the stationary growth phase and its content was higher at 30 °C than at 15 °C regardless of the growth phase. The neutral lipids were the major class of lipid found in all the cultures. The stationary phase culture had a higher proportion of neutral lipids than the exponential phase culture and the proportion decreased slightly when culture temperature was increased from 15 °C to 30 °C. Phospholipid levels remained constant at the two temperatures, but slightly decreased in the stationary phase. Glycolipids in the exponentially growing cells were higher than those from stationary growth phase and increased with temperature. Polyunsaturated fatty acids (PUFAs) predominated in glycolipids and phospholipids. Cells grown at 15 °C contained higher proportion of 18:3 (n–3) and 22:6 (n–3) with a corresponding decrease in 18:2 (n–6), monounsaturated and saturated fatty acids. This revised version was published online in August 2006 with corrections to the Cover Date.     

The effects on boar sperm quality of dietary supplementation with omega-3 polyunsaturated fatty acids differ among porcine breeds

The present study was undertaken to shed light on the relationship between boar sperm quality and dietary supplementation with omega-3 polyunsaturated fatty acids, which has been reported inconsistently in the literature. With this aim, such effects were evaluated and compared among three different porcine breeds: Duroc, Large-White, and Pietrain. Animals were randomly separated into two groups and fed either with a control diet or with a diet supplemented with omega-3. Sperm quality of these boar (ejaculate volume, sperm concentration, sperm viability, acrosome and mitochondrial sheath integrity, sperm motility, sperm morphology, and osmotic resistance of spermatozoa) was assessed every week for a 26-week period. Supplementing boar's diet with omega-3 did not affect ejaculate volume, sperm concentration, sperm motility, sperm viability, and acrosome and mitochondrial sheath integrity. In contrast, supplemented diet positively affected both sperm morphology in Large-White and Pietrain breeds and the osmotic resistance of Pietrain spermatozoa. No effects were seen for the same sperm parameters in Duroc breed. These breed-differences in boar fed with the supplemented diet could explain the contradictions in literature and might be related with differences in the composition of plasma membrane among breeds reported by other authors. Because no harmful effects were observed in the three evaluated breeds, but positive effects in Large-White and Pietrain boar, we can conclude that omega-3 fatty acids may be added to boar's diet at the levels used in this study to improve their sperm quality. More research is, however, needed to determine how these fatty acids differently affect the morphology and the osmotic resistance of the spermatozoa in these breeds.     

Nonesterified fatty acids and lipid peroxidation

Oxygen free radicals damage cells through peroxidation of membrane lipids. Gastrointestinal mucosal membranes were found to be resistant to in vitro lipid peroxidation as judged by malonaldehyde and conjugated diene production and arachidonic acid depletion. The factor responsible for this in this membrane was isolated and chemically characterised as the nonesterified fatty acids (NEFA), specifically monounsaturated fatty acid, oleic acid. Authentic fatty acids when tested in vitro using liver microsomes showed similar inhibition. The possible mechanism by which NEFA inhibit peroxidation is through iron chelation and iron-fatty acid complex is incapable of inducing peroxidation. Free radicals generated independent of iron was found to induce peroxidaton of mucosal membranes. Gastrointestinal mucosal membranes were found to contain unusually large amount of NEFA. Circulating albumin is known to contain NEFA which was found to inhibit iron induced peroxidation whereas fatty acid free albumin did not have any effect. Addition of individual fatty acids to this albumin restored its inhibitory capacity among which monounsaturated fatty acids were more effective. These studies have shown that iron induced lipid peroxidation damage is prevented by the presence of nonesterified fatty acids.     

Peroxidation of n-3 and n-6 polyunsaturated fatty acids in the acidic tumor environment leads to ferroptosis-mediated anticancer effects

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Dietary omega-3 fatty acids from linseed oil improve quality of post-thaw but not fresh sperm in Holstein bulls

Docosahexaenoic acid (DHA), a member of the n-3 fatty acid family present in fish oil, has several positive effects on bovine sperm, including membrane integrity, motility and viability, as well as cold sensitivity. Our objective was to investigate effects of varying amounts of omega-3 fatty acids from linseed oil, administered orally, on quality of fresh and frozen-thawed bull sperm. Twenty fertile Holstein bulls (874 ± 45.38 kg) were randomly and equally assigned to four groups and received encapsulated (rumen-protected) fats for 12 weeks, as follows: group P, 300 g palm oil; group Pl, 200 g palm oil + 100 g linseed oil; group pL, 100 g palm oil + 200 g linseed oil; and group L, 300 g linseed oil. Sperm quality of fresh and frozen-thawed semen was evaluated by routine assays including sperm motion characteristics (CASA), membrane integrity (eosin-nigrosin), membrane activity (hypo-osmotic swelling test; HOST) and malondialdehyde (MDA) content. There were no significant differences among groups in semen volume, sperm concentration or sperm quality parameters in fresh semen. However, after freezing-thawing, total and progressive motility in group P (59.61 ± 1.95 and 40.19 ± 2.48%, respectively; LSM ± SEM) were lower (P < 0.05) than in groups Pl (66.06 ± 1.95 and 47.53 ± 2.48%), pL (65.67 ± 1.95 and 47.48 ± 2.48%) and L (65.36 ± 1.95 and 47.62 ± 2.48)%, with no significant differences among the latter three groups. Furthermore, membrane integrity (eosin-nigrosin) and activity (HOST) were lower (P < 0.05) in group P (55.79 ± 2.15 and 42.19 ± 2.17%) compared to groups Pl (62.73 ± 2.15 and 48.93 ± 2.17%), pL (64.06 ± 2.15 and 50.01 ± 2.17%) and L (64.47 ± 2.15 and 49.68 ± 2.17%), with no significant differences among the latter three. Furthermore, there were more (P < 0.05) morphologically abnormal sperm in group P (25.99 ± 1.62%) than in groups Pl, PL and L (21.55 ± 1.62, 21.69 ± 1.62 and 20.90 ± 1.62%). In conclusion, feeding Holstein bulls 100–300 g linseed oil daily improved sperm cryotolerance.