Dietary Oil Supplementation Research Articles

Effects of dietary fish oil on learning function and apoptosis of hippocampal pyramidal neurons in streptozotocin-diabetic rats

Previous research has demonstrated that diabetes induces learning and memory deficits. However, the mechanism of memory impairment induced by diabetes is poorly understood. Dietary fatty acids, especially polyunsaturated fatty acids, have been shown to enhance learning and memory and prevent memory deficits in various experimental conditions. The present study investigated the effects of fish oil supplementation on the neuron apoptosis in the hippocampus of streptozotocin (STZ)-induced diabetes rats. The effects of diabetes and fish oil treatment on the spatial learning and memory were also evaluated using the Morris Water Maze. Diabetes impaired spatial learning and memory of rats. Diabetes increased the expression of Bax and caspase-3, which led the apoptosis of the CA1 pyramidal neurons, and further contributed to the deficits in learning and memory processing. Fish oil dietary supplementation in diabetic rats conducts neuron-protective function through an anti-apoptotic pathway and significantly improves the ability of learning and memory. These results partially explain the mechanism of the effect of diabetes and fish oil treatment on learning and memory, supporting a potential role for fish oil as an adjuvant therapy for the prevention and treatment of diabetic complications.

Dietary emu oil supplementation suppresses 5-fluorouracil chemotherapy-induced inflammation, osteoclast formation, and bone loss

Cancer chemotherapy can cause osteopenia or osteoporosis, and yet the underlying mechanisms remain unclear, and currently, no preventative treatments are available. This study investigated damaging effects of 5-fluorouracil (5-FU) on histological, cellular, and molecular changes in the tibial metaphysis and potential protective benefits of emu oil (EO), which is known to possess a potent anti-inflammatory property. Female dark agouti rats were gavaged orally with EO or water (1 ml·day(-1)·rat(-1)) for 1 wk before a single ip injection of 5-FU (150 mg/kg) or saline (Sal) was given. The treatment groups were H(2)O + Sal, H(2)O + 5-FU, EO + 5-FU, and EO + Sal. Oral gavage was given throughout the whole period up to 1 day before euthanasia (days 3, 4, and 5 post-5-FU). Histological analysis showed that H(2)O + 5-FU significantly reduced heights of primary spongiosa on days 3 and 5 and trabecular bone volume of secondary spongiosa on days 3 and 4. It reduced density of osteoblasts slightly and caused an increase in the density of osteoclasts on trabecular bone surface on day 4. EO supplementation prevented reduction of osteoblasts and induction of osteoclasts and bone loss caused by 5-FU. Gene expression studies confirmed an inhibitory effect of EO on osteoclasts since it suppressed 5-FU-induced expression of proinflammatory and osteoclastogenic cytokine TNFα, osteoclast marker receptor activator of nuclear factor-κB, and osteoclast-associated receptor. Therefore, this study demonstrated that EO can counter 5-FU chemotherapy-induced inflammation in bone, preserve osteoblasts, suppress osteoclast formation, and potentially be useful in preventing 5-FU chemotherapy-induced bone loss.

Effects of dietary soyabean, rapeseed and linseed oils on performance, slaughter yield and fatty acid profile of breast meat in turkeys

The objective of this study was to determine the physiological effect of supplementing turkey diets with different vegetable oils, i.e. soyabean (S) oil, rapeseed (R) oil and linseed (L) oil, which have different concentrations of polyunsaturated fatty acids (PUFA). The total contents of n-6 PUFA and n-3 PUFA were as follows: diet S, 49.7 and 7.02%, diet R, 33.0 and 7.96%, and diet L, 30.3 and 30.6%; the n-6/n-3 PUFA ratio was 7.3, 4.4 and 1.0, respectively. The experimental materials comprised four groups of turkey hens (14 replications of fifteen birds each). The amount of dietary oil supplementation was increased from 2% in the first four weeks to 6% at the final stage of fattening (14-15 weeks). The apparent total tract digestibility of crude fat in 7-week-old turkeys (2.5% oil in diet) ranged from 89.9 to 91.1%, and showed no statistically significant differences. Dressing percentage, breast, thigh, and drumstick muscle contents did not differ among groups. Group L had a significantly higher intestinal fat weight (0.84% body weight (BW)) than the other groups (0.60-0.62%). In comparison with diet S, diets R and L contributed to a significant decrease in the levels of saturated fatty acids (from 32.9% to 30.3 and 30.2%) in breast meat lipids. In group L turkeys, the share of PUFA in total fatty acids in breast meat lipids was significantly higher (37.3%

Effect of soybean oil on atherogenic metabolic risks associated with estrogen deficiency in ovariectomized rats

The aim of the present study was to investigate the cardiac biomarker changes in experimental bilateral ovariectomized (OVX) rats in addition to evaluating the role of soybean oil-supplemented diet to attenuate these alterations. Female rats were divided into four groups and treated for 2 months as follows: groups 1 and 2 fed with standard diet with or without 15% soybean oil. Groups 3 and 4 were bilateral OVX and received the standard diet with or without 15% soybean oil. The results revealed that rats subjected to ovariectomy exhibited an inhibition in estrogen and high-density lipoprotein cholesterol levels and marked increase of lipid profile, low-density lipoprotein cholesterol, and VLDL-C accompanied with a marked elevation in atherogenic index, cardiac enzyme activity, tumor necrosis factor-α, and C-reactive protein. Signs of cardiovascular injury which included an increase in cardiac thiobarbituric acid-reactive substances were concomitantly noticed with a reduction in the reduced glutathione, total antioxidant capacity, and superoxide dismutase. However, supplementation of soybean oil resulted in the restoration of the changed lipid profile and improved cardiac biomarkers near to normal values as well as improved inflammatory and antioxidant status. It was concluded that consumption of soybean oil may have a role in retarding atherosclerosis and risk of cardiovascular disorders associated with estrogen deficiency in ovariectomy status.

Folic acid and safflower oil supplementation interacts and protects embryos from maternal diabetes-induced damage

Maternal diabetes increases the risk of embryo malformations. Folic acid and safflower oil supplementations have been shown to reduce embryo malformations in experimental models of diabetes. In this study we here tested whether folic acid and safflower oil supplementations interact to prevent embryo malformations in diabetic rats, and analyzed whether they act through the regulation of matrix metalloproteinases (MMPs), their endogenous inhibitors (TIMPs), and nitric oxide (NO) and reactive oxygen species production. Diabetes was induced by streptozotocin administration prior to mating. From Day 0.5 of pregnancy, rats did or did not receive folic acid (15 mg/kg) and/or a 6% safflower oil-supplemented diet. Embryos and decidua were explanted on Day 10.5 of gestation for further analysis of embryo resorptions and malformations, MMP-2 and MMP-9 activities, TIMP-1 and TIMP-2 levels, NO production and lipid peroxidation. Maternal diabetes induced resorptions and malformations that were prevented by folic acid and safflower oil supplementation. MMP-2 and MMP-9 activities were increased in embryos and decidua from diabetic rats and decreased with safflower oil and folic acid supplementations. In diabetic animals, the embryonic and decidual TIMPs were increased mainly with safflower oil supplementation in decidua and with folic acid in embryos. NO overproduction was decreased in decidua from diabetic rats treated with folic acid alone and in combination with safflower oil. These treatments also prevented increases in embryonic and decidual lipid peroxidation. In conclusion, folic acid and safflower oil supplementations interact and protect the embryos from diabetes-induced damage through several pathways related to a decrease in pro-inflammatory mediators.

Dietary treatments enriched in olive and safflower oils regulate seric and placental matrix metalloproteinases in maternal diabetes

Objectives Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in placental development and function, although related to the pro-inflammatory environment when produced in excess. Previous studies have identified MMP-2 and MMP-9 overactivities in the placenta from diabetic rats. In this study, we aimed to determine whether diets supplemented with olive and safflower oil, enriched in natural PPAR ligands, are able to regulate MMP-2 and MMP-9 activities in the placenta and serum from diabetic rats. Study design Diabetes was induced in rat neonates by streptozotocin administration (90 mg/kg s.c.). Control and diabetic rats were fed with 6% olive oil- or 6% safflower oil-supplemented diets from days 0.5–13.5 of gestation. Main outcome measures On day 13.5 of gestation, placentas and sera were isolated for further determination of matrix metalloproteinases (MMPs) 2 and 9 activities by zymography. Placental MMP-2 and MMP-9 protein concentration and immunolocalization were also determined. Results Sera from diabetic pregnant animals showed MMP-2 and MMP-9 overactivities when compared to controls. Serum MMP-9 activity was significantly decreased when the diabetic animals received the olive and safflower oil dietary treatments. Placentas from diabetic rats showed increased MMP-2 and MMP-9 activities and protein concentrations, and both were decreased when diabetic rats received the olive and safflower dietary treatments. Conclusions This study demonstrates that both olive and safflower oil-supplemented diets were able to prevent MMPs overactivities in the placenta from diabetic rats, and that these beneficial effects are reflected in rat sera.

Effects of dietary palm oil supplements with oxidized and non-oxidized fish oil on growth performances and fatty acid compositions of juvenile Japanese sea bass, Lateolabrax japonicus

The aim of the present study was to investigate the effects of replacement of fresh fish oil (FFO) by palm oil (PMO) and/or oxidized fish oil (OXF) mixed with PMO on growth performances, tissue fatty acid composition and oxidative status in juvenile Japanese sea bass. A 50-day feeding trial on Japanese sea bass (average weight 1.7 g) was conducted in triplicate groups of fish fed with seven test diets containing different level of FFO and PMO at 100%FFO (10F, a positive control), 60%FFO and 40%PMO (6F4P), 40%FFO and 60%PMO (4F6P), 100%OXF (10OF), 60%OXF and 40%PMO (6OF4P), 40%OXF and 60%PMO (4OF6P) and 100%PMO (10P, a negative control), respectively. Body weight gain (BWG), specific growth rates (SGR), feed conversion ratio (FCR), fatty acid compositions, vitamin E contents and thiobarbiturate reactive substances (TBARS) in muscles and livers were taken at the end of a trial. Survival rates were relatively high and almost similar among all groups. There were no significant differences in BWG and SGR among 10F, 6F4P and 4F6P or 10OF, 6OF4P and 4OF6P, respectively. However, addition of OXF reduced the growth rates of fish regardless of PMO supplementation. Contents of saturates and n − 6 fatty acids in tissue increased linearly with increasing dietary PMO level. However EPA and DHA decreased gradually with higher inclusion of PMO among treatments. These results demonstrated that 50% FFO could be replaced by PMO for juvenile Japanese sea bass. Moreover, although the replacement of OXF (POV: 26 meq/kg diet) with PMO could reduce lipid peroxidation in fish intestine and muscle, it could not improve fish growth performances.

팜유의 급여가 한우의 도체 및 육질에 미치는 영향

팜유의 급여가 한우의 도체성적 및 육질에 미치는 영향을 구명하고자 실시하였다. 30개월령 거세 한우를 팜유의 급여(100 g/head/d) 유무에 따라 3개월 동안 공시하였으며, 시료는 등심(M. longissimus) 부위를 <TEX>$4^{\circ}C$</TEX>에 9일 동안 저장하였다. 도체성적, 총육색소 함량, pH, 총환원력 및 근소편화지수는 팜유의 급여에 따른 차이가 없었다. 일반성분 함량은 팜유 급여구의 조지방 함량이 대조구에 비해 높았으며(p<0.05), 이로 인해 보수력과 연도는 팜유 급여구가 높았다(p<0.05). 지방산 조성은 팜유 급여구에서 대조구에 비해 높은 palmitic acid(C16:0) 함량과 낮은 다가 불포화지방산(PUFA) 함량 을 보였다 (p<0.05). 저장 중 품질은 팜유 급여구가 대조구보다 높은 지방산화 안정성, 육색소산화 안정성 및 육색 안정성을 보였다. 따라서 한우에게 팜유를 급여했을 때 쇠고기의 마블링 및 저장성은 증가되었으나, 다가불포화지방산은 감소되었다. This study was carried out to investigate the effect of dietary palm oil supplementation on the quality of the carcass and meat of Hanwoo (Korean cattle). Thirty-month-old steers were fed on a concentration with or without (control) palm oil for 3 mon prior to slaughter. The samples of M. longissimus were taken from all carcasses and then stored at <TEX>$4^{\circ}C$</TEX> for 9 d. The carcass traits, total myoglobin content, pH value, total reducing ability, and myofibrillar fragmentation index were unaffected by supplementation with palm oil. However, the fat content, water-holding capacity, and tenderness were significantly increased by dietary palm oil (p<0.05). In the fatty acid composition, the palm oil group had a higher palmitic acid (C16:0) content and lower polyunsaturated fatty acids (PUFA) content compared to the control group (p<0.05). The lipid oxidation stability, myoglobin oxidation stability, and color stability were increased by dietary palm oil. It is concluded that supplemental palm oil increased the marbling and storage quality but decreased the PUFA in Hanwoo beef.

Evaluation of breed effects onn-3 PUFA metabolism with dietary flaxseed oil supplementation in dogs

PUFA are important for human and animal health. To our knowledge, previous studies investigating the metabolism of PUFA in dogs have not examined breed differences. The aim of the present study was to evaluate the potential to elongate PUFA in two pure breeds of dogs. Plasma fatty acid composition (%) was measured in dogs during 3 weeks supplementation with flaxseed oil (57 % α-linolenic acid (ALA) and 17 % linolenic acid (LA)) at the rate of 100 ml/kg food following 4 months of feeding an identical standard basal diet. Plasma extracted at fasting state from five beagles and five greyhounds was analysed by GC. Plasma ALA, EPA and LA increased steadily and significantly from days 0 to 22 (P < 0.05); however, no significant breed differences were shown. Plasma DHA levels, on the other hand, showed no significant increase over time, but a significant breed difference was observed, with beagles having higher plasma level from day 0 (P = 0.002). This breed difference requires further investigation. Levels of ALA and EPA were still rising significantly between days 15 and 22, indicating that PUFA levels in plasma had not stabilised in 3 weeks. These findings together suggest that flaxseed oil could be a useful source of PUFA in dogs, especially ALA and EPA, and that breed differences may be important.

Effect of dietary krill oil supplementation on the endocannabinoidome of metabolically relevant tissues from high-fat-fed mice

BackgroundOmega-3 polyunsaturated fatty acids (ω-3-PUFA) are known to ameliorate several metabolic risk factors for cardiovascular disease, and an association between elevated peripheral levels of endogenous ligands of cannabinoid receptors (endocannabinoids) and the metabolic syndrome has been reported. We investigated the dose-dependent effects of dietary ω-3-PUFA supplementation, given as krill oil (KO), on metabolic parameters in high fat diet (HFD)-fed mice and, in parallel, on the levels, in inguinal and epididymal adipose tissue (AT), liver, gastrocnemius muscle, kidneys and heart, of: 1) the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), 2) two anandamide congeners which activate PPARα but not cannabinoid receptors, N-oleoylethanolamine and N-palmitoylethanolamine, and 3) the direct biosynthetic precursors of these compounds.MethodsLipids were identified and quantified using liquid chromatography coupled to atmospheric pressure chemical ionization single quadrupole mass spectrometry (LC-APCI-MS) or high resolution ion trap-time of flight mass spectrometry (LC-IT-ToF-MS).ResultsEight-week HFD increased endocannabinoid levels in all tissues except the liver and epididymal AT, and KO reduced anandamide and/or 2-AG levels in all tissues but not in the liver, usually in a dose-dependent manner. Levels of endocannabinoid precursors were also generally down-regulated, indicating that KO affects levels of endocannabinoids in part by reducing the availability of their biosynthetic precursors. Usually smaller effects were found of KO on OEA and PEA levels.ConclusionsOur data suggest that KO may promote therapeutic benefit by reducing endocannabinoid precursor availability and hence endocannabinoid biosynthesis.

Dietary Perilla Seed Oil Supplement Increases Plasma Omega-3 Polyunsaturated Fatty Acids and Ameliorates Immunoglobulin A Nephropathy in High Immunoglobulin A Strain of ddY Mice

Background/Aims: The beneficial effects of omega-3 polyunsaturated fatty acids (n–3 PUFA) in the treatment of immunoglobulin A nephropathy (IgAN) have been reported. Perilla frutescens (Linn.) Britton var. frutescens is grown in Eastern Asia and its seed (perilla seed) is rich in α-linolenic acid, an n–3 PUFA. We investigated the antinephritic effects of perilla seed oil in a mouse model of IgAN. Methods: Ten-week-old high IgA ddY mice were fed diets containing either perilla seed oil (PS group) or corn oil (C group, control). After 20 weeks, we compared body weight, blood pressure, serum creatinine levels, IgA levels, fatty acid composition, urinary protein excretion, mesangial matrix expansion, and glomerular transforming growth factor-β₁ mRNA expression between groups. Results: Serum n–3 PUFA levels were higher in the PS group than the C group (p < 0.001). Blood urea nitrogen levels were lower (p = 0.0246) and urinary protein excretion was reduced (p = 0.0198) in the PS group. Mesangial matrix expansion (p = 0.0063) and glomerular transforming growth factor-β₁ mRNA expression (p = 0.0291) were suppressed in the PS group. No significant differences between groups were found in body weight, blood pressure, serum IgA, and creatinine levels. Conclusions: Dietary perilla seed oil supplement could suppress the progression of IgAN.

Dietary red palm oil supplementation decreases infarct size in cholesterol fed rats

Background and AimsThe effect of red palm oil (RPO) supplementation on infarct size after ischaemia/reperfusion in a cholesterol enriched diet-induced hyperlipidemic animal model has not been reported. Previous studies reported results on the effect of RPO in a normal diet, whilst evidence of protection has been linked to improved functional recovery, prosurvival kinase, anti-apoptosis and NO-cGMP. Therefore, we aimed to investigate the effects of dietary RPO supplementation in a cholesterol-enriched diet-induced hyperlipidemic rat model and to investigate the involvement of matrix metalloproteinase 2 (MMP2) inhibition as a possible mechanism of protection.Materials and MethodsMale Wistar rats were fed either a standard rat chow diet (Norm) or a 2% cholesterol-enriched diet (Chol) for nine weeks. Additionally, two more groups received the same treatment, however, at the week 4, diet was supplemented with RPO for the last five weeks (Norm+RPO and Chol+RPO), respectively. After the feeding period hearts were isolated, perfused according to Langendorff and subjected to 30 minutes of normothermic global ischaemia followed by two hours of reperfusion. Infarct size was measured by 2,3,5-triphenyltetrazolium chloride staining at the end of reperfusion.ResultsCholesterol-enriched diet increased myocardial infarct size from 23.5 ± 3.0% to 37.2 ± 3.6% (p < 0.05) when compared to normal diet. RPO supplementation significantly reduced infarct size either in Norm+RPO or in Chol+RPO (to 9.2 ± 1.0% and 26.9 ± 3.0%), respectively. Infarct size in Chol+RPO was comparable to the Norm group. MMP2 activity before ischaemia was significantly reduced in the Chol+RPO group when compared to the Chol group. However, the MMP2 activity of the hearts of the RPO fed rats was significantly increased when compared to the normal diet group after ischaemia.ConclusionsFor the first time it was shown that dietary RPO supplementation attenuated the increased susceptibility of the hearts in cholesterol fed rats to ischaemia/reperfusion injury. This was shown by reduced infarct size. For the first time we also show that red palm oil supplementation altered pre-ischaemic levels of MMP-2, which may indicate that myocardial MMP2 may be implicated as a possible role player in RPO mediated protection against ischaemia/reperfusion injury in hearts of cholesterol supplemented rats.

Plasma lipid profile of Wistar albino rats fed palm oil-supplemented diets

The effect of palm oil-supplemented diet on plasma lipid profile of Wistar albino rats was investigated by feeding the experimental animals with 20% palm oil-supplemented diets for 12 weeks. The plasma levels of Total cholesterol (TC), Triglycerides (TG), Low-density lipoprotein (LDL), and High-density lipoprotein (HDL) were determined at 4-, 8-, and 12-week intervals. The results showed significant (p

Effects of an Oregano Based Dietary Supplement on Performance of Broiler Chickens Experimentally Infected with Eimeria Acervulina and Eimeria Maxima

A study was conducted to examine the effect of dietary oregano essential oil supplementation on the performance of broiler chickens challenged with Eimeria acervulina and Eimeria maxima at 14 days of age. A total of 375 day-old Cobb-500 male chicks separated into 5 equal groups with three replicates each, were used in this study. Two of the groups, one challenged with 1×105 sporulated oocysts of E. acervulina along with 1×105 sporulated oocysts of E. maxima and the other not, were given a basal diet and served as controls. The other three groups also challenged with combined E. acervulina and E. maxima were administered diets supplemented with oregano essential oil by adding the product OregoStim (containing 5% oregano essential oil) at the levels of 300 or 600mg/kg, and the last group the anticoccidial substance salinomycin at the dosage of 60mg/kg. Following the challenge, survival rate, bloody diarrhea and oocysts excretion, as well as intestinal lesion score were all determined. Throughout the experimental period that lasted 35 days, body weight gain and feed intake were weekly recorded, and feed conversion ratios were calculated. The results showed that dietary oregano oil supplementation in both oregano supplemented groups, attained body weight gains and feed conversion ratios not differing (p>0.05) to those of the non-challenged group or the salinomycin group. The challenged control presented lower (p>0.05) performance than those of the other groups for the consecutive three weeks after the challenge. These performance parameters along with lesion scoring indicated that oregano essential oil exerted an anticoccidial effect against E. acervulina and E. maxima, comparable to salinomycin.

The effect of Ala293Val single nucleotide polymorphism in the stearoyl-CoA desaturase gene on conjugated linoleic acid concentration in milk fat of dairy cows

The objectives of this study were to determine the effects of the Ala293Val single nucleotide polymorphism in stearoyl-CoA desaturase (SCD) on the concentration of cis-9, trans-11 conjugated linoleic acid (CLA) in milk fat of dairy cows, and to identify a phenotypic indicator of cows with a greater genetic capability to produce CLA that is not affected by dietary lipid content. In Study 1, 12 cows, four of each Ala293Val SCD genotype, were fed either a control or an oil-supplemented diet in a cross-over design to examine effects of diet, genotype and their interaction. The CLA concentration in milk fat was greater for cows fed the oil-supplemented (4.4%) vs. the control diet (0.6%), but was not affected by the Ala293Val SCD genotype. In Study 2, the Ala293Val SCD genotype of 215 dairy cows at a commercial dairy did not affect milk yield, composition, or CLA concentration in milk fat. However, in both studies, C14:1 desaturation index was greater for the AA genotype compared with the others. The Ala293Val SCD genotype may not affect CLA production although the SCD Ala293 allele is associated with a higher C14:1 desaturation index possibly because effects of the SCD genotype vary depending on fatty acid chain length or origin.

Effect of Omega-3 Fatty Acids on Plasma Level of 8-Isoprostane in Kidney Transplant Patients

It has been shown previously that the serum level of F2-isoprostanes acts as an indicator of oxidative stress, which is a risk factor for vascular disease especially in end-stage renal disease. It is not known whether n-3 polyunsaturated fatty acids can decrease oxidative stress in renal recipient patients. In this single blind, randomized, placebo-controlled study, the effect of 3 and 6 months of fish oil administration on 8-isoprostane levels in renal transplant recipients was evaluated. Twenty-two renal transplant patients who fulfilled inclusion and exclusion criteria randomly received either fish oil dietary supplementation, 6 g/day (720 mg of DHA and 1,080 mg of EPA) or placebo for 6 months. Serum 8-isoprostane concentration was measured as markers of oxidative stress. A significant decrease in 8-isoprostane levels was observed only in the placebo group after transplantation compared to baseline (P < 0.05). However, the group receiving fish oil had a significantly lower cholesterol level than that of the placebo group (P < 0.05). On the basis of our results, omega-3 fatty acids supplementation decreased the beneficial effects of kidney transplantation on oxidative stress.

Lack of standardization in a cod liver oil dietary supplement: Three cases of hypervitaminosis D

Lack of standardization in a cod liver oil dietary supplement: Three cases of hypervitaminosis D

Effect of Grape Seed Extract, Cistus ladanifer L., and Vegetable Oil Supplementation on Fatty Acid Composition of Abomasal Digesta and Intramuscular Fat of Lambs

Thirty-six lambs were used in a 6 week experiment to evaluate the effect of vegetable oil blend supplementation (0 vs 60 g/kg of dry matter (DM)) and two dietary condensed tannin sources, grape seed extract (0 vs 25 g/kg of DM) and Cistus ladanifer L. (0 vs 250 g/kg of DM), on fatty acid (FA) composition of abomasal digesta and intramuscular polar and neutral lipids. Grape seed extract did not affect the FA profile of abomasal digesta or muscle lipid fractions. C. ladanifer had a minor effect in lambs fed diets with no oil but greatly changed the abomasal and muscle FA profiles in oil-supplemented lambs. It decreased 18:0 and increased 18:1 trans-11 in abomasal digesta and increased 18:1 trans-11 and 18:2 cis-9,trans-11 (P = 0.062) in muscle neutral lipids, resulting in an important enrichment of meat 18:2 cis-9,trans-11 when compared to other oil-supplemented diets (19.2 vs 41.7 mg/100 g of muscle).

T10,c12‐18:2‐Induced Milk Fat Depression is Less Pronounced in Cows Fed High‐Concentrate Diets

In intensively reared dairy cows, milk fat secretion is reduced in response to high-concentrate diets and it is often referred to as the "milk fat depression" (MFD) syndrome. Some trans fatty acid (FA) isomers produced in the rumen of the cows, including t10,c12-18:2, are known for their inhibitory effect on mammary lipogenesis. To study whether this effect depends on the basal diet, duodenal infusions of t10,c12-18:2 were performed on cows fed four different diets (a factorial arrangement of forage:concentrate ratio and linseed oil supplementation). The overall response obtained with t10,c12-18:2 infusion was consistent with previous studies: a decrease in milk fat content and yield without significant variations in milk yield. Mean transfer efficiency of infused t10,c12-18:2 was 19.6%. However, the decrease in milk fat and FA yields (both de novo synthesis and preformed long-chain FA) was less pronounced in cows fed high-concentrate diets (-27% of the initial level), compared with cows fed low-concentrate diets (-42% of initial level). This difference was independent of dietary oil supplementation and milk FA yield before infusion. Results pertaining to effects of dietary forage:concentrate ratio were confirmed by statistical meta-analysis of data from previously published t10,c12-18:2 infusion experiments. This study shows that in cows fed MFD diets the mammary gland becomes more resistant to or experiences a lower response potential to further inhibition of lipogenesis and/or delta-9 desaturation of FA.

Evaluation of the composition of omega‐3 fatty acids in dietary oil supplements

AbstractAim: The aim of the present study was to determine the fatty acid composition of 19 dietary oil supplements that are commercially available in Australia, comparing findings with manufacturers' reported omega‐3 fatty acid content.Methods: Fifteen fish oil supplements and four non‐fish oil supplements were obtained from Australian retail stores. Fatty acids were derivatised, and fatty acid methyl esters were quantitated using classical GC‐flame ionisation detection methods. Composition of eicosapentaenoic acid and docosahexaenoic acid reported by supplement manufacturers was compared with experimental values using the Bland‐Altman plot.Results: The combined eicosapentaenoic acid and docosahexaenoic acid content in the fish oil and non‐fish oil supplements was 17.63–71.45% and 0.00–0.05% respectively. A high level of congruency was observed for the composition of eicosapentaenoic acid and docosahexaenoic acid reported by manufacturers and determined experimentally (mean difference, eicosapentaenoic acid, 13.2 mg; docosahexaenoic acid, 12.8 mg).Conclusion: Current practice in pre‐market assessment of complementary medicines in Australia is satisfactory for supplements examined in the present study. Intake of these fish oil supplements can be used to provide high levels of long‐chain omega‐3 fatty acids that would be otherwise difficult to achieve through normal dietary intake alone.