SFO Group Research Articles

Dietary supplementation of pumpkin seed oil and sunflower oil along with vitamin E improves sperm characteristics and reproductive hormones in roosters

This study evaluates the effects of pumpkin seed oil and sunflower oil along with vitamin E on the reproductive characteristics of aged roosters. Thirty Ross breeder roosters (45-wk-old) were assigned into 6 groups (5 birds/group) with the following diets: 1) control group (basal diet), 2) basal diet with 2% pumpkin seed oil as omega-3 fatty acid (PSO group), 3) basal diet with 2% sunflower oil as omega-6 fatty acid (SFO group), 4) basal diet with 200 mg/kg vitamin E (Control + vitE group), 5) basal diet and 2% pumpkin seed oil along with 200 mg/kg vitamin E (PSO + vitE group) and 6) basal diet and 2% sunflower oil along with 200 mg/kg vitamin E (SFO + vitE group). Roosters were fed on the experimental diets for 60 d and different characteristics of sperm characteristics including routine semen analysis and several sperm functional tests in every 20 d were examined. Reproductive hormones were also evaluated in 0 d and at the end of the trial. Semen volume and morphology were not affected by any of the diets. The roosters fed with pumpkin seed oil + vitE showed the higher percentage of sperm concentration, total motility, progressive motility, viability and membrane integrity and the lower lipid peroxidation (P ≤ 0.05). The group 5 (PSO + vitE) had numerically the lowest sperm with fragmented DNA (DNA Fr+) at 0 of the experiment and sperm with non-fragmented DNA (DNA Fr−) was lowest in group 6 (SFO + vitE) on da 40 the experiment. Testosterone level was not affected by the experimental diets (P > 0.05), however other hormones (LH and FSH) were affected. Based on the results, the supplementation of aged roosters’ diet with pumpkin seed oil + vitE improves reproductive performance which can be an appropriate strategy to preserve the reproductive performance of aged roosters.

Replacement of dietary fish oil with plant oils improves the immunological responses and the antioxidant status in Oreochromis niloticus exposed to suboptimal temperature.

Here, we investigated the effects of total dietary fish oil (FO) substitution with plant oil (PO) on hematological indices, immune status, antioxidant activity, IL1β and TNF-α gene expression, and hypoxia stress resistance in Oreochromis niloticus at suboptimal temperatures. Fish (n = 360) were randomly divided into 12 circular fiberglass tanks (500L; 3 replicates for each dietary group, 30 fish/replicate, 90 fish/group). The control group was fed a basal diet with FO as the lipid source. The CO, SFO, and LSO groups were fed a basal diet with complete replacement of FO with corn, sunflower, and linseed oils, respectively. After 4weeks, no effects on hematological indices were observed in fish fed the experimental diets. The LSO and CO groups showed a significant increase in γ globulin levels. The highest levels of non-specific immune parameters, antioxidant activity, and IL-1β and TNF-α gene expressions were recorded in the LSO group. The LSO group also exhibited good resistance to hypoxia stress. Therefore, the total dietary substitution of FO with PO (especially LSO and CO) is recommended as a valuable strategy to ameliorate the immunosuppressive effects of suboptimal temperatures and enhance the resistance of O. niloticus to hypoxia stress.

Lutein and Zeaxanthin Isomers Reduce Photoreceptor Degeneration in the Pde6b rd10 Mouse Model of Retinitis Pigmentosa.

Purpose Lutein, RR-zeaxanthin, and RS-zeaxanthin (L-Z) are antioxidants which can reduce endoplasmic reticulum stress (ERS) and oxidative stress (OS), and ameliorate neurodegenerative diseases. However, their treatment effect in the Pde6brd10 (rd10) mouse model of retinitis pigmentosa (RP) and the underlying cellular mechanisms have not been studied. ERS is an important factor which causes photoreceptor apoptosis. The aim of the current project is to test the treatment effect of L-Z in rd10 mice and to investigate the underlying molecular mechanisms of ERS. Methods L-Z (Lutemax 2020, 10 mg/kg) diluted in sunflower oil (SFO, 1 mg/ml) or the same volume of SFO was administrated via gavage from postnatal day 6 (P6) to P20 daily in L-Z group (n=5) or SFO group (n=6) of rd10 mice. At P21, electroretinography (ERG) was performed to show the functional change of retinas. 78 kDa glucose-regulated protein (GRP78) and endoplasmic reticulum protein 29 (ERp29) were tested by western blot and immunostaining. Results The ERG amplitudes were larger in the L-Z group than those of the SFO group in all flash luminances of dark-adapted and light-adapted ERG (all p < 0.01). Western blot revealed that GRP78 in the retinas of the L-Z group was significantly downregulated compared to that of the SFO group (p < 0.01). Meanwhile, the retinal ERp29 protein was significantly upregulated in the L-Z treatment group than that of the SFO group (p < 0.01). Conclusions L-Z provide protection to the photoreceptors of rd10 mouse model of RP, which is probably associated with the reduction of ERS.

Diagnosis and treatment of pelvic wall and bowel fibrosis with bowel obstruction induced by neoadjuvant chemoradiotherapy for rectal carcinoma

To introduce the diagnosis and the treatment of the long-segment bowel stenosis above the anastomosis and bowel obstruction caused by the radiation-induced pelvic wall and bowel fibrosis. Between January 2008 and June 2014, 468 patients with rectal carcinoma underwent sphincter-preserving operation after neoadjuvant chemoradiotherapy in Fujian Medical University Union Hospital. Among 241 patients without postoperative anastomotic leakage, anastomosis stenosis, local recurrence and small bowel obstruction, severe pelvic and bowel fibrosis with obstruction during follow-up was found in 14 patients(SFO group). Associated data of these 14 patients were retrospectively collected. Clinical and image characteristics, and treatment outcomes of these 14 patients were analyzed and compared to those of other 227 patients without fibrosis and obstruction (control group). Compared to control group, SFO group had lower BMI(19.7±2.3 vs. 22.5±3.2, P=0.000), higher ratio of male (92.9% vs. 63.9%, P=0.039) and smoking patients(78.6% vs. 32.2%, P=0.001), shorter preoperative distance from lower edge of tumor to anal verge [(4.9±0.7) cm vs. (5.7±1.4) cm, P=0.043), and longer time from the end of radiation to operation [(9.4±2.3) week vs. (8.1±1.7) week, P=0.024). The largest thickness of the bilateral obturator internus increased significantly after chemoradiotherapy (left side: P=0.030, right side: P=0.020) as compared to pre-chemoradiotherapy on MR image. Patients of SFO group received corresponding treatments according to the status of bowel stricture, and the outcomes were all satisfactory. Reconstructed rectum stricture can be caused by the radiation-induced fibrosis of pelvic wall soft tissue and proximal colon. Severe stricture can be treated with corresponding methods to relieve symptoms.

Effects of safflower oil supplementation in diet on growth performance and body fatty acid composition of turbot (Psetta maxima)

The aim of the study was to investigate the effects of the diets that contain safflower oil and fish oil as lipid sources, on growth, feed conversion and body composition in turbot (Psetta maxima). Two iso-nitrogenous and iso-lipidic diets (55 % protein and 14 % lipid) were prepared that include 100 % fish oil (FO group) and 100 % safflower oil (SFO group) for turbots with average weight of 62.21 ± 1.28 g, and fish were fed with these diets for 104 days. At the end of the experiment, the weight gain, specific growth rate and feed conversion ratio were the highest in SFO group than in FO group (p < 0.05). Fatty acid composition of fish body reflected the fatty acid composition determined in the experimental diets. The amounts of palmitic acid (PA; C16:0), oleic acid (OA; C18:1n-9), linoleic acid (LA; C18:2n-6) and docosahexaenoic acid (DHA; C22:6n-3) were dominant fatty acids in fish body. It was confirmed that the usage of safflower oil instead of fish oil in turbot feed did not generate any negative effects on growth, feed conversion and the values regarding the growth performance.

Does grape seed oil improve inflammation and insulin resistance in overweight or obese women?

Grape seed oil (GSO) is reported to improve oxidative stress and lipid profile. However, the ameliorating effect of GSO on inflammation and insulin resistance has not being noticed so far. We aimed to examine the effects of GSO consumption on inflammation and insulin resistance in overweight or obese females. The subjects (n = 44) were randomly assigned into intervention group as “GSO” (consuming 15% of energy from GSO) and control group as sunflower oil “SFO” (consuming 15% of energy from SFO) through a weight loss diet for 8 weeks. Anthropometric measurements, dietary recall and fasting serum glucose, insulin, high sensitive C-reactive protein (hs-CRP) and tumor necrosis factor-alpha (TNF-α) were assessed before and after the intervention. Homeostatic model assessment of insulin resistance (HOMA-IR) scores, hs-CRP and TNF-α decreased in the GSO group. The hs-CRP was lower in GSO than the SFO group (p < 0.03). GSO consumption seems to improve inflammatory condition and insulin resistance in overweight/obese women.

Conjugated linoleic acid and other C 18 fatty acid composition of muscle and adipose tissues in lambs fed on diets containing vegetable oil supplementations or grass silage

An experiment was performed to study the effect of different vegetable oils containing high proportions of PUFA (5% soybean oil, SBO; and sunflower oil, SFO; respectively, in the DM of concentrate) or grass silage (150 g DM/d/animal, GSL) on the level of conjugated linoleic acid (CLA) isomers and other C18 fatty acids in muscle and adipose tissues of growing lambs. Control animals were fed on the same diet as SBO or SFO groups; however, instead of vegetable oils hydrogenated palm oil containing low level of PUFA was applied. In both muscle and adipose samples tested c-9, t-11 C18:2 showed the highest levels among the CLA isomers, however, t-10, c-12 CLA could also be measured in lower proportions. Considering vegetable oil supplementations, only SBO resulted in a significantly higher level of c-9, t-11 CLA in the triceps brachii muscle as compared to the control. Such a difference could not be detected in either the gracilis muscle or in the adipose tissue samples. However, lambs fed on the GSL diet had significantly higher c-9, t-11 CLA levels in both the triceps and gracilis muscles and lower proportion of t-10, c-12 CLA in the adipose than those fed on the control, SBO and SFO diets, respectively. Concerning C18 fatty acids other than CLA, SFO lambs showed significantly higher proportions of C18:1n-9 than those of control animals in both muscles and perirenal fat tested. However, level of C18:0 in the adipose tissue of GSL lambs was significantly lower than that of the animals fed both control or vegetable oil supplemented diets. Results of this experiments show that different dietary fatty acid sources have various potential to increase CLA contents in the meat of lambs. In addition to vegetable oils rich in PUFA, grass silage may be good dietary source for nutritional manipulation of the fatty acid composition of lamb meat.

Effect of Vegetable Oil Fortified Feeds on the Content of Fatty Acids in Breast and Thigh Muscles in Broiler Chickens

The main objective of this work was to compare the effect of six vegetable oils added to feeding mixtures that were administered to broiler chickens on the content of major fatty acids in chicken meat. The experiment started with 90 one-day-old Ross 308 meat hybrid male chickens that were divided into six groups. Chickens were fed complete feeding mixtures for the prefattening (BR1), fattening (BR2), and post-fattening (BR3) of broiler chickens. The BR1 feeding mixture was administered to chickens aged 1-10 days, the BR2 feeding mixture was given from Day 11 to Day 30, and the BR3 feeding mixture was then administered until Day 42. The BR1 feeding mixture that was administered to all six groups during the first ten days of the experiment was supplemented with soybean oil. BR2 and BR3 feeding mixtures used to feed chickens aged 11-42 days were fortified with soybean oil (SO Group), rapeseed oil (RO Group), sunflower oil (SFO Group), flaxseed oil (FO Group), olive oil (OO Group), and evening primrose oil (EPO Group). The vegetable oils used differed by the composition of fatty acids, particularly by the content of oleic acid, linoleic acid, α-linolenic acid. The use of the above-described experimental diets in young broilers from Day 11 to 42 had a significant effect on the content of fatty acids in the fat from breast and thigh muscles. The content of α-linolenic acid in breast and thigh muscles of broilers that received the feed containing flaxseed oil (21.16 g/100 g of oil and 17.13 g/100 g of oil, respectively) significantly increased (p ⪬ 0.01). The highest content of linoleic acid (p ⪬ 0.01) in breast and thigh muscles was found in chickens that were fed the feed containing primrose oil (59.13 g/100 g and 51.71 g/100 g). A significant increase (p ⪬ 0.01) in the level of oleic acid was detected in both breast and thigh muscles of broilers that received olive oil fortified feed (52.44 g/100 g and 43.70 g/100 g of oil). No significant variation was found in the content of palmitic acid and palmitooleic acid. The levels of oleic acid, linoleic acid and α-linolenic acid in feeding mixtures correlated with those found in breast and thigh muscles (r = 0.88; 0.94 and 0.99; r = 0.99; 0.98 and 0.99).

The influence of feeding linoleic, gamma-linolenic and docosahexaenoic acid rich oils on rat brain tumor fatty acids composition and fatty acid binding protein 7 mRNA expression

BackgroundExperimental studies indicate that gamma linolenic acid (GLA) and docosahexaenoic acid (DHA) may inhibit glioma cells growth but effects of oral consumption of these fatty acids on brain tumor fatty acid composition have not been determined in vivo.MethodsGLA oil (GLAO; 72% GLA), DHA oil (DHAO; 73% DHA) were fed to adult wistar rats (1 mL/rat/day) starting one week prior to C6 glioma cells implantation and continued for two weeks after implantation. Control group were fed same amount of high linoleic acid safflower oil (74–77% linoleic acid). Fatty acid composition of tumor samples was determined in a set of 8–12 animals in each group and serum fatty acid in 6 animals per each group. Gene expression of tumor fatty acid binding protein 7 (FABP7), epidermal growth factor receptor (EGFR), peroxisome proliferator activated receptor γ (PPAR-γ) and retinoid × receptor-α (RXR-α) were determined in a set of 18 animals per group.ResultsDHAO feeding increased EPA of brain tumors and decreased ratio of n-6/n-3 fatty acids. Serum levels of EPA were also increased in DHAO group. A similar trend in serum and tumor levels of DHA were observed in DHAO group but it did not achieve statistical significance. GLAO increased serum concentration of GLA but had no significant effect on tumor GLA or dihomo-gamma linolenic acid (DGLA) concentrations. Gene expression of FABP7 was up-regulated in tumors of DHAO group but no other significant effects were observed on EGFR, PPAR-γ or RXR-α expression, and expression of these genes in tumors of GLAO were not different from SFO group.ConclusionDietary supplementation of DHA containing oil could be an effective way to increase levels of long chain n-3 fatty acids in brain tumors and this increase may be mediated partly by up-regulation of FABP7 expression.

Lutein and Zeaxanthin in Leafy Greens and Their Bioavailability: Olive Oil Influences the Absorption of Dietary Lutein and Its Accumulation in Adult Rats

This study determined the lutein level in various green leafy vegetables (GLVs) and the influence of olive and sunflower oils on the postprandial plasma and eye response of dietary lutein in adult rats, previously induced with lutein depletion (LD). Fresh GLVs (n = 35) were assessed for lutein (L) and its isomer zeaxanthin (Z) levels by high-performance liquid chromatography and liquid chromatography-mass spectrometry. Among GLVs analyzed, Commelina benghalensis L. contained a higher level of L + Z (183 mg/100 g dry wt) and was used as a lutein source for feeding studies. Rats with LD were fed a diet containing powdered C. benghalensis (2.69 mg lutein/kg diet) with either olive oil (OO group), sunflower oil (SFO group), or groundnut oil (GNO group) for 16 days. The L + Z levels of the OO group were markedly (p > 0.05) higher than those of SFO and GNO groups, in plasma (37.6 and 40.9%) and eyes (22.7 and 30.8%), respectively. These results suggest that oleic acid or OO can be used as a suitable fat source to modulate the absorption of dietary lutein to manage age-related macular degeneration.

Effectiveness of Oils Rich in Linoleic and Linolenic Acids to Enhance Conjugated Linoleic Acid in Milk from Dairy Cows

Forty Holstein dairy cows were used to determine the effectiveness of linoleic or linolenic-rich oils to enhance C18:2cis-9, trans-11 conjugated linoleic acid (CLA) and C18:1trans-11 (vaccenic acid; VA) in milk. The experimental design was a complete randomized design for 9 wk with measurements made during the last 6 wk. Cows were fed a basal diet containing 59% forage (control) or a basal diet supplemented with either 4% soybean oil (SO), 4% flaxseed oil (FO), or 2% soybean oil plus 2% flaxseed oil (SFO) on a dry matter basis. Total fatty acids in the diet were 3.27, 7.47, 7.61, and 7.50 g/100g in control, SO, FO, and SFO diets, respectively. Feed intake, energy-corrected milk (ECM) yield, and ECM produced/kg of feed intake were similar among treatments. The proportions of VA were increased by 318, 105, and 206% in milk fat from cows in the SO, FO, and SFO groups compared with cows in the control group. Similar increases in C18:2cis-9, trans-11 CLA were 273, 150, and 183% in SO, FO, and SFO treatments, respectively. Under similar feeding conditions, oils rich in linoleic acid (soybean oil) were more effective in enhancing VA and C18:2cis-9, trans-11 CLA in milk fat than oils containing linolenic acid (flaxseed oil) in dairy cows fed high-forage diets (59% forage). The effects of mixing linoleic and linolenic acids (50:50) on enhancing VA and C18:2cis-9, trans-11 CLA were additive, but not greater than when fed separately. Increasing the proportion of healthy fatty acids (VA and CLA) by feeding soybean or flaxseed oil would result in milk with higher nutritive and therapeutic value.

Effects of Dietary Fat Sources on Occurrences of Conjugated Linoleic Acid and trans Fatty Acids in Rumen Contents

The effects of dietary sources of C18:2 n-6 or C18:3 n-3 fatty acids on the occurrence of conjugated linoleic acid (CLA) and time-dependent changes of free fatty acid fractions in rumen contents were investigated. Sheep (n=4) fitted with rumen fistula were used in a 44 Latin square design with each 14 d period. Sheep were fed one of four diets consisting of grass hay and concentrates in a ratio of 70:30. Dietary treatments were 100% concentrates (served as the control), and concentrates were replaced by safflower seed at 30% (SFS), safflower meal at 18% - safflower oil at 12% (SFO), and safflower meal at 18%-linseed oil at 12% (LNO). At the end of each experimental period, rumen contents from each sheep were collected before feeding and at 1, 3, 6 and 12 h after feeding. The levels of cis-9, trans-11 CLA in free fatty acid fraction were considerably increased in all treated groups relative to the control, but not significantly. The increase in cis-9, trans-11 CLA was slightly higher in SFS and SFO groups than group fed diet containing linseed oil. The level of cis-9, trans-11 CLA in free fatty acid fraction was reached to the maximum value at 1hr after feeding and, thereafter gradually decreased to near the value before feeding. The generation of trans-11 C18:1 was significantly higher in all treated groups than that of control. The level of trans-11 C18:1 was linearly increased after feeding of experimental diets, reaching the maximum value at 3 h. Feeding of diets containing polyunsaturated fats to sheep resulted in a marked increase in the levels of trans-11 C18:1 and a slight increase of CLA in free fatty acid fraction of rumen contents. Our results support that endogenous synthesis of CLA from trans-11 C18:1 may be involved the primary source of CLA in dairy product. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 2 : 222- 226)

Effects of γ-linolenic acid and its positional isomer pinolenic acid on immune parameters of brown-norway rats

Male Brown-Norway rats given purified diets containing safflower oil (SFO, linoleic acid, 18:2 n-6), evening primrose oil (EPO, γ-linolenic acid, 6,9,12- 18:3 n-6) or Korean pine seed oil (PSO, 5,9,12- 18:3) at the 10% level were immunized twice with intraperitoneal ovalbumin, on days 14 and 35 of the feeding diets, and killed one day after the second booster. The relative population of CD4 + T-lymphocytes in the spleen was significantly lower in rats fed SFO than in those fed EPO or PSO, while that of CD8 + subsets remained unchanged. There was a significant increase in the splenic production of IgG and IgE in the PSO group compared to the SFO group, while EPO significantly increased IgE. The periodical response patterns of the serum levels of IgG and IgE varied depending on the source of dietary fats, and the initial rise of total immunoglobulins tended to be higher in the EPO group. The release by peritoneal exudate cells of histamine was comparable among three groups irrespective of saturation by calcium ionophore A23187, while PSO significantly increased leukotriene B 4 production. These observations not only indicate specific roles of γ-linolenic acid but also diverse influences of different octadecatrienoic acids in various immune measurements.

Effects of repeated gestation and lactation on milk n-6 fatty acid composition in rats fed on a diet rich in 18:2n-6 or 18:3n-6.

The present study examined the effect of repeated gestation and lactation on the levels of long-chain n-6 polyunsaturated fatty acids in rat milk fat, and examined whether such levels might be modulated by supplementing the diet of the lactating dams with either (g/kg) 50 safflower oil (SFO; containing 800 g 18:2n-6/kg), or 50 evening primrose oil (EPO; containing 720 g 18:2n-6 and 90 g 18:3n-6/kg). The milk was collected at three different times (days 1, 8 and 15) in each given lactation period from female Sprague-Dawley rats which were successively bred for four pregnancies and lactations. Results showed that dietary fat and breeding frequency had no significant effects on milk triacylglycerol content, but they modified the pattern of milk fatty acids in both triacylglycerol and phospholipid fractions. After three or four successive breedings rats fed on EPO produced milk containing less saturated but more monounsaturated and polyunsaturated fatty acids compared with those fed on SFO. During the course of lactation the levels of n-6 metabolites, e.g. 18:3n-6, 20:3n-6 and 20:4n-6, in milk fat declined progressively. However, they were consistently higher in the EPO group than in the SFO group. These findings suggest that the levels of long-chain n-6 metabolites in the milk fat may be increased through supplementing the maternal diet with 18:3n-6.

Dietary manipulation with high marine fish oil intake of fatty acid composition and arachidonic acid metabolism in rat cerebral microvessels.

Male weanling Wistar rats were maintained on one of two semisynthetic diets, differing only in the type of oil used: (i) 10% by weight marine fish oil (MFO group) containing 20% eicosapentaenoic acid (EPA) and 17% docosahexaenoic acid (DHA), or (ii) 10% by weight sunflower oil (SFO group). The control group was kept on standard diet for 4 weeks. Blood-free microvessels were isolated from brain cortex by a rapid micromethod, and their fatty acid composition was determined by gas chromatography. It was found that the proportion of n-3 fatty acids (including EPA and DHA) increased significantly in the microvessels of the MFO group, accompanied by a decrease of the n-6 fatty acid series. The changes in fatty acid composition of endothelial cells were not significant in the SFO group in comparison to the control. The amounts of lipoxygenase and cyclooxygenase metabolites were determined. Dietary fish oil decreased the percentage of total products of arachidonate by 50%, while the SFO diet had no effect on it. The amount of lipoxygenase products in the MFO group decreased significantly from 16931 +/- 3131 dpm to 6399 +/- 357 dpm/300 mg wet weight of brain. Significantly less PGF-1 alpha, PGF-2 alpha and 12-hydroxyheptadecatrienoic acid (HHT) were found in the capillaries of MFO treated animals, in comparison to the SFO group. The ratios of vasoconstrictor and vasodilator metabolites of arachidonate cascade were not modified by the diets. Our results suggest that fish oil diet reduces the arachidonate cascade in cerebral microvessels. This effect may explain for the efficiency of n-3 fatty acids in vascular diseases.

Light damage in the rat retina: The effect of dietary deprivation of n-3 fatty acids on acute structural alterations

We investigated the effect of depleting membrane docosahexaenoic acid (DHA, 22:6n-3) content through dietary deprivation of n-3 fatty acids on the susceptibility of the photoreceptors and pigment epithelium cells to acute light-induced changes. Male Sprague-Dawley rats were raised throughout gestation, lactation and up to the age of 8 weeks on semi-purified diets containing either safflower oil (SFO, n-3 deficient diet) or soybean oil (SO) as the sole source of lipids. A third group was switched at weaning from safflower oil to soybean oil ( SFO SO ). Rats were maintained on a 12 hr 12 hr light/dark cycle in which the light level at the front of the cages was 5–10 lx. Light damage was produced by exposing dark-adapted animals to diffuse white fluorescent light of 700–800 lx for 30 min followed by 90 min of darkness. In order to study recovery from light damage, additional groups of SFO and SO rats were returned to dim cyclic light for 27 hr following bright light exposure. DHA content in retinal phosphatidylethanolamine and phosphatidylcholine was 65–75% lower in rats fed SFO than in rats fed SO. The decrease was compensated for by an increase in 22:5n-6, the total content of polyunsaturated fatty acids (PUFA) being similar in both the SFO and SO groups. The SFO SO rats had DHA levels similar to SO animals, but 22:5n-6 remained elevated resulting in a slightly higher level of total PUFA. Severe rod outer segment (ROS) membrane disruptions were seen following bright light exposure in rats on the SO and SFO SO diets. The appearance of these disruptions did not change significantly during more than 24 hr in dim cyclic light. In contrast, there were virtually no acute ROS lesions in the SFO group. Furthermore, there was a strong light-elicited disk-shedding response in the SO rats but not in the other two groups. The pigment epithelium of the DHA deficient retinas showed a significantly greater accumulation of large lipid droplets in the dark-adapted state. Notably, whole retina rhodopsin levels were 15% higher in the SFO than in the SO group. These results indicate that depletion of retinal DHA reduces the susceptibility of the rod outer segments to acute light damage and at the same time may alter visual pigment photochemistry and other photoreceptor and pigment epithelium functions.

Effects of various combinations of omega 3 and omega 6 polyunsaturated fats with saturated fat on serum lipid levels and eicosanoid production in rats.

The effects of varying the ratio of polyunsaturated/saturated fatty acids (P/S) and omega 3/omega 6 polyunsaturated fatty acids (PUFA) of dietary fats on lipid metabolism were studied in rats using safflower oil (SFO), linseed oil (LSO), palm oil (PLO), and a 1:1 combination of these oils. The hypocholesterolemic and hypotriglyceridemic effects depended on the P/S ratio of dietary fats, LSO (omega 3 PUFA) being more effective than SFO (omega 6 PUFA). A similar pattern of the response was observed on liver cholesterol and triglyceride. The liver cholesterol-lowering effect of LSO, but not SFO, remained even when they were combined with PLO. The activity of liver delta 6-desaturase tended to be higher while that of liver phospholipase A2 was significantly lower in the LSO group than in the SFO or PLO groups. The aortic PGI2 production and the production by platelets of thromboxane A2 were significantly low in rats fed LSO accompanying a distinct reduction of arachidonate in tissue phospholipids. The depressing effect of LSO disappeared when it was combined with SFO but not with PLO. There were no significant differences in enzyme activities and eicosanoid production between SFO and PLO in spite of a large difference in their P/S ratio. Thus, lipid parameters examined were complicatedly regulated by the ratios of omega 3/omega 6 as well as P/S, suggesting an existence of an appropriate ratio for these variables.

Effects of various polyunsaturated fatty acids on blood cholesterol and eicosanoids in rats.

The hypocholesterolemic efficacy of various polyunsaturated fatty acids was compared in rats given cholesterol-enriched diets with (0.004%) or without indomethacin, the cyclooxygenase inhibitor. Evening primrose oil (EPO, linoleic+ γ-linolenic), safflower oil (SFO, linoleic) or soybean oil (SBO, linoleic + α-linolenic) were added to diets at the 10% level. The serum cholesterol level of the EPO group was consistently lower than the other groups and after 3 weeks, it was significantly different from the SFO group without indomethacin and the SBO group with indomethacin. In rats fed EPO, the aorta tended to produce more prostacyclin whereas the concentration of plasma thromboxane B2 was much lower than in rats fed SFO or SBO. The effects of indomethacin on these eicosanoids were less evident in rats fed EPO. Thus, in addition to the hypocholesterolemic action of β-linolenic acid (GLA) in preference to linoleic and possibly α-linolenic acid, GLA appears to cultivate an environment suitable for the prevention...

Effect of dietary fats on desaturase activities and the biosynthesis of fatty acids in rat-liver microsomes.

Four groups of rats were fed diets containing 15% (w/w) high-oleic safflower oil (SFO, rich in cis-18:1 acids), a mixture of 80% partially hydrogenated soybean oil plus 20% corn oil (H + CO, rich in trans-18:1 acids), lard (L, rich in saturated fatty acids) and corn oil (Co, rich in 18:2 omega 6). Fatty acid composition of liver microsomes and activities of the delta 5, delta 6 and delta 9 desaturases were determined. Microsomal delta 6 desaturase activity and arachidonic acid were lower in the H + CO group compared with SFO of L. No difference was found in the delta 5 or delta 6 desaturase activity of CO and SFO groups. Thus, the oleic-acid level of the SFO diet had no effect on the metabolism of 18:2 omega 6. Fluorescent polarization studies, using trans-parinaric acid as a probe, showed no differences between the physical states of phospholipid vesicles made from lipids isolated from each group. We concluded that the trans-18:1 acids in partially hydrogenated soybean oil have a more inhibitory effect than saturated acids on EFA metabolism, even in the presence of adequate amounts of essential fatty acid.