Tallow Group Research Articles

Dietary Fatty Acid Composition Influences Energy Accretion in Rats

To study the influence of dietary fatty acid composition on energy metabolism, forty male rats were fed elemental diets containing 42% of energy as fish oil, safflower oil, olive oil or beef tallow for 12 wk. Food intakes and body weights were measured daily. Energy expenditure and body composition were determined using doubly labeled water on the final 2 d. Pooled fecal energy losses differed in response to dietary manipulation, with losses greatest in rats fed beef tallow and least in those fed olive oil. Higher lean body mass gains and lower fat mass gains were observed in rats fed diets containing fish oil, compared with rats fed olive oil or beef tallow. Total energy gains in rats fed olive oil (3632 +/- 145 kJ) and beef tallow (3850 +/- 136 kJ) were higher than those in rats fed fish oil (2905 +/- 196 kJ). Energy efficiency in both the olive oil and beef tallow groups was also higher than that in the fish oil group. There were no differences in energy expenditure measured by doubly labeled water technique among the four groups. The data suggest that dietary fatty acid composition alters the efficiency of energy substrate accretion in rats.

Source of Dietary Fat in Pig Diet Affects Adipose Expression of Genes Related to Cancer, Cardiovascular, and Neurodegenerative Diseases.

It has been known for many years that excessive consumption of saturated fats has proatherogenic properties, contrary to unsaturated fats. However, the molecular mechanism covering these effects is not fully understood. In this paper, we aimed to identify differentially expressed genes (DEGs) using RNA-sequencing, following feeding pigs with different sources of fat. After comparison of adipose samples from three dietary groups (rapeseed oil (n = 6), beef tallow (n = 5), coconut oil (n = 5)), we identified 29 DEGs (adjusted p-value < 0.05, fold change > 1.3) between beef tallow and rapeseed oil and 2 genes between coconut oil and rapeseed oil groups. No differentially expressed genes were observed between coconut oil and beef tallow groups. Almost all 29 DEGs between rapeseed oil and beef tallow groups are connected to neurodegenerative, cardiovascular diseases, or cancer (e.g., PLAU, CYBB, NCF2, ZNF217, CHAC1, CTCFL). Functional analysis of these genes revealed that they are associated with fluid shear stress response, complement and coagulation cascade, ROS signaling, neurogenesis, and regulation of protein binding and protein catabolic processes. Furthermore, gene set enrichment analysis (GSEA) of the whole datasets from all three comparisons suggests that both beef tallow and coconut oil may trigger changes in the expression level of genes crucial in the pathogenesis of civilization diseases.

PSV-23 Effects of different fat sources and vitamin E levels on tissue tocopherol concentration, antioxidant status, and fatty acid composition in the backfat of pigs grown to 150 kg

Abstract The study objective was to assess the contribution of fat source and vitamin E (VE) supplementation on tissue tocopherol concentration, antioxidant status, and fatty acid composition in the backfat of pigs at heavy slaughter weight (149.38 ±1.56 kg). A total of 64 individually-fed pigs (32 barrows, 32 gilts; 28.41 ±0.83 kg) were randomly assigned to 8 dietary treatments in a 4 × 2 factorial arrangement. Fat treatments included corn-starch (CS), tallow (TW), corn oil (CO) and coconut oil (CN). VE supplementation levels were 11 and 200 IU/kg. Loin muscle, backfat, and liver samples were collected at slaughter. Data analysis were performed by ANOVA using GLM in SAS. No interactions between dietary fat source and VE supplementation were observed. Increasing dietary VE level from 11 to 200 IU/kg increased (P &lt; 0.001) the tocopherol concentration in both liver (4.73 vs. 21.06 ppm wet liver) and loin muscle (1.25 vs. 2.67 ppm wet muscle). Pigs from the CO group had higher liver SOD activity (P &lt; 0.05) than the other treatments (CS 22.51, TW 22.67, CO 24.40, and CN 20.92 U/mg protein). Pigs from the CN group had the highest (P &lt; 0.05) total saturated fatty acid content (CS 44.33, TW 40.33, CO 36.29, and CN 51.70%), but the lowest (P &lt; 0.05) total polyunsaturated fatty acid content (CS 9.26, TW 9.80, CO 25.41, and CN 8.75%) and iodine value (CS 56.61, TW 60.66, CO 77.83, and CN 49.90) in the backfat. Pigs from the TW group had the highest (P &lt; 0.05) total monounsaturated fatty acid content (CS 46.40, TW 49.87, CO 38.30, and CN 39.56%) in the backfat. Under conditions of this study, a higher level of VE supplementation increased liver and muscle tocopherol concentrations whereas dietary fat sources altered liver antioxidant activity and fatty acid composition in the backfat.

Original Research: Effect of various dietary fats on fatty acid profile in duck liver: Efficient conversion of short-chain to long-chain omega-3 fatty acids.

Omega-3 fatty acids, especially long-chain omega-3 fatty acids, have been associated with potential health benefits for chronic disease prevention. Our previous studies found that dietary omega-3 fatty acids could accumulate in the meat and eggs in a duck model. This study was to reveal the effects of various dietary fats on fatty acid profile and conversion of omega-3 fatty acids in duck liver. Female Shan Partridge Ducks were randomly assigned to five dietary treatments, each consisting of 6 replicates of 30 birds. The experimental diets substituted the basal diet by 2% of flaxseed oil, rapeseed oil, beef tallow, or fish oil, respectively. In addition, a dose response study was further conducted for flaxseed and fish oil diets at 0.5%, 1%, and 2%, respectively. At the end of the five-week treatment, fatty acids were extracted from the liver samples and analyzed by GC-FID. As expected, the total omega-3 fatty acids and the ratio of total omega-3/omega-6 significantly increased in both flaxseed and fish oil groups when compared with the control diet. No significant change of total saturated fatty acids or omega-3 fatty acids was found in both rapeseed and beef tallow groups. The dose response study further indicated that 59-81% of the short-chain omega-3 ALA in flaxseed oil-fed group was efficiently converted to long-chain DHA in the duck liver, whereas 1% of dietary flaxseed oil could produce an equivalent level of DHA as 0.5% of dietary fish oil. The more omega-3 fatty acids, the less omega-6 fatty acids in the duck liver. Taken together, this study showed the fatty acid profiling in the duck liver after various dietary fat consumption, provided insight into a dose response change of omega-3 fatty acids, indicated an efficient conversion of short- to long-chain omega-3 fatty acid, and suggested alternative long-chain omega-3 fatty acid-enriched duck products for human health benefits.

Electrospun composite matrices of poly(ε-caprolactone)-montmorillonite made using tenside free Pickering emulsions

The production of composite electrospun matrices of poly(ε-caprolactone) (PCL) using an emulsifier-free emulsion, made with minimal organic solvent, as precursor is reported. Pickering emulsions of PCL were prepared using modified montmorillonite (MMT) clay as the stabilizer. Hydrophobic tallow group of the modified MMT clay resulted in analogous interaction of clay with oil and aqueous phase and its adsorption at the interface to provide stability to the resultant emulsion. Composite fibrous matrices of PCL and MMT were produced using electrospinning under controlled conditions. The fiber fineness was found to alter with PCL concentration and volume fraction of the aqueous and oil phases. A higher tensile strength and modulus was obtained with inclusion of MMT in PCL electrospun matrix in comparison to a matrix made using neat PCL. The presence of clay in the fibrous matrix did not change the cell proliferation efficiency in comparison to neat PCL matrix. Composite fibrous matrices of PCL/MMT bearing enhanced tensile properties may find applications in areas other than tissue engineering for example food packaging and filtration.

Modulation of omega‐3 fatty acid profile in the duck liver by various dietary fats

Omega‐3 fatty acids, especially long‐chain EPA and DHA, have been suggested to inhibit inflammation and prevent chronic diseases. To offer omega‐3 fatty acid enhanced duck products, our previous studies found that dietary omega‐3 fatty acids could be accumulated in the meat and eggs in a duck model. However, little study has been reported regarding the omega‐3 fatty acid profile in the liver. In this study, 585 Shan Partridge Ducks were randomly assigned to five groups fed basal diet with or without 2% of flaxseed oil, rapeseed oil, beef tallow, or fish oil. In addition, a dose response study was further conducted for flaxseed and fish oil diets at 0.5%, 1%, and 2%, respectively. In the end of five weeks, fatty acids were extracted from the liver samples and analyzed by GC‐FID. As expected, the total omega‐3 fatty acids and the ratio of total omega‐3/omega‐6 significantly increased in both flaxseed and fish oil groups when compared with the control diet. No significant change of omega‐3 fatty acids was found in both rapeseed and beef tallow groups. It is interesting that the short‐chain omega‐3 ALA‐enriched flaxseed oil was efficiently converted to long‐chain DHA in the duck liver. The dose‐response study further indicated that 1% of dietary flaxseed oil produced DHA synthesis to an extent similar to a 0.5% of dietary fish oil supplement. Taken together, this study showed the fatty acid profiling in the duck liver after various dietary fat consumption, provided insight into a dose response change of omega‐3 fatty acids, indicated an efficient conversion of short‐ to long‐chain omega‐3 fatty acid, and suggested a long‐chain omega‐3 fatty acid‐enriched duck product for potential health benefits.Support or Funding InformationSupported by International Science &amp; Technology Cooperation Program of China 2013DFA31880

Effects of L-Carnitine Supplementation on Growth Performance and Fatty Acid Proportion in Epididymal Adipose Tissue of Rats Fed Diets containing Fat from Different Sources

Effects of L-Carnitine Supplementation on Growth Performance and Fatty Acid Proportion in Epididymal Adipose Tissue of Rats Fed Diets containing Fat from Different Sources Two experiments were conducted to evaluate the effects of Lcarnitine supplementation on growth performance and epididymal adipose tissue fatty acid composition in rats fed diets containing different sources of fat. In the first study, rats were assigned to four groups receiving dietary treatments to evaluate the effects of supplementation with L-carnitine 0 ppm or L-carnitine 50 ppm in combination with two types of dietary fat: 100% soybean oil and a mixture of 50% soybean oil and 50% beef tallow. In the second study, the animals walked 2 h/day at a speed of 840 m/h. No significant differences were observed in the growth test results of each study. In experiment 1, the total saturated fatty acid (SFA) proportion was significantly higher in the L-carnitine 0 ppm 50% soybean oil and 50% beef tallow group than in the other groups. Dietary Lcarnitine suppressed the increase in the SFA proportion observed upon beef tallow consumption. In experiment 2, Lcarnitine decreased the SFA proportion and increased the monounsaturated fatty acid (MUFA) proportion. No interaction between the ingested fat type and L-carnitine supplementation on the proportions of individual fatty acids was observed, but Lcarnitine supplementation increased the C16:1 proportion and decreased the C18:0 proportion as a main effect in experiment 2. In conclusion, the current results suggest that dietary Lcarnitine decreased the SFA proportion in accordance with C18:0 utilization for energy production in walking rats.

Adipose Triglyceride Lipase (ATGL) Clone, Expression Pattern, and Regulation by Different Lipid Sources and Lipid Levels in Large Yellow Croaker (Pseudosciaena crocea R.)

Adipose triglyceride lipase (ATGL) was recently identified as a triglyceride (TG)-specific lipase. In this study, we first obtained from large yellow croaker fish a 1,820-bp (GenBank ID: HQ916211) ATGL cDNA fragment with a 141-bp 5'UTR, a 1,485-bp open reading frame, and a 194-bp 3'UTR. The predicted fish ATGL had 494 amino acids (GenBank ID: ADY89608) and a calculated molecular weight of 55.1kDa. ATGL was highly expressed in liver and, to a lesser degree, in heart, muscle, and abdominal fat. ATGL gene expression was high at 4.5g and then decreased at 157.9g and increased again at 474.2g. The effects of lipid levels and lipid sources on ATGL expression in vivo were also investigated. A high-lipid diet decreased ATGL expression in fish significantly (P < 0.01). Fish in soybean oil group exhibited significantly lower ATGL expression than fish in the fish oil and beef tallow groups (P < 0.01). These data enhance our understanding of ATGL in fish lipid metabolism.

Effects of High-Fat Diets Containing Different Fats on Cholesterol Metabolism in Starvation-Refeeding Rats

The present study was performed to investegate the effects of high-fat diets containing different fats on cholesterol metabolism in starvation-refeeding rats. Forty female Donryu rats were divided into two groups and then fed high-fat diets containing beef tallow or corn oil without cholesterol for 14 days. Then, 10 rats from each group were divided into high-cholesterol and cholesterol-free groups (Experiment 1). Another 10 rats from beef tallow and corn oil groups were divided into high-cholesterol and high-cholesterol-cholestyramine groups (Experiment 2). All rats were fasted for 2 days followed by 3 days of feeding. In Experiment 1, the high-cholesterol diet caused significant increases in plasma total cholesterol and cholesteryl ester concentrations in the beef tallow diet group. In Experiment 2, dietary cholestyramine markedly decreased plasma and liver cholesterol levels; however, these cholesterol levels were higher in the beef tallow diet group even if cholestyramine was added to the diet. These results suggested that the cholesterol- lowering effect of dietary corn oil may not be due solely to reabsorption of bile acids. This study suggested that high-fat diets containing different fats affected cholesterol metabolism under conditions of starvation-refeeding.

The Effect of Dietary Docosahexaenoic Acid Enrichment on the Expression of Porcine Hepatic Genes

To study the effect of dietary docosahexaenoic acid (DHA) enrichment on the expression of hepatic genes in pigs, weaned, crossbred pigs (30 d old) were fed diets supplemented with either 2% tallow or DHA oil for 18 d. Hepatic mRNA was extracted. Suppression subtractive hybridization was used to explore the hepatic genes that were specifically regulated by dietary DHA enrichment. After subtraction, we observed 288 cDNA fragments differentially expressed in livers from pigs fed either 2% DHA oil or 2% tallow for 18 d. After differential screening, 7 genes were found to be differentially expressed. Serum amyloid A protein 2 (SAA2) was further investigated because of its role in lipid metabolism. Northern analysis indicated that hepatic SAA2 was upregulated by dietary DHA enrichment (p<0.05). In a second experiment, feeding 10% DHA oil for 2d significantly increased the expression of SAA2 (compared to the 10% tallow group; p<0.05). The porcine SAA2 full length cDNA sequence was cloned and the sequence was compared to the human and mouse sequences. The homology of the SAA2 amino acid sequence between pig and human was 73% and between pig and mouse was 62%. There was a considerable difference in SAA2 sequences among these species. Of particular note was a deletion of 8 amino acids, in the pig compared to the human. This fragment is a specific characteristic for the SAA subtype that involved in acute inflammation reaction. Similar to human and mouse, porcine SAA2 was highly expressed in the liver of pigs. It was not detectable in the skeletal muscle, heart muscle, spleen, kidney, lung, and adipose tissue. These data suggest that SAA2 may be involved in mediation of the function of dietary DHA in the liver of the pig, however, the mechanism is not yet clear.

Anti-obesity Effects of Eucommia ulmoides Leaves

In this paper, we have examined the anti-obesity effects of Eucommia ulmoides leaves in rats and mice.A high fat diet was orally administered to rats. In addition to this diet, a water solution of E. ulmoides leaf extract was administered. After 60 min, the levels of serum triglyceride decreased significantly in the 400 mg/kg E. ulmoides leaf extract group as compared with that in the high-fat diet group.A diet of 40% beef tallow was fed to rats. These rats were divided into three groups; the E. ulmoides leaf extract powder (E-EP) group received 10% E-EP, the E. ulmoides leaf green powder (E-GP) group received 10% E-GP and the E. ulmoides leaf powder (E-LP) received 10% E-LP in addition to the beef tallow. Food and water were fed ad libitum. After 4 weeks, the body weight, visceral fat, and serum of triglyceride levels of the E-E and E-L groups were significantly lower than those of rats in the 40% beef tallow group.

Dietary n-3 and n-6 fatty acids alter avian glucose metabolism

1. This investigation studied the effects of dietary saturated and polyunsaturated fatty acids (PUFAs) from the n-3 and n-6 series on insulin action and glucose uptake in broiler chickens. 2. One-day-old male chicks were fed on a commercial starter diet for 3 weeks, randomly divided into three groups (n = 6) and fed ad libitum on isonitrogenous experimental diets of equal energy density for a further 6 weeks. The diets contained 20·8 g/100 g protein and 80 g/kg of either edible tallow, fish oil or sunflower oil, giving diets high in saturated fatty acids, n-3 PUFAs or n-6 PUFAs, respectively. 3. Jugular catheterisation was performed under general anaesthesia during week 4 of the dietary treatments and the birds given 7 d post-surgery to recover. To estimate insulin action, a bolus glucose infusion (1 g/kg) was given to each chicken and sequential blood samples taken over a one-hour period. To estimate the disappearance rate of glucose from the plasma and its incorporation into tissues, 2-deoxy-D-3H glucose (2DG-3H glucose) was infused into each chicken (50 µCi) 2 d later. 4. Although there were no significant differences in glucose clearance rate following the glucose infusion, the maximal insulin release in response to the glucose infusion was higher in the tallow group than in either the n-3 or n-6 PUFA dietary groups. There were no significant differences in the clearance rate of 2DG-3H glucose. Labelled glucose incorporation into the breast muscle was greater in birds given fish oil than in birds given tallow and significantly greater than in birds given sunflower oil. 5. The data suggest that the type of dietary fat can influence glucose metabolism and that this change in glucose utilisation may alter the energy metabolism of the broiler.

아마인유와 채종유 급여가 돼지고기의 n-3 지방산 함량에 미치는 영향

본 연구는 아마인유와 채종유내에 들어있는 n-3 지방산의 돈육내 축적효과를 조사하기 위해 실시하였다. 3원 교잡종 수퇘지(체중 50 ㎏) 12마리를 이용하여서 4가지 실험사료중 한가지를 급여하였으며 실험사료는 우지, 아마인유, 채종유 또는 아마인유와 채종유의 혼합유를 함유하였다. 110 ㎏ 시판 체중 도달시에 희생하였다. 아마인유와 채종유속에 들어있는 n-3 지방산은 돼지의 일당증체량, 사료섭취량 및 사료 효율에 아무런 영향을 미치지 않았다. 혈액 포화지방산 함량은 우지 첨가구가 가장 높았고 아마인유 첨가구, 채종유 첨가구 또는 혼합유 첨가구는 우지 첨가구보다 11.84%~16.54% 낮게 나타났다(p0.05). 혈액 n-3 지방산 함량은 우지 첨가구에서는 거의 검출되지 않았으나 아마인유 첨가구, 채종유 첨가구 또는 혼합유 첨가구는 우지 첨가구보다 4.68%~12.83% 높게 나타났다(p0.05). n-3 고도불포화지방산을 함유하는 3가지 지질 급원 모두는 우지 첨가구에 비교하여 돼지고기 삼겹살 내 α-linolenic acid(18:3n-3) 함량을 9.43%까지 유의적으로 높였다(p0.05). 아마인유 또는 채종유 급여는 삼겹살내 n-3:n-6 비율을 0.68로 높였으며 고도불포화지방산 :포화지방산 비율은 0.70으로 증가시켰다. 결론적으로 아마인유와 채종유 급여에 의해 n-3지방산이 강화된 새로운 기능성 돈육을 생산할 수 있음을 보여주었다.

Evaluation of beef tallow as a natural source of conjugated linoleic acid

Cis-9, trans-11 conjugated linoleic acid (9c, 11t CLA) is a potential anticarcinogen that is found in higher concentrations in beef lipids. However, the effect of CLA on lipid peroxidation, which is closely related to carcinogenesis, is controversial. In this study, we determined the levels of 9c, 11t CLA contents and thiobarbituric acid reactive substances (TBARS) in the tissues of rats fed beef lipid. Sprague-Dawley rats (male, 8 weeks old) were fed experimental diets containing 20% lyophilized beef, and 12% beef tallow or vegetable oils, for 56 days. With the exception of the brain, the tissues from the rats fed the experimental diets accumulated 9c, 11t CLA, depending on the levels of CLA in the diets. The beef tallow group showed significantly higher 9c, 11t CLA contents in all tissues examined than the other diet groups. The intake of beef lipid did not affect the TBARS levels in the rat tissues. The hepatic lipid content from the beef tallow group was lower than that from the group fed vegetable oils. These results suggest that beef is a good source of 9c, 11t CLA, and that the intake of an appropriate level of beef lipid is not hazardous to health.

Effect of dietary energy supply and fat source on the fatty acid pattern of adipose and lean tissues and lipogenesis in the pig.

Forty Large White barrows were used to determine whether the effects of dietary fat source (tallow or soy oil at 5% of the diet) on lipogenesis and fatty acid profile of porcine adipose and lean tissue were dependent on dietary digestible energy density (8.8 vs 14.0 MJ DE/kg). Barrows were allocated to one of four groups and offered a fixed amount of feed (170 g x BW0.569/d) from 27 to 105 kg BW. The fatty acid composition of the backfat layers (BF), omental fat (OF), and i.m. adipose tissue of longissimus muscle as well as the activity of lipogenic enzymes of the adipose tissues were determined. Growth performance and carcass characteristics were affected by the dietary energy level (P < 0.01) but not by fat source. In accordance with the lower carcass fat deposition, the activity of lipogenic enzymes were decreased in the low-energy groups (P < 0.01). Within dietary energy level, inclusion of soy oil resulted in increased proportion of PUFA that was compensated by decreased saturated (SFA) and monounsaturated fatty acid (MUFA) proportions (P < 0.01). The SFA changes accounted for 23 (BF) and 24% (OF) of the PUFA changes in the high-energy and 31 (BF) and 39% (OF) in the low-energy diets. The differences in the fatty acid proportions between the soy oil and tallow group were more pronounced in the low-energy groups (fat source x energy density interactions: P < 0.01). Pigs fed the soy oil, low-energy diet had decreased SFA (BF: 28%; OF: 30%) and MUFA (BF: 13%; OF: 19%) concentration, whereas PUFA concentration was increased (BF: 59%; OF: 88%) compared with pigs fed the soy oil, high-energy diet. However, in the tallow groups, pigs fed the low-energy diets had slightly decreased SFA (BF: 14%; OF: 12%) and relatively constant MUFA (BF: 3%; OF: 1%), whereas PUFA concentration increased (BF: 39%; OF: 62%) relative to pigs fed the tallow high-energy diet. Lipid content of the i.m. adipose tissue was decreased in the low-energy groups (P < 0.05). Contrary to what was observed in the adipose tissues, increased PUFA concentration in the neutral and polar lipid fractions of the longissimus muscle was predominantly compensated by reduced MUFA deposition. In the polar lipid fraction, the proportions of both SFA and MUFA were decreased by the low-energy diet. Thus, the extent to which tissue concentration of fatty acids are altered from dietary fats differing in the degree of unsaturation depends on the dietary energy level.

INFLUENCE OF FEED FAT SOURCE ON FATTY ACID COMPOSITION, UNSATURATION AND LIPID OXIDATION OF BACKFAT AND SENSORY QUALITY OF PORK

ABSTRACTThe effect of different fats in a 9% fishmeal feed on backfat fatty acid composition, oxidation and pork sensory attributes was studied. The hydrogenated fish oil group (HFO) had significantly increased uptake of certain fatty acids in contrast to the other groups. Iodine values were highest in the fish oil group, followed by the lamb tallow group (LT) with the control group, containing no added fat, tailing. Backfat from the HFO group had more polyunsaturated fatty acids compared to the other groups and stearic/linoleic acid ratio suggested more oxidative problems with this group. The HFO group led the LT group in oxidation with the control group being most stable. Sensory traits of fresh and frozen pork chops correlated with the oxidation results. Fat from pigs fed hydrogenated fish oil in their diet are therefore more susceptible towards oxidation possibly due to more polyunsaturated fatty acids and oxidation products in the backfat.

Cardiac (n-3) Non-Esterified Fatty Acids Are Selectively Increased in Fish Oil-Fed Pigs following Myocardial Ischemia

The effect of fish oil supplementation on the nonesterified fatty acid (NEFA) concentration and composition in the normoxic and hypoxic myocardium of pigs was examined. Two groups of female pigs (n = 7) were fed a diet supplemented with either 5 g beef tallow/kg (as control) or 5 g fish oil/kg (MaxEPA) rich in (n-3) fatty acids. After 6 wk of supplementation, the pigs were anesthetized, hearts exposed by thoracotomy followed by occlusion of the left anterior descending artery. Normoxic and hypoxic regions of the heart were examined for NEFA concentration and composition by using a combination of thin layer and gas chromatography. Nonesterified (n-6) and (n-3) fatty acid concentration and composition differed significantly between the two groups in both the normoxic and hypoxic areas of the heart. Eicosapentaenoic and docosahexaenoic acid concentration in the NEFA fraction of the normoxic myocardium were higher in the fish oil group than in the beef tallow group (P < 0.001). In the fish oil-fed pigs, the (n-3) NEFA concentration was significantly higher in the hypoxic compared to the normoxic region of the heart. The fish oil-fed group had lower levels of arachidonic acid in the NEFA fraction compared to the beef tallow-fed group, whereas the hypoxic myocardium had higher levels of arachidonic acid, regardless of the dietary fat supplementation. Despite large differences in the proportions of saturated fatty acids in the experimental diets, there was little or no difference in the saturated fatty acid content of cardiac phospholipid and NEFA fractions. Following myocardial ischemia, (n-3) fatty acids in the NEFA fractions were selectively increased in the fish oil-fed pigs, implicating the possible role of nonesterified (n-3) polyunsaturated fatty acids in the prevention of arrhythmias.

Fish Oil Feeding Delays Influenza Virus Clearance and Impairs Production of Interferon-γ and Virus-Specific Immunoglobulin A in the Lungs of Mice

Ingestion of fish oil can suppress the inflammatory response to injury and may impair host resistance to infection. To investigate the effect of a diet containing fish oil on immunity to viral infection, 148 BALB/c mice were fed diets containing 3 g/100 g of sunflower oil with either 17 g/100 g of fish oil or beef tallow for 14 d before intranasal challenge with live influenza virus. At d 1 and d 5 after infection, the mice fed fish oil had higher lung viral load and lower body weight (P < 0.05). In addition to the greater viral load and weight loss at d 5 after infection, the fish oil group consumed less food (P < 0.05) while the beef tallow group was clearing the virus, had regained their preinfection weights and was returning to their preinfection food consumption. The fish oil group had impaired production of lung interferon-γ (IFN-γ), serum immunoglobulin (Ig) G and lung IgA-specific antibodies (all P < 0.05) although lung IFN-α/β and the relative proportions of bronchial lymph node CD4+ and CD8+ T lymphocytes did not differ between groups after infection. The present study demonstrates a delay in virus clearance in mice fed fish oil associated with reduced IFN-γ and antibody production and a greater weight loss and suppression of appetite following influenza virus infection. However, differences observed during the course of infection did not affect the ultimate outcome as both groups cleared the virus and returned to preinfection food consumption and body weight by d 7.

Dietary fat type and energy restriction interactively influence plasma leptin concentration in rats

To investigate whether dietary fat source and energy restriction interactively influence plasma leptin levels and its association of leptin with insulin action, rats were fed diets containing either fish, safflower oil, or beef tallow (20% wt/wt) for 10 weeks. Groups of rats consumed each diet ad libitum or at 85% or 70% of ad libitum energy intake in a design that held fat intake constant. Graded levels of energy restriction caused body weight to decrease (P < 0.001) differently according to the dietary fat provided. Plasma leptin concentrations were 60% higher (P < 0.05) in the groups fed fish oil and safflower oil ad libitum compared with those in the beef tallow group, despite smaller perirenal fat mass and fat cell size in the fish oil-fed animals. Energy restriction resulted in a 62% decrease (P < 0.05) in leptin levels in fish oil- and safflower oil-fed rats, whereas no changes were observed in beef tallow-fed animals. Plasma insulin levels were lower (P < 0.05) in the fish oil group fed ad libitum compared with those in the two other diet groups.▪ These data demonstrate a hyperleptinemic effect in animals consuming diets rich in polyunsaturated fatty acid, which can be normalized to the level of saturated fat consumption by mild energy restriction. Thus, dietary fatty acid composition, independent of adipose tissue mass, is an important determinant of circulating leptin level in diet-induced obesity.—Cha, M. C., and P. J. H. Jones. Dietary fat type and energy restriction interactively influence plasma leptin concentration in rats.

Effects of Dietary Vitamin E Level and Unsaturation of Fatty Acids on Chick Immune Responses

We reported previously that supplemental vitamin E enhances disease resistance and antibody titers and depresses bursal prostaglandin (PG) E2 in chicks. In order to determine if dietary fat composition alters PG response and interacted with vitamin E, tallow or vegetable oil high in n-6 polyunsaturated fatty acids were added to a cornsoybean meal chick diet. Comparisons were made among control cockerels and those fed diets containing safflower or corn oils or beef tallow at 3, 6 or 9% with each of these diets supplemented with 0 or 300 mg of all-rac-a-tocopheryl acetate (dla-tocophery1 acetate). In the first experiment chick antibody titers to sheep red blood cells were markedly stimulated by 6% tallow without added vitamin E. Unexpectedly, supplemental vitamin E depressed antibody titers only in the 6% tallow group. Dietary fat and supplemental vitamin E altered bursal but not splenic PGE2 values independent of inoculation. Overall, the combination of tallow and vitamin E supplementation vitamin E suppressed antibody production in only tallow fed chicks. The depressive effect of supplemental vitamin E on bursal but not splenic PGE2 content was also confirmed. Bursal PGE2 content was increased over two-fold by corn oil consumption and was associated with a significant increase in the amount of phospholipid arachidonate. Considering the biphasic effects of vitamin E and PGE2 on immune response then it is not inconsistent that vitamin E did not enhance antibody titers and were actually depressed when tallow was fed.