Lard Diet Research Articles

Health benefits of dietary fat reduction by a novel fat replacer: Mimix

The primary goals of this study were to identify any health benefits of the replacement of dietary fat with a novel fat replacer, Mimix, and to assure that the consumption of this fat replacer did not convey any deleterious health effects. Male, weanling, Fischer 344 rats were fed one of six diets containing between 5 and 20% w/w as fat for 8 weeks. These diets included two high fat diets (safflower oil or lard), a low fat diet and three diets where 15% of the fat in the high fat diets was replaced with various amounts of Mimix. When animals were fed a diet rich in saturated fat they consumed significantly more energy than other diet groups. When 15% saturated fat (lard) was replaced with safflower oil animals adjusted their food intake so that no difference in energy intake was observed between the high safflower diet and the low fat and Mimix diets. When the various Mimix fat replacements were compared to animals fed a high fat lard diet there was incomplete compensation of energy intake. Animals fed the high fat lard diet also had higher glucose and total serum cholesterol than their low fat and fat replacement counterparts. Feeding a high fat safflower oil diet to rats resulted in a significantly lower total serum cholesterol and serum triglyceride than all other diets. Replacement of dietary fat with Mimix demonstrated no deleterious effects on the heart, liver and intestinal tract that were all of normal weight, morphology and colour compared to other diet groups. Body composition analysis demonstrated that animals fed high fat diets had higher body fat mass at the expense of lean body mass. This was most obvious for animals fed high fat lard diets who had heavier epididymal fat pads. These data demonstrate that the replacement of dietary fat with the novel fat replacer Mimix can convey a number of health benefits in the absence of any deleterious effects.

Effects of dietary maritime pine (Pinus pinaster)-seed oil on high-density lipoprotein levels andin vitrocholesterol efflux in mice expressing human apolipoprotein A-I

Maritime pine (Pinus pinaster)-seed oil contains two Delta5 unsaturated polymethylene interrupted fatty acids (all cis-5,9, 12-18:3 and all cis-5,11,14-20:3 acids) one of which resembles eicosapentaenoic acid. The goal of the present study was to test whether maritime pine-seed oil consumption affects HDL and apolipoprotein (Apo) A-I levels as well as the ability of serum to promote efflux of cholesterol from cultured cells. To this end, wild type (WT) non-transgenic mice and transgenic mice expressing human ApoA-I (HuA-ITg) were fed on isoenergetic diet containing either 200 g maritime pine-seed oil/kg or 200 g lard/kg for 2 weeks. WT and HuA-ITg mice fed maritime pine-seed oil had lower cholesterol, HDL-cholesterol, LDL-cholesterol and HuA-ITg mice had lower human ApoA-I than those fed lard. The differences in cholesterol (P < 0.0001) and HDL-cholesterol (P < 0.003) levels between mice fed on the two diets were more pronounced in the HuA-ITg than in the WT mice. The ability of HuA-ITg serum to promote cholesterol efflux in cultured cells was greater (P < 0.008) than that of WT animals. However, the maritime pine-seed oil diet was associated with lower (P < 0.005) in vitro cholesterol efflux ability than the lard diet in both mice genotypes. This suggests a negative effect of the maritime pine-seed oil on reverse cholesterol transport. Cholesterol efflux was correlated with serum free or esterified cholesterol and phospholipid levels. The slope of the regression line was smaller in the HuA-ITg than in the WT mice indicating that overexpression of human ApoA-I reduces the negative impact of maritime pine-seed oil on cholesterol efflux. In conclusion, maritime pine-seed oil diet lowers HDL-cholesterol and diminishes in vitro cholesterol efflux. This potentially detrimental effect is attenuated by overexpression of human ApoA-I in mice.

Dietary Soy Protein Is Associated with Reduced Intestinal Mucosal Polyamine Concentration in Male Wistar Rats

Quantitation of polyamine levels has been correlated with biomarkers of proliferation in the colon mucosa where dysregulated epithelial hyperproliferation is associated with colorectal cancer risk. This study was performed to assess the response of polyamine measurements to dietary factors in an animal model. Male Wistar rats were fed purified diet or diets substituted by 20% lard fat, 20% beet fiber and 20% soy protein. After 2 wk, mucosal polyamines were measured along intestinal tracts by HPLC. In rats fed the control diet (n = 10), mucosal polyamines were found at high levels in the duodenum, jejunum and ileum but at low levels in the cecum, colon and rectum. Compared with rats fed the control diet, those fed the 20% lard diet showed greater polyamine levels in the large intestine (P < 0.05, n = 10), but those fed the 20% fiber diet exhibited lower polyamine levels in the small intestine (P < 0.05, n = 9). However, rats fed the 20% soy protein diet had lower polyamine levels in both small and large intestines (P < 0.05, n = 15). Significant linear correlations were observed between rectal polyamine levels and the dietary energy intakes in these four diet groups (r = 0.972-0.991, P < 0.001). Supplementation of 0.1% soy isoflavones to the basal diet or 0.3% DL-methionine to the 20% soy protein diet for 4 wk did not affect polyamine levels. The results indicate that soy protein reduced mucosal polyamine levels, at least in part, through reduction of energy intakes. Further studies are warranted to verify that polyamine levels in intestinal mucosa are useful as an intermediate endpoint of the dietary risk factors.

Pinus pinaster Oil Affects Lipoprotein Metabolism in Apolipoprotein E-Deficient Mice

The aim of the present study was to assess the antiatherogenic properties of Pinus pinaster (maritime pine) seed oil. To this end, the effects of P. pinaster oil supplementation on lipoprotein levels and atherosclerotic lesions were compared to those of lard or sunflower oil in apolipoprotein E-deficient mice. Plasma total cholesterol (P < 0.0001) and VLDL + intermediary density lipoprotein (IDL)-cholesterol (P < 0.0001) levels were lower in mice fed P. pinaster and sunflower oil than in those fed the lard diet. In contrast, triglycerides (P < 0.0001) and VLDL + IDL-triglycerides (P < 0.0001) levels were higher in mice fed P. pinaster oil than sunflower oil or lard. The VLDL + IDL lipid composition of apolipoprotein E-deficient mice fed P. pinaster oil was intermediate between that of lard-fed transgenic mice and that of wild-type mice fed nonpurified diet. Using the Triton WR1339 method, the fractional catabolic rate of plasma triglycerides was found to be lower in mice fed P. pinaster oil (P < 0.0001) than sunflower oil or lard diet, suggesting a defective clearance of triglycerides in the P. pinaster group. Finally, the susceptibility of triglyceride-rich lipoproteins to in vitro lipoprotein lipase-mediated lipolysis was lower in the P. pinaster oil-fed group than in the lard-fed group. Despite the differences in VLDL + IDL level and lipid composition, the surface areas of aortic atherosclerotic lesions were not significantly different among mice fed P. pinaster, sunflower or lard diets. In conclusion, the results of the present study indicated that feeding P. pinaster oil had no better preventive effect on aortic atherosclerotic lesion extension in apolipoprotein E-deficient mice than other saturated or polyunsaturated fats.

Effects of genetic and diet-induced obesity on lipid metabolism.

C57BL/6J obese (ob/ob) and lean mice fed ad libitum on a normal mouse chow diet (Normal), were compared with lean mice of the same age and strain fed ad libitum on a high-fat diet, consisting of the Normal diet with the addition of beef lard (Lard), from age 3 months for 34 days. The lard-fed mice were seen to have significantly higher (P<0.05) body weight in this 34-day period than that of the other two groups fed on the Normal diet. Epididymal fat depot and adipocyte cell size were significantly larger (P<0.05) in the Lard-fed lean mice and in the obese (ob/ob) mice than were those of the Normal-fed lean mice. Dietary Lard intake did not significantly affect concentrations of plasma triglyceride although those of plasma cholesterol were significantly increased (P<0.05). The development of obesity in these Lard-fed mice appeared to be accelerated and significant.

Allyl-Containing Sulfides in Garlic Increase Uncoupling Protein Content in Brown Adipose Tissue, and Noradrenaline and Adrenaline Secretion in Rats

The effects of garlic supplementation on triglyceride metabolism were investigated by measurements of the degree of thermogenesis in interscapular brown adipose tissue (IBAT), and noradrenaline and adrenaline secretion in rats fed two types of dietary fat. In Experiment 1, rats were given isoenergetic high-fat diets containing either shortening or lard with or without garlic powder supplementation (8 g/kg of diet). After 28 d feeding, body weight, plasma triglyceride levels and the weights of perirenal adipose tissue and epididymal fat pad were significantly lower in rats fed diets supplemented with garlic powder than in those fed diets without garlic powder. The content of mitochondrial protein and uncoupling protein (UCP) in IBAT, and urinary noradrenaline and adrenaline excretion were significantly greater in rats fed a lard diet with garlic powder than in those fed the same diet without garlic. Other than adrenaline secretion, differences due to garlic were significant in rats fed shortening, also. In Experiment 2, the effects of various allyl-containing sulfides present in garlic on noradrenaline and adrenaline secretion were evaluated. Administration of diallyldisulfide, diallyltrisulfide and alliin, organosulfur compounds present in garlic, significantly increased plasma noradrenaline and adrenaline concentrations, whereas the administration of disulfides without allyl residues, diallylmonosulfide and S-allyl-L-cysteine did not increase adrenaline secretion. These results suggest that in rats, allyl-containing sulfides in garlic enhance thermogenesis by increasing UCP content in IBAT, and noradrenaline and adrenaline secretion.

Two major loci control variation in beta-lipoprotein cholesterol and response to dietary fat and cholesterol in baboons.

We explored the genetic control of cholesterolemic responses to dietary cholesterol and fat in 575 pedigreed baboons. We measured cholesterol in beta-lipoproteins (low density lipoprotein cholesterol [LDLC]) in blood drawn from baboons while they were consuming a baseline (low in cholesterol and fat) diet, a high-saturated fat (lard) diet, and a high-cholesterol, high-saturated fat diet. In addition to baseline levels (LDLC(Base)), we analyzed two variables for diet response: LDLC(RF), which represents the LDLC response to increasing dietary fat (ie, high-fat diet minus baseline), and LDLC(RC), which represents the LDLC response to increasing dietary cholesterol level (ie, high-cholesterol, high-fat diet minus high-fat diet). Heritabilities (h2) of the 3 traits were 0.59 for LDLC(Base), 0.14 for LDLC(RF), and 0.59 for LDLC(RC). In addition, LDLC(Base) and LDLC(RC) had a significant genetic correlation (ie, rhoG=0.54), suggesting that 1 or more genes exert pleiotropic effects on the 2 traits. Segregation analyses detected a single major locus that accounted for nearly all genetic variation in LDLC(RC) and some genetic variation in LDLC(Base) and LDLC(RF) and confirmed the presence of a different major locus that influences LDLC(Base) alone. Preliminary linkage analyses indicated that neither locus was linked to the LDL receptor gene, a likely candidate locus for LDLC. Detection of these major loci with large effects on the LDLC response to dietary cholesterol in a nonhuman primate offers hope of detecting and ultimately identifying similar loci that determine LDLC variation in human populations.

Broiler breeder age and dietary fat influence the yolk fatty acid profiles of fresh eggs and newly hatched chicks

The purpose of the present study was to investigate the combined effects of breeder age (36-, 51-, or 64-wk) and different dietary fat sources (3% added corn oil, poultry fat, or lard) on lipids in fresh egg yolks and yolks of newly hatched chicks. Isocaloric breeder diets were altered by the inclusion of different types of dietary fat such that the poultry fat and lard diets had the highest levels of saturated fatty acids when compared to the corn oil diet. Fresh egg yolks obtained from 36-wk-old breeders exhibited higher levels of palmitoleic acid when compared to the levels observed in fresh egg yolks of 51- or 64-wk-old breeders. Furthermore, these levels decreased significantly by 21 d of incubation only in eggs from 36-wk-old hens. At 36 wk of breeder age, the levels of oleic and arachidonic acid were higher in yolks from hatched chicks than in previous fresh egg values, regardless of type of added dietary fat; whereas the level of linoleic acid was higher only in yolks from hatched chicks compared to those of fresh eggs from 36-wk-old hens fed 3% added corn oil. These data suggest that breeder age influences the utilization of yolk lipid by developing embryos, and that the type of fat provided in the diet may have an additional influence.

Effects of added lard fed to broiler chickens during the starter phase. 2. Serum lipids

The effects of lard added to starter diets on various serum lipids were determined in broiler chickens between 14 and 42 d of age. Nonisocaloric starter diets were formulated to contain either 0, 3, or 7% added lard, where the megacaloric percentages of all major nutrients were held constant. Birds received either 0, 3, or 7% added lard in starter diets through 10 d of age (S1), followed by either 3 or 7% added dietary lard through 21 d of age (S2). All possible combinations of the three S1 diets and two S2 diets yielded six total dietary treatments. A common grower diet was provided after 21 d. Concentrations of various serum lipids were determined weekly from 14 to 42 d of age. The effects of both the S1 and S2 diets on total cholesterol, low density lipoprotein cholesterol (LDLC), and high density lipoprotein cholesterol (HDLC) were inconsistent and were influenced by sex between 14 and 42 d of age. However, serum triglycerides and very low density lipoprotein cholesterol concentrations showed progressive increases over the 14 to 42 d period in birds that received dietary lard at either level in the S1 diet. These same serum constituents also increased to the greatest extents over the same period when birds were provided 3% added lard in the S2 diet. It was concluded that the response of broiler chickens between 14 and 42 d to different levels of dietary lard were influenced by age of feeding during the starter period. Furthermore, the specific effects of the diets on serum cholesterol, LDLC, and HDLC concentrations between 14 and 42 d varied with the sex and age of the bird.

Effects of added lard fed to broiler chickens during the starter phase. 1. Body and selected organ weights, feed conversion, hematology, and serum glucose

The effects of added lard in starter diets on BW, selected organ weights, feed conversion, hematological indices, and serum glucose were determined weekly in broiler chickens between 14 and 42 d of age. Nonisocaloric starter diets were formulated to contain either 0, 3, or 7% added lard, where the megacaloric percentages of all major nutrients were held constant. Broiler chickens received either 0, 3, or 7% added lard in starter diets through 10 d of age (S1), followed by either 3 or 7% added dietary lard through 21 d of age (S2). All possible combinations of the three S1 diets and two S2 diets yielded six total dietary treatments. A common grower diet was provided after 21 d. Body weight was not affected by diet and feed conversion did not increase between 21 and 42 d when birds were fed 3 or 7% added lard in the S1 diet. The effects of the S1 and S2 diets on relative liver weight were inconsistent over time and were not influenced by sex. Hematocrits were increased across time in birds fed 3% S1 diets and plasma protein concentrations were increased at 14 d in birds fed 7% S1 diets. It was concluded that the response of broiler chickens between 14 and 42 d to different levels of dietary lard was influenced by age of feeding during the starter period.

Effect of dietary lard on performance, fatty acid composition and susceptibility to lipid peroxidation in growing-finishing female and entire male pigs

The effect of increasing the energy concentration of growing-finishing pig diets through inclusion of lard on performance, carcass and meat composition and lipid susceptibility to peroxidation was studied. A total of 720 Landrace × Large White male and female pigs (equal number of entire males and females) were used. Experimental diets were formulated to have a low (3000 kcal ME kg−1) or high (3200 kcal ME kg−1) energy level, but in all cases to have a constant lysine:ME ratio. This was achieved using a low (6.8 g kg−1) and a high (49.3 g kg−1) level of dietary lard inclusion. Gilts had lower daily gain (P &lt; 0.0001) and worse feed conversion efficiency (P &lt; 0.0001) than entire males. Susceptibility to oxidation was not affected by sex. Fat concentration in pig diets equilibrated in metabolizable energy and protein did not modify average gain, but reduced feed intake (P &lt; 0.02), improved the gain:feed ratio (P &lt; 0.0001), increased dressing percentage (P &lt; 0.02) and produced higher carcass weight (P &lt; 0.01). Carcass backfat and lean percentage were not affected by dietary treatment. A reduction in the proportion of (n-3) fatty acids in phospholipids (P &lt; 0.03), a higher (n-6):(n-3) ratio (P &lt; 0.01) and a lower susceptibility of muscle homogenates to oxidation was found in animals receiving higher levels of dietary lard (P &lt; 0.01). Key words: Pig, boar, diet, lard, lipid oxidation

Improved insulin sensitivity by bezafibrate in rats: relationship to fatty acid composition of skeletal-muscle triglycerides.

We investigated the effect of the lipid-lowering agent, bezafibrate, on insulin sensitivity in a dietary model of insulin resistance. Male Sprague-Dawley rats were divided into four groups: control group, administered a standard diet; high-fructose group, given a 40% fructose diet; high-fructose plus lard group, given a 40% fructose diet with 7% lard; and bezafibrate group, given a 40% fructose plus 7% lard diet with 10 mg x kg-1 x day-1 of oral bezafibrate. Insulin action was assessed after 2 weeks with a steady-state plasma glucose (SSPG) level. The fatty acid (FA) composition of skeletal-muscle triglycerides was also determined. A higher SSPG level (20.9 +/- 0.9 vs. 16.5 +/- 1.1 mmol/l in the control group, P < 0.05) as well as a higher systolic blood pressure (120 +/- 2 vs. 101 +/- 2 mmHg, P < 0.01) was observed in the high-fructose plus lard group, but not in the high-fructose group. These changes were prevented by bezafibrate administration. The FA composition of skeletal-muscle triglycerides demonstrated a higher percentage of saturated and monounsaturated FAs (P < 0.01) and a lower percentage of polyunsaturated FAs (P <0.01) in the high-fructose plus lard group versus the control group. These changes were consistent with differences in the dietary intake of FAs. Bezafibrate virtually normalized the FA composition in the high-fructose plus lard group. The ratio of C20:4 to C20:3, an index of delta5 desaturase activity, was significantly higher in the bezafibrate group versus the high-fructose plus lard group (8.60 +/- 0.76 vs. 2.04 +/- 0.27, P < 0.01). In conclusion, the dietary FA composition was closely related to insulin resistance in rats fed 40% fructose. Bezafibrate increased delta5 desaturase activity. Such action may contribute to the improvement of insulin sensitivity.

Effects of added dietary lard on body weight and serum glucose and low density lipoprotein cholesterol in randombred broiler chickens

The effects of dietary lard on serum glucose (GLU) and lipids were determined in Athens-Canadian randombred broiler chickens. Birds were provided either 0, 3, or 7% added lard in nonisocaloric starter diets through 10 d of age (S1), followed by either 3 or 7% added dietary lard through 21 d of age (S2). A common grower diet was fed to all birds after 21 d. Body and organ weights, feed conversion, and concentrations of various blood constituents, including serum GLU and lipids, were determined weekly from 14 to 42 d of age. Constant levels of added fat in both S1 and S2 diets generally led to higher BW in males at 42 d. Relative testes weight at 14 d was higher in males fed 3% than in those fed 7% S2 diets, whereas 7% added lard in S2 diets preceded by no added fat in S1 diets resulted in higher relative spleen weights in males at 42 d. Serum GLU concentrations were highest in males that received 3% lard rather than no added lard in the S1 diet. Serum low density lipoprotein cholesterol (LDLC) concentrations at 14 d were highest in females fed constant levels of lard at either 3 or 7% in both starter periods. It was concluded that added lard fed to randombred chickens at various times and levels in starter diets elicited responses in organ weight and serum LDLC and GLU concentrations that varied with the sex and age of the bird and were not consistently related to BW.

Lipid structure of rat adipocyte plasma membranes following dietary lard and fish oil

We have determined the changes in the lipid structure of the adipocyte plasma membranes of rats receiving lard or fish oil in their diet. For this purpose, mature Wistar rats were fed 20% (w/w) lard or fish oil diets for 22 days, when the plasma membranes of the epididymal and perirenal adipocytes were prepared. Detailed analysis of the membrane lipids by chromatographic methods showed that dietary fat exerted a major effect on the lipid class and molecular species composition of the phospholipids. As a result of fish oil feeding, significant increases in the 20:5( n−3), 22:5( n−3) and 22:6( n−3) were detected in all glycerophospholipid classes, while the 18:1( n−9) and 18:2( n−6) and to a lesser extent 20:4( n−6) decreased. Incorporation of n−3 fatty acids increased the phosphatidylcholine/sphingomyelin ratio without changing the total phospholipid or free cholesterol content of the membrane. Fish oil feeding also caused a marked increase in the proportion of 24:1 in sphingomyelins, which occurred mainly at the expense of 18:0 and 24:0. New n−3 fatty acid-containing species appeared in the choline and ethanolamine glycerophospholipids, when compared to membrane lipids from lard-fed rats. Membranes from fish oil fed rats also had moderately higher levels of ether lipids. Few differences were seen between the membranes of the epididymal and perirenal adipocytes. It is concluded that dietary fish oils modify the lipid structure of rat adipocyte plasma membranes by increasing the ratio of phosphatidylcholine to sphingomyelin and by increasing the proportion of molecular species with polyunsaturated fatty acids, which would be anticipated to increase the fluidity of the lipid bilayer of adipocyte plasma membranes.

Alteration of Cardiovascular Function in Trained Rats Fed With Fish Oil

In vivo cardiovascular function of sedentary and exercise-trained rats were studied after a 3 week feeding period of diets containing either 10% fish oil, sunflower oil or lard. Rats were randomly assigned to six groups: fish oil diet: sedentary (FS), exercise-trained (FT); sunflower oil diet; sedentary (SS), exercise-trained (ST); lard diet: sedentary (LS), exercise-trained (LT). The exercised rats ran on a treadmill at a speed of 16 m/min, for 60 min/d, 7 days/week during 3 weeks. There was no significant difference in body weights and heart weights among the 6 groups at the end of the study. Heart function was evaluated in closed-chest rats after catheterization of the left ventricle with an ultraminiature catheter pressure transducer. Cardiovascular function of trained rats fed on fish oil diet was significantly different from that of other rats studied (FS, SS, ST, LS, LT). There was a 20% reduction in left ventricular systolic pressure (LVSP), LVdP/dtmax, mean aortic pressure (MAP), heart rate (HR) and a 30% reduction in LVdP/dtmin. We conclude that fish oil diet might induce a change in hemodynamic parameters only when associated with stress, such as the moderate exercise protocol in our experiments.

Serum Triiodothyronine Concentration and Na+,K+-ATPase Activity in Liver and Skeletal Muscle Are Influenced by Dietary Fat Type in Rats

It has been shown previously that dietary fat type influences body fat accumulation in rats. The effects of dietary fat type on serum thyroid hormone, activity of Na+,K+-ATPase and lipoprotein lipase were studied. Rats were fed an experimental diet containing lard, high oleic safflower oil, safflower oil or linseed oil for 12 wk. Carcass fat content was significantly higher in rats fed the lard diet than in those fed the other diets. However, intra-abdominal adipose tissue weights were not affected by type of dietary fat. The serum triiodothyronine concentration and the activity of Na+,K+-ATPase in the liver and skeletal muscle were significantly lower in the lard diet group than in the other diet groups. The lipoprotein lipase activity of abdominal subcutaneous fat was significantly higher in rats fed the lard diet than in rats fed the other diets, but the activity of lipoprotein lipase in intra-abdominal fat was not significantly different. These results suggest that the intake of lard, compared with the intake of the vegetable oils, may decrease Na+,K+-ATPase activity in the liver and skeletal muscle by lowering serum triiodothyronine concentration, resulting in the promotion of body fat accumulation.

Effects of a fish oil-lard diet on rat plasma lipoproteins, liver FAS, and lipolytic enzymes.

The effects of a fish oil concentrate on blood lipids and lipoproteins were examined in relation to their effects on liver fatty acid synthase (FAS), 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, adipose tissue lipoprotein lipase (LPL), and hepatic triglyceride lipase (H-TGL). For 15 days, 2-mo-old rats were fed a control diet (10% of calories from fat, 4% fat by weight) or diets with 50% of calories (25% wt/wt) provided by lard, lard and fish oil calories (35%/15%), or lard and corn oil (35%/15%). The high-lard diet increased plasma chylomicron and liver triglycerides. The high-lard diet greatly decreased FAS, HMG-CoA reductase, and LPL activities; it also reduced H-TGL activity. Compared with the lard diet, the lard-fish oil diet decreased plasma TG by drastically lowering chylomicron (4-fold, P < 0.001) and very-low-density lipoprotein levels (P < 0.001). It also reduced high-density lipoprotein levels. The lard-fish oil diet prevented hepatic triglyceride accumulation and decreased FAS activity and mass by 3.5-fold (P < 0.001) but did not further decrease HMG-CoA reductase activity. Adipose tissue LPL activity was 2.5-fold (P < 0.001) higher with the lard-fish oil diet than with the lard diet, and H-TGL activity decreased significantly (-32%, P < 0.01), despite unaltered levels of H-TGL mRNA. These effects were significant with only 10% fish oil concentrate in the lard diet. They were not observed with the lard-corn oil diet.(ABSTRACT TRUNCATED AT 250 WORDS)

The Effects of Dietary Fat on Growth Performance, Carcass Composition, and Feed Efficiency in the Broiler Chick ,

In two experiments broiler chicks were fed nonisocaloric diets with either 0, 3, or 7% added lard. Megacaloric percentages of all major nutrients were the same in all diets. In Experiment 1 (broiler chicks 0 to 5 d of age), added dietary lard did not affect body, heart, spleen, or pancreas weight. Liver weight was suppressed by the inclusion of lard in the diet, yet liver composition changed, becoming higher in protein and lower in fat. Yolk sac weight decreased during the first 5 d posthatch, with the decrease being most pronounced by 3 d of age. There were no differences in feed consumption due to treatment in Experiment 1. In Experiment 2 (broiler chicks 6 to 11 d of age), added dietary fat resulted in differences in liver, body, and fecal excreta composition. Chicks given 7% added lard had lower liver fat throughout the trial than chicks fed no added lard. Additionally, these chicks had a higher body protein content at 6 and 7 d of age. However, body fat only increased in chicks fed 7% added lard by 11 d of age. Furthermore, chicks receiving 7% added lard had elevated fecal fat at Day 6, but did not consume more feed than chicks receiving 0 or 3% added lard. Additionally, chicks fed lard had lower liver weights than those fed 0% added lard.

Amount and Type of Dietary Fat Regulate Pancreatic Lipase Gene Expression in Rats

AbstractBoth amount and type of dietary triglycerides regulate pancreatic lipase, but the mechanism is not fully understood. This study investigated the effects of type (safflower oil and lard) and amount [low (50 g/kg diet) or moderate (174 g/kg diet)] of fat on rat pancreatic lipase (rPL) activity and mRNA levels. Polyunsaturated safflower oil resulted in 80% greater lipase activity compared with the saturated lard at moderate levels, whereas safflower oil resulted in 50% lower lipase activity compared with lard at low levels. The rPL-3 mRNA levels were greater in rats fed the moderate safflower oil diet (163%) or the moderate lard diet (212%) than in those fed the respective low fat diets and were 45% greater in those fed safflower oil than in those fed lard. The rPL-1 mRNA levels were greater in rats fed moderate safflower oil (50%) or lard (135%) than in those fed the respective low fat diet, but these levels were not affected by type of fat, in contrast to rPL-3 mRNA levels. The amount of fat independent of its type regulates pancreatic lipase pre-translationally, because increasing dietary saturated or polyunsaturated fat resulted in parallel changes in rPL-3 and rPL-1 mRNA levels. However, type of fat may regulate pancreatic lipase at other levels such as translational or post-translational, because the 212% increase in rPL-3 mRNA in rats fed the moderate lard diet compared with the low lard diet did not result in greater pancreatic lipase activity

Dietary fish oil-induced decrease in low density lipoprotein binding to fibroblasts is mediated by apolipoprotein E.

In a previous study we demonstrated that isocaloric substitution of fish oil (FO) for lard in the diet of cynomolgus monkeys resulted in low density lipoproteins (LDL) that were poorer competitors for binding of a standard 125I-labeled LDL and led to less cholesteryl ester accumulation in skin fibroblasts (Linga, V., et al. 1993. J. Lipid Res. 34: 769-778). The decreased binding and cholesteryl ester accumulation by FO LDL appeared related to the LDL apolipoprotein E (apoE) content. We hypothesized that FO LDL had reduced binding to skin fibroblasts due to a decrease in receptor active apoE. To test this hypothesis and determine the relative contribution of apoE versus apolipoprotein B (apoB) in binding of LDL to skin fibroblasts, LDL from cynomolgus monkeys fed lard or FO-containing diets were isolated, characterized, radioiodinated, and tested for binding in the absence or presence of a 10-fold molar excess of monoclonal antibody to the receptor binding domain of apoE (1D7) or apoB-100 (MB47). FO LDL were smaller, contained less apoE (E/B molar ratio = 0.48 +/- 0.03 vs. 1.85 +/- 0.22; P < 0.001), and had a weaker binding affinity (Kd = 11.3 +/- 1.6 vs. 3.8 +/- 0.80 microgram/ml; P < 0.01) compared to the lard counterparts. Furthermore, the apoE/B molar ratio of LDL appeared inversely related to the Kd for binding to skin fibroblasts. Incubation of LDL with skin fibroblasts in the presence of a 10-fold molar excess of monoclonal antibody directed at the receptor binding domain of apoB-100 (MB47) eliminated 96 +/- 3% of binding of FO LDL, but eliminated only 43 +/- 18% of binding for lard LDL. Incubation with a 10-fold molar excess of monoclonal antibody to the receptor-binding domain of apoE (1D7) eliminated only 23 +/- 6% of FO LDL binding to fibroblasts relative to a no-antibody control, but for lard LDL 44 +/- 11% of binding to fibroblasts was eliminated. Both antibodies together blocked all binding of LDL from both diet groups. In a fluid phase precipitation assay > 75% of the LDL particles from both diet groups was precipitated with saturating amounts of MB47, indicating that the proportion of LDL particles expressing this epitope was the same for both diet groups. The same assay using 1D7 showed approximately 4-fold greater precipitation of LDL in the lard versus FO group.(ABSTRACT TRUNCATED AT 400 WORDS)