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D E Jewell

Publications and source records attributed to D E Jewell.

At least 19 recordsLinked to original sources
PubMed2005

Dietary (n-3) fatty acids alter plasma fatty acids and leukotriene B synthesis by stimulated neutrophils from healthy geriatric Beagles.

The study objective was to determine the effect of feeding food enriched in (n-3) fatty acids (FA) on plasma FA profiles and leukotriene B (LTB) synthesis by stimulated peripheral blood neutrophils from dogs. For 36 weeks, two groups of dogs (n = 5) were fed food that contained either a low ratio of (n-6)-(n-3) FA (1.31:1; fish oil-enriched food) or a high ratio of (n - 6)-(n-3) FA (40.6:1; corn oil-enriched food). Consumption of food enriched in fish oil resulted in higher plasma concentrations of eicosapentaenoic acid and docosahexaenoic acid and lower concentrations of arachidonic acid. Neutrophils from dogs fed fish oil-enriched food produced 7.6-fold more LTB(5)(P = 0.002), and the ratio of LTB(5)-LTB(4) concentrations was 8.3-fold higher (P < 0.001) compared with dogs fed corn oil-enriched food. Dietary FA can modulate leukotriene production by neutrophils in dogs, and suggests that foods enriched in (n-3) FA from fish oil may have value in the treatment of canine inflammatory diseases.

Aging↗
PubMed2000

Dietary conjugated linoleic acid reduces rat adipose tissue cell size rather than cell number.

We investigated the basis for the reduction in fat pad size in rats fed conjugated linoleic acid (CLA). In the first study, growing female Sprague-Dawley rats (initial weight150 g) were fed diets containing 0, 0.25 and 0.5 g/100 g diet of a purified (97% CLA) and 0.5% of a feed-grade (55% CLA) source of CLA for 5 wk to determine the effects on growth performance and fat mass. There was no effect of CLA on growth rate or food intake. Dietary CLA reduced retroperitoneal fat pad weight 13, 25 and 32% in rats fed 0.25 and 0. 5% of the pure CLA and 0.5% of the feed-grade CLA, respectively (P < 0.05). Similar effects were observed in the parametrial fat pad. The reduced pad size was due to smaller adipocyte size rather than a reduced cell number. Relative to the control group, mean cell volume was 15, 28 and 29% lower in tissue from rats fed 0.25 and 0.5% of the pure CLA and 0.5% of the feed-grade CLA, respectively (P < 0.01). In the second study, rats were fed CLA (0 vs. 0.5%) for 7 or 49 d. Reductions in fat pad weight were observed within 7 d. In addition, the effects of CLA on energy metabolism were studied in the chronically fed rats. There were no significant effects of CLA on oxygen consumption, CO(2) or heat production. During wk 4 of feeding, but not at other times, there was a 5% lower respiratory quotient in CLA-fed rats (P < 0.05). There was a time-dependent accumulation of CLA in adipose tissue and a decrease in monounsaturated fatty acids. These results suggest that the reduction in fat mass in rats fed CLA can be accounted for by a reduction in cell size rather than a change in cell number.

Adipose Tissue↗
PubMed1999

Conjugated linoleic acid inhibits differentiation of pre- and post- confluent 3T3-L1 preadipocytes but inhibits cell proliferation only in preconfluent cells.

Conjugated linoleic acid (CLA; 18:2) is a group of isomers (mainly 9-cis, 11-trans and 10-trans, 12-cis) of linoleic acid. CLA is the product of rumen fermentation and can be found in the milk and muscle of ruminants. Animals fed CLA have a lower body fat content. The objective of this study was to establish the possible mechanisms by which CLA affects adipogenesis. 3T3-L1 is a well-established cell line that is used extensively in studying adipocyte biology. These cells typically grow in a culture medium until they reach confluence, at which time they are induced to differentiate by hormonal treatment (d 0). Treatment of 3T3-L1 cells with 25 to 100 micromol/L CLA inhibited differentiation in a dose-dependent manner, while linoleic acid treatment did not differ from DMSO-treated controls. Continuous treatment from d -2, -1, 0 or 2 to d 8 and treatment from d -2 to d 0 and from d 0 to d 2 inhibited differentiation. Differentiation was monitored morphologically (oil Red-O staining), enzymatically (reduction of activity of glycerol-3-phosphate dehydrogenase), and by northern analysis of peroxisome proliferator-activated receptor gamma2, CCAAT/enhancer binding protein alpha and adipocyte specific protein 2 mRNA. CLA inhibited cell proliferation of nonconfluent cells but did not affect cell division of confluent cells, as indicated by 5-bromo-2'-deoxyuridine incorporation and mitochondria metabolism. Therefore, CLA inhibited differentiation before confluence and during induction. However, cellular proliferation was only inhibited prior to induction. These results imply that fat reduction caused by CLA treatment may be attributed to its inhibition of both proliferation and differentiation of preadipocytes in animals.

3T3 Cells↗
PubMed1999

Effect of dietary n-6-to-n-3 fatty acid ratio on complete blood and total white blood cell counts, and T-cell subpopulations in aged dogs.

OBJECTIVE: To determine effect of diets with variable n-6-to-n-3 fatty acid (FA) ratio on CD4+ and CD8+ T-lymphocyte subpopulations, and on results of routine laboratory analyses (CBC and total WBC count, serum biochemical analyses, and urinalysis). ANIMALS: 20 healthy, aged (9.5 to 11.5 years old) female Beagles. PROCEDURE: Dogs were fed 1 of 3 diets that contained 6% fat by weight but differed in amounts of n-6 and n-3 FA. For 11 weeks, 6 dogs were fed a low concentration of n-3 FA (ratio, 31:1), 7 were fed a medium concentration (5.4:1), and 7 were fed a high concentration (1.4:1). Preprandial blood and urine samples were collected before beginning the study and at 8 weeks for evaluation of laboratory variables. Before and at 3, 6, and 8 weeks during the study, blood was drawn for total WBC and lymphocyte counts and for characterization of T-cell subpopulations. At 8 and 10 weeks, dogs were vaccinated with keyhole limpet hemocyanin suspension. Blood was drawn 4 days after each vaccination, and lymphocytes were isolated for flow cytometry. Effects of diet and vaccination on each variable were determined. RESULTS: After vaccination, total lymphocyte count increased and CD4+ T lymphocyte count and the CD4(+)-to-CD8+ ratio decreased in dogs consuming the diet with n-6-to-n-3 FA ratio of 1.4:1. CONCLUSION: Feeding a diet with n-6-to-n-3 FA ratio of 1.4:1 had significant effects on CD4+ T lymphocytes in healthy, aged Beagles after vaccination.

Aging↗
PubMed1997

Nutritional modification of inflammatory diseases.

Regulation of the immune system is extremely complex. We are only starting to understand how the immune system coordinates the body's response to a disease or invading pathogen. Immunomodulation, as the term implies, can be used to designate either a suppression or an augmentation of an immune response. Suppressing the function of the immune system may be important in cases of inflammation and augmenting the immune response when increased resistance to disease is required. Nutrition does and can play an important role in modulation of the animal's immune system. The majority of scientific literature published on the interaction of nutrition and the immune system correlates the effects of nutrient deficiency and modulation of an immune response. These studies have evaluated deficiencies of protein; energy; the fat soluble vitamins A, D, and E; the B-complex vitamins; vitamin C; and the minerals selenium, iron, zinc, and copper and their relationship to immune dysfunction. Most recently, researchers have concentrated efforts on evaluating the impact specific fatty acids have on modulation of the immune system. Undoubtedly, the nutritional status of the animal plays an important role in resistance mechanisms against disease causing organisms and may influence the outcome of disease in infected animals. The focus of this chapter is to concentrate on the role specific polyunsaturated fatty acids have on the immune response of animals and to consider the potential for nutritional modification of diseases related to inflammation.

Adjuvants, Immunologic↗
PubMed1997

The ratio of dietary (n-6) to (n-3) fatty acids influences immune system function, eicosanoid metabolism, lipid peroxidation and vitamin E status in aged dogs.

We studied the effects of feeding experimental diets containing (n-6) to (n-3) fatty acid ratios of 31:1, 5.4:1, and 1.4:1 to 20 healthy female geriatric Beagles (9.5-11.5 y) for 8-12 wk on various indices of the immune response. Compared with the 31:1 diet, consumption of the 5.4:1 and 1.4:1 diets significantly increased (n-3) fatty acids in plasma (2.17 +/- 0.64, 9.05 +/- 0.64, 17.46 +/- 0.64 g/100 g fatty acids, respectively, P < 0.0001). Although supplementation with (n-3) fatty acids did not significantly alter the humoral immune response to keyhole limpet hemocyanin (KLH), it significantly suppressed the cell-mediated immune response based on results of a delayed-type hypersensitivity (DTH) skin test. The DTH response after intradermal injection of KLH at 24 h was significantly lower in the group consuming the 1.4:1 diet compared with the group consuming the 5.4:1 (P = 0.02) or the 31:1 diets (P = 0.04), and remained significantly suppressed at 48 h in the group fed 1.4:1 relative to the group fed 31:1. After consumption of the 1.4:1 diet, stimulated mononuclear cells produced 52% less prostaglandin E2 (PGE2) than those from dogs fed the 31:1 diet (224 +/- 74 and 451 +/- 71 pmol/L, respectively, P = 0.04). Plasma concentration of alpha-tocopherol was 20% lower in dogs fed the 1.4:1 diet compared with those fed the 31:1 diet (P = 0.04), and lipid peroxidation was greater in both plasma (P = 0.03) and urine (P = 0.002). These data suggest that although a ratio of dietary (n-6) to (n-3) fatty acids of 1.4:1 depresses the cell-mediated immune response and PGE2 production, it increases lipid peroxidation and lowers vitamin E concentration.

Aging↗
PubMed1996

Effect of supplemental pig milk replacer on litter performance: seasonal variation in response.

The objective of this study was to determine the effect of supplemental milk replacer on sow and litter performance. The study was conducted in 12 farrowing groups (171 litters) over a 3.5-yr period (October 1990 to April 1994). Commercial milk replacer was prepared fresh daily (150 g/L) and offered with ad libitum access in the farrowing crates within 24 h of parturition and was continued through weaning (d 21). Average pig weight (control, 5.5 kg/pig; supplemented, 6.4 kg/pig; P < .001) and total litter weight (control, 52.2 kg/litter; supplemented, 60.9 kg/litter; P < .001) at weaning were greater for litters receiving supplemental milk replacer. There was no effect (P > .2) of supplemental milk replacer on feed intake, backfat thickness, or body weight loss in the sow. Consumption of milk replacer varied greatly among litters. A portion of this variation in intake was accounted for by differences in ambient temperature among farrowing groups. Average milk replacer intakes (liters per pig) from birth to d 21 were 2.5 L/pig (.375 kg dry matter) and 9.9 L/pig (1.49 kg dry matter) for pigs born during the cool and warm seasons, respectively (P < .001). The weaning weight advantage conferred by milk replacer was most evident during the warmer months. Sow feed intakes averaged 5.8 and 3.9 kg/d over the same periods (P < .001). These results demonstrate the advantage of milk replacer on weaning weight and indicate that the greatest benefit from the supplement is during the warmer months when sow feed intake and subsequent milk production are lower.

Animals↗
PubMed1995

Diet-dependent and diet-independent metabolic responses underlie growth stasis of pigs at weaning.

The weaning transition in domestic animals involves profound environmental and nutritional changes. Growth stasis is commonly observed in pigs during this period, resulting in significant losses to the swine industry. It has been suggested that the reduced growth rate reflects immune sensitivity to soy antigens in commercial diets; however, few studies have defined metabolic responses in pigs weaned to diets containing soybean meal. The impact of environmental and social changes at weaning on physiological functions, i.e., the metabolic adjustment to new nutritional substrates, has also been overlooked. Accordingly, the aim of this study was to distinguish diet-dependent and diet-independent metabolic responses in pigs weaned to a commercially available corn-soy diet. Focus was on the endocrine pancreas and cytokines associated with stress responses. Three-week-old crossbred pigs were weaned to a corn-soy (cereal) or a milk-based (milk) diet. Blood samples taken 0 (weaning), 1, 2, 5 and 7 d post-weaning demonstrated diet-independent responses including increased (P < 0.05) plasma glucagon concentrations, decreased (P < 0.05) glucose concentrations, increased (P < 0.05) interleukin-1 (IL-1) concentrations during the first 2 d post-weaning, and increased (P < 0.05) fibrinogen concentrations during the latter part of the study. In response to dietary treatment, milk-fed pigs had higher (P < 0.05) plasma insulin and glucose concentrations, reflective of higher food intake during the early post-weaning period. This clear distinction between diet-dependent and diet-independent metabolic responses at weaning suggests consideration of novel strategies to overcome the characteristic weanling growth stasis in pigs.

Animals↗
PubMed1992

Effect of feeding finishing pigs extruded full-fat soybeans on performance and pork quality.

This experiment was designed to test whether changing the type and amount of added dietary fat would affect performance or meat quality. Dietary fat was added as tallow or extruded full-fat soybeans (FFS). Isoenergetic diets containing 10% FFS, 20% FFS, or 4% tallow were fed for 3 or 6 wk before slaughther. A conventional corn-soybean meal diet served as a no-added-fat control. Each of the seven dietary groups contained 20 pigs, equally distributed among four pens, with barrows and gilts segregated. Significance of treatment, sex, and interaction effects were evaluated for 34 meat quality, composition, and sensory evaluation traits. Treatment x sex interactions were not detected (P greater than .05). Treatment main effects were detected for percentage of fat and water in the bacon and for lipid oxidation in bacon and the longissimus muscle. The 6 df for treatment were partitioned into six contrasts to test for the trends within and between diets. A trend toward reduced fat and increased moisture in bacon was detected in the 10% FFS diet over time (P less than .05). In general, lipid oxidation of bacon and longissimus muscle increased with level of FFS in the diet, length of time on the diet, and storage time of the meat. Although statistically significant, the magnitude of these effects was small and did not affect the sensory characteristics of longissimus muscle samples. It was concluded that short-term feeding of FFS before slaughter did not adversely affect animal growth or meat quality.

Adipose Tissue↗
PubMed1992

Characterization of lipid in loin and bacon from finishing pigs fed full-fat soybeans or tallow.

This experiment tested whether the lipid composition of pork could be altered by changes in dietary lipid, that what effects these changes would have on production and meat characteristics. Pigs were fed diets containing 10 or 20%+ extruded full-fat soybeans (FFS) or 4% tallow for a 3- or 6-wk finishing period, with a corn-soybean meal diet fed as a control. Seventy barrows and 70 gilts were allotted into seven treatment groups with four pens per group. Analysis was on 28 experimental units, which were composite samples from pens. The significance of treatment, sex, and treatment x sex interaction F-statistics was evaluated on chloroform-methanol extractable total lipid, triacylglycerol, phospholipids, cholesterol, individually fatty acids (FA), and the major classes of FA obtained from longissimus muscle and bacon. Treatment effects (P less than .05) were detected for cholesterol content of longissimus and for total lipid and phospholipid content of bacon. Treatment effects (P less than .01) were detected for monoenoic, dienoic, and polyenoic (P) FA in both tissues, and for saturated (S) FA in bacon (P less than .05). Treatment effects (P less than .001) were detected in both tissues for the P:S ratio. The P:S ratio increased 54% for longissimus and 100% for bacon in the pigs fed FFS for 6 wk compared with pigs consuming a corn-soybean meal diet.

Adipose Tissue↗
PubMed1989

Fetal hypophysectomy causes a decrease in preadipocyte growth and insulin like growth factor-1 in pigs.

Fetal pigs in one uterine horn of each of five gilts were hypophysectomized (HX) in utero by electrical cauterization at 72-74 days of gestation and sera collected at 110 days of gestation. Sera from HX fetuses had lower levels of insulin-like growth factor-1 compared to control littermates (P less than .05). Sera were tested for their effects on primary cultures of stromal-vascular cells from adipose tissue. The soluble protein concentration/dish was lower when pig cells were cultured in sera from HX fetuses compared to sera from control fetuses (P less than .01). Sera from HX fetuses inadequately supported growth of stromal-vascular cells so subsequent experiments utilized pooled sera from normal and HX adult pigs. Sera from HX and control fetuses were mixed with sera from the two adult pools and tested for incorporation of tritiated thymidine into rat preadipocytes and the appearance of adipocytes (determined histochemically) in pig stromal-vascular cultures. In cultures fed sera from HX fetuses there was a lower (P less than .05) number of pig fat cells/culture and a lower level (P less than .06) of preadipocyte proliferation in rat cell cultures when compared to control fetal sera. Fetal pig serum contains factors (adipogenic) which promote the proliferation and differentiation of adipocytes in culture. Serum from HX fetuses has a lower level of adipogenic factors.

Adipose Tissue↗
PubMed1988

Effect of sera from control and overfed rats on preadipocyte growth in culture.

Increased body lipid was induced in 4-wk-old rats through oral gavage. Rats were either fed ad libitum, tube-fed 100% or tube-fed 150% of the ad libitum intake. After 1 wk of tube-feeding animals were killed and sera collected. Sera were used to support the growth of rat stromal-vascular cells in culture. Sera were also analyzed for growth hormone and insulin concentrations. In rats that were tube-fed, levels of adiposity were greater but sera from these rats decreased stromal-vascular and preadipocyte proliferation in culture when compared with sera from ad libitum-fed rats. Sera from tube-fed animals promoted an increase in preadipocyte differentiation as revealed by esterase staining. Results indicate that overfeeding in juvenile rats causes sera changes that support fat cell differentiation but not fat cell hyperplasia.

Adipose Tissue↗
PubMed1988

Sera from pigs infected with Sarcocystis suicanis and cachectin decrease preadipocyte differentiation in primary cell culture.

The macrophage-secreted hormone cachectin depressed lipoprotein lipase activity and lipogenic enzymes in adipose cells. Cachectin reduced differentiation of preadipocytes in cultures of stromal-vascular cells from rat adipose tissue. Differentiation was measured by two methods of estimating lipid accumulation. Adipocytes were separated from the stromal-vascular cells by centrifugation and staining (oil red 0) for intracellular lipid. Lipolytic activity was measured by using esterase histochemistry. Sera from pigs that were infected with Sarcocystis suicanis showed cachectin-like activity compared with sera collected from the same animals before infection. Cachectin and sera collected from infected animals specifically decreased fat cell number without decreasing the stromal-vascular cell number.

Adipose Tissue↗
PubMed1988

The effect of insulin on primary cultures of rat preadipocytes grown in fetal or postnatal pig serum.

Stromal vascular cell cultures, prepared from the inguinal pads of 50-g Sprague Dawley rats, were exposed to media with 10% fetal pig serum which is inherently low in insulin, for the first 3 to 5 d of culture. Insulin was supplemented to media for periods of 2 to 6 d. In cultures treated (2 to 4 d) with 10(-9), to 10(-10) or 10(-11) M insulin, differentiated cells (lipid and esterase staining) appeared 1.5 to 2 times wider than differentiated cells in control cultures. At 10(-9) M insulin (4 to 5 d), in cultures grown in the presence of fetal pig serum the number of esterase reactive cells was increased twofold to threefold. The percentage of total cells that were esterase reactive was elevated 50 to 300% relative to control cultures. Insulin-treated preadipocytes were more reactive for lipoprotein lipase activity (histochemical assay) compared with reactivity of control cells. Quantitative analysis of percentage of light transmittance (Zeiss photometer) through stained cells indicated an increase (P less than .001) in lipoprotein lipase staining at 10(-9), 10(-11) and 10(-13) M insulin (2 d). The specific activity of glycerol phosphate dehydrogenase was elevated twofold to threefold (P less than .05) and soluble protein elevated 50 to 100% (P less than .05) in cultures treated (3 to 6 d) with 10(-9) M insulin. Decreasing the cell plating density (50%) in cultures grown in the presence of pig serum reduced the elevation in enzyme activity induced by insulin in preadipocyte cultures. Physiological levels of insulin enhanced lipogenic enzyme activity in preadipocytes and may enhance the conversion of stromal cells to preadipocytes.

Adipose Tissue↗
PubMed1988

Sera-controlled preadipocyte growth in culture: an ontogeny study with sera from lean and obese pigs.

Genetically lean and obese swine were used to investigate the control of preadipocyte growth in culture by porcine serum. Sera were collected from fetuses from obese and lean strains at 70, 90 and 110 d of gestation. Postnatal serum samples were collected from both lines of pigs at 23 to 27 kg. Rat preadipocytes were isolated and grown in culture. Preadipocyte and stromal-vascular cell proliferation was greater in cultures grown in sera obtained postnatally than in cultures grown in sera from fetuses. Sera from lean and obese fetuses were equipotent in promoting cell proliferation. Glycerol-phosphate dehydrogenase (GPDH) activity was higher in cultures fed serum from obese pigs and fetuses than in cultures fed serum from lean pigs and fetuses. Cultures grown in serum from obese fetuses and pigs had soluble protein levels similar to cultures grown with serum from lean pigs and fetuses. These results demonstrate that serum from genetically obese swine, in the pre-obese (fetal) and obese (postnatal) state, caused increased adipogenic activity in adipocytes in culture.

Adipose Tissue↗
PubMed1983

The biotin status of weanling pigs fed semipurified diets as evaluated by plasma and hepatic parameters.

Twenty-four pigs were weaned at four weeks of age and fed either spray dried egg albumen (DA) or autoclaved DA (ADA) as the only protein source were used to evaluate plasma and hepatic parameters as indicators of biotin status. Pigs were fed one of four semipurified diets during the 42-day study: DA basal, DA + 1.1 g sulfamethazine/day (DA + S), ADA basal or ADA + .5 mg biotin/day (ADA + H). Autoclaving DA at 121 degrees C for 30 minutes reduced both the biotin binding properties of the avidin fraction and the trypsin inhibitor activity of DA. Pigs fed ADA and ADA + H had greater (P less than .05) liver pyruvate carboxylase (EC 6.4.1.1) activity and DNA concentrations, lower (P less than .05) plasma urea nitrogen levels and greater and more efficient (P less than .05) weight gain than either DA or DA + S fed pigs. Biotin supplementation further enhanced (P less than .05) liver DNA concentration but had no effect on the liver levels of RNA or total protein. Plasma levels of glucose and free fatty acids or blood levels of lactate and pyruvate were not influenced by the addition of biotin to the ADA basal diet.

Animals↗