Search PubMed⌕ Search

Biomedical subjects

D L Palmquist

Publications and source records attributed to D L Palmquist.

At least 55 records · Page 3Linked to original sources
PubMed1987

Effect of dietary fat and lactation status on insulin binding to bovine milk fat globule membranes.

Lactating cows were used to examine the relationship between lactation status and insulin binding to milk fat globule membranes. Variables evaluated were daily milk yield, stage of lactation, breed, age, lactation number, daily milk fat and protein yields, milk fat and protein percentages, breeding status, body weight, body weight.75, and mammary health. Milk yield was correlated with insulin binding and accounted for 20% of the binding variability. No other variables were related to insulin binding. Insulin binding to milk fat globule membranes increased with supplemental dietary fat up to 4% added fat in the diet dry matter. Milk fat globule membranes may provide a useful model for assessing insulin receptor regulation in the mammary gland. Sources of variation in insulin binding to mammary membranes remain to be identified.

Animals↗
PubMed1987

Rumen and total diet digestibilities in lactating cows fed diets containing full-fat rapeseed.

Effects of full-fat crushed rapeseed (0, 1, or 2 kg/d) on rumen and total digestion, rumen biohydrogenation, and rumen microbial protein synthesis were studied in lactating cows. Rumen digestibilities (%) of DM, NDF, and cellulose were 52.1, 46.1, and 51.8, respectively, for control. Rapeseed decreased rumen and total DM digestibilities and proportion of DM digested in the rumen. Rumen digestibility of cellulose was decreased by rapeseed, but this was apparently compensated by hindgut fermentation. Dry matter, NDF, and hemicellulose digestibilities were compensated at 1 kg but not at 2 kg/d. Biohydrogenation of 18:1 fatty acids increased with increasing dietary fat, whereas that of 18:2 and 18:3 was 85% on all diets. Fatty acid digestibility was not different among diets. Microbial nitrogen in the duodenum increased from 142 g/d for control to 191 g/d for 1 and 2 kg/d. Efficiency of microbial protein synthesis (grams of microbial nitrogen per kilogram organic matter apparently digested in the rumen) was 17.3, 24.8, and 26.6 for 0, 1, and 2 kg/d. Slow release of fat from crushed rapeseed minimized negative effects on rumen metabolism; 1 to 2 kg/d of full-fat crushed rapeseed may be fed to lactating cows without detrimental metabolic effects.

Animals↗
PubMed1987

Selenium content of foods purchased or produced in Ohio.

Approximately 450 samples of about 100 types of foods consumed by rural and urban Ohioans were analyzed for selenium. Meat, dairy products, eggs, and grain products produced in Ohio have considerably lower selenium content than corresponding products produced in high selenium areas, such as South Dakota. Retail Ohio foods with interregional distribution tended to be higher in selenium content than corresponding foods produced in Ohio. Best sources of selenium in Ohio foods commonly consumed were meat and pasta products. Poor sources of selenium were fruits, most vegetables, candies, sweeteners, and alcoholic and nonalcoholic beverages. Establishment of an accurate data base for selenium depends on knowledge of the interregional distribution of foods, the selenium content of foods at their production site, and the selenium content of foods with wide local distribution.

Food Analysis↗
PubMed1986

Characterization of insulin binding to bovine liver and mammary microsomes.

Bovine liver and mammary gland (MG) appear metabolically independent of insulin, yet the specificity and kinetics of 125I-insulin (125I-INS) binding to bovine liver and MG microsomes (MIC) indicate the presence of insulin receptors in MIC from both tissues. The insulin receptors from bovine liver (Kd = 7.6 X 10(-10) M) and MG (Kd = 9.6 X 10(-11) M) were similar to each other and to other insulin receptors in their binding affinities and pH optima. Perturbation of rat liver and bovine MG MIC by phospholipase or NaCl treatment increased 125I-INS binding to the membranes, suggesting exposure of cryptic insulin receptors. Different responses in 125I-INS binding to membrane perturbation suggest differences between rat and bovine membranes.

Animals↗
PubMed1986

Effect of dietary fat and calcium source on insoluble soap formation in the rumen.

Diets with and without added fat and with different amounts of soluble and insoluble calcium were fed to rumencannulated cows to determine roles of fat and calcium in formation of insoluble calcium soaps in the rumen. Percent of total fatty acids in soap was increased only by addition of soluble calcium (CaCl2). The amount of fatty acid in soap was highly dependent on amount of fat in the rumen and was not changed by calcium addition. Concentration of ionized calcium in rumen content was halved by fat addition and was inversely correlated with rumen pH, whereas proportion of fatty acid in soap was directly related to pH. Rumen pH was lower 8 to 12 h postfeeding when calcium was added to the diet, which was related nonsignificantly with total volatile fatty acid concentration. Addition of fat to diets tended to lower the ratio of acetic to propionic acids in the rumen; this trend was reversed by calcium addition. Beneficial effects of added calcium in high fat diets were not caused by increased calcium soap formation in the rumen.

Animal Feed↗
PubMed1986

Ruminal fermentation in vivo as influenced by long-chain fatty acids.

Responses of ruminal microbes to long-chain fatty acids in forms of free acids, calcium salts, or triglycerides were measured in trials with rumen cannulated heifers. Addition of fatty acids at 10% to a basal diet of 50% corn silage and 50% grain increased fat content 3 to 10 to 12%. Long-chain fatty acids with a high melting point (stearic acid) and calcium salts of long-chain fatty acids (vegetable fat and tallow) decreased acetate:propionate by about 20%. Long-chain fatty acids with a low melting point (oleic acid) and the triglyceride form of long-chain fatty acid (tallow) decreased acetate to propionate ratio by 50 to 60%. Even though they were not completely inert in the rumen, responses with the hard long-chain fatty acids (stearic acid) and with calcium salts of long-chain fatty acids confirm that these are efficacious for protecting ruminal microbes from adverse effects of fat. With calcium salts of long-chain fatty acids, dietary buffers may be needed to maintain ruminal pH so that dissociation of salts does not occur. Long-chain fatty acid supplementation at 10% of the diet is probably more than the amount needed to optimize productivity and health. With most diets, 6 to 8% supplemental long-chain fatty acid is probably sufficient.

Animals↗
PubMed1984

Effect of fatty acids or calcium soaps on rumen and total nutrient digestibility of dairy rations.

Two trials ascertained whether feeding fatty acids as preformed calcium soaps would permit normal digestibility of fiber without reducing availabilities of fatty acids or energy. Six diets contained no added fat (control) or the equivalent of 4.5% added fatty acids as tallow or soy fatty acids, tallow or soy calcium soaps, or tallow combined with the nonnutritive carrier verxite. Six cows were fed each diet in trial 1 to ascertain digestibilities of total nutrients, whereas control, tallow fatty acid, and tallow soap diets were fed to steers with duodenal cannulae in trial 2 to evaluate effects of fat source on rumen fermentation. Digestibility of total fiber in trial 1 was reduced 13% by tallow fatty acids. In trial 2, tallow fatty acids markedly reduced digestibility of dry matter and fiber in the rumen. Diets supplemented with tallow calcium soaps had normal digestibilities of fiber in the rumen and totally, but digestibility of fatty acids was reduced 6% and digestibility of energy reduced 3% compared to feeding tallow fatty acids. Efficiency of synthesis of microbial protein was 39% higher for tallow fatty acids than for control. Feeding tallow verxite also permitted normal digestibility of fiber in trial 1 but caused reduced availabilities of fatty acids and energy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Selenium status of a rural (predominantly Amish) community living in a low-selenium area.

Selenium intake and blood selenium and selenium-dependent glutathione peroxidase concentrations were assessed in a rural, 71% Amish, sample of residents in a region with low availability of soil selenium and in urban (Columbus, OH) residents. Subjects were interviewed (24-h dietary recalls) on three separate occasions over an 18-month period, and blood and food samples were taken for analysis (maximum subject observations = 452). Mean selenium intake of the entire population was 82.8 +/- 4.4 micrograms/day. Rural and urban residents at 82.0 +/- 4.9 and 83.6 +/- 4.4 micrograms/day, respectively, did not differ significantly in intake. A breakdown by gender within location demonstrated that rural males consumed the most selenium (104.7 +/- 6.1 micrograms/day) and rural females the least (59.3 +/- 6.3 micrograms/day). Rural subject groups had significantly lower mean whole blood, plasma, and erythrocyte selenium levels (12.5 to 14.5%) as well as blood selenium-dependent glutathione peroxidase concentrations (5.6 to 10.8%) than urban groups. Subjects in both cohorts were in adequate selenium status as judged by blood parameters, even though about one-fourth of the dietary observations were below the safe and adequate range of selenium intake established by the Food and Nutrition Board. The rural diet was 18.3% lower in selenium density than the urban diet. High selenium grain products (greater than 0.2 micrograms/g) were the most important dietary selenium source in both groups, providing 29.3 to 41.6% of total intake.

Adolescent↗
PubMed1983

Vitamin E supplementation of high fat diets for dairy cows.

High fat diets +/- 1 g alpha-tocopheryl acetate per head per day were fed to 28 cows for 4 mo to determine whether dietary fat increases dietary requirement for vitamin E. Tocopherol supplementation did not affect milk production or composition. After 4 mo there was no difference between treatment groups for oxidative stability (thiobarbituric acid test) of milk stored for 5 days with .1 ppm added copper, but milk of supplemented cows was more stable when 1 ppm copper was added. Oxidative stability was normal in the unsupplemented group. Tocopherol concentration of blood plasma increased and selenium concentration decreased with tocopherol supplementation; activity of glutathione peroxidase was lower in plasma, whole blood, and erythrocytes of the supplemented group. Tissue integrity was unchanged by tocopherol supplementation, as estimated by erythrocyte hemolytic resistance and activities of lactic dehydrogenase and glutamic oxalacetic transaminase in blood serum. Clearance of bromosulphthalein from blood plasma was less for cows fed fat and supplemented with tocopherol than for control cows fed neither fat nor vitamin E. No indication of impaired vitamin E status was observed when 4% stabilized fat was added to the diet.

Animals↗
PubMed1982

Incorporation of [hydrogen-3] alkylglycerolether and [carbon-14] hexadecanol into bovine colostrum and milk lipids.

[Hydrogen-3] glycerol ether and [carbon-14] hexadecanol were infused into the mammary gland or jugular vein of cows in colostral or full phases of lactation to determine their relative rates of synthesis and degradation. Neutral alkylglycerols were both synthesized and cleaved in the bovine gland. Oxidation of fatty alcohols and cleaving of neutral alkylglycerol ethers was faster during the milk than the colostral phase of lactation. In the colostral phase, both increased rate of synthesis and decreased cleavage contributed to increased neutral alkylglycerol concentration; however, synthesis changes were greater. Disappearance of [carbon-14] fatty alcohol and [hydrogen-3] alkylglycerol ether from the blood was the magnitude of fatty acid disappearance in previous studies, but uptake by the mammary gland was slower. Alkylglycerols were taken up from the blood and secreted intact into both colostrum and milk.

Animals↗
PubMed1981

Effects of long-chain Fatty acids on growth of rumen bacteria.

The effects of low concentrations of long-chain fatty acids (palmitic, stearic, oleic, and vaccenic) on the growth of seven species (13 strains) of rumen bacteria were investigated. Except for Bacteroides ruminicola and several strains of Butyrivibrio fibrisolvens, bacterial growth was not greatly affected by either palmitic or stearic acids. In contrast, growth of Selenomonas ruminantium, B. ruminicola, and one strain of B. fibrisolvens was stimulated by oleic acid, whereas the cellulolytic species were markedly inhibited by this acid. Vaccenic acid (trans Delta11 18:1) had far less inhibitory effect on the cellulolytic species than oleic acid (cis Delta9 18:1). Inclusion of powdered cellulose in the medium appeared to reverse both inhibitory and stimulatory effects of added fatty acids. However, there was little carry-over effect observed when cells were transferred from a medium with fatty acids to one without. Considerable variation in response to added fatty acids was noted among five strains of B. fibrisolvens. In general, exogenous long-chain fatty acids appear to have little, if any, energy-sparing effect on the growth of rumen bacteria.

Journal Article↗
PubMed1981

Dietary fat effects on blood insulin, glucose utilization, and milk protein content of lactating cows.

Relationships among dietary fat, glucose and insulin in blood plasma, and milk protein were investigated to determine mechanisms by which high fat diets depress milk protein percentage of lactating cows. Glucose clearance, determined by intravenous glucose infusion tolerance tests, of cows fed high fat diets was lower and insulin release higher than of control cows. Negative relationship between glucose utilization rate and insulin release was linear (correlation -.85), suggesting that fat feeding induced insulin resistance. Feeding lipid in a protected supplement did not change production of milk or milk protein but depressed milk protein percentage and increased quantity and concentration of milk fat. Concentrations of total lipids in blood plasma were increased whereas glucose and insulin were reduced by protected lipid supplement. Dietary fat may impair amino acid transport into the mammary gland and milk protein synthesis by inducing insulin resistance.

Animals↗
PubMed1980

Fat in lactation rations: review.

Recent research has demonstrated the effectiveness of added fat in diets to maintain milk production and fat percent. Much of the earlier work which indicated that fat affects digestion negatively may not be applicable because of great differences in the nature of diets and fats fed and especially in total feed intake. Nevertheless, much remains to be learned about interactions of fat, fiber, calcium, and rumen microorganisms if feeding of fat is to be maximized. The uniquely high acidity in the duodenum combined with detergent action of bile acids, lysolecithin, and fatty acids causes saturated fatty acids to be more digestible in ruminants than in nonruminants. Large quantities of added dietary fat increase concentrations in plasma of very low density lipoprotein triglyceride which increases their uptake by the mammary gland with inhibition of short chain fatty acid synthesis and consequent changes in milk fatty acid composition. In some cases, secretion of milk fat is increased. Current research and practice demonstrate that 3 to 5% fat may be added to diets for lactation to increase energy intake of high-producing cows and/or to reduce starch feeding, thereby increasing the ratio of forage to concentrate to prevent depression of milk fat.

Animal Feed↗
PubMed1980

High fat rations dairy cows, tallow and hydrolyzed blended fat at two intakes.

Tallow and blended animal-vegetable fat were mixed as 10% of diet concentrate and compared with a concentrate containing no added fat. Concentrate containing fat was fed at two percents of diet dry matter, 50% (supraenergetic) and 33% (isoenergetic). The dry matter of the control diet was 50% concentrate. Isoenergetic high fat diets contained more fiber than control or supraenergetic high fat diets. Change of body weight and intake of feed dry matter were not different among feed groups. Milk and 4% fat-corrected milk production were less when high tallow was fed. Milk fat percent was lowest on the high concentrate diet, intermediate with high grain-high fat feeding, and normal with high fat isoenergetic rations. Multiple regression analysis of digestibility data showed that fat did not influence diet digestibility negatively and that calcium positively influenced digestibility of all diet components.

Animal Nutritional Physiological Phenomena↗
PubMed1977

Absence of eicosatrienoic acid in plasma of sheep parenterally infused with a high glucose fat-free solution.

Five yearling wether sheep were maintained on total intravenous, fat-free feeding for periods in excess of 4 weeks. Analysis of plasma total lipid, neutral lipid, and phospholipid fatty acid patterns showed a decrease in linoleic acid during the first week, after which levels tended to stabilize. Rate of decrease in linoleic acid content of plasma phospholipids of two sheep was different. Changes in nonessential fatty acids were variable. 5,8,11- and 8,11,14-Eicosatrienoic acids were not detected in any of the sheep.

8,11,14-Eicosatrienoic Acid↗
PubMed1977

Re-evaluation of effects of meal feeding on lipogenic activation by glucose in rats.

Based upon analyses of epididymal fat pads, gorging rats have been reported to synthesize fatty acids from glucose carbon 200 times faster than nibbling rats. This contrasts with our earlier study in mice in which no such adaptation was found in gorgers. Three methods were used to re-evaluate lipogenesis from glucose carbon in fasted-refed nibbling and gorging rats. Two methods in which [U-14C]glucose was injected intraperitoneally before or after different test-meals confirmed an apparent 100- to 200-fold increase in lipogenesis (14C incorporation into fatty acids) in epididymal fat pads of gorgers; however, incorporation of 14C into total fatty acids in the whole body of gorgers was only five times greater than in nibblers. Quantitative tracer techniques (intravenous and oral [U-14C]-glucose) were used to evaluate glucose carbon flux (22-hour fasted) and lipogenic activation following the ingestion of a labeled glucose test-meal. Glucose carbon conversion to total fatty acids (whole rat) increased from 2.7 (24-hour fasted) to 11 microng C/minute/200 g body weight, a fourfold activation, within 15 minutes after feeding the test-meal to nibbling rats. The corresponding increase in gorging rats was from 3.7 to 53 micrgong C/minute/200 g body weight, a 14-fold activation. These data indicate a species difference exists between rats and mice during adaptation to a gorging food-intake pattern.

Adipose Tissue↗
PubMed1977

Biohydrogenation and availability of linoleic acid in lactating cows.

Linoleic acid biohydrogenation, absorption and availability for maintenance and milk production in dairy cows fed high grain (60--85% of dry matter) diets were quantitatively estimated by isotope dilution, using two methods of dosing. [1-14C]Linoleic acid-labeled chylomicra and very low density lipoproteins (VLDL) were obtained from lymph of a calf fed [1-14C]linoleic acid and fitted with a thoracic duct-venous shunt. Labeled chylomicra were injected intravenously into two cows: a Jersey (trial 1), and a Holstein (trial 2). Labeled VLDL was injected intravenously into a Holstein cow (trial 3). In trials 4 and 5 the [1-14C]linoleic acid was placed into the omasal canal of two rumen-fistulated Holstein cows. Linoleic acid biohydrogenation (%), absorption (g/day), and availability above requirements for milk production (mg/kg body wt 3/4) were: 68.1 +/- 2.28, 52.1 +/- 2.92, and 244 +/- 19.4 (mean +/- SE), respectively. The biohydrogenation data indicate that both methods of dosing the cows were equally dependable. The estimates of linoleic acid biohydrogenation are consistent with limited data previously reported, indicating that the isotope dilution technique used is a reliable method to estimate linoleic acid absorption in lactating cows. Linoleic acid available to the lactating cow above milk production requirements was more than double the requirement of weanling female rats, when compared on the basis of metabolis body size.

Animal Feed↗