Biomedical subjects

D L Palmquist

Publications and source records attributed to D L Palmquist.

3 recordsLinked to original sources

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↗

PubMed1976

A kinetic concepto of lipid transport in ruminants.

Summarization of the literature shows a strong correlation between dietary fatty acid intake and total lipid concentration in plasma in lactating cows whereas total milk fat secreted is related to neither of these. In the process of plasma triglyceride removal, chylomicra and very low density lipoproteins are converted to low density lipoproteins. Limited kinetic data indicate that the fractional removal rates for chulomicra and very low density lipoproteins are rapid in lactating cows whereas fractional removal of low density lipoproteins is slower, resulting in accumulation of the latter in plasma. Under such conditions, low density lipoprotein concentrations of plasma would not be expected to reflect quantitatively the transfer of plasma triglyceride fatty acids to milk fat. Quantitative analysis or triglyceride fatty acid turnover in density less than 1.006 lipoproteins should delineate the role of plasma lipid transport in milk fat synthesis. High fat diets protected from rumen biohydrogenation have proven to be a useful approach in studying ruminant fat metabolism and may be used more extensively to elucidate the role of cholesterol in plasma lipid transport and the metabolism of essential fatty acids in ruminants.

Acetyl-CoA Carboxylase↗

PubMed1976

Polyunsaturated meat and dairy products in fat-modified food patterns for hyperlipidemia.

Polyunsaturated meat and dairy products were compared with their saturated counterparts to determine their usefulness in a fat-modified diet for hyperlipidemic persons and their spouses. These polyunsaturated animal products were produced by feeding cattle a supplement of oil droplets coated with denatured protein. As a result, the polyunsaturated fatty acid content was 27 to 28 per cent of the meat fat and butterfat; saturated fatty acids (C12:0 to tc16:0) were 18 to 19 per cent. Of the eleven free-living subjects three were normocholesteremic, three had type IIa hyperlipidemia and five had type VI (IIb). In the fourteen-week study, an adjustment period of three weeks was followed by two consecutive experimental periods of four weeks each, then by a three-week follow-up period. During the adjustment period, participants continued to follow their usual eating patterns. During both experimental periods all followed the same prescribed fat modified food pattern using polyunsaturated margarine and oil. Five participants ate polyunsaturated beef and dairy products during the first experimental period and their saturated counterparts in the second; six participants ate saturated products first, then polyunsaturated. During the follow-up period, all participants selected all their own food. Serum cholesterol levels in five participants who had not previously followed a fat-modified diet were reduced by 18 per cent with polyunsaturated animal products and 11 per cent with saturated products. Serum cholesterol in six participants, previously on a fat-modified diet, was not significantly changed with polyunsaturated products. In ten of eleven participants, serum cholesterol levels were an average of 6 per cent lower with polyunsaturated products than with saturated products. It is concluded that polyunsaturated animal products are suitable for use in fat-modified food patterns for reducing hyperlipidemia, with some restrictions in the amount of polyunsaturated animal fat and with the inclusion of polyunsaturated oil and margarine.

Adult↗