The relationships between dietary fatty acids, plasma lipid composition and milk fat secretion in the cow
- 1 October 1969
- journal article
- Published by Cambridge University Press (CUP) in Journal of Dairy Research
- Vol. 36 (3) , 383-392
- https://doi.org/10.1017/s0022029900012899
Abstract
Summary The effects of the isocaloric replacement of starch in a low-fat concentrate mixture by either 5 or 10% ‘stearic acid’ (85% pure) or by 10% ‘palmitic acid’ (85% pure) on the composition of the plasma lipids were investigated in a feeding experiment with 12 cows in mid-lactation. The concentrate mixtures were given with a high roughage diet that supplied daily 4·4 kg of hay and 2·7 kg of sugar-beet pulp. A study was made of the relationships between the compositions of the plasma and milk lipids. The inclusion of 10% ‘stearic acid’ or 10% ‘palmitic acid’ in the concentrate mixture increased the concentration of total plasma fatty acids. Irrespective of dietary treatment, about 40% of the total plasma fatty acids occurred in the cholesteryl ester fraction, 54% in the phospholipid fraction, 3% in the triglyceride fraction and 3% in the unesterified fatty acid fraction. There was a positive curvilinear relationship between the concentration of unesterified fatty acids in the plasma and the yield of total milk fatty acids. In the plasma triglycerides, the concentrations of 16:0 and 16:1 were decreased and the concentration of 18:0 was increased when the concentrate mixture contained ‘stearic acid’; the concentration of 16:0 was increased and the concentrations of 18:0, 18:1 and 18:2 were decreased when the concentrate mixture contained ‘palmitic acid’. Similar changes were observed in the compositions of the plasma unesterified fatty acids when the cows were given the different diets. In the plasma cholesteryl esters, the concentration of 16:0 was decreased and the concentrations of 18:3 and 20:4 were increased when the concentrate mixture contained stearic acid; the concentrations of 16:1, 18:3 and 20:4 were increased and the concentration of 18:2 was decreased when the diet was supplemented with palmitic acid. The addition of stearic acid to the diet increased the concentration of 18:0, 18:1 and 18:3 in the plasma phospholipids but decreased the concentrations of 16:0, 18:2, 20:3 and 20:4. When the diet contained palmitic acid the concentrations of 16:0, 16:1, 18:1 and 18:3 in the plasma phospholipids were increased but the concentrations of 18:0, 18:2 and 20:3 were decreased. The major fatty acid circulating in the plasma of the cows was 18:2, which accounted for about 45% of the total plasma fatty acids. Only about 0·7% of the total plasma 18:2 occurred in the plasma triglycerides. The results are discussed in relation to the changes in the composition of the milk fatty acids produced by the cows when they were given the experimental diets.Keywords
This publication has 17 references indexed in Scilit:
- The effects of dietary palmitic and stearic acids on milk fat composition in the cowJournal of Dairy Research, 1969
- The effects of dietary palmitic and stearic acids on milk yield and composition in the cowJournal of Dairy Research, 1969
- Factors affecting the polyunsaturated fatty acid content of the plasma lipids of sheepBritish Journal of Nutrition, 1968
- The effects of a series of saturated fatty acids in the diet on milk-fat secretion in the cowJournal of Dairy Research, 1968
- The effects of mono-unsaturated and saturated fatty acids in the diet on milk-fat secretion in the cowJournal of Dairy Research, 1968
- The effects of dietary tallow and cottonseed oil on milk fat secretion in the cowJournal of Dairy Research, 1968
- Dietary fat and milk fat secretion in the cowProceedings of the Nutrition Society, 1968
- Vascular permeability to particulate fat: morphological observations on vessels of lactating mammary gland and of lungProceedings of the Royal Society of London. B. Biological Sciences, 1968
- The oxidation and utilization of palmitate, stearate, oleate and acetate by the mammary gland of the fed goat in relation to their overall metabolism, and the role of plasma phospholipids and neutral lipids in milk-fat synthesisBiochemical Journal, 1967
- Plasma non-esterified fatty acids in sheepAustralian Journal of Agricultural Research, 1960