Positional distribution of fatty acids in the triglycerides of bovine milk fat with elevated levels of linoleic acid

To evaluate the effects of fat source on milk fat composition and milk conjugated linoleic acid (CLA) concentration, cows were fed diets that were high in either C18:2 or C18:0. Twenty-two Holstein cows were blocked by parity and milk production and randomly assigned within block to one of two dietary treatments containing either 3% pork fat (LARD) or 3% linola oil (OIL) on a dry matter (DM) basis. The diets were fed for 21 d. Feed intake and milk and milk component yields were unaffected by treatment, whereas milk fat percent was decreased with the linola oil treatment. The cis-9, trans-11 CLA concentration of milk from cows fed linola oil was significantly higher than from cows fed pork lard. Key words: CLA, fatty acids, linola oil, milk

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Synthesis of milk fat and opportunities for nutritional manipulation

BSAP Occasional Publication ◽

10.1017/s1463981500040826 ◽

2000 ◽

Vol 25 ◽

pp. 201-223 ◽

Cited By ~ 2

Author(s):

J.J. Murphy

Keyword(s):

Fatty Acids ◽

Mammary Gland ◽

Linoleic Acid ◽

Milk Fat ◽

Unsaturated Fatty Acids ◽

De Novo ◽

Bovine Milk ◽

Dietary Factors ◽

De Novo Synthesis ◽

Long Chain

AbstractMilk fat consists of approximately 960-980 g of triacylglycerol, 20-25 g of 1,2-diacylglycerol, 10 g of phospholipid, 5g of cholesterol and very small quantities of free fatty acids and monoacylglycerol per kg. There are three stages in milk fat biosynthesis: the accumulation of fatty acids in the mammary cells through de-novo synthesis or absorption from the blood stream, triacylglycerol construction and fat globule assembly and secretion. Fatty acids in mammary secretory cells arise from two sources. Those having between 4 and 14 carbon atoms are synthesised de-novo in the mammary gland whereas those with 18 carbon atoms are of dietary origin and are absorbed from the blood stream. Palmitic acid (16 carbon atoms) is supplied almost equally from the diet and de-novo synthesis. In ruminants the principal sources of carbon for fatty acid synthesis are acetic acid and b-hydroxybutyrate.Alteration of milk fat concentration is achieved by changimore spreadable butter. Monounsaturated fatty acids in the diet have been shown to have beneficial effects on the plasma lipoprotein indicators of coronary heart disease risk. From a human nutrition point of view it could be beneficial to incorporate the long chain omega-3 fatty acids, eicosapentanoic (EPA, C20:5) and docosahexanoic (C22:6) acids, into milk fat. The principal source of these fatty acids is fish oil but research to date indicates that their transfer into milk fat is inefficient. Conjugated linoleic acid (CLA) is a collective term describing one or more positional and geometric isomers of linoleic acid (cis-9, cis-12 C18:2). CLA has been shown to have anticarcinogenic activity, antiatherogenic activity, an ability to reduce the catabolic effects of immune stimulation and an ability to enhance growth promotion and reduce body fat. It is present in ruminant milk and meat as a result of biohydrogenation in the rumen where it is an intermediate. Its concentration in bovine milk fat is influenced by dietary factors such as pasture feeding and supplementation with full fat oilseeds. Two other components of bovine milk fat which have been shown to have anticarcinogenic properties are butyric acid and sphingomyelin and their concentration warrants further study. It is likely that research will continue into means of manipulating both the content and composition of milk fat but ultimately the adoption of any of the strategies in practice is likely to depend on strong economic or consumer imperatives.ng either the level of de-novo synthesis in the mammary gland or the supply of long chain fatty acids in the diet. Dietary factors that affect the supply of acetic acid from the rumen for de-novo synthesis include fibre quantity and quality, forage to concentrate ratio, buffer inclusion, concentrate composition and concentrate feeding frequency. The effects of fat supplements on fat concentration are variable. In general, feeding rumen protected fat increases milk fat concentration whereas moderate amounts of unprotected unsaturated fat tend to decrease it.Most nutritional manipulation has been directed at increasing the proportion of unsaturated fatty acids in milk fat in order to enhance its appeal to the consumer and to produce a softer fat. A more spreadable butter could be produced from such fat thus overcoming a major criticism of conventional butter.If unsaturated fatty acids are fed to ruminants in an unprotected form rumen microbial digestion can be impaired and the unsaturated fatty acids are extensively saturated in the rumen. One strategy to overcome this is to include unsaturated fatty acids in a form protected from microbial digestion in the rumen. This resulted in the production of polyunsaturated milk fat from which a low melting point butter was produced. This product was predisposed to oxidative deterioration. More recently whole oilseeds have been fed to dairy cows. The unsaturated 18-carbon fatty acids in these seeds are hydrogenated in the rumen but the activity of a D-9 desaturase in the mammary gland and to a lesser extent the intestine converts the stearic acid (C18:0) to the monounsaturated fatty acid, oleic acid (C18:1). Milk fat rich in oleic acid is softer than conventional milk fat allowing the manufacture of a more spreadable butter. Monounsaturated fatty acids in the diet have been shown to have beneficial effects on the plasma lipoprotein indicators of coronary heart disease risk.From a human nutrition point of view it could be beneficial to incorporate the long chain omega-3 fatty acids, eicosapentanoic (EPA, C20:5) and docosahexanoic (C22:6) acids, into milk fat. The principal source of these fatty acids is fish oil but research to date indicates that their transfer into milk fat is inefficient. Conjugated linoleic acid (CLA) is a collective term describing one or more positional and geometric isomers of linoleic acid (cis-9, cis-12 C18:2). CLA has been shown to have anticarcinogenic activity, antiatherogenic activity, an ability to reduce the catabolic effects of immune stimulation and an ability to enhance growth promotion and reduce body fat. It is present in ruminant milk and meat as a result of biohydrogenation in the rumen where it is an intermediate. Its concentration in bovine milk fat is influenced by dietary factors such as pasture feeding and supplementation with full fat oilseeds. Two other components of bovine milk fat which have been shown to have anticarcinogenic properties are butyric acid and sphingomyelin and their concentration warrants further study.It is likely that research will continue into means of manipulating both the content and composition of milk fat but ultimately the adoption of any of the strategies in practice is likely to depend on strong economic or consumer imperative.

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Influence of Dietary Fish Oil on Conjugated Linoleic Acid and Other Fatty Acids in Milk Fat from Lactating Dairy Cows

Journal of Dairy Science ◽

10.3168/jds.s0022-0302(00)75155-1 ◽

2000 ◽

Vol 83 (11) ◽

pp. 2620-2628 ◽

Cited By ~ 139

Author(s):

D.C. Donovan ◽

D.J. Schingoethe ◽

R.J. Baer ◽

J. Ryali ◽

A.R. Hippen ◽

...

Keyword(s):

Fatty Acids ◽

Linoleic Acid ◽

Fish Oil ◽

Dairy Cows ◽

Conjugated Linoleic Acid ◽

Milk Fat ◽

Lactating Dairy Cows ◽

Dietary Fish

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Influence of elevated levels of linoleic acid on the thermal properties of bovine milk fat

Lipids ◽

10.1007/bf02533423 ◽

1979 ◽

Vol 14 (4) ◽

pp. 391-394 ◽

Cited By ~ 12

Author(s):

I. M. Morrison ◽

J. C. Hawke

Keyword(s):

Thermal Properties ◽

Linoleic Acid ◽

Milk Fat ◽

Bovine Milk

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Fatty acid positional distribution (sn-2 fatty acids) and phospholipid composition in Chinese breast milk from colostrum to mature stage

British Journal Of Nutrition ◽

10.1017/s0007114518002994 ◽

2018 ◽

Vol 121 (1) ◽

pp. 65-73 ◽

Cited By ~ 9

Author(s):

Ke Wu ◽

Runying Gao ◽

Fang Tian ◽

Yingyi Mao ◽

Bei Wang ◽

...

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Linoleic Acid ◽

Fatty Acid Profile ◽

Unsaturated Fatty Acids ◽

Fatty Acid Content ◽

Positional Distribution ◽

Phospholipid Composition ◽

Mature Stage ◽

Feeding Time

AbstractThis study quantified the fatty acid profile with emphasis on the stereo-specifically numbered (sn) 2 positional distribution in TAG and the composition of main phospholipids at different lactation stages. Colostrum milk (n 70), transitional milk (n 96) and mature milk (n 82) were obtained longitudinally from healthy lactating women in Shanghai. During lactation, total fatty acid content increased, with SFA dominating in fatty acid profile. A high ratio of n-6:n-3 PUFA was observed as 11:1 over lactation due to the abundance of linoleic acid in Chinese human milk. As the main SFA, palmitic acid showed absolute sn-2 selectivity, while oleic acid, linoleic acid and α-linolenic acid, the main unsaturated fatty acids, were primarily esterified at the sn-1 and sn-3 positions. Nervonic acid and C22 PUFA including DHA were more enriched in colostrum with an sn-2 positional preference. A total of three dominant phospholipids (phosphatidylethanolamine (PE), phosphatidylcholine (PC) and sphingomyelin (SM)) were analysed in the collected samples, and each showed a decline in amount over lactation. PC was the dominant compound followed by SM and PE. With prolonged breast-feeding time, percentage of PE in total phospholipids remained constant, but PC decreased, and SM increased. Results from this study indicated a lipid profile different from Western reports and may aid the development of future infant formula more suitable for Chinese babies.

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Independent effects of dietary linoleic and linolenic fatty acids on the conjugated linoleic acid content of cows’ milk

Animal Science ◽

10.1017/s1357729800052334 ◽

2002 ◽

Vol 74 (1) ◽

pp. 163-176 ◽

Cited By ~ 113

Author(s):

A.L. Lock ◽

P.C. Garnsworthy

Keyword(s):

Fatty Acids ◽

Mammary Gland ◽

Linoleic Acid ◽

Conjugated Linoleic Acid ◽

Linolenic Acid ◽

Milk Fat ◽

Latin Square ◽

Health Benefit ◽

Low Linolenic Acid ◽

Low Linolenic

AbstractIt may be desirable to increase the level of conjugated linoleic acid (CLA) in milk as a health benefit in human nutrition. The purpose of this work was to separate the effects of linoleic and linolenic acids on CLA production in dairy cows and to determine to what extent endogenous synthesis contributes to cis-9, trans-11 CLA concentration in milk fat. Eight lactating cows and four non-lactating duodenal fistulated cows were used in a 4 ✕ 4 Latin-square design. All cows received a basal diet of grass silage that was supplemented with one of four concentrates, which were designed to differ in their linoleic and linolenic acid contents. The oil components of the concentrates were produced from mixtures of olive, linseed, rape, soya and sunflower oils to produce the four treatments: low linoleic/ low linolenic acid (LL), low linoleic/high linolenic acid (LH), high linoleic/low linolenic acid (HL) and high linoleic/ high linolenic acid (HH). Milk cis-9, trans-11 CLA contents were 0·8, 0·9, 0·9 and 1·1 g/100 g fatty acid methyl esters (P < 0·05) and yields were 5, 7, 7 and 8 g/day (P < 0·05) for the LL, LH, HL and HH treatments, respectively. The yields of trans-C18:1 fatty acids in milk were 19, 22, 21 and 23 g/day (P < 0·05), respectively. Taking the data for the cis-9, trans-11 CLA content and flow of duodenal fluid from the fistulated cows and representing this in terms of dietary intake by the lactating animals, the amounts of cis-9, trans-11 CLA produced in the rumen were calculated to be 0·8, 0·9, 1·2 and 1·1 g/day (P < 0·05) and for trans-C18:1 fatty acids 58, 58, 66 and 69 g/day (P < 0·05). Increasing linoleic and/or linolenic acids in the diet can increase the cis-9, trans-11 CLA content of cows’ milk. Only diets high in linoleic acid increased cis-9, trans-11 CLA production in the rumen. On all four diets, more than 80% of cis-9, trans-11 CLA in milk was produced endogenously by Δ9-desaturase from trans-11 C18:1 in the mammary gland. Cows on the same diet have different milk fat cis-9, trans-11 CLA concentrations that may be partially explained by differences in Δ9-desaturase activity between cows. Increasing the activity of Δ9-desaturase in the mammary gland may offer greater potential for enhancing the cis-9, trans-11 CLA content of milk fat than increasing cis-9, trans-11 CLA production in the rumen.

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Dietary effect on bovine milk fat conjugated linoleic acid content

BSAP Occasional Publication ◽

10.1017/s1463981500040875 ◽

2000 ◽

Vol 25 ◽

pp. 283-293

Author(s):

F. Lawless ◽

J.J. Murphy ◽

S. Fitzgerald ◽

B. O’Brien ◽

R. Devery ◽

...

Keyword(s):

Fatty Acid ◽

Linoleic Acid ◽

Conjugated Linoleic Acid ◽

Growth Rates ◽

Milk Fat ◽

Methyl Esters ◽

Bovine Milk ◽

Fold Increase ◽

Linoleic Acid Content ◽

Grass Growth

AbstractConjugated linoleic acid (cis-9, trans-11-C18:2; CLA) in milk arises as a result of microbial biohydrogenation of dietary linoleic and linolenic acids in the rumen (Kepler and Tove, 1967). Milk fat CLA concentrations were significantly (P<0.05) higher when cows were fed silage supplemented with pulp’n brew (a mixture of brewers grains, a by-product of the brewing industry, and sugar beet pulp in dry matter proportions of 0.65:0.35), compared with silage alone (Trial 1). Intake of spring grass resulted in a 2.1–fold increase in milk fat CLA concentrations over cows receiving autumn grass. Throughout lactation in Trial 2, spring calving cows produced higher milk fat CLA concentrations (from 0.5-2.7 g/100 g fatty acid methyl esters (FAME)) than autumn calving cows (0.3-1.7 g/100 g FAME); the former having spent 80% and the latter 50% of lactation on pasture. The CLA content was higher in late lactation milk compared with early lactation milk in both herds. There were no significant differences in milk yields or milk constituent yields between the herds. Manufacturing milk obtained between March and September was analyzed for milk fatty acid composition and the data correlated with grass growth throughout the season. Significant positive correlations were obtained between grass growth rates and concentrations of CLA and linolenic acid in milk fat. The data indicate that seasonal variation in milk fat CLA concentrations may be attributed to variation in pasture growth rates.

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Effect of dietary fat supplements on levels of n-3 poly-unsaturated fatty acids,transacids and conjugated linoleic acid in bovine milk

Animal Science ◽

10.1017/s135772980005147x ◽

1999 ◽

Vol 69 (3) ◽

pp. 613-625 ◽

Cited By ~ 97

Author(s):

N. W. Offer ◽

M. Marsden ◽

J. Dixon ◽

B. K. Speake ◽

F. E. Thacker

Keyword(s):

Fatty Acids ◽

Linoleic Acid ◽

Conjugated Linoleic Acid ◽

Milk Yield ◽

Milk Fat ◽

Trans Fatty Acids ◽

Unsaturated Fatty Acids ◽

Linseed Oil ◽

The Other ◽

Fat Supplements

AbstractThe effects of three fat supplements on milk yield and composition were measured using 12 mid-lactation in-calf Hoistein-Friesian cows in a balanced incomplete change-over design over three periods each of 3 weeks. All cows received a basal diet consisting of 36 kg/day grass silage (dry matter (DM) 270 g/kg, metabolizable energy (ME) 11·6 MJ/kg DM) and 7 kg/day o f a concentrate mixture containing (g/kg) rolled barley (501), molassed sugar-beet pulp shreds (277), soya-bean meal (208) and a standard cow mineral supplement (14). Treatments were CON (control-no supplement); LIN and FISH (250 gl day of either linseed oil or marine oil, providing approximately 0·046 of ME intake) or TOA (95 glday of tuna orbital oil, providing 0·018 of total ME intake).There were no significant effects on silage DM intake or milk yield (means 9·25 and 17·2 kg/day respectively). The FISH and TOA treatments depressed (F < 0·05) milk fat concentration (45·4, 44·6, 34·5 and 41·6 (s.e.d. 1·08) g/kg for CON, LIN, FISH and TOA respectively; note — the same treatment order is used for all results quoted). Compared with values for CON, yield of f at (glday) was significantly (F < 0·05) greater for LIN and significantly lower for FISH (739, 808, 572 and 732, s.e.d. 28·7). All three oil supplements reduced (F < 0·05) milk protein content (33·6, 32·5, 30·6 and 32·4 (s.e.d. 0·43) g/kg) but, apart from a small increase for LIN, protein yield (glday) was unaffected (545, 586, 510 and 574, s.e.d. 20·2).The concentrations (g/100 g) of short-chain fatty acids (< C14) and C16 : 0 in milk f at were lower (F < 0·05) for LIN than for the other treatments. All supplements increased the concentrations ofC18:1 (F < 0·05), the value for LIN being greater (F < 0·05) than for the other treatments (21·0, 27·2, 25·3 and 23·7, s.e.d. 0·74). The FISH and TOA treatments increased (F < 0·05) the concentrations of long chain (< C2O) (n-3) poly-unsaturated fatty acids (PUFA), (0·19, 0·17, 0·49 and 0·27, s.e.d. 0·026) but less than proportionately 0·03 of dietary intake of these acids was transferred to milk, probably because they were found to be mostly in the phospholipid and cholesterol ester fractions of plasma. The FISH and TOA treatments increased (F < 0·05) the percentages of total trans fatty acids in milk fat (1·13, 2·19, 10·26 and 3·62, s.e.d. 0·728) whilst a significant (F < 0·05) increase in conjugated linoleic acid (CLA) was observed only for FISH (0·16, 0·28, 1·55, and 0·52, s.e.d. 0·154). Concentrations of CLA and total trans acids in milk were highly correlated (r = 0·91, no. =36, F < 0·001) whilst trans acids in milk were inversely correlated with milk fat content (r = -0·63, no. = 36, F < 0·001) supporting the theory that milk fat depression may be caused by increased supply of trans fatty acids to the mammary gland. The health implications of these changes in milk fat composition are discussed.

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