The composition of ewe's milk fat during early and late lactation

1970 ◽  
Vol 37 (2) ◽  
pp. 297-301 ◽  
Author(s):  
R. C. Noble ◽  
W. Steele ◽  
J. H. Moore

SummaryThe composition of ewe's milk during the first 4 days of lactation and on the 100th day of lactation was investigated. The total fat content was highest (17· 9%) on the day of parturition but decreased rapidly to reach a level on the 2nd day after parturition that was similar to that observed on the 100th day of lactation (9·9 %).The concentration of octadecenoic acid, which was the major fatty acid of ewe's milk, was very much higher in early lactation than in late lactation. As the concentration of octadecenoic acid decreased the concentration of the shorter chain fatty acids (6:0−14:0) increased. The major octadecenoic acid was the cis-9 isomer. However, the proportion of the trans-11 isomer increased from 5·5 % of the total octadecenoic acid concentration in early lactation to 11·9 % in late lactation. Although linoleic acid remained a minor component of the fatty acids of the milk during lactation, its concentration increased from less than 1 % during early lactation to 1·4 % by the 100th day of lactation.

1980 ◽  
Vol 44 (1) ◽  
pp. 47-52 ◽  
Author(s):  
E. Payne ◽  
P. V. Rattray

1. The fatty acid composition of milk fat of Coopworth sheep offered varying pasture allowances has been determined after 1, 14 and 35 d of lactation. Differences in fatty acids occurred, particularly between 1 and 14 d, with a major increase in C18:0 whilst C16:0, C14:0 and C18:3 showed decreases.2. When pasture allowances were restricted there were decreases in the short-chain fatty acids from C6 to C14 and an increase in C18:1 as has been observed previously for cattle. The C18:1:C10 value is a convenient measure of these changes and can be determined more rapidly than determining all the lower fatty acids.3. The increased demand for milk resulting from suckling twin lambs caused an increase in C18:1 and decreases in C10 and C12 due to an increased utilization of body reserves.4. The level of linoleic acid was much greater than has been previously observed in sheep given hay and contributes to the rapid rise in linoleic acid levels in lambs born under grazing conditions.


1962 ◽  
Vol 40 (7) ◽  
pp. 847-855 ◽  
Author(s):  
D. C. Leegwater ◽  
C. G. Youngs ◽  
J. F. T. Spencer ◽  
B. M. Craig

The production of neutral lipids and phospholipids by submerged cultures of the mushroom Tricholoma nudum, as well as the fatty acid composition of these two fractions, was studied as a function of time. The bulk of the neutral lipids was produced after 2 days when the organism appeared to be in a non-proliferative phase. The major fatty acids of the neutral lipids were palmitic, oleic, and linoleic acid (23–35% each); stearic acid was a minor component (8–13%); myristic, palmitoleic, and linolenic acid were present in small amounts (0.5–4.8%). The major fatty acid of the phospholipids was linoleic acid (55–70%); palmitic (15–19%), stearic (1.8–4.6%), and oleic (7–19%) acid were minor components; myristic, palmitoleic, and linolenic (0–2.3%) were present in small amounts. Linolenic acid was a major fatty acid (26–30%) only in the early stages of growth.A preliminary investigation was carried out with a 4-day-old culture to establish the identity of the various components of the neutral lipids and phospholipids. The neutral lipids were mainly triglycerides (92%). Small amounts of ergosterol esters (1%), free fatty acids (< 1%), ergosterol (1.7%), and unidentified non-saponifiable compounds were also present. The phospholipids contained phosphatidyl choline (59%) as the major component; phosphatidyl ethanolamine (26%), phosphatidyl serine and phosphatidic acid (7.8%), and an inositol containing phospholipid were minor components.Some of the techniques applied were specially developed for the present type of studies and are described in detail.


1962 ◽  
Vol 40 (1) ◽  
pp. 847-855 ◽  
Author(s):  
D. C. Leegwater ◽  
C. G. Youngs ◽  
J. F. T. Spencer ◽  
B. M. Craig

The production of neutral lipids and phospholipids by submerged cultures of the mushroom Tricholoma nudum, as well as the fatty acid composition of these two fractions, was studied as a function of time. The bulk of the neutral lipids was produced after 2 days when the organism appeared to be in a non-proliferative phase. The major fatty acids of the neutral lipids were palmitic, oleic, and linoleic acid (23–35% each); stearic acid was a minor component (8–13%); myristic, palmitoleic, and linolenic acid were present in small amounts (0.5–4.8%). The major fatty acid of the phospholipids was linoleic acid (55–70%); palmitic (15–19%), stearic (1.8–4.6%), and oleic (7–19%) acid were minor components; myristic, palmitoleic, and linolenic (0–2.3%) were present in small amounts. Linolenic acid was a major fatty acid (26–30%) only in the early stages of growth.A preliminary investigation was carried out with a 4-day-old culture to establish the identity of the various components of the neutral lipids and phospholipids. The neutral lipids were mainly triglycerides (92%). Small amounts of ergosterol esters (1%), free fatty acids (< 1%), ergosterol (1.7%), and unidentified non-saponifiable compounds were also present. The phospholipids contained phosphatidyl choline (59%) as the major component; phosphatidyl ethanolamine (26%), phosphatidyl serine and phosphatidic acid (7.8%), and an inositol containing phospholipid were minor components.Some of the techniques applied were specially developed for the present type of studies and are described in detail.


1996 ◽  
Vol 316 (3) ◽  
pp. 859-864 ◽  
Author(s):  
N. P. ROTSTEIN ◽  
G. L. PENNACCHIOTTI ◽  
H. SPRECHER ◽  
M. I. AVELDAÑO

The formation of 14C-labelled long-chain and very-long-chain (n-3) pentaenoic and hexaenoic fatty acids was studied in bovine retina by following the metabolism of [14C]docosapentaenoate [C22:5, n-3 fatty acid (22:5 n-3)], [14C]docosahexaenoate (22:6 n-3), and [14C]acetate. With similar amounts of 22:5 n-3 and 22:6 n-3 as substrates, the former was actively transformed into 24:5 n-3, whereas the latter was virtually unmodified. Labelled 24:5, 26:5, 24:6 and 22:6 were formed from [1-14C]22:5 n-3, showing that pentaenoic fatty acids including 24:5 n-3 can be elongated and desaturated within the retina. When retinal microsomes were incubated with [1-14C]22:5 n-3, 24:5 n-3 was the only fatty acid formed. In retinas incubated with [14C]acetate, 24:5 n-3 was the most highly labelled fatty acid among the polyenes synthesized, 24:6 n-3 being a minor product. Such selectivity in the elongation of two fatty acids identical in length, 22:5 n-3 and 22:6 n-3, despite the fact that 22:5 is a minor and 22:6 a major fatty acid constituent of retina, suggests that the active formation of 24:5 n-3 plays a key role in n-3 polyunsaturated fatty acid (PUFA) metabolism. This compound might give rise to even longer pentaenes via elongation, and to the major PUFAs of retina, 22:6 n-3, by 6-desaturation and chain shortening. Of all retinal lipids, a minor component, triacylglycerol (TG), incorporated the largest amounts of [14C]22:5 and 22:6. TG also concentrated most of the [14C]24:5 formed in retina, whether from [14C]22:5 n-3 or from [14C]acetate, suggesting an important role for this lipid in supporting PUFA metabolism and the synthesis of 22:6 n-3.


1968 ◽  
Vol 22 (4) ◽  
pp. 609-614 ◽  
Author(s):  
J. E. Storry ◽  
A. J. Hall ◽  
V. W. Johnson

1. The effects, on the secretion in milk of fat and its component fatty acids, of supplementing a basal diet low in fat with red palm oil at three levels are reported.2. The secretion of total fat and of the fatty acids contained in the oil supplement was positively correlated with the dietary intakes, except for linoleic acid which was hydrogenated in the rumen before its absorption and secretion in milk.3. Evidence for the synthesis de novo of palmitic acid and for the possible depression of intramammary de novo synthesis by high levels of dietary fat is discussed.


2000 ◽  
Vol 83 (11) ◽  
pp. 2620-2628 ◽  
Author(s):  
D.C. Donovan ◽  
D.J. Schingoethe ◽  
R.J. Baer ◽  
J. Ryali ◽  
A.R. Hippen ◽  
...  

1971 ◽  
Vol 51 (3) ◽  
pp. 721-727 ◽  
Author(s):  
L. J. FISHER ◽  
J. D. ERFLE ◽  
F. D. SAUER

Glutamate, succinate, propylene glycol, or glycerol were added to a basic concentrate at 3.3% of air-dry feed. Each concentrate was fed both ad libitum and in restricted amounts to four cows in early lactation. Dietary intake, milk yield and composition, molar proportions of rumen volatile fatty acids and blood glucose, ketones and plasma free fatty acids were used as criteria of effect of these supplements. Propylene glycol in the diet resulted in a lower intake of concentrate compared with glycerol (11.44 versus 14.30 kg/day) and significantly decreased (P < 0.05) rumen butyrate and plasma beta-hydroxybutyrate. Glutamate supplementation prevented the fall in milk fat content which occurred when the other three supplemented concentrates were fed ad libitum, and this effect may have been related to the constancy in the ratio of acetate to propionate in the rumen fluid.


1968 ◽  
Vol 35 (3) ◽  
pp. 343-352 ◽  
Author(s):  
W. Steele ◽  
J. H. Moore

SummaryThe effects of the isocaloric replacement of part of the dietary concentrate mixture by cottonseed oil on the yield and composition of the milk fat and on the pattern of rumen fermentation was investigated in 2 feeding experiments with a total of 8 cows in mid-lactation. The concentrate mixtures were given with high- or low-roughage diets that supplied 9·1 or 1·8 kg of hay/day.In expt 1 the yield of milk fat was not altered by the addition of 10% cottonseed oil to the concentrate mixtures given either with the high- or with the low-levels of dietary roughage. On the low-roughage treatment, dietary cottonseed oil increased milk yield but reduced the fat content of the milk. The change from the high- to the low-roughage diets containing no cottonseed oil resulted in reductions in the yield and percentage of fat in the milk. In expt 2 the yields of milk and milk fat were similar irrespective of whether the concentrate mixture contained 5 or 10% cottonseed oil.In expt 1 the inclusion of 10% cottonseed oil in the concentrate mixture reduced the yields and percentages of the medium-chain fatty acids (12:0, 14:0 and 16:0) and increased the yields and percentages of the C18 fatty acids in the milk fat. In expt 2, when the concentrate mixture contained 5% cottonseed oil, the yields and percentages of all the fatty acids in the milk fat were similar to the values obtained when the concentrates contained 10% cottonseed oil. For any given concentrate mixture, the change from the high- to the low-roughage treatments in both expts 1 and 2 resulted in increases in the percentage of oleic acid in the milk fat. The highest concentration of trans-octadecenoic acid was observed in the milk fat of the cows when they were given the high-roughage diet with the concentrate mixture containing 10% cottonseed oil.In expt 2 the level of cottonseed oil in the concentrate mixture did not influence the pattern of rumen fermentation as measured by the concentrations of the various volatile fatty acids in the rumen liquor. However, the change from the high- to the low-roughage diets reduced the proportion of acetic and increased the proportions of propionic and n-valeric acids in the total volatile fatty acids in the rumen liquor.


2002 ◽  
Vol 74 (1) ◽  
pp. 163-176 ◽  
Author(s):  
A.L. Lock ◽  
P.C. Garnsworthy

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.


2003 ◽  
Vol 73 (3) ◽  
pp. 171-179 ◽  
Author(s):  
Salvatori ◽  
Maiorano ◽  
Pantaleo ◽  
Brienza ◽  
Filetti ◽  
...  

A diet rich in saturated fatty acids promotes plasmatic cholesterol levels and coronary disease in humans, whereas a high intake of polyunsaturated fatty acids reduces atheromatous plaque thickness. This study aimed at establishing a dietary energy level, which combined with intramuscular vitamin E treatment, would improve the nutritional lipid quality and shelf-life of lamb meat. Twenty male lambs were evaluated in a 2 × 2 factorial experiment: they were fed a low- and normal-energy diet (0.85 and 1.00 UFV NE/kg DM, respectively), and were injected intramuscularly with 0 and 150 IU dl-alpha-tocopheryl acetate/weekly for eight weeks. Thereafter, total fat, cholesterol, fatty acid profile, and lipostability were measured in meat samples. Meat total fat was significantly reduced by low energy intake diet and vitamin E administration. Cholesterol was significantly lower in meat from lambs fed the 0.85 UFV NE/kg DM diet. Vitamin E treatment increased linoleic acid percent values and decreased myristic acid levels. Moreover, linoleic acid percentage was inversely correlated with muscle total fat concentration. Meat sensitivity to lipoperoxidation was inversely correlated with muscle vitamin E concentration. This study demonstrates that nutritional characteristics and shelf-life of meat benefit from a low-energy diet and intramuscular vitamin E treatment.


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