The effect of a blend of dietary unesterified and saturated long-chain fatty acids on the performance of dairy cows in mid-lactation

1990 ◽  
Vol 41 (1) ◽  
pp. 129 ◽  
Author(s):  
KR King ◽  
CR Stockdale ◽  
TE Trigg

This experiment studied the effects of feeding a supplement of a blend of unesterified and saturated long-chain fatty acids on the productivity of dairy cows in mid-lactation. Twenty-three cows in their fourth month of lactation were individually fed ad libitum, a mixed balanced ration based on maize silage, lucerne hay and rolled grain. Varying quantities, up to 1020 g cow-1 day-1 of the fatty acid supplement, were mixed into the ration. Yields of milk and milk products were linearly related to total long-chain fatty acid intake. Milk fat content increased linearly while milk protein content averaged 3.59 (s.d. � 0.15)%. The marginal returns from feeding 1 kg of the supplement were 3.3 kg milk, 0.33 kg fat and 0.07 kg protein. The proportions of C 10:0, C12:0 and C 14:0 fatty acids in milk were decreased, while those of C 18:0 and C18:1 were increased as the result of feeding long-chain fatty acids. The concentration of lipid in plasma was increased, but acetate and D-(3)-hydroxybutyrate levels in blood remained unchanged with increased levels of dietary long-chain fatty acid. Efficiency of milk production was increased by 11% from feeding 1 kg of the supplement. In vivo digestibilities of dry matter, neutral and acid detergent fibres, and dietary long-chain fatty acids were unaffected by supplement.

1995 ◽  
Vol 73 (5-6) ◽  
pp. 223-234 ◽  
Author(s):  
Dev Mangroo ◽  
Bernardo L. Trigatti ◽  
Gerhard E. Gerber

Long chain fatty acids are important substrates for energy production and lipid synthesis in prokaryotes and eukaryotes. Their cellular uptake represents an important first step leading to metabolism. This step is induced in Escherichia coli by growth in medium containing long chain fatty acids and in murine 3T3-L1 cells during differentiation to adipocytes. Consequently, these have been used extensively as model systems to study the cellular uptake of long chain fatty acids. Here, we present an overview of our current understanding of long chain fatty acid uptake in these cells. It consists of several distinct steps, mediated by a combination of biochemical and physico-chemical processes, and is driven by conversion of long chain fatty acids to acyl-CoA by acyl-CoA synthetase. An understanding of long chain fatty acid uptake may provide valuable insights into the roles of fatty acids in the regulation of cell signalling cascades, in the regulation of a variety of metabolic and transport processes, and in a variety of mammalian pathogenic conditions such as obesity and diabetes.Key words: acyl-CoA synthetase, adipocyte, Escherichia coli, fatty acid, transport, uptake.


2000 ◽  
Vol 279 (6) ◽  
pp. E1286-E1293 ◽  
Author(s):  
Lambertus Benthem ◽  
Klaasjan Keizer ◽  
Coen H. Wiegman ◽  
Sietse F. de Boer ◽  
Jan H. Strubbe ◽  
...  

We tested the hypothesis that excessive portal venous supply of long-chain fatty acids to the liver contributes to the development of insulin resistance via activation of the hypothalamus-pituitary-adrenal axis (HPA axis) and sympathetic system. Rats received an intraportal infusion of the long-chain fatty acid oleate (150 nmol/min, 24 h), the medium-chain fatty acid caprylate, or the solvent. Corticosterone (Cort) and norepinephrine (NE) were measured as indexes for HPA axis and sympathetic activity, respectively. Insulin sensitivity was assessed by means of an intravenous glucose tolerance test (IVGTT). Oleate infusion induced increases in plasma Cort (Δ = 13.5 ± 3.6 μg/dl; P < 0.05) and NE (Δ = 235 ± 76 ng/l; P < 0.05), whereas caprylate and solvent had no effect. The area under the insulin response curve to the IVGTT was larger in the oleate-treated group than in the caprylate and solvent groups (area = 220 ± 35 vs. 112 ± 13 and 106 ± 8, respectively, P < 0.05). The area under the glucose response curves was comparable [area = 121 ± 13 (oleate) vs. 135 ± 20 (caprylate) and 96 ± 11 (solvent)]. The results are consistent with the concept that increased portal free fatty acid is involved in the induction of visceral obesity-related insulin resistance via activation of the HPA axis and sympathetic system.


2013 ◽  
Vol 5 (3) ◽  
pp. 270-274 ◽  
Author(s):  
Anamaria COZMA ◽  
Doina MIERE ◽  
Lorena FILIP ◽  
Sanda ANDREI ◽  
Roxana BANC ◽  
...  

Milk fat and its fatty acid profile are important determinants of the technological, sensorial, and nutritional properties of milk and dairy products. The two major processes contributing to the presence of fatty acids in ruminant milk are the mammary lipogenesis and the lipid metabolism in the rumen. Among fatty acids, 4:0 to 12:0, almost all 14:0 and about a half of 16:0 in milk fat derive from de novo synthesis within the mammary gland. De novo synthesis utilizes as precursors acetate and butyrate produced through carbohydrates ruminal fermentation and involves acetyl-CoA carboxylase and fatty acid synthetase as key enzymes. The rest of 16:0 and all of the long-chain fatty acids derive from mammary uptake of circulating lipoproteins and nonesterified fatty acids that originate from digestive absorption of lipids and body fat mobilization. Further, long-chain fatty acids as well as medium-chain fatty acids entering the mammary gland can be desaturated via Δ-9 desaturase, an enzyme that acts by adding a cis-9-double bond on the fatty acid chain. Moreover, ruminal biohydrogenation of dietary unsaturated fatty acids results in the formation of numerous fatty acids available for incorporation into milk fat. Ruminal biohydrogenation is performed by rumen microbial population as a means of protection against the toxic effects of polyunsaturated fatty acids. Within the rumen microorganisms, bacteria are principally responsible for ruminal biohydrogenation when compared to protozoa and anaerobic fungi.


2004 ◽  
Vol 59 (7-8) ◽  
pp. 549-553 ◽  
Author(s):  
Thomas Götz ◽  
Peter Böger

AbstractThe first elongation step to form very-long-chain fatty acids (VLCFAs) is catalyzed by the VLCFA-synthase. CoA-activated fatty acids react with malonyl-CoA to condense a C2-unit. As shown with recombinant enzyme this reaction is specifically inhibited by chloroacetamide herbicides. The inhibition is alleviated when the inhibitor (e.g. metazachlor) is incubated together with adequate concentrations of the substrate (e.g. oleoyl-CoA). Malonyl-CoA has no influence. However, once a chloroacetamide has been tightly bound to the synthase after an appropriate time it cannot be displaced anymore by the substrate. In contrast, oleoyl- CoA, is easily removed from the synthase by metazachlor. The irreversible binding of the chloroacetamides and their competition with the substrate explains the very low half-inhibition values of 10-8 м and below. Chiral chloroacetamides like metolachlor or dimethenamid give identical results. However, only the (S)-enantiomers are active.


1996 ◽  
Vol 313 (2) ◽  
pp. 487-494 ◽  
Author(s):  
Bernardo L. TRIGATTI ◽  
Gerhard E. GERBER

To understand the mechanism of long-chain fatty acid permeation of the plasma membrane in mammalian cells, the effects of changes in the cytoplasmic pH on the internalization of physiologically relevant, submicromolar concentrations of uncomplexed long-chain fatty acids were investigated in 3T3-L1 adipocytes. The acidification of the cytoplasm upon NH4Cl prepulsing of intact cells was accompanied by a rapid reduction of cellular long-chain fatty acid uptake (measured as the total accumulation of [9,10-3H]oleate). This was followed by a slow recovery to normal levels of uptake as the cytoplasmic pH recovered. Conventional filtration assays do not distinguish between fatty acid movement across the plasma membrane and intracellular steps, such as binding to cytoplasmic fatty acid-binding proteins or metabolism. While the in vitro binding of a photoreactive fatty acid, 11-m-diazirinophenoxy[11-3H]undecanoate, to a cytoplasmic fatty acid-binding protein was insensitive to changes in pH from pH 7.5 to 5.5, the in vitro conversion of oleate into oleoyl-CoA by cellular acyl-CoA synthetase decreased dramatically. Therefore, the labelling of the 15 kDa cytoplasmic fatty acid-binding protein in intact cells by the photoreactive fatty acid was used as a more direct measure of the permeation of the probe across the plasma membrane. Acidification of the cytoplasm resulted in an immediate reduction in the labelling of this protein in intact adipocytes. Its photolabelling recovered, however, upon the recovery of the cytoplasmic pH to normal levels. This was due to effects of the cytoplasmic pH on the permeation of the photoreactive fatty acid across the plasma membrane rather than its binding to the 15 kDa protein or metabolism in vivo. This is the first demonstration that the movement of physiologically relevant, submicromolar concentrations of uncomplexed long-chain fatty acids across the plasma membrane of intact cells is coupled to the cytoplasmic pH and suggests that it occurs by the diffusion of the protonated long-chain fatty acid through the lipid bilayer.


1982 ◽  
Vol 53 (7) ◽  
pp. 499-502
Author(s):  
Hisao ITABASHI ◽  
Takeru KOBAYASHI ◽  
Noriaki YAMAGISHI ◽  
Hiroaki SHISHIDO

1990 ◽  
Vol 30 (1) ◽  
pp. 11 ◽  
Author(s):  
KR King ◽  
CR Stockdale ◽  
TE Trigg

Three groups of 8 cows in their second month of lactation grazed irrigated perennial pasture alone, or grazed and were supplemented with either 3.3 kg/day of a high energy supplement or 3.8 kg of a high energy supplement containing additional long-chain fatty acids. Yields of milk and milk products were generally highest for those cows fed the supplement containing fat. Yield of milk fat was 13% higher in fat supplemented cows than those in the other supplemented treatment because these cows overcame the negative effect of starch supplements on milk fat test. Inclusion of long-chain fatty acids in the diet caused only minor changes in the fatty acid composition of the milk fat and in the various rumen parameters. The immediate marginal increases in daily yields of milk and milk fat per kg of long-chain fatty acids consumed by cows were 1.8 and 0.33 kg/cow. After comparison with data from other experiments, we concluded that the type of basal diet is not an important factor influencing the response of dairy cows to dietary long-chain fatty acids


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