scholarly journals Uptake of substrates for milk-fat synthesis by lactating-rabbit mammary gland

1978 ◽  
Vol 174 (1) ◽  
pp. 291-296 ◽  
Author(s):  
C S Jones ◽  
D S Parker
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Milk Fat ◽  
Blood Analysis ◽  
Esterified Fatty Acids ◽  
Cannulation Technique ◽  
Before And After ◽  
Fat Synthesis ◽  
Milk Fat Synthesis

1. A cannulation technique is described for measuring arteriovenous differences across the lactating-rabbit mammary gland. 2. Analysis of milk obtained before and after surgery shows no effect of cannulation on milk constituents. 3. Results of blood analysis show significant net changes in the concentrations of glucose, acetate, 3-hydroxybutrate, triacylglycerols and non-esterified fatty acids across the mammary gland. 4. The molar proportions of individual fatty acids in both the triacylglycerol and non-esterified fatty acid fractions did not alter between the arterial and venous samples. 5. The extraction rates are compared with those obtained from other species.

scholarly journals 50 Role of fatty acid nutrition in milk fat synthesis

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 24-25
Author(s):  
Adam L Lock
Keyword(s):  
Adipose Tissue ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Dairy Cows ◽  
Milk Fat ◽  
Energy Partitioning ◽  
Milk Lipid ◽  
Wide Range ◽  
Fat Synthesis ◽  
Milk Fat Synthesis

Abstract Our understanding of fatty acid (FA) digestion and metabolism in dairy cows has advanced significantly in the last few decades. We now recognize that FA, both of dietary and rumen origin, can have different and specific effects on feed intake, rumen metabolism, small intestine digestibility, milk fat synthesis in the mammary gland, and energy partitioning between the mammary gland and other tissues. We will present research focusing on specific FA and how dairy cows respond differently to combinations of FA. Recent research has highlighted differences in intestinal digestibility among palmitic acid (C16:0), stearic acid (C18:0), and oleic (cis-9 C18:1) acids, which impacts the amount and profile of absorbed FA available for metabolic purposes including milk fat synthesis. C16:0, C18:0, and cis-9 C18:1 usually comprise the majority of FA present in milk fat and adipose tissue of dairy cows. In addition, these FA comprise the major FA in a wide range of commercially available fat supplements. While these FA have different functions in metabolism, they may also interact with each other by competitive or complementary mechanisms under different physiological conditions. In the mammary gland, milk FA are derived from 2 sources; 16 carbon FA originating from extraction from plasma. 16-carbon FA originate from either de novo or preformed sources. Milk lipid synthesis in the mammary gland is dependent upon the simultaneous supply of short/medium-chain FA and long-chain FA. C16:0 has a higher preference as a substrate to start triglyceride synthesis than C18:0 or cis-9 C18:1. Also, if the amount of preformed FA surpasses the capacity of the mammary gland, these might be redirected to other tissues (e.g. adipose tissue) altering energy partitioning. In the future, the opportunity and challenge will be to continue to improve our understanding of how and which FA affect nutrient digestion, energy partitioning, and milk synthesis in lactating dairy cows and effectively apply this knowledge in the feeding and management of high producing dairy cows.

MicroRNA-432 inhibits milk fat synthesis by targeting SCD and LPL in ovine mammary epithelial cells

2021 ◽  
Author(s):  
Zhiyun Hao ◽  
Yuzhu Luo ◽  
Jiqing Wang ◽  
Jon Hickford ◽  
Huitong Zhou ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Milk Production ◽  
Milk Fat ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Differentially Expressed ◽  
Differentially Expressed Mirnas ◽  
Fat Synthesis ◽  
Milk Fat Synthesis

In our previous studies, microRNA-432 (miR-432) was found to be one of differentially expressed miRNAs in ovine mammary gland between the two breeds of lactating sheep with different milk production...

scholarly journals Bta-miR-34b regulates milk fat biosynthesis by targeting mRNA decapping enzyme 1A (DCP1A) in cultured bovine mammary epithelial cells1

2019 ◽  
Vol 97 (9) ◽  
pp. 3823-3831 ◽  
Author(s):  
Yujuan Wang ◽  
Wenli Guo ◽  
Keqiong Tang ◽  
Yaning Wang ◽  
Linsen Zan ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Droplet ◽  
Milk Fat ◽  
Fatty Acid Synthase ◽  
Binding Protein ◽  
Mammary Epithelial ◽  
Luciferase Reporter ◽  
Fatty Acid Binding ◽  
Fat Synthesis ◽  
Milk Fat Synthesis

Abstract Milk fat is a main nutritional component of milk, and it has become one of the important traits of dairy cow breeding. Recently, there is increasing evidence that microRNAs (miRNA) play significant roles in the process of milk fat synthesis in the mammary gland. Primary bovine mammary epithelial cells (BMEC) were harvested from midlactation cows and cultured in DMEM/F-12 medium with 10% fetal bovine serum, 100 units/mL penicillin, 100 µg/mL streptomycin, 5 µg/mL bovine insulin, 1 µg/mL hydrocortisone, and 2 µg/mL bovine prolactin. We found that miR-34b mimic transfection in BMEC reduced the content of intracellular triacylglycerol (TAG) and lipid droplet accumulation via triacylglycerol assay and Oil Red O staining; meanwhile, overexpression of miR-34b inhibited mRNA expression of lipid metabolism-related genes such as peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FASN), fatty acid binding protein 4 (FABP4), and CCAAT enhancer binding protein alpha (C/EBPα). Whereas miR-34b inhibitor resulted in completely opposite results. Furthermore, q-PCR and western blot analysis revealed the mRNA and protein expression levels of DCP1A were downregulated in miR-34b mimic transfection group and upregulated in miR-34b inhibitor group. Moreover, luciferase reporter assays verified that DCP1A was the direct target of miR-34b and DCP1A gene silencing in BMEC-inhibited TAG accumulation and suppressed lipid droplet formation. In conclusion, these findings revealed a novel miR-34b–DCP1A axis that has a significant role in regulating milk fat synthesis and suggested that miR-34b may be used to improve the beneficial ingredients in milk.

scholarly journals Transacylation as a chain-termination mechanism in fatty acid synthesis by mammalian fatty acid synthetase. Synthesis of butyrate and hexanoate by lactating cow mammary gland fatty acid synthetase

1980 ◽  
Vol 186 (1) ◽  
pp. 287-294 ◽  
Author(s):  
J K Hansen ◽  
J Knudsen
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthetase ◽  
Short Chain Fatty Acids ◽  
Acid Synthesis ◽  
Chain Termination ◽  
Short Chain ◽  
Esterified Fatty Acids ◽  
A Chain

1. Purified cow mammary gland fatty acid synthetase synthesized long-chain unesterified and short-chain esterified fatty acids. 2. A direct relationship was observed between the amount of short-chain products synthesized and the concentration of acetyl-CoA in the incubation medium. 3. The short-chain products were identified as butyryl-CoA and hexanoyl-CoA. 4. Inhibition of the terminating thioester hydrolase of the fatty acid synthetase complex with phenylmethanesulphonyl fluoride did not inhibit the synthesis of short-chain products. 5. It is suggested that the synthesis of short-chain fatty acids involves the reverse of the ‘loading’ reaction.

Effect of feeding protected lipid to dairy cows in early lactation on the composition of blood lipoproteins and secretion of fatty acids in milk

1980 ◽  
Vol 94 (3) ◽  
pp. 503-516 ◽  
Author(s):  
J. E. Storry ◽  
P. E. Brumby ◽  
B. Tuckley ◽  
V. A. Welch ◽  
D. Stead ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Milk Fat ◽  
Low Density Lipoproteins ◽  
Total Serum ◽  
Low Density ◽  
Dietary Intakes ◽  
Vldl Triglyceride

SummaryEffects of 0, 1·7, 3·3 or 5·0 kg/day of a protected soya bean – tallow supplement, incorporated into a hay:concentrate diet (25:75) and fed ad libitumto Friesian cows, on intake and digestion of fatty acids, on output of milk fatty acids and on blood lipoprotein composition were measured.Most of the increased intake of fatty acids, approximately 1 kg/day, was accounted for by increased intakes of C16:0, C18:0 and C18:1. At low intakes, amounts of all fatty acids apparently digested were linearly related to their respective intakes. At high intakes of C16 and C18 acids, curvilinear relationships were established.Yield of total milk fat was related positively to dietary intakes of total fatty acid and carbohydrate and negatively to live-weight change. Yields of short and intermediate chain acids in milk, synthesized within the mammary gland, were negatively correlated and yields of C18 fatty acids positively correlated with respective dietary intakes of these acids. Decreased proportions of C4–16 and increased proportions of C18:0 and C18:1 fatty acids in milk were associated with increased protected tallow in the diet. Yields of C16:1 and C18:1 were positively related to corresponding outputs of saturated acids and negatively to weeks of lactation. The proportion of C18:1 in milk was positively related to the corresponding proportion of C18:0.The increased intake of fatty acids resulted in increased concentrations of very low density lipoproteins (VLDL, d < 1·019 g/ml), low density lipoproteins (LDL1 + LDL2, 1·019 < d < 1·06 g/ml), high density lipoproteins (d > 1·060 g/ml) and serum free fatty acids. Most of the increase in low density lipoproteins was accounted for by a very large increase in LDL1, whose proportion increased from 17 to 75% (2 to 22% of total serum lipid). The proportion of triglyceride in the combined low density lipoprotein fraction decreased from 11 to 2% whilst phospholipids increased from 29 to 36%. These changes were attributed to the increased proportion of LDL1 present.The proportions of VLDL and LDL triglyceride taken up by the mammary gland averaged 0·79 and 0·34 respectively. The proportion of VLDL+LDL triglyceride taken up by the gland decreased with increased amounts of fatty acid digested. Yields of C18 fatty acids in milk tended to be positively related to apparent uptakes of VLDL triglyceride and to VLDL C18 fatty acids, but negatively related to apparent uptakes of LDL triglycerides and LDL C18 fatty acids. It is suggested that the increased LDL1 resulted from the utilization of VLDL triglyceride for milk fat formation.Protected lipid feeding increased the proportion of C14:0, C16:0 C16:1 and C18:1 and decreased the proportions of C14:1 and C18:0 fatty acids in jugular serum triglycerides. Similar changes were observed in jugular VLDL triglycerides. Differences in the compositions of VLDL and LDL triglycerides across the mammary gland were observed and attributed either to selective uptake or to interchange of fatty acids between triglycerides and free fatty acids.

scholarly journals A Review of the Metabolic Origins of Milk Fatty Acids

2013 ◽  
Vol 5 (3) ◽  
pp. 270-274 ◽  
Author(s):  
Anamaria COZMA ◽  
Doina MIERE ◽  
Lorena FILIP ◽  
Sanda ANDREI ◽  
Roxana BANC ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Milk Fat ◽  
De Novo ◽  
Long Chain Fatty Acids ◽  
De Novo Synthesis ◽  
Ruminal Biohydrogenation ◽  
Long Chain ◽  
Chain Fatty Acids

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.

Responses in rumen fermentation and milk-fat secretion in cows receiving low-roughage diets supplemented with protected tallow

1974 ◽  
Vol 41 (2) ◽  
pp. 165-173 ◽  
Author(s):  
J. E. Storry ◽  
P. E. Brumby ◽  
A. J. Hall ◽  
V. W. Johnson
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Dietary Supplement ◽  
Fatty Acid Synthesis ◽  
Milk Fat ◽  
Acid Synthesis ◽  
Rumen Fermentation ◽  
Total Fatty Acids ◽  
Friesian Cows

SummaryThe effects on rumen fermentation and milk-fat secretion of a dietary supplement of protected tallow given to 4 Friesian cows established on a low-roughage ration and with depressed milk fat is reported. The ratios of acetate to propionate in the rumen were unaffected by the supplement and remained typical of those associated with low-roughage diets in that the proportion of propionate was increased. The supplement produced almost complete recoveries in yield and content of milk fat without any increase in intramammary fatty-acid synthesis. The recoveries were due to transfer of about 20% of the total fatty acids of the tallow supplement. These results are discussed in relation to the effects of low-roughage diets on milk-fat secretion and it is concluded that in the ‘low-fat syndrome’ the capacity of the mammary gland to absorb preformed fatty acids is not impaired.

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