scholarly journals Impact of post-ruminally infused macronutrients on bovine mammary gland expression of genes involved in fatty acid synthesis, energy metabolism, and protein synthesis measured in RNA isolated from milk fat

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kelly Nichols ◽  
André Bannink ◽  
Jurgen van Baal ◽  
Jan Dijkstra
1974 ◽  
Vol 41 (2) ◽  
pp. 165-173 ◽  
Author(s):  
J. E. Storry ◽  
P. E. Brumby ◽  
A. J. Hall ◽  
V. W. Johnson

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.


1972 ◽  
Vol 128 (3) ◽  
pp. 509-519 ◽  
Author(s):  
Christopher R. Strong ◽  
Isabel Forsyth ◽  
Raymond Dils

1. When freshly prepared explants from pseudopregnant-rabbit mammary gland were incubated with sodium [1-14C]acetate plus glucose, they synthesized triglyceride and phospholipid containing long-chain fatty acids. Explants cultured with insulin and corticosterone also synthesized these products. The addition of prolactin to this culture medium increased the rate of fatty acid synthesis up to 40-fold and the explants synthesized predominantly triglyceride enriched with C8:0 and C10:0 fatty acids characteristic of rabbit milk. 2. The maximum rates of fatty acid synthesis obtained by explants from pseudopregnant-rabbit mammary gland after culture with insulin, corticosterone and prolactin were similar to those observed with freshly prepared explants from lactating-rabbit mammary gland. The time in culture required to attain these maximum rates varied between animals, and did not appear to be connected with the time required (6–7 days) to synthesize the maximum proportions of C8:0 and C10:0 acids. 3. As the pattern of short- and medium-chain milk fatty acids is characteristic for many species, the techniques described to determine the time-course for the development of this pattern can be used to investigate hormonal response.


1983 ◽  
Vol 99 (2) ◽  
pp. 261-268 ◽  
Author(s):  
J. V. Smith ◽  
I. R. Falconer

The possible role of K+ as a 'second messenger' for prolactin was investigated. Explants obtained from mammary glands of pseudopregnant rabbits were cultured (a) in media with varying potassium concentrations and (b) in the presence of the potassium-specific ionophore, nigericin. The explants were examined histologically and the rate of protein synthesis was measured to determine the viability of the tissue. Increase in the rate of fatty acid synthesis in the presence of prolactin was used as a marker of prolactin stimulation. At low K+ concentrations prolactin-stimulated fatty acid synthesis decreased with the decrease in K+ concentration of the media, whereas there was no similar trend in the rate of protein synthesis. Nigericin (0·01–0·1 μmol/l) inhibited fatty acid synthesis and protein synthesis in the presence or absence of prolactin without significantly affecting tissue K+ content. The mechanism of nigericin inhibition is hence unclear and the results do not provide support for K+ as a 'second messenger' for prolactin.


1989 ◽  
Vol 259 (3) ◽  
pp. 925-927 ◽  
Author(s):  
S A McCune ◽  
L G Foe ◽  
R G Kemp ◽  
R R Jurin

Aurintricarboxylic acid (ATA) was found to be a very potent inhibitor of purified rabbit liver phosphofructokinase (PFK), giving 50% inhibition at 0.2 microM. The inhibition was in a manner consistent with interaction at the citrate-inhibitory site of the enzyme. The data suggest that inhibition of PFK by ATA was not due to denaturation of the enzyme or the irreversible binding of inhibitor, since the inhibition could be reversed by addition of allosteric activators of PFK, i.e. fructose 2,6-bisphosphate or AMP. Two other tricarboxylic acids, agaric acid and (-)-hydroxycitrate, were found to inhibit PFK. ATA at much higher concentrations (500 microM) was shown to inhibit fatty acid synthesis from endogenous glycogen in rat hepatocytes; however, protein synthesis was not altered.


2020 ◽  
Vol 11 (10) ◽  
pp. 8625-8636
Author(s):  
Zhi Chen ◽  
Shuangfeng Chu ◽  
Yusheng Liang ◽  
Tianle Xu ◽  
Yujia Sun ◽  
...  

Both mRNA and miRNA play an important role in the regulation of mammary fatty acid metabolism and milk fat synthesis.


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