Control of fatty acid synthesis in lactation

Vernon, Richard G.; Flint, David

doi:10.1079/pns19830035

Cited by 61 publications

(48 citation statements)

References 90 publications

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“…In rats, the extent of decrease in thermogenic capacity is related to litter size (Isler et al 1984), but this does not appear to be the case in mice ( Trayhurn & Wusterman 1987a,b). These morphological, physiological and biochemical changes in BATappear to be controlled by reduced sympathetic activity in lactation (Trayhurn & Wusterman 1987a,b), which may be responsive to elevated corticosteroid levels ( Vernon & Flint 1983). Treatment of lactating rats with exogenous leptin completely reversed the downregulation of UCP-1 gene expression in BAT (Xiao et al 2004).…”

Section: Indirect Costs (A) Optional Compensatory Costs (I) Thermoregmentioning

confidence: 99%

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The physiological costs of reproduction in small mammals

Speakman

2007

Phil. Trans. R. Soc. B

654

694

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Life-history trade-offs between components of fitness arise because reproduction entails both gains and costs. Costs of reproduction can be divided into ecological and physiological costs. The latter have been rarely studied yet are probably a dominant component of the effect. A deeper understanding of life-history evolution will only come about once these physiological costs are better understood. Physiological costs may be direct or indirect. Direct costs include the energy and nutrient demands of the reproductive event, and the morphological changes that are necessary to facilitate achieving these demands. Indirect costs may be optional 'compensatory costs' whereby the animal chooses to reduce investment in some other aspect of its physiology to maximize the input of resource to reproduction. Such costs may be distinguished from consequential costs that are an inescapable consequence of the reproductive event. In small mammals, the direct costs of reproduction involve increased energy, protein and calcium demands during pregnancy, but most particularly during lactation. Organ remodelling is necessary to achieve the high demands of lactation and involves growth of the alimentary tract and associated organs such as the liver and pancreas. Compensatory indirect costs include reductions in thermogenesis, immune function and physical activity. Obligatory consequential costs include hyperthermia, bone loss, disruption of sleep patterns and oxidative stress. This is unlikely to be a complete list. Our knowledge of these physiological costs is currently at best described as rudimentary. For some, we do not even know whether they are compensatory or obligatory. For almost all of them, we have no idea of exact mechanisms or how these costs translate into fitness trade-offs.

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Section: Indirect Costs (A) Optional Compensatory Costs (I) Thermoregmentioning

confidence: 99%

“…A response to hyperthermia might be to direct blood flow away from the mammary glands to other peripheral areas to dissipate heat by vasodilatation (Black et al 1993). Blood flow in the mammary glands has been shown to have a direct effect on milk production (Vernon & Flint 1983).…”

Section: Direct Costs (A) Increased Demand For Energy and Nutrients (mentioning

confidence: 99%

The physiological costs of reproduction in small mammals

Speakman

2007

Phil. Trans. R. Soc. B

654

694

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“…The main point about control of the faty acids synthesis is the acetyl-CoA carboxylase, and it seems that the Fatty Acidsendocrine control is very similar in, at least, adipose tissue (insulin activation, inhibition of catecholamine) of ruminants and nonruminants [48].…”

Section: Genetic Markers and Metabolic Pathways Associated With Meat mentioning

confidence: 99%

Genetic Factors that Determine the Meat Fatty Acids Composition

Lemos¹,

Pereira²,

Regatieri³

et al. 2017

Fatty Acids

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In relation the nutritional atributes of beef meat quality, the composition of faty acid is important not only because it afects the meat palatability, but also it can afect the human health. The faty acids harmful to human health have received atenuating atention in recent years. Some studies, with taurine breed, have shown that there is a genetic variation for the trait faty acid proile of the meat and, therefore, the possibility of genetic improvement of this trait in beef catle. Meantime, in zebu catle, the genetic parameter estimates for faty acid proile are scarce. Furthermore, the trait meat faty acid proile is something diicult and costly to measure and for this kind of trait is indicated the use of genomic selection, which is a type of marker-assisted selection. The objective of this chapter is showing the genetic variability of meat faty acid proile diferent catle breeds and makes an approach of the implement models and methods that use genomic information to improve the faty acid composition of beef meat.

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“…The involvement of insulin in the maintenance of glucose homeostasis is well known (McDowell, 1983), the hormone acting in concert with glucagon, catecholamines and the sympathetic nervous system. Homeorhetic changes in adipose tissue metabolism during pregnancy and lactation involve changes in the ability of insulin to stimulate lipogenesis and inhibit lipolysis, mediated by progesterone, prolactin and growth hormone modifying either the numbers of insulin receptors present or the responsiveness of intracellular metabolism to insulin (Vernon & Flint, 1983). Similarly changes in the proportions of protein and fat deposited during growth in ruminants may reflect changes in the relative ability of insulin to stimulate net protein and fat deposition, under homeorhetic regulation by changing growth hormone and cortisol secretion (Weekes, 1986).…”

Section: Hormonal Co-ordination Of Metabolismmentioning

confidence: 99%

Key hormonal and metabolic control systems modifying nutrient use

Weekes

1986

Proc. Nutr. Soc.

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University of Newcastle upon T y e , Newcastle upon Tyne NEI 7RUThis review focuses on the mechanisms by which the n e m d o c r i n e environment of a ruminant animal participates in the control of nutrient use. Examples of the regulation of ruminant carbohydrate metabolism are used to illustrate the type of information required to obtain a quantitative description of endocrine control of metabolism. Finally, attention is directed to an example of a metabolic response, that to exercise, in which a quantitative analysis of hormone actions will be of value. Metabolic pathwaysMetabolic pathways have traditionally been treated as a series of enzyme-catalysed chemical reactions taking place within a specific tissue. The majority of such pathways involved in the metabolism of absorbed nutrients, energy provision and energy storage have apparently been identilied and partially characterized in ruminant tissues. Some uncertainties remain, for instance the pathway of ketogenesis in the rumen epithelium (Emmanuel et al. 1982), but interest is increasingly directed to quantitative measurements of flux through the pathways and their control. T o understand the way in which nutrients are partitioned between competing anabolic and catabolic processes, a wider concept of a metabolic pathway is required, starting from either absorption of a nutrient input or nutrient mobilization from a tissue store. Following transport through the blood stream, nutrients are taken up and metabolized by one or more tissues before finally being excreted or deposited in a storage form. Within such an extended metabolic pathway, flux may be regulated by extracellular neuro-endocrine control of tissue blood flow and nutrient transport as well as by intracellular acute regulation of enzyme activities by substrates, products and allosteric effectors and chronic regulation of enzyme amount and the ability of the tissue to respond to acute regulation.Recent theories of metabolic regulation propounded by Kacser & Burns (1979) suggest that flux through a metabolic pathway is not wholly controlled by a single 'rate-limiting' step but rather that control is shared to varying degrees by all steps in a pathway. The size of the control coefficient for an individual reaction depends on the environment of the whole pathway, rather than being a fixed property of an individual enzyme. This concept has been used to study the control of mitochondrial respiration (Groen et al. 1982) and may prove useful in understanding regulation of ruminant metabolism in the future, although theoretical difficulties do exist with this approach (Crabtree & Newsholme, 1985).at https://www.cambridge.org/core/terms. https://doi

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Control of fatty acid synthesis in lactation

Cited by 61 publications

References 90 publications

The physiological costs of reproduction in small mammals

The physiological costs of reproduction in small mammals

Genetic Factors that Determine the Meat Fatty Acids Composition

Key hormonal and metabolic control systems modifying nutrient use

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