Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake
ABSTRACT: Conceptual models developed over the past century describe 2 key constraints to feed intake (FI) of healthy animals: gut capacity and metabolic demand. Evidence that greater energy demands (e.g., greater milk production) drive a corresponding increase in caloric intake led to the dominant...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-03-01
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| Series: | Journal of Dairy Science |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022030222007408 |
| _version_ | 1797897393346183168 |
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| author | Rodrigo I. Albornoz Katherine M. Kennedy Barry J. Bradford |
| author_facet | Rodrigo I. Albornoz Katherine M. Kennedy Barry J. Bradford |
| author_sort | Rodrigo I. Albornoz |
| collection | DOAJ |
| description | ABSTRACT: Conceptual models developed over the past century describe 2 key constraints to feed intake (FI) of healthy animals: gut capacity and metabolic demand. Evidence that greater energy demands (e.g., greater milk production) drive a corresponding increase in caloric intake led to the dominant concept that animals “eat to energy requirements.” Although this model provides reasonable initial estimates of FI, it lacks a proposed physiological basis for the control system, does not consider nutrient constraints beyond energy, and fails to explain differential energy intake responses to different fuels. To address these gaps, research has focused on mechanisms for sensing nutrient availability and providing feedback to hypothalamic centers that integrate signals to control feeding behavior. The elimination of FI response to certain nutrients by vagotomy suggests that peripheral tissues play a role in nutrient sensing. These findings and the central role of the liver in metabolic flux led to the development of the hepatic oxidation theory (HOT). According to the HOT, liver energy charge is the regulated variable that induces dietary intake changes and consequently affects whole-body energy balance. Evidence in support of HOT includes associations between hepatic energy charge and meal patterns, increased FI in response to phosphate trapping, and reduced FI in response to phosphate loading. In accordance with the HOT, infusion studies in dairy cattle have consistently demonstrated that providing fuels that either oxidize or stimulate oxidation in the liver decreases FI and energy intake to a greater extent than fuels that bypass the liver. Importantly, this holds true for glucose, which is readily oxidized by nerve cells, but is rarely taken up by the bovine liver. Although the brain integrates multiple signals including those related to gastric distention and illness, the HOT provides a physiological framework for understanding the dominant role the liver likely plays in sensing short-term energy status. Understanding this model provides insights into how to use or bypass the regulatory system to manage FI of animals. |
| first_indexed | 2024-04-10T07:56:47Z |
| format | Article |
| id | doaj.art-c3c15bf2ea8848ecb219583f2f290751 |
| institution | Directory Open Access Journal |
| issn | 0022-0302 |
| language | English |
| last_indexed | 2024-04-10T07:56:47Z |
| publishDate | 2023-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Dairy Science |
| spelling | doaj.art-c3c15bf2ea8848ecb219583f2f2907512023-02-23T04:29:43ZengElsevierJournal of Dairy Science0022-03022023-03-01106321612166Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intakeRodrigo I. Albornoz0Katherine M. Kennedy1Barry J. Bradford2Dairy Australia, Melbourne 3006 Australia; Corresponding authorResearch Institute for Farm Animal Biology, Dummerstorf 18196 GermanyDepartment of Animal Science, Michigan State University, East Lansing 48824ABSTRACT: Conceptual models developed over the past century describe 2 key constraints to feed intake (FI) of healthy animals: gut capacity and metabolic demand. Evidence that greater energy demands (e.g., greater milk production) drive a corresponding increase in caloric intake led to the dominant concept that animals “eat to energy requirements.” Although this model provides reasonable initial estimates of FI, it lacks a proposed physiological basis for the control system, does not consider nutrient constraints beyond energy, and fails to explain differential energy intake responses to different fuels. To address these gaps, research has focused on mechanisms for sensing nutrient availability and providing feedback to hypothalamic centers that integrate signals to control feeding behavior. The elimination of FI response to certain nutrients by vagotomy suggests that peripheral tissues play a role in nutrient sensing. These findings and the central role of the liver in metabolic flux led to the development of the hepatic oxidation theory (HOT). According to the HOT, liver energy charge is the regulated variable that induces dietary intake changes and consequently affects whole-body energy balance. Evidence in support of HOT includes associations between hepatic energy charge and meal patterns, increased FI in response to phosphate trapping, and reduced FI in response to phosphate loading. In accordance with the HOT, infusion studies in dairy cattle have consistently demonstrated that providing fuels that either oxidize or stimulate oxidation in the liver decreases FI and energy intake to a greater extent than fuels that bypass the liver. Importantly, this holds true for glucose, which is readily oxidized by nerve cells, but is rarely taken up by the bovine liver. Although the brain integrates multiple signals including those related to gastric distention and illness, the HOT provides a physiological framework for understanding the dominant role the liver likely plays in sensing short-term energy status. Understanding this model provides insights into how to use or bypass the regulatory system to manage FI of animals.http://www.sciencedirect.com/science/article/pii/S0022030222007408hepatic oxidationenergy chargehomeostasis |
| spellingShingle | Rodrigo I. Albornoz Katherine M. Kennedy Barry J. Bradford Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake Journal of Dairy Science hepatic oxidation energy charge homeostasis |
| title | Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake |
| title_full | Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake |
| title_fullStr | Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake |
| title_full_unstemmed | Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake |
| title_short | Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake |
| title_sort | symposium review fueling appetite nutrient metabolism and the control of feed intake |
| topic | hepatic oxidation energy charge homeostasis |
| url | http://www.sciencedirect.com/science/article/pii/S0022030222007408 |
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