Energy partitioning and growth in mice selected for high and low body weight

Stephenson, SK; Malik, R. S.

doi:10.1017/s0016672300026100

Cited by 9 publications

(4 citation statements)

References 32 publications

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“…A value of 2 KJg Ϫ1 day Ϫ1 was chosen to represent the basal metabolic rate of the house mouse, averaged over an extensive dataset (Mychra et al 1969;Mychra 1975;Studier 1979;Bronson 1984;Stephenson and Malik 1984;Kö nig et al 1988;Manning and Bronson 1990;Mutze et al 1991;Hayes et al 1992;Hammond et al 1994;Richardson et al 1994). Half of this energy is used in essential service functions and the remaining half is available for cell maintenance functions.…”

Section: Model Parametersmentioning

confidence: 99%

Calorie Restriction and Aging: A Life-History Analysis

Shanley¹,

Kirkwood²

2000

Evolution

267

191

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Abstract. The disposable soma theory suggests that aging occurs because natural selection favors a strategy in which fewer resources are invested in somatic maintenance than are necessary for indefinite survival. However, laboratory rodents on calorie-restricted diets have extended life spans and retarded aging. One hypothesis is that this is an adaptive response involving a shift of resources during short periods of famine away from reproduction and toward increased somatic maintenance. The potential benefit is that the animal gains an increased chance of survival with a reduced intrinsic rate of senescence, thereby permitting reproductive value to be preserved for when the famine is over.We describe a mathematical life-history model of dynamic resource allocation that tests this idea. Senescence is modeled as a change in state that depends on the resources allocated to maintenance. Individuals are assumed to allocate the available resources to maximize the total number of descendants. The model shows that the evolutionary hypothesis is plausible and identifies two factors, both likely to exist, that favor this conclusion. These factors are that survival of juveniles is reduced during periods of famine and that the organism needs to pay an energetic ''overhead'' before any litter of offspring can be produced. If neither of these conditions holds, there is no evolutionary advantage to be gained from switching extra resources to maintenance. The model provides a basis to evaluate whether the life-extending effects of calorie-restriction might apply in other species, including humans.

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Section: Model Parametersmentioning

confidence: 99%

Calorie Restriction and Aging: A Life-History Analysis

Shanley¹,

Kirkwood²

2000

Evolution

267

191

View full text Add to dashboard Cite

show abstract

“…Maintenance. A value of 2 KJg Ϫ1 day Ϫ1 was chosen to represent the basal metabolic rate of the house mouse, averaged over an extensive dataset (Mychra et al 1969;Mychra 1975;Studier 1979;Bronson 1984;Stephenson and Malik 1984;Kö nig et al 1988;Manning and Bronson 1990;Mutze et al 1991;Hayes et al 1992;Hammond et al 1994;Richardson et al 1994). Half of this energy is used in essential service functions and the remaining half is available for cell maintenance functions.…”

Section: Model Parametersmentioning

confidence: 99%

Calorie Restriction and Aging: A Life-History Analysis

Shanley

Kirkwood

2000

Evol

View full text Add to dashboard Cite

The disposable soma theory suggests that aging occurs because natural selection favors a strategy in which fewer resources are invested in somatic maintenance than are necessary for indefinite survival. However, laboratory rodents on calorie-restricted diets have extended life spans and retarded aging. One hypothesis is that this is an adaptive response involving a shift of resources during short periods of famine away from reproduction and toward increased somatic maintenance. The potential benefit is that the animal gains an increased chance of survival with a reduced intrinsic rate of senescence, thereby permitting reproductive value to be preserved for when the famine is over.We describe a mathematical life-history model of dynamic resource allocation that tests this idea. Senescence is modeled as a change in state that depends on the resources allocated to maintenance. Individuals are assumed to allocate the available resources to maximize the total number of descendants. The model shows that the evolutionary hypothesis is plausible and identifies two factors, both likely to exist, that favor this conclusion. These factors are that survival of juveniles is reduced during periods of famine and that the organism needs to pay an energetic ''overhead'' before any litter of offspring can be produced. If neither of these conditions holds, there is no evolutionary advantage to be gained from switching extra resources to maintenance. The model provides a basis to evaluate whether the life-extending effects of calorie-restriction might apply in other species, including humans.

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“…If it is ascertained that providing nesting materials is advantageous e.g. by promoting natural behaviours, increasing behavioural diversity, or decreasing food intake with no effect on growth (Lacy et al 1978, Stephenson & Malik 1984, it could be argued that we should routinely supply these materials to both breeding and non-breeding animals. But, if provision of such environmental enrichment is to be widely adopted, the desired changes to behaviour or performance of the appropriate activity should be expressed by a large proportion of the population.…”

mentioning

confidence: 99%

Observations on the prevalence of nest-building in non-breeding TO strain mice and their use of two nesting materials

Sherwin

1997

Lab Anim

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SummaryThe spontaneous performance of nest-building behaviour by non-breeding laboratory mice suggests that routinely providing nesting material might be a suitable environmental enrichment. If nesting material is to be provided routinely, this should have characteristics which are preferred, or at least accepted by a considerable proportion of the animal population; it should also be inexpensive. The present study therefore examined the prevalence of nest-building behaviour in 39 individually-housed, non-breeding, female mice, and their preferences for a commercial nesting product and a less expensive source of material (paper towels). Within minutes of the materials being placed in the cages, the mice began manipulating the paper towels. Thirty-six of the mice subsequently constructed nests during the first dark phase after the materials had been placed in the cage -the remaining three mice constructed nests during the following 48 h. The nests were usually constructed from a mixture of the two materials, though observations indicated the mice might have preferred characteristics of the inexpensive paper towels. There was a strong tendency to build nests in the same location used for sleeping prior to the nesting material being provided, and similarly, the mice were conservative in the site chosen to build a second nest after the first was removed. The most frequently chosen site for nest-building was under the feeder. Other studies have reported a high motivation for nest-building behaviour, widespread performance amongst many strains, and nest-building as a thermoregulatory behaviour by animals housed in standard laboratory air temperature. In conjunction with these findings, the present results suggest that routinely providing paper towels is an inexpensive and practical means of environmental enrichment for non-breeding, laboratory mice.

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Energy partitioning and growth in mice selected for high and low body weight

Cited by 9 publications

References 32 publications

Calorie Restriction and Aging: A Life-History Analysis

Calorie Restriction and Aging: A Life-History Analysis

Calorie Restriction and Aging: A Life-History Analysis

Observations on the prevalence of nest-building in non-breeding TO strain mice and their use of two nesting materials

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