Energy Expenditure During Lactation in Relation to Litter Size in Free-Living Golden-Mantled Ground Squirrels

Kenagy, G. J.; Masman, Dirkjan; Sharbaugh, Susan M.; Nagy, Kenneth A.

doi:10.2307/5159

Cited by 102 publications

(64 citation statements)

References 36 publications

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“…However, it is notable that neither the food intake nor energy output of the LS-18 group was significantly higher than that of the LS-12 group. These data are consistent with the results of previous research on mice (Hammond et al, 1996;Zhao et al, 2010aZhao et al, , 2013aZhao, 2012) and other rodent species (Fiorotto et al, 1991;Kenagy et al, 1990;Rogowitz, 1996;Zhao et al, 2010a), suggesting that there are limits to SusEI during lactation (Hammond and Diamond, 1997;Koteja, 1996a,b;Speakman and Król, 2005). SusEI in lactating Swiss mice is probably already at maximum capacity and females are consequently unable to increase milk production to support more than 12 pups (Zhao et al, 2010b).…”

Section: The Effects Of Litter Size On Energy Balancesupporting

confidence: 83%

Sustained energy intake in lactating Swiss mice: a dual modulation process

Wen

Tan

Qiao

et al. 2017

Journal of Experimental Biology

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Limits to sustained energy intake (SusEI) during lactation are important because they provide an upper boundary below which females must trade off competing physiological activities. To date, SusEI is thought to be limited either by the capacity of the mammary glands to produce milk (the peripheral limitation hypothesis) or by a female's ability to dissipate body heat (the heat dissipation hypothesis). In the present study, we examined the effects of litter size and ambient temperature on a set of physiological, behavioral and morphological indicators of SusEI and reproductive performance in lactating Swiss mice. Our results indicate that energy input, energy output and mammary gland mass increased with litter size, whereas pup body mass and survival rate decreased. The body temperature increased significantly, while food intake (18 g day −1 at 21°C versus 10 g day −1 at 30°C), thermal conductance (lower by 20-27% at 30°C than 21°C), litter mass and milk energy output decreased significantly in the females raising a large litter size at 30°C compared with those at 21°C. Furthermore, an interaction between ambient temperature and litter size affected females' energy budget, imposing strong constraints on SusEI. Together, our data suggest that the limitation may be caused by both mammary glands and heat dissipation, i.e. peripheral limitation is dominant at room temperature, but heat dissipation is more significant at warm temperatures. Further, the level of the heat dissipation limits may be temperature dependent, shifting down with increasing temperature.

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Section: The Effects Of Litter Size On Energy Balancesupporting

confidence: 83%

Sustained energy intake in lactating Swiss mice: a dual modulation process

Wen

Tan

Qiao

et al. 2017

Journal of Experimental Biology

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“…If the energy allocation to pups is decreased, it may retard their growth or cause mortality, but on the positive side, it could reduce maternal risk, particularly if maternal ability to increase energy assimilation is limited (cf. Kenagy et al, 1989Kenagy et al, , 1990Mover et al, 1989;Diamond, 1992, 1994).…”

Section: A Case Study: Constraints On Lactation In Slgmodon H1spidusmentioning

confidence: 99%

“…Mothers appear to approach an upper limit or "ceiling" to their rate of energy assimilation during lactation (Kenagy et al, 1989(Kenagy et al, , 1990Mover et al, 1989;Diamond 1992, 1994 ing lactation, digestive accommodation can occur in which the gut expands and becomes more absorptive (Souders and Morgan, 1957;Fell et al, 1963). However, the increase in nutrient uptake associated with gut hypertrophy may not keep pace with the increase in food intake at peak lactation (Hammond and Diamond, 1992).…”

Section: Introductionmentioning

confidence: 99%

Trade-offs in Energy Allocation During Lactation

Rogowitz

1996

Am Zool

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SYNOPSIS. During lactation, mothers require energy to meet both maternal and offspring requirements. If a mother exports too much energy to dependent offspring (in milk), her weight loss may be excessive and maternal risk may increase. Conversely, too little energy allocation to offspring may reduce the growth rate or induce mortality of dependent offspring. This paradigm was evaluated in cotton rats (Sigmodon hispidus) supporting small (3 pup) and large (6 pup) litters from early to late lactation. Several types of evidence indicate that physiological constraints limit the ability of mothers with large litters to provide resources to offspring. Mothers with large litters produced a dilute, energy-poor milk and their rates of food intake, weight loss and energy export per litter appeared to approach physiological maxima. Whereas the energy exported to pups in small litters increased from early to late lactation, the energy flow per pup in large litters was consistently low; consequently, offspring in large litters had low growth rates. An increase in either maternal food intake or weight loss (catabolism of maternal tissue) could have provided additional energy to offset the low growth rate of pups in large litters. However, mothers with large litters did not substantially increase their food intake or weight loss compared with mothers supporting small litters. These results indicate that the maternal support of offspring in large litters is limited. The pattern of energy allocation shown by cotton rats with large litters likely reflects a compromise between meeting maternal and offspring energy requirements (cf., Parker and Macnair, 1979). The energy flow is greater than optimal for the parent but less than optimal for the offspring. Less maternal-offspring conflict occurs in small than large litters because offspring in small litters maintain a high growth rate at a relatively low maternal cost. Yet, under favorable environmental conditions, the reduction in maternal-offspring conflict has no apparent fitness benefit.

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“…I 522-215212006n903-4166$15.00 cation decisions between two or more processes compete for a limited amount of resources (Stearns 1992). Studying phys iology helps to illuminate the mechanisms that cause these trade-offs, leading to a better understanding of allocation de cisions and life-history constraints (Kenagy et al 1990;Stearns 1992). Understanding how females maximize their reproductive success is particularly important because females are usually the limiting sex due to their greater investment in the offspring (Trivers 1972).…”

Section: Introductionmentioning

confidence: 99%

Physiology and Behavior Influence Lactation Efficiency in Northern Elephant Seals (Mirounga angustirostris)

McDonald

Crocker

2006

Physiological and Biochemical Zoology

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The efficiency with which mothers convert acquired energy into milk is a key determinant of the magnitude of parental in vestment in mammals; however, the mech~isms underlying lactation efficiency are poorly understood. Investigations on northern elephant seals have shown lactation efficiency, mea sured as the proportion of total energy expenditure that goes to the pup as milk, increases with age. In a cross-sectional study the physiological and behavioral determinants of lactation ef ficiency were investigated in eight young and seven prime (older) elephant seals by conducting behavioral observations and collecting milk, blood, and tissue on days 3 and 22 of lactation. Milk composition, circulating fatty acid and triglyc eride concentrations, and mammary and blubber lipoprotein lipase activity were determined. Prime females had significantly greater percent milk fat and circulating fatty acids on day 3 than did young females, but these differences disappeared by day 22. The ability for prime females to produce higher-energy milk early in lactation may allow them to increase lactation efficiency by increasing the rate of energy transfer. In addition, prime females spent significantly more time resting. A com bination of reduced activity and more rapid energy delivery likely explains the increase in lactation efficiency with age found in a previous study.

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Energy Expenditure During Lactation in Relation to Litter Size in Free-Living Golden-Mantled Ground Squirrels

Cited by 102 publications

References 36 publications

Sustained energy intake in lactating Swiss mice: a dual modulation process

Sustained energy intake in lactating Swiss mice: a dual modulation process

Trade-offs in Energy Allocation During Lactation

Physiology and Behavior Influence Lactation Efficiency in Northern Elephant Seals (Mirounga angustirostris)

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