Implications of being born late in the active season for growth, fattening, torpor use, winter survival and fecundity

Mahlert, Britta; Gerritsmann, Hanno; Stalder, Gabrielle; Ruf, T.; Zahariev, Alexandre; Blanc, Stéphane; Giroud, Sylvain

doi:10.7554/elife.31225

Cited by 24 publications

(24 citation statements)

References 70 publications

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“…These diets were made by adding a 10-wt % of linseed oil as the source of n−3 fatty acids (notably ALA 18:3 n−3), or safflower oil as the source of n−6 fatty acids (mainly LA 18:2 n−6), or a 5-wt % of linseed oil and 5-wt % of safflower oil to the pellets with which animals are routinely fed in the colony (Topix, Saturn Petcare GmbH, Bremen, Germany). Details of the exact composition of the colony diet is available in Mahlert et al (2018) (Mahlert et al, 2018). This led to either low, intermediate or high amounts of LA, reversely mirrored by the contents of ALA, in the diets that were termed low LA ("LOW"), intermediate LA ("INT"), and high LA ("HIGH"), respectively.…”

Section: Dietsmentioning

confidence: 99%

The Ratio of Linoleic and Linolenic Acid in the Pre-hibernation Diet Influences NFκB Signaling in Garden Dormice During Torpor

Logan

Watts

Posautz

et al. 2020

Front. Mol. Biosci.

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The fatty acid composition of a pre-hibernation diet can influence the depth and duration of metabolic suppression achieved by hibernators. More specifically, a diet high in n−6 polyunsaturated fatty acids (PUFAs) relative to n−3 PUFAs is essential to maximize torpor expression. However, few studies have investigated how diets with different n−6/n−3 PUFA ratios change stress-inducible cell signaling. Garden dormice (Eliomys quercinus) were fed one of three diets designed with different ratios of n−6 PUFA linoleic acid (LA) and n−3 PUFA linolenic acid (ALA). Then, NFκB signaling was assessed in the white adipose, brown adipose, and liver tissues of euthermic and hibernating dormice via multiplex and RT-qPCR analyses of relative protein and transcript levels, respectively. Dormice fed a high LA diet regulated NFκB signaling in a protective manner in all tissues. NFκB signaling was generally decreased in the high LA group, with significant decreases in the protein levels of NFκB mediators IKKα/β, IκBα, and downstream pro-apoptotic protein FADD. Liver and white adipose from torpid dormice fed a high LA diet increased sod2 expression relative to the other diets or relative to euthermic controls, indicating protection against ROS generated from potentially increased β-oxidation of n−6 PUFAs. The low LA diet increased biomarkers for apoptosis relative to other diets and relative to euthermia, suggesting low LA diets may be detrimental to hibernator health. Overall, this study suggests that changes in the ratio of n−6/ n−3 PUFAs in the diet influences apoptotic and antioxidant responses in white adipose, brown adipose, and liver of hibernating garden dormice.

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Section: Dietsmentioning

confidence: 99%

The Ratio of Linoleic and Linolenic Acid in the Pre-hibernation Diet Influences NFκB Signaling in Garden Dormice During Torpor

Logan

Watts

Posautz

et al. 2020

Front. Mol. Biosci.

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“…During months of fasting and immobilization, hibernating bears are protected from thrombotic complications and muscle wasting (for review, see Stenvinkel et al 2018 ). Such phenomena are also known to occur in small hibernators (de Vrij et al 2014 ; Mahlert et al 2018 ), although their patterns of eicosanoids change differ from the one of the bears in this study. The understanding of such phenomena therefore clearly deserves further studies.…”

Section: Discussionmentioning

confidence: 42%

“…Although most physiological functions are downregulated during hibernation, hibernators are capable of maintaining the integrity of key organs and important tissues. For instance, cardiovascular function and brain integrity are preserved (Andrews 2007 ; Johansson 1996 ; Magariños et al 2006 ; von der Ohe et al 2006 ; von der Ohe et al 2007 ; Wang et al 2002 ), loss of muscle mass and strength are minimized (Harlow et al 2001 ; Lohuis et al 2007 ; Mahlert et al 2018 ), and bone structure is maintained (Mahlert et al 2018 ; McGee-Lawrence et al 2015 ). Given the large influence of eicosanoids, characterizing the seasonal changes of eicosanoid levels in hibernators is of great interest for determining whether eicosanoid metabolism might play a role in regulating these physiological processes.…”

Section: Introductionmentioning

confidence: 99%

Seasonal changes in eicosanoid metabolism in the brown bear

Giroud

Evans

Chery

et al. 2018

Sci Nat

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Polyunsaturated fatty acids (PUFAs) exert several important functions across organ systems. During winter, hibernators divert PUFAs from oxidation, retaining them in their tissues and membranes, to ensure proper body functions at low body temperature. PUFAs are also precursors of eicosanoids with pro- and anti-inflammatory properties. This study investigated seasonal changes in eicosanoid metabolism of free-ranging brown bears (Ursus arctos). By using a lipidomic approach, we assessed (1) levels of specific omega-3 and omega-6 fatty acids involved in the eicosanoid cascade and (2) concentrations of eicosanoids in skeletal muscle and blood plasma of winter hibernating and summer active bears. We observed significant seasonal changes in the specific omega-3 and omega-6 precursors. We also found significant seasonal alterations of eicosanoid levels in both tissues. Concentrations of pro-inflammatory eicosanoids, such as thromboxane B2, 5-hydroxyeicosatetraenoic acid (HETE), and 15-HETE and 18-HETE, were significantly lower in muscle and/or plasma of hibernating bears compared to summer-active animals. Further, plasma and muscle levels of 5,6-epoxyeicosatrienoic acid (EET), as well as muscle concentration of 8,9-EET, tended to be lower in bears during winter hibernation vs. summer. We also found lower plasma levels of anti-inflammatory eicosanoids, such as 15dPGJ2 and PGE3, in bears during winter hibernation. Despite of the limited changes in omega-3 and omega-6 precursors, plasma and muscle concentrations of the products of all pathways decreased significantly, or remained unchanged, independent of their pro- or anti-inflammatory properties. These findings suggest that hibernation in bears is associated with a depressed state of the eicosanoid cascade.

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“…Sealed capillary tubes were vacuum distilled for 10 min and the resulting water distillate analyzed by a continuous flow isotope ratio mass spectrometer (IRMS; IRMS-DELTA V PLUS, Thermo, Bremen, Germany) as described previously (Chery et al, 2015;Mahlert et al, 2018). Distillates were pyrolyzed at 1400°C into H 2 and CO 2 gases in a glassy carbon tube under pure He flow at 90 ml min −1 .…”

Section: Isotope Analysesmentioning

confidence: 99%

Subtle short-term physiological costs of an experimental augmentation of fleas in wild Columbian ground squirrels

Roth

Dobson

Criscuolo

et al. 2019

Journal of Experimental Biology

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Parasites affect many aspects of host physiology and behavior, and thus are generally thought to negatively impact host fitness. However, changes in form of short-term parasite effects on host physiological markers have generally been overlooked in favor of fitness measures. Here, we studied flea (Oropsylla idahoensis and Oropsylla opisocroistis tuberculata) parasitism on a natural population of Columbian ground squirrels (Urocitellus columbianus) in Sheep River Provincial Park, AB, Canada. Fleas were experimentally added to adult female U. columbianus at physiologically demanding times, including birth, lactation and weaning of their young. The body mass of adult females, as well as their oxidative stress and immunity were recorded multiple times over the active season under flea-augmented and control conditions. We also measured the prevalence of an internal parasite (Trypanosoma otospermophili). Doubly labeled water (DLW) was intraperitoneally injected at peak lactation to examine energy expenditure. Effects of parasites on oxidative stress were only observed after offspring were weaned. There was no direct effect of experimentally heightened flea prevalence on energy use. A short-term 24 h mass loss (−17 g) was detected briefly after parasite addition, likely due to U. columbianus preferentially allocating time for grooming. Our parasite augmentation did not strongly affect hosts and suggested that shortterm physiological effects were unlikely to culminate in long-term fitness consequences. Columbian ground squirrels appear to rapidly manage parasite costs, probably through grooming.

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Implications of being born late in the active season for growth, fattening, torpor use, winter survival and fecundity

Cited by 24 publications

References 70 publications

The Ratio of Linoleic and Linolenic Acid in the Pre-hibernation Diet Influences NFκB Signaling in Garden Dormice During Torpor

The Ratio of Linoleic and Linolenic Acid in the Pre-hibernation Diet Influences NFκB Signaling in Garden Dormice During Torpor

Seasonal changes in eicosanoid metabolism in the brown bear

Subtle short-term physiological costs of an experimental augmentation of fleas in wild Columbian ground squirrels

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