Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA.
Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA.
J Comp Physiol B. 2022 Jul;192(3-4):529-540. doi: 10.1007/s00360-022-01437-6. Epub 2022 May 3.
Omega 3 polyunsaturated fatty acids (PUFAs) are well-documented for their influence on health and weight loss. Recent studies indicate omega 3 PUFAs may exert a negative impact on cellular stress and physiology in some hibernators. We asked if physiological stress indicators, lipid peroxidation and mass gain in Arctic Ground Squirrels (AGS) were negatively influenced by naturally occurring dietary omega 3 PUFA levels compared to omega 3 PUFA levels found in common laboratory diets. We found plasma fatty acid profiles of free-ranging AGS to be high in omega 3 PUFAs with balanced omega 6:3 ratios, while standard laboratory diets and plasma of captive AGS are high in omega 6 and low in omega 3 PUFAs with higher omega 6:3 ratios. Subsequently, we designed a diet to mimick free-range AGS omega 6:3 ratios in captive AGS. Groups of wild-caught juvenile AGS were either fed: (1) Mazuri Rodent Chow (Standard Rodent chow, 4.95 omega 6:3 ratio), or (2) balanced omega 6:3 chow (Balanced Diet, 1.38 omega 6:3). AGS fed the Balanced Diet had plasma omega 6:3 ratios that mimicked plasma profiles of wild AGS. Balanced Diet increased female body mass before hibernation, but did not influence levels of cortisol in plasma or levels of the lipid peroxidation product 4-HNE in brown adipose tissue. Overall, as the mass gain is critical during pre-hibernation for obligate hibernators, the results show that mimicking a fatty acid profile of wild AGS facilitates sex-dependent mass accumulation without increasing stress indicators.
ω-3 多不饱和脂肪酸（PUFA）对健康和减肥的影响已有充分的文献记载。最近的研究表明，ω-3PUFA 可能对某些冬眠动物的细胞应激和生理产生负面影响。我们想知道，与常见实验室饮食中发现的 ω-3PUFA 水平相比，北极地松鼠（AGS）饮食中天然存在的 ω-3PUFA 水平是否会对生理应激指标、脂质过氧化和体重增加产生负面影响。我们发现，自由放养的 AGS 血浆脂肪酸谱中 ω-3PUFA 含量较高，ω-6:3 比例平衡，而标准实验室饮食和圈养 AGS 的血浆中 ω-6 含量较高，ω-3PUFA 含量较低，ω-6:3 比例较高。随后，我们设计了一种饮食来模拟圈养 AGS 中的自由放养 AGS ω-6:3 比例。将野生幼年 AGS 分组，分别喂食：（1）Mazuri 啮齿动物饲料（标准啮齿动物饲料，ω-6:3 比例为 4.95），或（2）平衡 ω-6:3 饲料（平衡饮食，ω-6:3 比例为 1.38）。喂食平衡饮食的 AGS 血浆 ω-6:3 比例与野生 AGS 的血浆谱相似。平衡饮食增加了雌性在冬眠前的体重，但对血浆中皮质醇水平或棕色脂肪组织中脂质过氧化产物 4-HNE 的水平没有影响。总体而言，由于在冬眠前体重增加对于必需冬眠动物至关重要，因此研究结果表明，模拟野生 AGS 的脂肪酸谱有助于性别依赖性体重增加，而不会增加应激指标。
