MASS CHANGES AND METABOLISM DURING THE PERINATAL FAST - A COMPARISON BETWEEN ANTARCTIC (ARCTOCEPHALUS-GAZELLA) AND GALAPAGOS FUR SEALS (ARCTOCEPHALUS-GALAPAGOENSIS)
MASS CHANGES AND METABOLISM DURING THE PERINATAL FAST - A COMPARISON BETWEEN ANTARCTIC (ARCTOCEPHALUS-GAZELLA) AND GALAPAGOS FUR SEALS (ARCTOCEPHALUS-GALAPAGOENSIS)
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DOI：
10.1086/physzool.61.2.30156147
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发表时间：
1988-03-01
期刊：
影响因子：
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通讯作者：
TRILLMICH, F
中科院分区：
文献类型：
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作者：
COSTA, DP;TRILLMICH, F
测量了南极和加拉帕戈斯毛海豹雌性海豹在围产期的体重损失和代谢率以及幼崽体重的变化。南极毛海豹雌性海豹的体重减少了3.15%，即每天减少1.231公斤，它们最初的体重约为39公斤。体重较大的雌鸟生下较重的幼鸟(r=.644，P<；.05；n=12)，每天的体重损失明显多于较小的雌鸟(r=.796，P<；.01；n=12)。相比之下，加拉帕戈斯雌性毛海豹(37.4kgd-1)的体重减去了一半(1.68%day-1；0.639 kgday-1)。用双标记水法测定，南极毛海豹的代谢率(4.56W kg-1)显著高于加拉帕戈斯毛海豹(1.49W kg-1)。我们认为，加拉帕戈斯毛海豹雌性海豹的低代谢率是对赤道温暖栖息地陆地上热应激的一种适应。对水流入的代谢率的测量高估了用双标记水法测量的南极海豹的新陈代谢只有3.2%，而饮用海水排除了它在加拉帕戈斯海豹中的使用。非哺乳期南极毛海豹的代谢率与哺乳期个体的代谢率没有差异。这与其他研究是一致的，这些研究表明，哺乳成本主要与牛奶的能量含量有关，由于牛奶合成成本的增加，新陈代谢几乎或没有明显增加。使用全身水分测定(57.2%加拉帕戈斯群岛；59.7%南极)估计分娩时总脂肪含量分别为26%和22%。因为这只有大约一半的报告，对于有磷的雌性，我们认为更多的脂肪储存的磷海豹是使它们在整个哺乳期禁食的一个主要因素。
Female mass loss and metabolic rate were measured along with changes in pup mass during the perinatal period in Antarctic and Galapagos fur seals. Antarctic fur seal females lost 3.15%, or 1.231 kg per day, of their initial body mass of roughly 39 kg. Heavier females gave birth to heavier young (r = .644, P < .05; n = 12) and lost significantly more mass per day than did smaller females (r = .796, P < .01; n = 12). In contrast, Galapagos fur seal females (37.4 kg) lost half as much mass per day (1.68% day-1; 0.639 kg day-1). Metabolic rates, determined by the doubly labeled water method, were considerably higher in Antarctic fur seals (4.56 W kg-1) than Galapagos fur seals (1.49 W kg-1). We suggest that the lower metabolic rate of Galapagos fur seal females is an adaptation to reduce thermal stress on land in the warm equatorial habitat. Measurements of metabolic rate from water influx overestimated metabolism measured with the doubly labeled water method by only 3.2% in Antarctic fur seals, while seawater drinking precluded its use in Galapagos fur seals. Metabolic rates of nonlactating Antarctic fur seals were not different from those of lactating individuals. This is consistent with other studies, which indicates that the cost of lactation is primarily associated with the energy content of milk, with little or no measurable increase in metabolism owing to the cost milk synthesis. Total body water determinations (57.2% Galapagos; 59.7% Antarctic) were used to estimate a total fat content of 26% and 22% at parturition, respectively. Because this is only about half that reported for phocid females, we suggest that the greater fat stores of phocid seals are a major factor enabling them to fast throughout lactation.