Ackman R G, Eaton C A, Kinneman J, Litchfield C
Lipids. 1975 Jan;10(1):44-9. doi: 10.1007/BF02532193.
The melon and jaw lipids of the freshwater dolphin Sotalia fluviatilis are composed mainly of isovaleroyl wax esters and diisovaleroyl triglycerides. The blubber fat contains only a trace of wax ester and is mostly tri-(long chain) and monoisovaleroyl triglycerides. Detailed gas liquid chromatographic analyses of the intact wax esters and triglycerides and of the derived fatty acids and fatty alcohols indicate common compositional patterns in the wax esters and triglycerides of the respective head lipids. Both odd and even long chain (C12-C16) isostructures are prominent in the melon and jaw lipids, but only higher odd chain length iso-acids are major components in the blubber. Sotalia fluviatilis (family Delphinidae) and Inia geoffrensis (family Platanistidae) share the same freshwater habitat in the upper Amazon River, and both utilize echolocation to navigate and to find food. Comparison of their respective bioacoustical lipid compositions show distinctive types of head fats, Sotalia being rich in iso-5:0 and Inia lacking iso-5:0. This indicates that iso-valeric acid per se has no obligatory role in dolphin echolocation.
淡水豚类亚马逊河豚的瓜脂和颌脂主要由异戊酰蜡酯和二异戊酰甘油三酯组成。鲸脂中仅含有微量蜡酯，主要是三（长链）甘油酯和单异戊酰甘油三酯。对完整蜡酯和甘油三酯以及衍生脂肪酸和脂肪醇进行的详细气相色谱分析表明，相应头部脂质的蜡酯和甘油三酯具有共同的组成模式。奇数和偶数长链（C12 - C16）异构体在瓜脂和颌脂中都很突出，但只有较高奇数链长的异酸是鲸脂中的主要成分。亚马逊河豚（海豚科）和亚马逊淡水豚（亚河豚科）在亚马逊河上游共享相同的淡水栖息地，并且都利用回声定位来导航和寻找食物。对它们各自生物声学脂质成分的比较显示出不同类型的头部脂肪，亚马逊河豚富含异戊酸（iso - 5:0），而亚马逊淡水豚缺乏异戊酸（iso - 5:0）。这表明异戊酸本身在海豚回声定位中没有必然作用。
