Brown adipose tissue in cetacean blubber.

Area of Science:

• Marine Biology
• Physiology
• Zoology

Background:

• Brown adipose tissue (BAT) is crucial for thermoregulation in cold environments.
• Cetacean blubber primarily serves insulation, energy storage, and streamlining.
• The presence and function of BAT in cetaceans remain largely unexplored.

Purpose of the Study:

• To investigate the existence and distribution of BAT within the blubber of four delphinoid cetacean species.
• To determine the functional implications of BAT in cetacean thermoregulation.

Main Methods:

• Histological analysis of blubber tissue from dolphins and porpoises.
• Biochemical analysis using Western blot to detect uncoupling protein 1 (UCP1).
• Computed tomography (CT) scanning of cetacean cadavers to map tissue distribution.

Main Results:

• Histology confirmed the presence of adipocytes with characteristics of BAT in the innermost blubber layers.
• Uncoupling protein 1 (UCP1), a marker for BAT, was detected specifically in these adipocytes.
• CT scans revealed a continuous layer of BAT throughout the cetacean body, excluding the rostrum, fin, and fluke.

Conclusions:

• Delphinoid cetaceans possess functional brown adipose tissue (BAT) within their blubber.
• This BAT likely contributes to thermoregulation, enabling marine mammals to inhabit cooler waters.
• BAT may provide an additional thermoregulatory mechanism beyond insulation, particularly during inactivity.