Fatty acid composition and intramolecular structure of triglycerides from adipose tissue of the red deer and the reindeer

Abstract

Rowett Research Institute, Bucksburn, Aberdeen, AB2 9SBTriglycerides extracted from perinephric, omental and subcutaneous adipose tissue of six female red deer and of two male and one female reindeer were analysed for the composition and intramolecular disposition of their component fatty acids.In their overall fatty acid composition, the triglycerides of normal and pregnant red deer were similar and resembled those of domesticated ruminants; trans‐unsaturated acids were present and the perinephric triglycerides contained a relatively high proportion of stearic acid compared with triglycerides from other bodily sites. The triglycerides from corresponding adipose tissue of lactating hinds contained much less stearic acid and relatively more myristic, palmitic and palmitoleic acids, suggesting that fatty acids of exogenous origin were not being deposited because they were in demand for milk fat synthesis.The adipose tissue triglycerides of the reindeer were unusual in that they were, apparently, mainly of endogenous origin and showed a notable resemblance to the triglycerides of lambs reared on a virtually lipid‐free diet. This was reflected in a comparatively low content of stearic acid in the perinephric triglycerides, and the absence of trans‐unsaturated acids from all the triglycerides. Analysis of the principal feed (‘reindeer moss’, Cladonia) showed that, compared with normal herbage, it is a very poor source of exogenous fatty acids.Regardless of their fatty acid composition, the intramolecular structure of the triglycerides of the red deer and the reindeer conformed to the general distribution pattern common to most animals. Stearic acid was, for the most part, esterified to the primary alcoholic groups of the glycerol moiety (positions 1 and 3), as was palmitic acid, except when it was present in lower overall proportion than stearic acid. Unsaturated acids and the medium‐chain acid, myristic acid, were mainly esterified to the secondary alcohol group (position 2).