Effects of Dietary Regimen and Tissue Site on Bovine Fatty Acid Profiles

Publisher Website
Google Scholar
Abstract
A study is presented of the variation in fatty acid composition of bovine tissue as a function of dietary regimen—forage vs grain—and of tissue location within the carcass. Detailed fatty acid profiles were obtained by procedures that included dry column lipid extraction with concomitant isolation of separate neutral and polar fractions, capillary column gas chromatography, and computer assisted data storage, consolidation and statistical analysis. Separate fatty acid profiles for neutral lipid and polar lipid fractions were obtained both as normalized reports (each fatty acid as percentage of total fatty acid), and as “gravimetric” reports (mg each fatty acid/100 g tissue). In each set, side-by-side profiles allowed comparisons and statistically valid (P<.05) conclusions to be made tissue-by-tissue within a dietary regimen and diet-by-diet for specific tissues. The fatty acids were grouped into several classes of unsaturation and branching for ease of comparison. Separate analysis of polar fractions allowed detailed examination of the polyunsaturates and gave profiles representative of muscle cells separate from contiguous intramuscular adipose cells. Numerous variations in specific fatty acid content are discussed. Reversals of some patterns occurred when comparisons were made gravimetrically rather than in a normalized manner. For example, normalized reports showed that tissues of forage-fed beef had higher percentages of normal and branched saturated fatty acids than did their grain-fed counterparts. However, because tissue of grain-fed beef is fattier than that of forage-fed beef, this pattern was reversed in the gravimetric reports. Among the polyunsaturates, tissues of grain-fed beef provided greater quantities of the essential fatty acids (including linoleate) than did the forage-fed counterparts, as seen in the gravimetric reports, whereas the fatty acids of tissue of forage-fed beef had greater percentages of oxidation-prone nondienoic polyenes (including linolenate) than did the fatty acids of tissue of grain-fed beef, as seen in the normalized reports. Tissue-by-tissue comparisons showed that psoas major muscle and kidney knob adipose generally had the highest amounts of saturated fatty acids (normalized and gravimetric data) and essential fatty acids (gravimetric data), though the fatty acids of semitendinosus muscle had the highest concentration of nondienoic polyenes (normalized data). Copyright © 1984. American Society of Animal Science . Copyright 1984 by American Society of Animal Science.

This publication has 0 references indexed in Scilit: