The occurrence of C13 to C31 branched‐chain fatty acids in the faeces of sheep fed rye grass, and of C12 to C34 normal acids in both the faeces and the rye grass

Abstract

Rye grass was fed to sheep and the fatty acid composition of the rye grass lipids and of the faecal lipids was determined. The outstanding features were (a) the occurrence of 10.7 % of branched-chain is0 and anteiso acids ranging from C13 to C31 (inclusive) in the fatty acids of the faeces but of only 0.1 % of these constituents (17:O unteiso) in the acids of the rye grass; (b) the presence in the faecal fatty acids of 23.9% of components above C18, of which 22.2 % were n-saturated and 0.5 %were branched, but of only 7.2 % of these higher molecular weight acids in the rye grass. n-Fatty acids from C12 to C34 (predominantly C14C18) occurred in both the diet and the faeces. Whereas the rye grass fatty acids were mainly unsaturated (74.6%) and included 56.5 % of linolenic acid, the faecal acids contained a preponderance of saturated components (80.2 %) and only 1.2 % of linolenic acid. The fatty acids above C18 from the dietary and faecal lipids were identified as follows: (a) C19 to C34 n-saturated acids (predominantly even-numbered) in both the rye grass and the faeces; (b) C19 to C27 n-unsaturated acids in the rye grass; (c) C19 to C34 (except C33) n-unsaturated acids in the faeces; (d) C19 to C31 is0 and unteiso constituents in the faecal fatty acids, but absent from the rye grass acids. The presence of both is0 and unteiso odd-numbered acids (C13 to C31) and of is0 even-numbered acids (C14 to C30) in the faeces, suggested that these branched constituents were of microbial origin in the digestive tract of the sheep.

The potential of long-chain fatty alcohols and long-chain fatty acids as diet composition markers: development of methods for quantitative analysis and faecal recoveries of these compounds in sheep fed mixed diets

“…There was no such effect in this experiment since sterols were removed during alcohol purification using solid-phase extraction columns. The results obtained in this experiment for acids are not in accordance with those of Body & Hansen (1978) and Grace & Body (1981) who reported negligible absorption of the C 19 -C 32 fatty acids. A possible explanation for this contradiction is that there were substantial differences between the experiment of Grace & Body (1981) and the present study.…”

“…The results obtained by these authors were based on measurements made on a single species (ryegrass or white clover). Moreover, the quantification of acids in feed and faeces, measured by Body & Hansen (1978), were based on intake and faecal output data obtained from animals different from those that consumed the experimental diet. The incomplete faecal recoveries of acids in faeces suggest that they are partially absorbed in the digestive tract.…”

The natural occurrence of unusual fatty acids. Part 1. Odd numbered fatty acids

“…The occurrence of these fatty acids in most organisms is of interest with regard to the different position of the double bond of the unsaturated fatty acids (Cll to Cz5). Even longer odd numbered fatty acids (Cz7 to C3J are found for instance in the faeces of sheeps, grass [83], sponges (Desmospongiae) or in bacteria.…”

Lipid composition of a clutch of kakapo (Strigops habroptilus) (Aves: Cacatuidae) eggs

“…In addition, plant mix 2 had greater quantities of both oleic (18:1) and long-chain saturated (20:0, 22:0, and 24:0) fatty acids than the other dietary source. These latter fatty acids were not substantially observed in the egg yolk lipids (fable 4) probably because they cannotreadily be absorbed from the maternal gut, as has been demonstrated with other animals (Body & Hansen 1978;Body & Grace 1983).…”