The fatty acid composition of the main phospholipid fractions of the rumen and abomasum tissues of foetal and adult sheep

Abstract

The fatty acid composition has been determined on phosphatidyl choline, phosphatidyl ethanolamine and sphingomyelin fractions earlier isolated from the rumen and abomasum tissues of foetal and of adult Romney sheep.The major proportion of polyunsaturated fatty acids was found in the phosphatidyl ethanolamine (17 to 43 %) fraction and this was reduced in the phosphatidyl choline (7 to 25 %) and sphingomyelin (1 to 4 %) fractions. These features are in keeping with the results for mammalian tissues generally. The phosphatidyl ethanolamine fractions were further characterised by the low content of palmitic acid (4 %) compared with 25 to 30% in the phosphatidyl choline fractions and 29 to 52 % in the sphingomyelin fractions and by the occurrence of cyclopropane fatty acids. Consistent with the findings of other workers on mammalian tissues, the sphingomyelin fractions contained a relatively high content (16 to 27%) of higher maturated fatty acids including 22: 0,23 : 0,24: 0 and 25 : 0 and of tetracos-14-enoic (24: 1 w9) acid (5 to 16%). The total amounts of acids above Czo tended to vary inversely with the levels of palmitic acid whereas the levels of stearic acid were relatively constant at 13 to 17%. Changes in fatty acid composition with age were generally not marked but the tissues of the foetus were distinguished from those of the adult by their substantial amount of eicosa-5,8,1l-trienoic (20: 3 09) acid together with relatively low contents of linoleic (18: 2 w6) and linolenic (1 8: 3 w3) acids and to a lesser extent by reduced level of acids of the w3 series. This was particularly reflected by the ratios of w6/w3 Czo + Cz2 acids in the phosphatidyl ethanolamine fractions, the values for the foetal rumen and abomasum tissues being 1.03 and 1.07, respectively, compared with corresponding values of 0.78 and 0.72 found in adult sheep.The results are consistent with a requirement for Czo and C,, polyunsaturated acids of the w3 and w6 series and some penetration of maternal fatty acids through the placenta. The resemblance between the fatty acid make-up and composition of foetal and maternal phospholipids suggests the possibility of transference of intact or lyso-phospholipids from the mother to the foetus through the placenta. However, such a possibility is counter-indicated by consideration of previous work using labelled intermediates and by the mechanism of conversion of linoleic and linolenic acids requiring their CoA derivatives in the formation of the corresponding polyunsaturated Cz0 4 Czz acids. Nevertheless, the sharp cut-off of exogenous maternal fatty acids from the foetal triglycerides and their inclusion in the foetal phospholipids are not readily explainable.

Effect of total lipids and phospholipids on warmed-over flavor in red and white muscle from several species as measured by thiobarbituric acid analysis

“…Hornstein et al (1961) only identified arachidonic acid in the phospholipid fraction of beef and pork; however, in a later study by the same group (Hornstein et al, 1967) they reported some three or four PUFAS in the phospholipid fraction of beef muscle. This is in contrast to the analyses reported recently for sheep muscle by Body and Shorland (1974), where they observed a wide range of C20 and C22 PUFAS and some 7% of 2,3-methylene fatty acids that had escaped the attention of other investigators. Hornstein et al (1961) also noted that the phospholipids and the total lipids developed rancid odors much more quickly than the neutral lipids, which adds further support to our contention that phospholipids play a major role in development of WOF.…”

“…Thus, linolenic (18:3) acid oxidizes twice as fast as linoleic (18:2), and arachidonic acid (20:4) twice as fast as linolenic. This indicates that the triglycerides are much less susceptible to oxidation than the phospholipids, which in the case of phosphatidylethanolamine from lamb tissues collectively contained up to 20% of the total fatty acids as tetra-, penta-, and hexaenoic acids (Body and Shorland, 1974). Thus, the importance of triglycerides in development of WOF would appear to have a minor influence as compared to that of the phospholipids, which is in agreement with the results of the present investigation.…”

Effects of dietary fat and vitamin E on the lipid composition and stability of veal during frozen storage

“…Overall, the mean triglyceride contents of the 1. dorsi tissues fell within the range of 0.63-1.01%, which is comparable to the mean of 0.67 % quoted by Wrenn et al (1973) for intramuscular tissue. The phospholipids (0.75-1.01%) in the 1. dorsi tissues were relatively constant and similar to results of other workers (Link et al, 1967; Body and Shorland, 1974). " Mean of four animals.…”

“…The phospholipid fatty acids (Table IV) ranged from 12:0 to 22:5 6 and included traces of unidentified fatty acids with ECN's approximating 13:0 and 19:0, respectively. The presence in the dietary fats of no more than traces of linolenic acid (18:3 3) precluded the occurrence of substantial levels of a>3 polyunsaturated fatty acids as found in pasture-fed ruminants (Body and Shorland, 1974); nevertheless, some 20:5 3 was detected in the phospholipids in the present work.…”

Lipid Degradation in Turkey Breast Meat During Cooking and Storage

“…Both PC and PE may play an important role in the development of rancid flavors in stored meat or meat products because of their high content of PUFA (Igene et al, 1981). Corliss and Dugan (1970), Tsai and Smith (1971), and Sharma et al (1982) reported mat PE was more rapidly oxidized than me other PL classes as it contained more highly unsaturated fatty acids (Hornstein et al, 1961;Keller and Kinsella, 1973;Body and Shorland, 1974). Changes in PE and PC may be indicative of the extent of lipid oxidation.…”