Esterification of essential and non-essential fatty acids into distinct lipid classes in ruminant and non-ruminant tissues

Abstract

Extensive microbial biohydrogenation of polyunsaturated fatty acids (PUFA) in the rumen reduces the essential fatty acids (EFA) available for absorption in ruminant animals, but there is no published documentation of ruminants developing EFA deficiency. In ruminants, most circulating PUFA are found in the phospholipid (PL) and cholesteryl ester lipid classes that have slow turn-over compared to other lipid classes. The objective of this experiment was to measure fatty acid esterification patterns of the non-EFA palmitic (16:0) and oleic acid (18:1), and the EFA linoleic (18:2) and linolenic acid (18:3) in small intestine, liver, and muscle tissue of cows and pigs to identify tissues participating in sequestration of these FA in less metabolically active lipid classes in ruminants. Bovine and porcine small intestine, liver, and muscle explants were prepared and incubated in media containing radiolabeled 16:0, 18:1, 18:2, or 18:3 to measure esterification of fatty acids into PL and TG. Neither bovine nor porcine small intestine explants preferentially incorporated non-EFA compared to EFA into PL vs TG. Bovine liver explants esterified a larger proportion of EFA than non-EFA into PL compared to TG, while incorporation was similar among the FA tested in porcine liver explants. Bovine muscle explants showed preferential incorporation of EFA into PL rather than TG. Results show that bovine and porcine liver and muscle esterify EFA and non-EFA differently and that the conservation of EFA in ruminants is a result of preferential incorporation of EFA into PL mediated by bovine liver and muscle, but not the small intestine.

Partitioning of Rumen‐Protected n‐3 and n‐6 Fatty Acids is Organ‐Specific in Growing Angus Heifers

“…The primary natural feed of ruminants is grass, the lipids of which contain high amounts of the essential FA α‐linolenic acid (18:3n‐3, ALA). In metabolism, ALA can be elongated to a small extent to the long‐chain n‐3 FA such as eicosapentaenoic acid (20:5n ‐ 3, EPA) and docosahexaenoic acid (22:6n‐3, DHA) and, therefore, increase their respective proportions in muscles and organs (Caldari‐Torres et al, ; Nguyen et al, ; Rosa et al, ). Feeding rumen‐protected oils rich in polyunsaturated fatty acids (PUFA) has been shown before to be an efficient means for incorporating n‐3 and n‐6 FA in bovine liver (Cook et al, ; Demirel et al, ).…”

N-3 Polyunsaturated Fatty Acids as a Nutritional Support of the Reproductive and Immune System of Cattle—A Review

“…The amount of long-chain unsaturated fatty acids affects the degree of the biohydrogenation of polyunsaturated fatty acids and decreases with an increase in saturated FAs [55]. It is also dependent on the size of the rumen: in small ruminants (goats and sheep), the degree of total biohydrogenation is lower [56]. The introduction of a fat supplement into the diet of ruminants, especially one containing polyunsaturated fatty acids, can, therefore, have a negative impact on the rumen fermentation process and ultimately affect total feed digestibility.…”

Función y metabolismo de ácidos grasos en el tejido adiposo y hepático de rumiantes en producción: una revisión

“…Esencialmente, el tipo de biomoléculas lipídicas (ej: ácidos grasos, triglicéridos, esfingofosfolípidos, etc) en los tejidos de rumiantes es similar al de los no rumiantes; sin embargo, las concentraciones de los diferentes tipos de moléculas biolipídicas varían entre rumiantes y no rumiantes, lo cual está asociado a las diferencias en el metabolismo de lípidos, entre estos dos tipos de especie 8 .…”