Rumen biohydrogenation of linoleic and linolenic acids is reduced when esterified to phospholipids or steroids

Abstract

Manipulation of rumen biohydrogenation (BH) is of great importance, since decreased BH of linolenic acid (LNA) and linoleic acid (LA) is linked to increased content of the beneficial polyunsaturated fatty acids (PUFA) in dairy products and decreased content of trans fatty acids (FAs). We hypothesized that PUFA esterified to the complex lipid fractions are less prone to BH compared with PUFA esterified to the simple lipid fractions due to reduced lipolysis. In vitro rumen BH of different single lipid fractions was investigated, including free fatty acids (FFA), and esterified FA to triglycerides (TG), cholesterol esters (CE), and phospholipids (PL). A mixture of a buffer solution and rumen fluid was incubated with different lipid fractions, and C18 FAs were quantified by gas chromatography. In vitro BH kinetic parameters were quantified according to Michaelis–Menten equation and the maximum BH (Vmax) and time to achieve 50% of maximum amount (KM) estimated. Regardless of fatty acids, BH in CE and PL was lower than FFA and TG. The highest amount of cis‐9, trans‐11 conjugated linoleic acid (CLA) and trans‐10, cis‐12 CLA was observed in lipid fractions containing LA and LNA, respectively, regardless of lipid fractions. The present study demonstrates the importance of lipid fractions on BH of LNA and LA and formation of CLA isomers. The results show that BH of FAs depends on the lipid fractions.

Effect of toasting and decortication of oat on rumen biohydrogenation and intestinal digestibility of fatty acids in dairy cows

“…Some C18: 3n -3 was removed with the hull, causing a decline in the C18: 3n -3 proportion of the FA intake. Despite the effect of treatments, unexpected lower BH of C18: 3n -3 compared with C18: 2n -6 in our study could be due to the nature of the oat fat, which is rich in phospholipids (Kaimainen et al, 2012), as BH of C18: 3n -3 was shown to be lower when esterified to phospholipids (Lashkari et al, 2019).…”

Advances in fatty acids nutrition in dairy cows: from gut to cells and effects on performance

“…Due to the pathway involved in biohydrogenation, the main CLA escaping the rumen are cis-9, trans-11 and trans-9, trans-11 while trans-11 is the most abundant from C18:1, but many more positional and geometric isomers of CLA outflow the rumen and are present in milk of dairy cows [11,16]. A very recent study demonstrated that PUFA esterified to more complex lipids, such as phospholipids and cholesterol esters proportionally abundant in forages, are less prone to biohydrogenation compared to PUFA esterified to TAG, abundant in seeds and derived oil [17]. Findings from that study can have important implication in feeding dairy cows to increase enrichment of PUFA in milk.…”

“…The biohydrogenation of C18:3 in the rumen is decreased when this FA is associated with the membrane fraction [343]. Recent in vitro data demonstrated that biohydrogenation of PUFA is decreased when associated with complex lipid fractions, such as phospholipids and cholesterol ester, compared to simple lipid fractions, such as TAG [17]. The utilization of FA from grazing plants is also determined by the composition of the pastures.…”

Herbage utilisation method affects rumen fluid and milk fatty acid profile in Holstein and Montbéliarde cows

“…For instance, Butyrivibrio fibrisolvens was found to hydrolyse predominantly phospho-and galactolipids in the rumen, whereas also other bacteria such as Anaerovibrio lipolyticus are able to hydrolyse triacylglycerols (Enjalbert et al, 2017). Consequently, FAs esterified to phospholipids are less intensively biohydrogenated in the rumen compared to other lipid fractions (Lashkari et al, 2019). Eventually, the biohydrogenation of ALA, in particular its isomerisation to C18:3c9,t11c15, is faster than that of LA, as demonstrated in vitro by Meynadier et al (2018), a-c Values within a row with different superscripts differ significantly at P < 0.05.…”