Lipid Encapsulation Provides Insufficient Total-Tract Digestibility to Achieve an Optimal Transfer Efficiency of Fatty Acids to Milk Fat

<div><p>Transfer efficiencies of rumen-protected n-3 fatty acids (FA) to milk are low, thus we hypothesized that rumen-protection technologies allow for biohydrogenation and excretion of n-3 FA. The objectives of this study were to i) investigate the ruminal protection and post-ruminal release of the FA derived from the lipid-encapsulated echium oil (EEO), and ii) assess the bioavailability and metabolism of the EEO-derived FA through measuring the FA content in plasma lipid fractions, feces, and milk. The EEO was tested for rumen stability using the <i>in situ</i> nylon bag technique, then the apparent total-tract digestibility was assessed <i>in vivo</i> using six Holstein dairy cattle. Diets consisted of a control (no EEO); 1.5% of dry matter (DM) as EEO and 1.5% DM as encapsulation matrix; and 3% DM as EEO. The EEO was rumen-stable and had no effect on animal production. EEO-derived FA were incorporated into all plasma lipid fractions, with the highest proportion of n-3 FA observed in cholesterol esters. Fecal excretion of EEO-derived FA ranged from 7–14%. Biohydrogenation products increased in milk, plasma, and feces with EEO supplementation. In conclusion, lipid-encapsulation provides inadequate digestibility to achieve an optimal transfer efficiency of n-3 FA to milk.</p></div

Fatty acid composition (mg/g DM) of the diet components.

<p>Fatty acid composition (mg/g DM) of the diet components.</p

Fecal output of EEO-derived FA; palmitic acid (PA) [A], γ-linolenic acid (GLA) [B], α-linolenic acid (ALA) [C], steariodonic acid (SDA) [D] in comparison to intake of cows on baseline diet (CON), supplemented with 1.5% of DM as encapsulated echium oil (EEO) and 1.5% of DM as encapsulation matrix (LEO), and 3% DM as EEO (HEO).

<p>LSmeans (n = 6) and standard error. Means without a common letter differ significantly, <i>P</i><0.05.</p

<i>In situ</i> ruminal dry matter (DM) disappearance (%) of EEO and wheat straw (control).

<p>Data are presented as LS means (n = 6) and standard error of the mean.</p

Fecal output of EEO-derived FA; palmitic acid (PA) [A], γ-linolenic acid (GLA) [B], α-linolenic acid (ALA) [C], steariodonic acid (SDA) [D] in comparison to intake of cows on baseline diet (CON), supplemented with 1.5% of DM as encapsulated echium oil (EEO) and 1.5% of DM as encapsulation matrix (LEO), and 3% DM as EEO (HEO).

<p>LSmeans (n = 6) and standard error. Means without a common letter differ significantly, <i>P</i><0.05.</p

Temporal pattern of milk fatty acid yield (g/day) of γ-linoleic acid (GLA) [A], α-linolenic acid (ALA) [B], steariodonic acid (SDA) [C], and eicosapentaenoic acid (EPA) [D] from cows on baseline diet (CON: ●), supplemented with 1.5% of DM as encapsulated echium oil (EEO) and 1.5% of DM as encapsulation matrix (LEO:▲), and 3% DM as EEO (HEO:■).

<p>Data are presented as LSmeans (n = 6) and standard error. * = days significantly different from CON, ‡ = days significantly different from CON and LEO (<i>P</i><0.05).</p

Temporal incorporation (g/100g) of γ-linolenic acid (GLA) [A], α-linolenic acid (ALA) [B], steariodonic acid (SDA) [C], and eicosapentaenoic acid (EPA) [D] into plasma cholesterol esters of cows on baseline diet (CON), supplemented with 1.5% of DM as encapsulated echium oil (EEO) and 1.5% of DM as encapsulation matrix (LEO), and 3% DM as EEO (HEO).

<p>Data are presented as LSmeans (n = 6) and standard error. * = days significantly different from CON, ‡ = days significantly different from CON and LEO (<i>P</i><0.05).</p

Temporal incorporation (g/100g) of γ-linolenic acid (GLA) [A], α-linolenic acid (ALA) [B], steariodonic acid (SDA) [C], and eicosapentaenoic acid (EPA) [D] in plasma phospholipids of cows on baseline diet (CON), supplemented with 1.5% of DM as encapsulated echium oil (EEO) and 1.5% of DM as encapsulation matrix (LEO), and 3% DM as EEO (HEO).

<p>Data are presented as LSmeans (n = 6) and standard error. * = days significantly different from CON, ‡ = days significantly different from CON and LEO (<i>P</i><0.05).</p

Temporal incorporation (g/100g) of γ-linolenic acid (GLA) [A], α-linolenic acid (ALA) [B], steariodonic acid (SDA) [C], and eicosapentaenoic acid (EPA) [D] in plasma triacylglycerides of cows on baseline diet (CON), supplemented with 1.5% of DM as encapsulated echium oil (EEO) and 1.5% of DM as encapsulation matrix (LEO), and 3% DM as EEO (HEO).

<p>Data are presented as LSmeans (n = 6) and standard error. * = days significantly different from CON, ‡ = days significantly different from CON and LEO (<i>P</i><0.05).</p

Transfer efficiencies^a (%) of fatty acids derived from encapsulated-echium oil into milk fat.

<p>Transfer efficiencies<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164700#t005fn001" target="_blank">^a</a> (%) of fatty acids derived from encapsulated-echium oil into milk fat.</p