Grape seed and linseed, alone and in combination, enhance unsaturated fatty acids in the milk of Sarda dairy sheep

Abstract

This study evaluated the effect of dietary inclusion of grape seed and linseed, alone or in combination, on sheep milk fatty acids (FA) profile using 24 Sarda dairy ewes allocated to 4 isoproductive groups. Groups were randomly assigned to 4 dietary treatments consisting of a control diet (CON), a diet including 300 g/d per animal of grape seed (GS), a diet including 220 g/d per animal of extruded linseed (LIN), and a diet including a mix of 300 g/d per animal of grape seed and 220 g/d per animal of extruded linseed (MIX). The study lasted 10 wk, with a 2-wk adaptation period and an 8-wk experimental period. Milk FA composition was analyzed in milk samples collected in the last 4 wk of the trial. The milk concentration of saturated fatty acids (SFA) decreased and that of unsaturated, monounsaturated, and polyunsaturated fatty acids (UFA, MUFA, and PUFA, respectively) increased in GS, LIN, and MIX groups compared with CON. The MIX group showed the lowest values of SFA and the highest of UFA, MUFA, and PUFA. Milk from ewes fed linseed (LIN and MIX) showed an enrichment of vaccenic acid (VA), oleic acid (OA), α-linolenic acid (LNA), and cis-9,trans-11 conjugated linoleic acid (CLA) compared with milk from the CON group. The GS group showed a greater content of milk oleic acid (OA) and linoleic acid (LA) and tended to show a greater content of VA and cis-9,trans-11 CLA than the CON group. The inclusion of grape seed and linseed, alone and in combination, decreased the milk concentration of de novo synthesized FA C10:0, C12:0, and C14:0, with the MIX group showing the lowest values. In conclusion, grape seed and linseed could be useful to increase the concentration of FA with potential health benefits, especially when these ingredients are included in combination in the diet.

Effect of Dietary Grape Pomace and Seed on Ewe Milk and Meat Quality of Their Suckling Lambs

“…Contradicting our results, Correddu et al found lower milk fat concentration of these fatty acids, which was attributed to the increase source of PUFA when grape seed was included in the diet of ewes [30], since long-chain fatty acids available in plasma from diet (or from fat mobilisation) decrease medium chain fatty acids (C8:0 to C14:0) percentages in the milk, both by a dilution effect and by a reduction in their synthesis [16]. The higher concentration of PUFA in the wine by-products in the concentrates of the present study might be minimal to observe this effect and, by the other hand, hay provided could have an influence.…”

“…Other studies have showed different results, where dried and ensiled grape pomace and grape seeds increased total MUFA, mainly due to the higher concentrations of oleic acids in ruminant milk [23,30], and owed to the higher concentration of fat and linoleic acid in the grape residues. Considering the individual SFA in milk, we have found higher concentrations of even fatty acids from 6 to 14 carbons in the wine by-products groups, whereas only grape pomace differed from the control in the C16:0 and C18:0 fatty acids, being higher and lower, respectively, in the pomace group (Table 1).…”

“…Total percentage of PUFA in milk was not affected too much by dietary supplementation with grape pomace in another study with ewes [28] and with grape pomace silage in cows [29], but contradicting our results, these authors did not found also differences in total MUFA and SFA. On the other hand, grape seed inclusion in the diet of dairy sheep can decrease the SFA and increase MUFA and PUFA milk concentration [30], which was thought to be caused by this subproduct being a rich source of linoleic acid and polyphenols, which could modulate the ruminal biohydrogenation of PUFA. The discrepancies with our results are maybe due to the low differences in PUFA between treatments or because our control group may have already a high percentage of unsaturated fatty acids.…”

Use of multivariate factor analysis to characterize the fatty acid profile of buffalo milk

“…The FAME were separated using a gas chromatograph (Turbo 3400 CX; Varian Inc., Palo Alto, CA), equipped with a capillary column (CP-select CB for FAME; 100 m × 0.32 mm i.d., 0.25 μm film thickness; Varian Inc.), a flame ionization detector (FID) and an automatic injector 8200 CX (Varian Inc.). Chromatographic conditions were set according to Correddu et al (2016). The FAME peaks were routinely identified by comparing their retention times with those of authentic lipid standards and with published studies, as detailed in Nudda et al (2005).…”

“…Milk concentration of n-6 and n-3 FA could be also related to differences in concentration of C18:2 n-6 or C18:3 n-3 in the diet of animals, thus allowing discrimination of animals fed different diets or reared in different systems (intensive or extensive). An investigation on milk FA composition from sheep fed diets rich in C18:2 n-6 or C18:3 n-3 using principal component analysis highlighted an opposite sign of eigenvector coefficients for PUFA n-6 and PUFA n-3 in the same principal component that was named "n-6 to n-3 ratio" (Correddu et al, 2016). Similarly, the use of the C18:2 n-6 to C18:3 n-3 ratio has proven to be very effective in the discrimination of dairy goat fed diets supplemented with different lipid sources (Marín et al, 2012).…”