Dietary Manipulation to Increase the Concentration of N-3 Fatty Acids in Milk Fat

Abstract

Abstract. Linseed is an excellent source of PUFA, especially linolenic acid (18:3n-3), but it is not commonly used in dairy diet in Hungary. Aim of this study was to investigate the effect of the supplemented whole linseed on fatty acid profile of milk fat, with particular reference to health promoting components (α-linolenic acid). A total of thirty multiparous Holstein cows were used in two dairy farms to determine the effect of feeding whole linseed rich in linolenic (C18:3) fatty acids on fatty acid composition of milk fat. The experiment was conducted on two large-scale dairy farms located in Hajdú-Bihar County (referred to as farm "A" and "B"). Fifteen multiparous Holstein-Friesian (165 average days in milk) on farm A and fifteen multiparous Holstein-Friesian (200 average days in milk) on farm B were randomly allocated to treatment groups to investigate the effect of whole linseed supplementation on the composition of fatty acids of milk fat. The group on farm A and B fed TMR based maize silage without whole linseed during the control-period. In the experimental-period the cows received the same TMR on both farms, but it was supplemented with 2.60% DM of whole linseed on farm A, and 2.16% DM of whole linseed on farm B. The experimental period was four weeks in both farms. The supplementation of whole linseed had no effect (P > 0.05) on the short chain saturated fatty acid (SFA), and most of the medium chain saturated fatty acid. During the trial the oleic acid (18:1c) content in milk fat significantly increased (21.33% at the start, 24.71% after 2 weeks and 22.51% after 4 weeks on farm B, respectively). The proportion of α-linolenic acid (18:3n-3) increased (P > 0.05) during the experimental period compared to the control period (0.23% at the start, 0.58% after 2 weeks and 0.59% after 4 weeks on farm B). The concentration of long-chain polyunsaturated fatty acids (eicosapentaenoic acid and docosapentaenoic acid) significantly increased in milk fat after 4 weeks on both farms. The n-6/n-3 ratio narrowed from 13.52:1 to 3.83:1 and 3.69:1 on farm B, respectively, but this result was not significant. This study concluded that dietary supplementation of whole linseed decreased the proportion of some SFA and increased the proportion of some MUFA and PUFA.

The Effects of Feeding Milled Rapeseed Seeds with Different Forage:Concentrate Ratios in Jersey Dairy Cows on Milk Production, Milk Fatty Acid Composition, and Milk Antioxidant Capacity

“…In this research, VA increased by supplementing diets with MR (LR and HR diets compared to L and H diets), but the concentration of cis -9, trans -11 CLA in milk was not affected ( Table 4 ). The results similar to those obtained by us were previously reported by Egger et al [ 43 ] and Suli et al [ 3 ], who concluded that the inclusion of rapeseed or flaxseed in the diet of cows did not influence the content of cis -9, trans -11 CLA in milk fat. Other studies have shown that vegetable oil supplementation can influence the concentration of cis -9, trans -11 CLA in milk only when high amounts of oil are used in a diet that has an extreme FC ratio [ 22 ].…”

“…Nowadays, many consumers are aware of the relation between diet and health. A major interest in modifying milk fatty acids (FAs) composition, aiming to enhance the health status of consumers, was noticed in the last two decades [ 1 , 2 , 3 ]. Such changes are intended to decrease the proportion of saturated FAs (SFAs) in milk fat composition, and to increase the proportion of healthy FAs, such omega-3 FAs (n-3 FAs), conjugated linoleic acid (CLA, cis -9, trans -11 C18:2), oleic acid (OA, C18:1 cis -9), and vaccenic acid (VA, C18:1 trans -11) [ 4 ].…”

“…The FAs profile of milk depends on several factors; nutritional management being one of most important [ 7 , 8 ]. Supplementing cow diets with different sources and types of fat is an effective way of manipulating the FAs profile of milk fat [ 3 , 9 , 10 ]. Previous research demonstrated that supplementing cow diets with vegetable oils led to an increase in n-3 FAs and CLA concentration in milk fat [ 7 , 11 ].…”

“…Previous research demonstrated that supplementing cow diets with vegetable oils led to an increase in n-3 FAs and CLA concentration in milk fat [ 7 , 11 ]. Oils rich in linoleic acid (LA, C18:2 n-6; e.g., sunflower oil) were more effective in increasing CLA in milk fat than oils rich in α-linolenic acid (ALA, C18:3 n-3; e.g., linseed oil), which was more effective in increasing n-3 FAs in milk fat [ 3 , 12 ]. Only a limited number of studies have examined how oils which are OA-rich (oleic acid, C18:1 cis -9) (e.g., rapeseed oil) affect lactation performance, the FAs content of milk [ 13 , 14 , 15 ], and enteric methane emissions in dairy cows [ 16 , 17 ].…”