Milk Fat Globule in Ruminant: Major and Minor Compounds, Nutritional Regulation and Differences Among Species

Abstract

Recent knowledge is presented on the composition of ruminant milk fat fractions and the nutritional strategies known to alter their amount. The development of lipidomic and proteomic analyses has allowed for the characterization of minor components, such as proteins, liposoluble vitamins, and phospholipids of the milk fat globule (MFG), in addition to the triacylglycerols (TAG), which are the major constituents of the MFG core. Few differences in these components among ruminant species exist, and they have been outlined mainly on the fatty acids (FA) profile of the TAG, whereas comparative data are still lacking on vitamins and proteins. The effects of dietary treatments enriched in n‐3 polyunsaturated FA (PUFA) on the composition of the milk fat fraction are explored. In particular, pasture and plant oilseeds increase milk n‐3 PUFA and cis‐9,trans‐11 CLA and decrease saturated FA, whereas data with new feed resources, such as algae, are still rare. The peculiarities of the response of the milk fat to diets that induce a milk fat depression in cows but in lesser extent in small ruminants are described. The potential effects of polar lipids, proteins, and liposoluble vitamins of the MFG on human health are reviewed, highlighting the nutraceutical properties of milk. Practical Applications: This review provides an overview of the different components of the milk fat fraction in ruminant species and on nutritional strategies to alter their amounts to improve the nutritional quality of milk. Furthermore, this review presents recent data on species peculiarities of the milk fat fraction composition and of its response to nutritional factors, which offers a promising model to identify news levers of regulation of this fraction and foster the identification of new feeding strategies to better control milk fat composition and feed efficiency. This review synthesizes data on the composition of the milk fat fraction in ruminant species, reports advances in nutritional strategies to alter their amounts and species‐specific responses to nutrition, as well as the potential effects on human health of the major and minor components of this fraction.

Milk saturated fatty acids, odd- and branched-chain fatty acids, and isomers of C18:1, C18:2, and C18:3n-3 according to their duodenal flows in dairy cows: A meta-analysis approach

“…This phenomenon could explain the limited transfer of C18: 3n -3 into milk fat because C18: 3n -3 is present highly in phospholipids (Bernard et al, 2008;Stamey Lanier et al, 2013). Moreover, a possible regulation of the glycerol transferase enzymes involved in the triglyceride synthesis (glycerol-3-phosphate acyltransferase, acylglycerol phosphate acyltransferase, and diacylglycerol O-acyltransferase) by C18: 2n -6 or C18: 3n -3 availability could be implicated and interact with the transfer of these FA into milk (Bernard et al, 2008(Bernard et al, , 2018.…”

Effects of berry seed residues on ruminal fermentation, methane concentration, milk production, and fatty acid proportions in the rumen and milk of dairy cows

“…One possible reason for this is that FA proportions in the rumen fluid do not fully reflect those in the duodenum, which is the main absorption site for FA (Szczechowiak et al, 2016). The milk FA proportions also depend on the activity of mammary gland desaturases, especially ∆ 9 desaturase, and genes participating in milk fat synthesis and secretion (Brzozowska and Oprządek, 2016;Bernard et al, 2018;Cappucci et al, 2018).…”

The Dietary Addition of Fish Oil or Sunflower Oil Plus Starch Differently Modulates the Lipid Classes in Plasma of Lactating Cows and Goats

“…Analyzed using LSD method of LS-means with the PDIFF option. 1 The dietary treatment (D) species (S) and the interaction between dietary treatment  species (D  S) effects were analyzed by ANOVA using the mixed procedure of SAS (SAS, Inc. 9.4) with animal in group as random effect. 2 SEM are means of error types obtained for each Latin square (species) by ANOVA analysis.…”

“…In the literature, a great number of studies reported large effects of diets, particularly lipid supplementation, on ruminant milk fatty acid (FA) composition . These lipid supplements were studied for their capacity to increase the poly‐unsaturated fatty acid (PUFA) content in milk, particularly omega 3 FA or conjugated linoleic acid (CLA), which are known for their beneficial effects on human health .…”

“…In the literature, a great number of studies reported large effects of diets, particularly lipid supplementation, on ruminant milk fatty acid (FA) composition. [1,2] These lipid supplements were studied for their capacity to increase the poly-unsaturated fatty acid (PUFA) content in milk, particularly omega 3 FA or conjugated linoleic acid (CLA), which are known for their beneficial effects on human health. [3] The effects of lipid supplements on milk PUFA composition is due to regulation of ruminal, postabsorptive, and mammary lipid metabolisms that determine the nature and level of circulating FA and their availability for mammary uptake.…”