Invited review: Roles of dietary n-3 fatty acids in performance, milk fat composition, and reproductive and immune systems in dairy cattle

Abstract

Mammals can synthesize all of the fatty acids (FA) necessary for proper health and functioning with the exception of FA in the n-3 (omega-3) and n-6 (omega-6) families of polyunsaturated fatty acids (PUFA), which should be supplied in the diet. The PUFA are the predominant type of lipid in dairy cattle diets; however, common feedstuffs are rich in n-6 FA, whereas the supply of n-3 FA in the intensive dairy industry is mainly limited to flaxseed and fish oils. The n-3 FA are involved in many biological systems and processes, and therefore their dietary supplementation is of special interest in dairy cattle. Furthermore, because milk, milk products, and meat are among the most important and widely used components in traditional and modern human diets, enrichment of these food products with n-3 FA is of special importance. The purpose of this review is to provide a comprehensive description of different aspects and outcomes involved in dietary n-3 FA supplementation in dairy cattle. I provide an inclusive review of the effects of n-3 FA on milk and milk solids and the FA profile in milk fat upon feeding a variety of flaxseed products or fish oil. Selective uptake of n-3 FA has been demonstrated in the ovary compartments, as well as in bull sperm and in the unborn calf through the placenta. Incorporation of these unique FA into the reproductive system influences many processes and exerts some positive effects on fertility. In addition, beneficial effects of feeding n-3 FA on the reproductive system of females and males can be achieved with supplementation of α-linolenic acid from flaxseed or from eicosapentaenoic and docosahexaenoic acids from fish oil. This work provides a broad perspective and demonstrates the importance and potential of n-3 FA dietary supplementation in dairy cattle on the animal itself, as well as its secondary effects, which are associated with human nutrition and health.

Role of nutraceuticals during the transition period of dairy cows: a review

“…Supplementing PUFAs in dairy cows' diets differentially affects productive performances depending on the dose and type administered ( Table 1). Fish oil is known to decrease feed intake when supplemented in non-rumen protected forms and when percentages included in the diet are higher than 1% DM [21]. Decreased DMI reported with PUFAs could account for the reduced milk yield (MY) reported in several experiments.…”

“…Such a shift of fatty acids composition is reflected in many body compartments (i.e. cell membranes, follicular fluid, granulosa cells and oocytes), exerting different effects based on the dose, physical form, and administration time of n-3 rich feeds [21].…”

A Comparative Analysis of Oocyte Development in Mammals

“…A PUFA, namely oleic acid, could restore the quality of bovine oocyte that had been previously exposed to high levels of saturated fatty acids, partly through an increase in the amount of lipids stored in lipid droplets of cumulus cells [209]. In bovine, n-3 PUFA supplementation increases gestation rate and the cryotolerance of in vitro produced embryos, and reduces early embryo mortality in vivo [209][210][211]. Such dietary supplementation has also been reported to potentially enhance oocyte quality in the ewe [212], whereas it can be detrimental in the mouse [213].…”

Colostrum supplementation with n-3 fatty acids and α-tocopherol alters plasma polyunsaturated fatty acid profile and decreases an indicator of oxidative stress in newborn calves

“…In cattle, daily dietary supplements of n-3 fatty acids (FA) have been recognized for their influence on health (Moallem, 2018), inflammation, and oxidative stress . Previous studies indicate that n-3 FA supplementation to milk replacer improved growth, health, or indicators of immune function in calves Karcher et al, 2014).…”