Animal Genetics and Nutrition, Veterinary Sciences Discipline, College of Public Health, Medical and Veterinary Sciences, Division of Tropical Health and Medicine, James Cook University, Townsville QLD 4811, Australia.
College of Economics and Techniques, Thai Nguyen University, Thai Nguyen 252166, Vietnam.
Nutrients. 2019 Mar 29;11(4):743. doi: 10.3390/nu11040743.
Omega-3 polyunsaturated fatty acids ( PUFA) are termed essential fatty acids because they cannot be synthesized by humans due to the lack of delta-12 and delta-15 desaturase enzymes and must therefore be acquired from the diet. PUFA include α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and the less recognized docosapentaenoic acid (DPA, 22:5n-3). The three long-chain (≥C) PUFA (n-3 LC-PUFA), EPA, DHA, and DPA play an important role in human health by reducing the risk of chronic diseases. Up to the present time, seafood, and in particular, fish oil-derived products, have been the richest sources of n-3 LC-PUFA. The human diet generally contains insufficient amounts of these essential FA due largely to the low consumption of seafood. This issue provides opportunities to enrich the content of PUFA in other common food groups. Milk and milk products have traditionally been a major component of human diets, but are also among some of the poorest sources of PUFA. Consideration of the high consumption of milk and its processed products worldwide and the human health benefits has led to a large number of studies targeting the enhancement of PUFA content in dairy products. The main objective of this review was to evaluate the major strategies that have been employed to enhance PUFA content in dairy products and to unravel potential knowledge gaps for further research on this topic. Nutritional manipulation to date has been the main approach for altering milk fatty acids (FA) in ruminants. However, the main challenge is ruminal biohydrogenation in which dietary PUFA are hydrogenated into monounsaturated FA and/or ultimately, saturated FA, due to rumen microbial activities. The inclusion of oil seed and vegetable oil in dairy animal diets significantly elevates ALA content, while the addition of rumen-protected marine-derived supplements is the most effective way to increase the concentration of EPA, DHA, and DPA in dairy products. In our view, the mechanisms of LC-PUFA biosynthesis pathway from ALA and the biohydrogenation of individual LC-PUFA in ruminants need to be better elucidated. Identified knowledge gaps regarding the activities of candidate genes regulating the concentrations of 3 PUFA and the responses of ruminants to specific lipid supplementation regimes are also critical to a greater understanding of nutrition-genetics interactions driving lipid metabolism.
ω-3 多不饱和脂肪酸（PUFA）被称为必需脂肪酸，因为由于缺乏 δ-12 和 δ-15 去饱和酶，人体无法合成它们，因此必须从饮食中获取。PUFA 包括 α-亚麻酸（ALA，18:3n-3）、二十碳五烯酸（EPA，20:5n-3）、二十二碳六烯酸（DHA，22:6n-3）和不太被认可的二十二碳五烯酸（DPA，22:5n-3）。三种长链（≥C）PUFA（n-3LC-PUFA）、EPA、DHA 和 DPA 通过降低慢性病风险在人类健康中发挥着重要作用。到目前为止，海鲜，特别是鱼油衍生产品，一直是 n-3LC-PUFA 的最丰富来源。由于海鲜摄入量低，人类饮食中这些必需脂肪酸的含量普遍不足。这一问题为在其他常见食物组中富集 PUFA 提供了机会。牛奶及其乳制品一直是人类饮食的主要组成部分，但也是 PUFA 最贫乏的来源之一。考虑到牛奶及其加工产品在全球范围内的高消耗量及其对人类健康的益处，已经进行了大量旨在提高乳制品中 PUFA 含量的研究。本综述的主要目的是评估已用于提高乳制品中 PUFA 含量的主要策略，并揭示该主题进一步研究的潜在知识空白。迄今为止，营养操纵一直是改变反刍动物牛奶脂肪酸（FA）的主要方法。然而，主要的挑战是瘤胃生物氢化，由于瘤胃微生物的活动，日粮中的 PUFA 被氢化形成单不饱和脂肪酸和/或最终饱和脂肪酸。在奶牛日粮中添加油籽和植物油可显著提高 ALA 含量，而添加瘤胃保护的海洋衍生补充剂是提高乳制品中 EPA、DHA 和 DPA 浓度的最有效方法。在我们看来，需要更好地阐明从 ALA 合成 LC-PUFA 途径的机制以及在反刍动物中单不饱和脂肪酸的生物氢化。确定关于调节 3 种 PUFA 浓度的候选基因的活性以及反刍动物对特定脂质补充方案的反应的知识空白，对于更好地理解驱动脂质代谢的营养-遗传相互作用也至关重要。
