Milk Odd and Branched Chain Fatty Acids in Dairy Cows: A Review on Dietary Factors and Its Consequences on Human Health

SIMPLE SUMMARY: The objective of this review is to highlight the importance of odd and branched chain fatty acids and dietary factors that may affect their content in milk acids in dairy cows. The primary source of odd and branched chain fatty acids is ruminal bacteria. In contrast to saturated fatty acids, odd and branched chain fatty acids have health protective effects against certain diseases as cardiovascular diseases, type II diabetes, cancers, Alzheimer’s disease and metabolic syndrome. Ruminant products are the main source of these fatty acids in the human diet. Odd and branched chain fatty acids profile in cow milk is mainly affected by dietary fatty acids and fatty acids metabolism in the rumen. Additionally, lipid mobilization in the body and fatty acids metabolism in mammary glands affect the milk odd and branched chain fatty acids profile. Understanding the origin of odd and branched chain fatty acids in milk and manipulating the diet of dairy cows to produce odd and branched chain fatty acids-enriched milk can be of scientific and industrial significance. ABSTRACT: This review highlights the importance of odd and branched chain fatty acids (OBCFAs) and dietary factors that may affect the content of milk OBCFAs in dairy cows. Historically, OBCFAs in cow milk had little significance due to their low concentrations compared to other milk fatty acids (FAs). The primary source of OBCFAs is ruminal bacteria. In general, FAs and OBCFAs profile in milk is mainly affected by dietary FAs and FAs metabolism in the rumen. Additionally, lipid mobilization in the body and FAs metabolism in mammary glands affect the milk OBCFAs profile. In cows, supplementation with fat rich in linoleic acid and α-linolenic acid decrease milk OBCFAs content, whereas supplementation with marine algae or fish oil increase milk OBCFAs content. Feeding more forage rather than concentrate increases the yield of some OBCFAs in milk. A high grass silage rate in the diet may increase milk total OBCFAs. In contrast to saturated FAs, OBCFAs have beneficial effects on cardiovascular diseases and type II diabetes. Furthermore, OBCFAs may have anti-cancer properties and prevent Alzheimer’s disease and metabolic syndrome.