title: Dietary unsaturated fatty acids affect the mammary gland integrity and health in lactating dairy cows.
abstract: BACKGROUND
  Information about the effects of unsaturated fatty acids (UFA) supplementation on the health and integrity of the mammary gland in lactating dairy cows is lacking. Therefore, the aim of this study was to determine the effects of unprotected dietary UFA on the global expression pattern of genes in the mammary gland tissue of grazing dairy cows, and to translate this information into relevant biological knowledge.
  
  
  METHODS
  Twenty-eight Holstein-Friesian dairy cows were randomly assigned to 4 different concentrated UFA-sources for 23 days after which all cows were switched to a non-UFA-supplemented concentrate for an additional 28 days. On the last day of both periods, mammary gland biopsies were taken to study genome-wide differences in gene expression on Bovine Genome Arrays.
  
  
  RESULTS
  Supplementation with UFA reduced the concentration of short chain fatty acids (FA), C16 FA and saturated FA in the milk, whereas that of trans-FA increased. One major finding was that canonical pathways associated with remodelling and immune functions of the mammary gland were predominantly down-regulated during UFA supplementation and negatively correlated with the concentration of milk trans-FA.
  
  
  CONCLUSIONS
  Supplementing grazing dairy cows with unprotected dietary UFA can affect the remodelling and immune functions of the mammary gland with potential consequences for its integrity and health, as well as milk quality.
authors.affiliation: Animal Breeding and Genomics Centre, Wageningen UR Livestock Research, P,O, Box 65, 8200 AB Lelystad, The Netherlands. nuria.mach@wur.nl.
authors.forename: Núria
authors.initials: N
authors.lastname: Mach
authors.forename: Jürgen
authors.initials: J
authors.lastname: van Baal
authors.forename: Leo
authors.initials: L
authors.lastname: Kruijt
authors.forename: Antoon
authors.initials: A
authors.lastname: Jacobs
authors.forename: Mari
authors.initials: M
authors.lastname: Smits