Insights provided by nutrigenomics into the effect of diet on metabolism and milk production

Abstract Text: The impact of diet on metabolism and milk production has been well appreciated by dairy nutritionist for many years.  Nutrigenomics has provided tools and experimental approaches critical to identifying the functional mechanism of nutrients.  First, nutrigenomics has led to the discovery of basic mechanisms using cell culture and rodent models that provide strong candidate mechanisms for testing in the cow.  Secondly, the application of nutrigenomics approaches in the cow has provided direct insight into novel mechanisms of the cow.  The presentation will focus on the application of nutrigenomics to understanding diet-induced milk fat depression and dietary regulation of the circadian rhythm of the mammary gland.  Milk fat depression is caused by specific intermediates of ruminal biohydrogenation of polyunsaturated fatty acids and is a clear example of nutritional regulation of metabolism.  Advances in lipid analysis and chemistry allowed identification of the bioactive conjugated linoleic acid isomers, but nutrigenomic approaches were key to identification of mechanism.  Specifically, microarray analysis identified candidate systems and transgenic approaches have allowed demonstration of the functional mechanism.  Nutrient intake also entrains the daily rhythm of metabolism through regulation of a transcriptionally regulated biological clock.  Although the exact nutrient is not clear, nutritional entrainment of the mammary gland clock has been demonstrated.  Understanding the mechanisms of bioactive nutrients has allowed development of targeted nutritional strategies and has great future potential as an experimental approach.

Keywords: Nutrigenomics, Milk fat Depression, gene expression