Mammary cell turnover and expression of lipogenic genes in response to silage induced CLA and diet energy density in lactating cows
Abstract:The objective of this experiment was to investigate possible effects of silage induced differences in milk conjugated linoleic acids (CLA) and diet energy density on cell turnover and production capacity in the mammary gland. Cows were given high levels of canola fat and fed either grass or maize silage at either a high or a low diet energy density. Mammary biopsies were obtained and evaluated for cell turnover and gene expression. Diet energy density did not affect CLA concentration in milk fat and cell turnover. Feeding maize silage increased milk fat concentrations of cis9, trans11-CLA and trans10, cis12-CLA compared to grass silage. Cell proliferation tended to be greater in cows fed with maize compared to grass silage, indicating no negative effects of CLA on cell number. Feeding high energy density diets and maize silage diets tended to lower abundances of mammary lipogenic gene mRNAs presumable due to the effect of trans10, cis12-CLA.
Document Type: Research Article
Affiliations: 1: Department of Animal Health, Welfare and Nutrition, Faculty of Agricultural Sciences, University of Aarhus, Tjele, Denmark 2: Department of Animal Sciences, The University of Arizona, Tucson, USA
Publication date: September 1, 2008