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Effects of dietary polyunsaturated fatty acid sources on lipid-related genes in bovine milk somatic cells.

E. Vargas-Bello-Pérez

Abstract:

255
Effects of dietary polyunsaturated fatty acid sources on lipid-related genes in bovine milk somatic cells.
E. Vargas-Bello-Pérez*1,2, N. Cancino-Padilla1, C. Geldsetzer-Mendoza1, M. S. Morales3, H. Leskinen4, P. C. Garnsworthy5, J. J. Loor6, J. Romero7. 1Departamento de Ciencias Animales, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile Santiago, Chile, 2Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg C, Denmark, 3Departamento de Fomento de la Producción Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile La Pintana, Santiago, Chile, 4Milk Production, Production Systems, Natural Resources Institute Finland (Luke) Jokioinen, Finland, 5School of Biosciences, Sutton Bonington Campus, The University of Nottingham Loughborough, United Kingdom, 6Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois Urbana, IL, 7Laboratorio de Biotecnología en Alimentos, Unidad de Alimentos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Macul, Santiago, Chile.

The objective of this study was to determine the effects of the number of double bonds of dietary lipids on expression of genes related to lipid metabolism in milk somatic cells (MSC) in dairy cows. For this, 15 dairy cows (2ndand 3th lactation, 42 L milk/day, 195 ± 35 d in milk) were randomly assigned to a control diet (CD) containing no added lipid (n = 5 cows); and diets supplemented with soybean oil (SO) (n = 5 cows; unrefined SO; 3% DM) or fish oil (FO) (n = 5 cows; manufactured from salmon oil; 3% DM); cows were fed for 63 d. On d 21, 42 and 63, MSC were obtained 4 h after first milking from all cows. Milk production, milk fat, and milk protein were not affected by treatments. Relative abundance of mRNA from 17 genes involved in lipid metabolic functions: fatty acid (FA) importation into cells, FA synthesis and desaturation, acetate and FA activation, FA intra-cellular transport, triacylglycerol synthesis, and lipid droplet formation regulation. Products of transcription (mRNA) from MSC were obtained by qPCR. The mRNA from cows fed CD on d 42 and 63 were compared with mRNA relative abundance at d 21 to evaluate fold-changes. Those genes from CD group without changes over the time (ACACA, PPARGC1, LPIN1, INSIG1, DGAT1 and FABP3) were selected to analyze effects of SO and FO. The relative abundance software tool (REST) was used to analyze qPCR results. This software incorporates PCR efficiency correction and reference gene normalization. Compared with CD, SO downregulated (P < 0.01) ACACA, INSIG1, and DGAT1. Compared with CD, FO downregulated (P < 0.01) ACACA, PPARGC1, LPIN1 and FABP3. Overall, data indicated that there are differential transcriptomic effects of lipid-related genes in MSC and that will depend on the number of double bonds of dietary lipids.

Keywords: oils, mammary gland, gene expression.