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Effect of Choline in Rumen Protected Forms on Hepatic Metabolism in Dry Cows Induced to Develop Fatty Liver

Grant number: 19/16257-7
Support type:Scholarships abroad - Research Internship - Master's degree
Effective date (Start): November 20, 2019
Effective date (End): February 29, 2020
Field of knowledge:Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
Principal Investigator:Flávio Augusto Portela Santos
Grantee:Djonatan Machado
Supervisor abroad: Jose Eduardo P. Santos
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
Local de pesquisa : University of Florida, Gainesville (UF), United States  
Associated to the scholarship:18/14214-6 - Performance and metabolism of early lactation feedlot cows receiving doses of calcium salts of fatty acids of PALMA oil associated or not with LYSOLECITHIN, BP.MS

Abstract

The objective of this experiment is to determine the effects of two methods of rumen protection and two doses of choline on hepatic tissue composition in cows induced to develop fatty liver. The cows will receive 1 of 5 treatments top-dressed daily, for 14 days: - A (negative control): top dressed with lipid coating material containing 0 g of choline ion; - B (positive control, Reashure low): top dressed with 60 g/d of a product containing rumen-protected choline chloride to supply 12.9 g of choline ion; - C (positive control, Reashure high): top dressed with 120 g/d of a product containing rumen-protected choline chloride to supply 25.8 g of choline ion; - D (new product, Prototype low): top dressed with X g/d of a product containing rumen-protected choline chloride to supply 12.9 g of choline ion; - E (new product, Prototype high): top dressed with 2X g/d of a product containing rumen-protected choline chloride to supply 25.8 g of choline ion. The experiment will be in Double-blinded, randomized complete block design, wherein 100 prepartum cows will be enrolled in the experiment, 20 per treatment. Cows will be fed for ad libitum intake from experiment days 1 to 5. Starting on day 6, feed will be restricted to supply approximately 50% of the net energy requirements. The lipid coating will be mixed as needed with treatments A to E to adjust the total amount of lipids and corn meal will be used to complete 200 g of daily top dress. Liver tissue will be collected for biopsy on experiment day 6 (last day of ad libitum feeding, cows already received treatments for 4 days) and again on day 13 (day 8 of feed restriction). Assays to be perform include: 1) hepatic tissue - quantify total lipids, triacylglycerol, glycogen and dry matter, mRNA and protein expression for pathways linked to gluconeogenesis, lipid trafficking, assembly and secretion of VLDL, and measures of pro-inflammatory markers; 2) blood composition - choline metabolites, concentrations fatty acids (NEFA), beta-hydroxybutyrate (BHB), glucose, insulin, triacylglycerol, fatty acids, cholesterol, serum amyloid A, apolipoprotein B48, and haptoglobin. Data will be analyzed with mixed models using the MIXED procedure of SAS. Contrast will be used to test the effects linear and quadratic of level of choline, of method of protection, of dose of choline and interaction between method of protection and dose.