Dietary copper and zinc effects on lipid metabolism in finishing steers

• Grant number: 18/17108-2
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: October 31, 2018
• End date: October 30, 2019
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Telma Teresinha Berchielli
• Grantee: Juliana Akamine Torrecilhas
• Supervisor: Terry e Engle
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Institution abroad: Colorado State University, United States
• Associated to the scholarship: 16/10953-3 - Growth physiology and meat quality of young cattle finished on pasture or feedlot submitted to different nutritional plans during the stocking phase, BP.DR

Abstract

Trace minerals have long been identified as essential components in the diets of domestic livestock species. Dietary Cu and Zinc, when fed at physiological concentrations, can be alter lipid metabolism. Therefore the main objectives of this experiment are to determine the effects of: 1) copper and zinc source on performance, mineral status, lipogenic gene expression, and carcass characteristics of finishing cattle. Upon entry into the feedlot, all steers will be weighed and will be blocked by ranch and stratified by bodyweight (2 d mean weight) and sorted into pens (six reps/treatment). Pens within blocks will be randomly assigned to treatments in a 2 X 2 factorial arrangement; factors will be 10 mg Cu/kg form DM from CuSO4 or 10 mg Cu/kg form DM from Availa-Cu and 90 mg Zn/kg from ZnSO4 or 36 mg Zn/kg from Availa-Zn + 54 mg of Zn form ZnSO4. Treatments will consist of: 1) 10 mg Cu/kg form DM from CuSO4 + 90 mg Zn/kg from ZnSO4, 2) 10 mg Cu/kg form DM from Availa-Cu + 90 mg Zn/kg from ZnSO4, 3) 10 mg Cu/kg form DM from CuSO4 + 36 mg Zn/kg from Availa-Zn + 54 mg of Zn form ZnSO4, 4) 10 mg Cu/kg form DM from Availa-Cu + 54 mg Zn/kg for ZnSO4. Steers will be fed a high concentrate finishing diet until they reach an approximate weigh of 570 kg. Steers will be weighed and bled every 28 d. Blood samples will be analyzed for cholesterol and trace mineral concentrations. Body weights will be used to calculate average daily gain, feed refusals will be used to calculate feed intake, and average daily gain and feed intake will be used to calculate feed efficiency. Three weeks prior to slaughter, adipose tissue biopsies will be obtained from one steer per pen for the determination of lipogenic gene expression. Adipose tissue biopsy will be obtained from the right side of the tail head. Approximately 5 grams of adipose will be removed, placed in aluminum foil, labeled and snap-frozen in liquid nitrogen. At the end of the experiment steers will be transported to a slaughter plant where carcass data will be collected. Fatty acid profile will also be determined on longissimus muscle tissue samples obtained postmortem.