Effect of energy sources (starch, pectin or fat) and chromium supplementation, on high energy diet, on serum concentrations of glucose, insulin, and non-esterified fatty acids on lactating dairy cows

• Grant number: 15/01533-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2015
• End date: April 30, 2016
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: José Luiz Moraes Vasconcelos
• Grantee: Leticia Aparecida Casarin Lourenço
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The objective of this study is to evaluate the influence of the energy source of the diet and chromium propionate supplementation on insulin resistance parameters using glucose tolerance test on lactating dairy cows. Twenty four multiparous lactating crossbred Holstein x Gir cows, within 80 ± 7 DIM will be blocked by milk yield and BCS, and randomly assigned to one of four treatments on d0 of the experiment: 1) diet formulated with corn to reach 160% of requirements for maintenance and lactation, without chromium supplementation (n=6); 2) the same diet from group 01 with chromium supplementation (n=6; 2,5g of KemTRACETM Chromium Propionate 0,4% - Kemin Industries, Inc. - added in 97,5g of corn meal/animal/day) 3) diet formulated with citrus pulp to reach 160% of requirements for maintenance and lactation, without chromium supplementation (n=6); 4) the same diet from gropu 03 with chromium supplementation (n=6; 2,5g of KemTRACETM Chromium Propionate 0,4% - Kemin Industries, Inc. - added in 97,5g of corn meal/animal/day). Glucose Tolerance Test (n=3) will be performed on d-2, d100 and d200 to determine glucose clearance rate and insulin release. Blood samples will be taken at -15, 0 (before infusion), 10, 20, 30, 45, 60, 90 e 120 min after glucose infusion (0,5g dextrose/ kg de PV) for glucose and insulin serum concentration. All variables will be analyzed using the MIXED procedure of SAS.