Addition of exogenous glucoamylase enzyme to corn silage based beef cattle diets in order to increase animal growth and efficiency

• Grant number: 23/02662-2
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: September 20, 2023
• End date: September 19, 2024
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Otávio Rodrigues Machado Neto
• Grantee: Rodrigo de Nazaré Santos Torres
• Supervisor: Jon Schoonmaker
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Institution abroad: Purdue University, United States
• Associated to the scholarship: 21/07222-5 - Effect of vitamin A restriction in finisher diets of F1 Angus animals with positive DEP for marbling on muscle gene and proteomic expression and the mechanisms involved in muscle fat deposition, BP.PD

Abstract

For animals in the finishing phase, the level of roughage in the diet has an inverse relationship with the energy density of the diet. In this context, the use of exogenous enzymes (amylases and fibrolytic) acts as a strategy to increase the availability of energy and nutrients in the diet. Becoming of interest to understand the activity of glucoamylase enzymes that act in the direct release of a glucose molecule, becoming more effective in the availability of energy for the rumen. Thus, we propose a study to investigate the effect of exogenous glucoamylase addition to beef feedlot cattle diets containing 3 concentrations of corn silage on performance, carcass parameters and digestibility. Two experiments will be conducted; a performance study (experiment 1) and a digestibility study (experiment 2). Experiment 1: One-hundred and eighty steers will be fed six treatments, arranged as a 3 x 2 factorial, investigating 3 forage concentrations (15, 41.5, and 68% corn silage) and 2 exogenous glucoamylase additions (0 or 183 enzyme units/kg of dry matter per day). Cattle will be weighed monthly, feed intake recorded daily and average daily gain, dry matter intake, and feed efficiency, hot carcass weight, rib-eye area, fat thickness, yield grade, marbling score, and quality grade. Experiment 2: Digestibility measurements will be accomplished by collecting diet samples from all bunks and fecal samples from the surface of each pen. (AU)