Effect of dietary additives on microbiome and metabolic outputs of in vitro ruminal fermentation

• Grant number: 23/11136-2
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: November 10, 2023
• End date: November 09, 2024
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Flávio Dutra de Resende
• Grantee: Igor Machado Ferreira
• Supervisor: Hilario Cuquetto Mantovani
• Host Institution: APTA Regional. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil
• Institution abroad: University of Wisconsin-Madison (UW-Madison), United States
• Associated to the scholarship: 22/00989-1 - USE OF EXOGENOUS ENZYMES IN FEEDLOTS DIETS: EFFECT ON THE DIGESTIBILITY, METABOLISM, PERFORMANCE, INTAKE, CARCASS CHARACTERISTICS AND DIFFERENTIALLY EXPRESSED GENES OF NELORE CATTLE, BP.DR

Abstract

The rapid screening of dietary additives is key to identifying potential rumen modifiers that could improve nutrient utilization efficiency. The study aims to evaluate the effect of feed additives on changes in microbiome composition, metabolic outputs of ruminal fermentation and improve nutrient utilization efficiency in-vitro. For this, the ruminal content will be sampled from 8 fistulated dairy cows. The ruminal content will be separated into solid and liquid fractions and the ruminal liquid will be diluted in a 1:2 ratio with anaerobic artificial saliva buffer. Subsequently, 200mL of this mixture will be added to an in vitro automated gas system (Ankom Technology). Each Ankom vial will receive 10 mg/ml of diet (with or without additive), 2g of ruminal solids, washed with oxygen-free CO2 and sealed. The rumen content of each animal will be divided into control group (TMR alone) and treatment groups (TMR + aditive; propionate, lactate, glycerol, gluconeogenic amino acids, molasses, urea) containing up to five levels of each additive (0.5, 1, 2, 5 and 10%). Fermentations will be run in parallel using triplicate flasks in a randomized design and a total of 15 units per run. Cumulative pressure measurements on the Ankon flasks will be recorded every 15 min to determine fermentation kinetics. In each flask samples of the liquid will be collected for analysis of VFAs, ammonia, pH, microbial protein and microbiome composition (16S rRNA). The headspace gas (20 ml) will be sampled and forced into a 5 ml extractor to determine the gas composition (CH4, CO2, H2) using gas chromatography. Additionally, the FAPESP 2022/00989-1 project will involve collaborative work with Dr. Mantovani to analyze the results of metagenome sequencing (16S rRNA) obtained from ruminal samples. As part of the BEPE program, the student will have the opportunity to expand their knowledge in ruminant nutrition, ruminal metagenome sequencing, and bioinformatic techniques applied to microbiome data. Besides, the student will also be involved in other research activities performed by Dr. Mantovani's group. It is expected that a scientific manuscript will be generated and published in a high-impact peer- reviewed journal towards the end of this internship activity performed at the University of Wisconsin. (AU)