Validation of an in vitro gas production assay to assess the impact of cereal grain processing on fermentation kinetics

• Grant number: 25/15881-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: April 01, 2026
• End date: September 30, 2026
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Murillo Ceola Stefano Pereira
• Grantee: Gabriela Mariana Fogaça
• Supervisor: Gregory Penner
• Host Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil
• Institution abroad: University of Saskatchewan (USASK), Canada
• Associated to the scholarship: 24/14012-5 - Roughage and physically effective neutral detergent fiber inclusion in finishing diets fed to feedlot cattle on ruminal fermentation and motility, bacterial community composition, eating behavior, and total tract digestibility, BP.MS

Abstract

The objective of this study will be to adapt and validate an in vitro gas production assay to incorporate unprocessed grain samples, enabling the evaluation of cereal grain processing effects on fermentation kinetics without laboratory re-grinding. The experimental design will follow the technique of Mauricio et al. (1999) with modifications to avoid re-processing and to assess repeatability across incubation volumes. Ruminal fluid will be collected from two cannulated beef cattle fed a barley-based finishing diet. Independent barley, wheat, and corn samples will be processed via dry rolling, temper rolling, or steam flaking, each at four severities from intact kernels to severe processing. Three incubation volumes (120, 500, and 1000 mL) will be compared, maintaining a constant grain-to-fluid ratio. Gas production will be measured at 0, 2, 4, 8, 12, 16, 24, 48, 72, 96, and 120 h to determine fermentation rate, lag time, and asymptotic gas production. Duplicate bottles will be run per treatment, with inherent processed grains compared to dried, ground samples. Data will be analyzed separately by grain type using a 3 × 4 + 1 factorial arrangement and a mixed model including fixed effects of incubation volume, processing severity, and their interaction, with grain source and run as random effects. Planned contrasts will compare inherent versus ground samples. We expect larger incubation volumes to improve representativeness and repeatability, and inherent form incubations to better capture processing effects than ground samples. The validated method will provide a practical, reproducible tool for assessing cereal grain processing under conditions representative of on-farm feeding, supporting improved feed efficiency, rumen health, and processing audits in research and industry applications. (AU)