Utilization of branched chain volatile fatty acids by rumen microbes with different dietary conditions in dual flow cultures

• Grant number: 19/04650-6
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: June 01, 2019
• End date: September 30, 2019
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Carla Maris Machado Bittar
• Grantee: Ariany Faria de Toledo
• Supervisor: Jeffrey L. Firkins
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: Ohio State University, Columbus, United States
• Associated to the scholarship: 18/01248-0 - Whole corn grain as fiber source for dairy calves: effects on performance, ruminal development and metabolism, BP.MS

Abstract

The experiment will be a 2 x 2 x 2 factorial arrangement of 8 treatments with 8 anaerobic dual-flow continuous cultures and 4 periods in a randomized incomplete block. The continuous cultures will be randomly assigned to a treatment with either BCVFA supplementation (2 mmol/d of isobutyrate, 2 mmol/d isovalerate, and 2 mmol/d 2-methylbutyrate) or no additional BCVFA, high forage: concentrate diet (70:30) or low forage: concentrate diet (30:70), and either supplemental PUFA (additional 3% of diet) or no additional PUFA. Each period of the experiment will be 10 days long, with 7 days of acclimation and 3 days of sampling. The cultures will be fed and dosed their respective treatments 2 times a day (30 g as fed) at 12-hour intervals. After background sampling, on day 4, 40 mg/d of 13C labeled isovalerate, 2-methylbutyrate, and isobutyrate (Cambridge Isotope Laboratories, Inc.) will be dosed and analyzed to monitor how treatments influence BCVFA recovery in bacterial membranes. 15N-labeled ammonia will be added to assess microbial nitrogen flow and efficiency of microbial protein synthesis. The buffer of the continuous cultures will be managed so that there is no difference in pH between any treatment. (AU)