Effect of condensed tannins on nitrogen metabolism in feedlot cattle fed different protein sources

• Grant number: 25/15483-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Ricardo Andrade Reis
• Grantee: Pedro Santana Marchiori
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated research grant: 22/15974-0 - Strategic grazing management and supplementation towards sustainable intensification at tropical pasture-based beef cattle production systems, AP.TEM

Abstract

The metabolism of nitrogenous compounds is one of the main factors influencing cattle performance and is also associated with environmental parameters. Its modulation, particularly in the digestive tract, can enhance animal performance and help mitigate negative environmental impacts. Therefore, the present project aims to evaluate the effect of different combinations of non-edible protein feedstuffs and condensed tannins (CT) during the finishing phase of feedlot cattle on nitrogen metabolism and microbial efficiency. Eight rumen-cannulated steers will be used in a balanced 4 × 4 double Latin square design, in which four experimental diets will be tested over four 21-day periods. Treatments will follow a 2 × 2 factorial arrangement, with Factor A being the protein source and Factor B the presence or absence of condensed tannins, resulting in four treatments: T1 - dried distillers grains with solubles (DDGS); T2 - DDGS + CT; T3 - peanut meal (PM); T4 - PM + CT. During the experimental periods, feces, urine, and ruminal content samples will be collected to assess nitrogen balance, nitrogen utilization efficiency, ruminal NH¿-N concentration, and microbial protein synthesis. The results will help fill existing knowledge gaps in feedlot cattle nutrition, particularly regarding the interaction between condensed tannins and different protein sources, as well as their effects on metabolic parameters that are key to animal performance and environmental impact.