Effect of dietary lysine restriction on performance and body composition of immunocastrated pigs with high genetic potential

• Grant number: 24/20338-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2025
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Luciano Hauschild
• Grantee: Eloá Bispo Bosso
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The project aims to evaluate the performance, body composition, nitrogen balance, and metabolic responses of entire male pigs subjected to a standardized ileal digestible lysine (SID Lys) restriction, as well as the dynamics of compensatory growth following the re-establishment of Lys levels before and after immunocastration. Sixty entire male pigs will be used, assessed over a 77-day experimental period divided into two phases: Phase 1 - animals with an average body weight of 50 to 75 kg (0-28 days) and Phase 2 - animals with an average body weight of 75 to 120 kg (29-78 days). On the first experimental day, animals will be randomly assigned to one of four experimental treatments: 55%, 70%, 85%, or 100% of the digestible Lys requirement according to Van Milgen et al. (2008; Phase 1). After this phase, all animals will be fed the same diet that meets the nutritional requirements according to Van Milgen et al. (2008; Phase 2). The animals will be immunized using a commercial vaccine (Vivax®, Zoetis) administered in two doses via subcutaneous injection, eight and four weeks before slaughter (at approximately 75 kg and 100 kg, respectively). An automated feeding system (Automatic and Intelligent Precision Feeder, University of Lleida, Spain) capable of individually monitoring the animals' feed intake will be used. Performance, body composition (evaluated using dual-energy X-ray absorptiometry; DXA), nitrogen balance, and metabolic parameters will be assessed. The execution of this proposal will support the development of nutritional strategies tailored to the digestible Lys requirements of pigs during the growing and finishing phases.