Formulating Diets for Improved Health Status of Pigs: Current Knowledge and Perspectives.

Abstract

Simple SummaryToday’s swine production systems are mostly intensive, and pigs are continuously exposed to pathogens and immune stimulatory antigens that may negatively impact productivity. It is known that immune system stimulation may reduce appetite, growth, and nutrient use efficiency compared to healthy animals. On the other hand, there is progressive pressure towards the reduction in antibiotic usage in livestock production, which highlights the need for furthering our understanding of the relationship between nutrition and the immune response. Swine nutritionists will need to consider the role of nutrition on health in order to develop programs that support production and robustness of pigs under a variety of stressful conditions. Among the nutritional strategies whose utilization may directly impact on the immune status of pigs, feeding low protein, amino acid-supplemented diets, supplementation of functional amino acids, dietary fiber level and source, diet complexity, organic acids, and plant secondary metabolites are at the forefront. As such, this review will discuss the impact of immune status on swine production and the interaction between nutrients and animal health, focusing on the roles of each nutritional strategy during times of immune challenge.Our understanding of nutrition has been evolving to support both performance and immune status of pigs, particularly in disease-challenged animals which experience repartitioning of nutrients from growth towards the immune response. In this sense, it is critical to understand how stress may impact nutrient metabolism and the effects of nutritional interventions able to modulate organ (e.g., gastrointestinal tract) functionality and health. This will be pivotal in the development of effective diet formulation strategies in the context of improved animal performance and health. Therefore, this review will address qualitative and quantitative effects of immune system stimulation on voluntary feed intake and growth performance measurements in pigs. Due to the known repartitioning of nutrients, the effects of stimulating the immune system on nutrient requirements, stratified according to different challenge models, will be explored. Finally, different nutritional strategies (i.e., low protein, amino acid-supplemented diets; functional amino acid supplementation; dietary fiber level and source; diet complexity; organic acids; plant secondary metabolites) will be presented and discussed in the context of their possible role in enhancing the immune response and animal performance.