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

Abstract

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.

Effects of Exposure to Low Zearalenone Concentrations Close to the EU Recommended Value on Weaned Piglets’ Colon

“…Many studies discussed the relationship between Lactobacillus and post-weaning diarrhoea [ 66 , 67 , 68 ] showing that lactic acid bacteria are frequently used as a probiotic in reducing diarrhoea incidence, as reported by Dell’Anno et al [ 69 ] or Wang et al [ 70 ]. Other studies also indicate increased diarrhoea incidence with decreased Lactobacillus counts [ 71 , 72 ].…”

Gut Health and Influencing Factors in Pigs

“…These pro-inflammatory cytokines redirect nutrients from growth to the immune system, which also compromises animal performance. Moreover, products of oxidative damage of lipids and proteins such as malondialdehyde (MDA) and carbonyls are known biological markers for OS [ 8 , 69 , 70 ]. Various stressors can be experienced by pigs in different stages of their productive life, which can affect their intestinal health, subsequently affecting their growth, performance, and productivity.…”

“…Lawsonia intracellularis causes porcine proliferative enteropathy (Ileitis) as it infects the small intestine and the large intestine; it causes inflammation and thickening of the ileum and proximal colon, reducing nutrient absorption [ 102 ]. Intestinal permeability influenced by stressors can lead to the entry of pathogenic bacteria, causing intestinal lesions and compromised functionality, which degrade the animals’ performance, demanding an efficient and sustainable remedy [ 70 ].…”

“…Rodrigues et al [ 70 ] stressed that high dietary protein (HDP) level in the diet could have a detrimental impact on the pigs’ gut health with presumptions of the undigested protein entering the large intestine, available for microbial fermentation and the possible influence of HDP level to support the proliferation of pathogenic bacteria (ETEC), by increasing the pH of the gut through the high buffering capacity of protein. Zhang et al [ 103 ] reported that the HDP levels in piglets’ diet caused detrimental changes in their intestinal morphology, permeability, pro-inflammatory cytokine concentrations, and alteration in the microbial community and increased the incidence of post-weaning diarrhea.…”

“…The definition and beneficial effects of various other feed additives (enzymes, pre and probiotics, organic acids, and secondary plant metabolites (essential oils)) on the gut health and development of pigs were discussed in detail elsewhere [ 70 , 134 , 135 ]. Therefore, only representative examples of research findings are presented in Table 2 .…”