The impact of phosphorus on the immune system and the intestinal microbiota with special focus on the pig

Abstract

There is increasing interest in dietary ingredients that are appropriate to support digestive and immune functions, but also maintain a stable microbial ecosystem in the gastrointestinal tract (GIT), particularly in weaned pigs. P is an essential nutrient for both microbes and their host, as it is involved, for example, in bone formation, energy metabolism, cellular signalling and stabilisation of cell membranes. Non-ruminant animals have limited access to phytate, the main storage form of P in plant seeds. The release of P bound to phytate requires phytase activity of plant or microbial origin, resulting in the formation of variable phosphorylated inositol phosphates (InsPs). The present review focuses on interactions between variations in dietary P supply, the immune system of the host, and the intestinal microbial ecosystem. Although results on the interaction between P and the immune system are inconsistent, several studies in different species have shown a positive impact of dietary P and phytase addition on the adaptive immune response. Recent studies with pigs suggest that P supply may influence intestinal microbial composition and activity. Individual InsPs or phosphate may also affect properties of pathogenic micro-organisms, such as metabolism or virulence. In conclusion, P may be considered as part of an integrated approach to support immune functions and maintain a stable microbial ecosystem in the GIT, thereby providing a barrier against potential pathogens. Within this regard, differences in phytate-P content and intrinsic phytase activity of plant feedstuffs, as well as the formation of individual InsPs, have to be taken into account.

Phytate degradation, intestinal microbiota, microbial metabolites and immune values are changed in growing pigs fed diets with varying calcium–phosphorus concentration and fermentable substrates

“…In pig nutrition, an oversupply of dietary CaP above the pigs’ actual requirements is considered to be disadvantageous compromising gastric barrier function in piglets (Lawlor, Lynch, Gaffrey, O’Reilly, & O’Connell, ). However, evidence exists that the CaP availability and the formation of individual inositol phosphates affect the intestinal microbiota in pigs (Heyer et al, ). In the present study, the effect of dietary CaP supply by adding different amounts of monocalcium phosphate has been studied.…”

“…Furthermore, the interaction between the intestinal microbiota including their metabolic products such as butyrate, the integrity of the epithelial barrier function, and the local and systemic immunity describes the close relationship between the intestinal microbiota and the immune system (Grenham, Clarke, Cryan, & Dinan, ). Several studies have shown interactions between dietary CaP supply and the microbial ecosystem of the GIT in pigs (Heyer et al, ). However, studies with pigs focusing on potential relationships between dietary CaP supply and the animals’ immune system are rare.…”

“…However, studies with pigs focusing on potential relationships between dietary CaP supply and the animals’ immune system are rare. There is increasing evidence that P has to be considered as part of an integrated approach to support digestive and immune function, with special focus on maintaining the intestinal eubiosis of pigs (Heyer et al, ). In the present study, the higher dietary concentration of CaP increased the abundance of one TRF that was assigned to an uncultured bacterium related to Porphyromonadaceae.…”

“…In piglets, graded levels of soybean meal at the expense of corn starch seem to have a positive linear effect on the growth of saccharolytic and potentially beneficial genera such as Bifidobacteria in ileal digesta and faecal samples (Rist et al, ). Evidence that dietary P modulates the porcine intestinal microbiota and immune defence is emerging, although results are not always consistent, as recently reviewed (Heyer et al, ). Physiologic effects of dietary CaP in combination with different fermentable substrates on immune cell abundance and functions, and the intestinal microbiota have not been investigated in pigs.…”

Bridging Gaps in the Agricultural Phosphorus Cycle from an Animal Husbandry Perspective—The Case of Pigs and Poultry

“…In this context, P serum levels are a primary signal for activating endocrine responses, as thereby several known and yet to be elucidated regulators are addressed. Accordingly, as endogenous mechanisms affect important adaptive immune responses, research on P homeostasis requires considerable attention due to its importance in health and disease [57]. In pigs, interactions between the dietary P supply and the immune system can be deduced [28,58].…”