Manipulation of gut morphology and gut immunity in swine using novel, naturally sustainable bioactives

Abstract Text:

As health and environmental regulations increase the constraints on the use of in-feed antibiotics and minerals in swine husbandry, the search for novel bioactives from sustainable natural resources increase.  A wealth of chemodiversity in nature has arisen from plants and animals developing protective molecules to survive in varying complex biosystems.  Many of these molecules have anti-inflammatory, antimicrobial and/or anti-oxidant properties, which help the host to survive a wide spectrum of environmental challenges.  We hypothesise that these non-nutritive molecules can be used in the diet to support the developing gastrointestinal tract of the piglet. The mammalian gastrointestinal tract is a dynamic environment, where a symbiotic relationship exists between the immune system, the resident microbiota and the digestive system.  The development of the immune system begins in-utero and is further developed following the colonization of the GIT with microbiota during birth and postnatal life. The early establishment of this relationship is fundamental to the development and long-term maintenance of gut homeostasis, with unfavorable alterations in the composition of the microbiota, known as dysbiosis, being implicated in many conditions. The weaning period of the piglet under modern husbandry conditions is very prone to dysbiosis in the gastrointestinal tract, resulting in a period of post-weaning diarrhea.  It involves complex dietary, social and environmental stresses that interfere with gut development, and is characterized by a reduction in feed intake and growth, atrophy of small intestine architecture, up-regulation of intestinal inflammatory cytokines, alterations in GIT microflora, diarrhea, and heightened susceptibility to infection.  In this review, we discuss the advances in our understanding of the immune mechanisms by which the dynamic interplay of the intestinal microbiota and its host normally favours a homeostatic, symbiotic relationship, and how feeding novel, naturally sustainable bioactives from marine flora and fauna and milk can be utilized to support this symbiotic relationship in times of challenge. The overall aim of our research program is to provide dietary support to ensure an appropriate level of immune reactivity in the gut to accommodate the presence of beneficial and dietary microorganisms, while allowing effective immune/inflammatory responses to clear pathogens. A variety of natural sustainable bioactives have been identified that target different components of the gastrointestinal tract environment.  Modes of action vary from commensal microbial stimulants, targeted antimicrobial activity, gut barrier repair, mucosal structure (villous architecture, absorptive capacity, nutrient transporters) and mucosal anti-inflammatory activity. Interestingly, ingestion of combinations of these bioactives can enhance bioavailability lower down in the colon.

Keywords: swine, natural, sustainable, bioactive, gut health