Piglet gut microbial shifts early in life: causes and effects

Abstract

The gut microbiome has long been known to play fundamentally important roles in the animal health and the well-being of its host. As such, the establishment and maintenance of a beneficial gut microbiota early in life is crucial in pigs, since early gut colonizers are pivotal in the establishment of permanent microbial community structures affecting the health and growth performance of pigs later in life. Emphasizing this importance of early gut colonizers, it is critical to understand the factors impacting the establishment of the piglet gut microbiome at weaning. Factors include, among others, diet, in-feed antibiotics, probiotics and prebiotic administration. The impact of these factors on establishment of the gut microbiome of piglets at weaning includes effects on piglet gut microbial diversity, structure, and succession. In this review, we thoroughly reviewed the most recent findings on the piglet gut microbiome shifts as influenced by weaning, and how these microbiome changes brought about by various factors that have been shown to affect the development of microbiota in piglets. This review will provide a general overview of recent studies that can help to facilitate the design of new strategies to modulate the gut microbiome in order to enhance gastrointestinal health, growth performance and well-being of piglets.

Keywords: 16S rRNA; Microbial diversity; Next generation sequencing; Swine microbiota; Weaning.

Fig. 1

Bacterial alpha diversity and composition shifts as influenced by diet. Alpha diversity indices of the piglet gut microbiota increase while the variability of the microbiota among individual piglets decreases as the piglets age. Significant differences between mean proportions of bacterial taxa at the family level in nursing and weaned pig fecal samples were indicated as the blue and red up arrows, whose relative abundances were higher in nursing and weaned piglets, respectively. Figure was modified with permission from the article by Frese et al. [39]

Fig. 2

The potential mechanisms by which probiotics affect intestinal microbial ecology. Probiotics may act through the following mechanisms: (1) manipulation of the microbiota by changing luminal pH, (2) competitive inhibition of pathogen, (3) production of antimicrobial substances and (4) stimulation of the pig’s immune system

Fig. 3

The functional capacities of the microbiome between nursing and weaned piglets in association with carbohydrate metabolism as revealed by whole metagenome shotgun sequencing. The scale bar indicates normalized abundance of the level 3 SEED subsystem classified reads associated with carbohydrate metabolism. The [P < 0.001], [P < 0.01] and [P < 0.05] were indicated as [***], [**] and [*], respectively