Galacto-oligosaccharides increase abundance of beneficial probiotic bacteria, improve gut architecture and goblet cell expression in poorly performing piglets

Abstract

Background: Suckling is a unique period in porcine development where establishment of the microbiota is essential for future growth and health of animals. However, poor pre-weaning performance and failure to thrive without signs of clinical disease during lactation is of concern in pig production and incurs significant economic loss. Prebiotic galacto-oligosaccharides are functionally similar to those of mammalian milk and modulate gut architecture and intestinal microbiota in healthy pigs. Study objectives were to investigate the effects of complete milk replacer supplemented with 1 % (w/w) galacto-oligosaccharides on the microbiome, gut architecture and immunomodulatory goblet cell expression of poorly performing piglets that could benefit from milk replacement feeding when separated from sows and fit siblings in environmentally controlled pens. This was compared with piglets that received complete milk replacer without galacto-oligosaccharide supplementation. Production data over 21 days were collected in four separate and repeated feed trials before post-mortem duodenal, jejunal, ileal, caecal, colonic and rectal samples were collected from thirty-five piglets across the four trials and the microbiome composition assessed by 16s rRNA gene sequencing. Gut architectural features, villus crypt ratio and enumeration of goblet cells in tissues were assessed by histopathological techniques. Results:Milk replacer supplemented with galacto-oligosaccharides was palatable and well tolerated but had no significant effect upon performance or alpha-diversity. Galacto-oligosaccharides added to milk replacer significantly modulated microbial communities as demonstrated by beta-diversity and significantly increased Lactobacillus and Bifidobacteriumthroughout the gastrointestinal tract. The most abundant taxa identified at genus level were Lactobacillus, Streptococcus, Prevotella, Lactococcusand Leuconostoc. Milk replacer plus galacto-oligosaccharide fed piglets showed significantly improved gut architectural features and villus crypt ratio throughout the gastrointestinal tract as well as an increased number of barrier enhancing and immunomodulatory goblet cells. Conclusions: Galacto-oligosaccharide supplemented milk replacer significantly increased differential abundance of beneficial probiotic bacteria, particularly Lactobacillus and Bifidobacterium, improved gut architecture and goblet cell expression in poorly performing piglets. In these respects, galacto-oligosaccharide supplemented milk replacer may be a useful addition to animal husbandry in poorly performing, non-thriving animals when moved to environmentally controlled pens away from sows and fit siblings, thereby modulating the microbiome and gastrointestinal tract performance.