# Combined supplementation of essential oils, Saccharomyces cerevisiae and isomaltooligosaccharides improves intestinal absorption and immune functions in weaned piglets

## TL;DR

A natural feed supplement improved gut health and immunity in young pigs, but its effectiveness varied depending on the farm environment.

## Contribution

The study demonstrates the synergistic benefits of a natural feed additive blend in weaned piglets under different farm conditions.

## Key findings

- ESI treatment improved intestinal villus height to crypt depth ratio and immune markers like IgA and cytokine expression.
- Farm environment significantly influenced immune gene expression and the effectiveness of the supplement.
- ESI showed comparable benefits to antibiotic supplementation in enhancing intestinal health and immunity.

## Abstract

This study evaluated the synergistic effects of essential oils (EOs), Saccharomyces cerevisiae (SC), and isomaltooligosaccharides (IMO) on intestinal health and systemic immunity in weaned piglets using a randomized block design across two commercial farms. Within each farm, 108 piglets weaned at 24 d of age were randomly divided into 3 groups (3 pens per group, 12 piglets per pen). The piglets were fed a basal diet (CON) and a basal diet supplemented with antibiotics (0.5 kg/t colistin sulfate + 0.5 kg/t tilmicosin) (ANTI) or additive mixture (0.1 kg/t EOs, 0.3 kg/t SC and 1 kg/t IMO) (ESI) for 28 days. The results showed that both ESI and ANTI treatments significantly increased the ratio of villus height to crypt depth (P < 0.05). Specifically, ESI supplementation elevated serum IgA, hepatic IgA, and jejunal mucosal sIgA levels (P < 0.05), while upregulating hepatic IL1B, IL2, IL6, and IFNG expression alongside jejunal mucosal IL1B, IL6, and PPARG expression—contrasting with its downregulation of jejunal mucosal IFNG mRNA (P < 0.05). Conversely, compared with the CON group, ANTI supplementation increased serum IgA level and jejunal mucosal concentrations of sIgA, IgG, IgM, IFN-γ, and IL-10, while also upregulating jejunal mucosal gene expression of IGF1 and TGFB1 (P < 0.05). In addition, compared with Farm I, piglets at Farm II exhibited higher jejunal pH, elevated serum levels of IgA and IL-1β, and upregulated gene expression of IL1B, IL2, IL6, and IFNG in the liver as well as TGFB1, IL1B, IL6, and PPARG in the jejunal mucosa (P < 0.05). Moreover, the robust diet × farm interaction effects on immune gene expression in the liver (IL1B, IL2, and IL6) and jejunal mucosa (IL1B, IL2, IL6, IFNG, IL10, and PPARG) were observed (P < 0.05). Collectively, ESI improved jejunal epithelial maturation, nutrient absorption, and immune function in weaned piglets, with efficacy partly dependent on farm environmental conditions.

This multi-farm intervention study reveals that a natural feed blend (essential oils, Saccharomyces cerevisiae, and isomaltooligosaccharides) can enhance intestinal health and immunity in weaned piglets, though its effectiveness depends on farm-specific environmental conditions.