Description: Seaweeds have high levels of bioactive compounds, which may have beneficial effects on the health of humans and domestic animals. Dietary supplementation with seaweed has been shown to modulate gut microbiota, enhance immune function, and reduce inflammation. Furthermore, bioactive compounds of seaweed and other plants have been proposed as novel anti-parasitic treatments in livestock, which is of increasing importance as resistance to conventional anti-parasitic drugs is widespread. Here, we tested the effect of dietary seaweed (Saccharina latissima) supplementation in pigs co-infected with Ascaris suum and Oesophagostomum dentatum on parasite burdens, gut microbiota composition, and immune responses. We found that inclusion of fermented S. latissima (Fer-SL) at 8% of the diet increased gut microbiota diversity with higher relative abundances of Firmicutes, Tenericutes, Verrucomicrobia, Spirochaetes and Elusimicrobia, and lower abundance of Prevotella copri. In the absence of helminth infection, the transcription of immune-related genes in the intestine was only moderately affected by seaweed. However, Fer-SL modulated the transcriptional response to infection in a site-specific manner in the gut, with an attenuation of infection-induced gene expression in the jejunum and an amplification of gene expression in the colon. Effects on systemic immune parameters (e.g. blood lymphocyte populations) were limited, indicating the effects of Fer-SL were mainly localized to the intestinal tissues. Despite previously documented in vitro activity against pig helminths, Fer-SL inclusion did not significantly affect parasite egg excretion or worm establishment. However, we observed a trend for reduced number of liver spots, caused by migrating A. suum larvae, and reduced hatching and development of O. dentatum eggs. Collectively, our results show that although Fer-SL inclusion did not substantially reduce parasite burdens, it had seemingly positive effects on the gut environment during enteric parasite infection, which encourages continued investigations into the use of seaweeds or related products as novel tools to improve gut health.

Data type: raw sequence reads

Sample scope: Multispecies

Last updated: 2022-03-17