Effect of seaweed extracts and galacto-oligosaccharides on growth performance and intestinal health in pigs following S. Typhimurium challenge

Pork and pork products are recognised as vehicles of Salmonella Typhimurium (S. Typhimurium) infection in humans. In recent years, galactooligosaccharides (GOS) and seaweed extracts (SWE) have been explored as novel sources of bioactive compounds that contain antimicrobial and immunomodulatory properties. The main bioactives in seaweed are the polysaccharides laminarin and fucoidan, which have antimicrobial, prebiotic and anti-inflammatory properties. Galacto-oligosaccharides are prebiotics and possess immunomodulatory properties, either through modification of intestinal microbiota and/or reducing the effects of intestinal inflammation. The objective of this study was to assess the effects of GOS and SWE on reducing S. Typhimurium numbers and intestinal inflammation in vivo after experimental challenge with S. Typhimurium.

Thirty pigs (n = 10/treatment, live weight 30.9 kg) were randomly assigned to 3 dietary treatments: (1) basal diet; (2) basal diet + 2.5 g/kg GOS; (3) basal diet + SWE (containing 180 mg/kg laminarin + 340 mg/kg fucoidan). Following an 11 day dietary adaptation period, pigs were orally challenged with 108 CFU/ml S. Typhimurium. Initial weight, weight at challenge and slaughter weight were recorded. In addition, feed intake was measured for the purpose of calculating average daily feed intake and feed efficiency. Fresh faecal samples were collected pre-challenge and on d 2, 4 and 7 postchallenge to enumerate S. Typhimurium. Pigs remained on their diets for a further 17 days and were then sacrificed. Digesta samples from the colon and caecum were collected for microbial analysis. Tissue was collected from the ileum and colon for cytokine gene profiling.

Supplementation with SWE reduced S. Typhimurium numbers in faecal samples collected 7 days post-challenge and in digesta from the caecum and colon (P < 0.05). Lactobacillus numbers were increased in the caecum and colon after GOS supplementation (P < 0.05). In the colon, both GOS and SWE supplementation reduced mRNA expression levels of IL-6, IL-22, TNF-α and Reg3-γ (P < 0.05). The growth performance and feed efficiency was improved after supplementation with GOS and SWE (P < 0.05).

It can be concluded that addition of SWE reduced faecal and intestinal S. Typhimurium numbers compared to the basal diet, while GOS supplementation improved intestinal Lactobacillus numbers but did not affect S. Typhimurium numbers. Supplementation with GOS and SWE reduced the intestinal inflammation of pigs and improved their growth performance after the experimental S. Typhimurium challenge .

Disclosure of Interest: None Declared.