Effects of Ascophyllum nodosum supplementation on Campylobacter jejuni colonisation, performance and gut health following an experimental challenge in 10day old chicks

Abstract

The objective was to determine the effects of nutritional supplementation of an extract of Ascophylum nodosum on Campylobacter jejuni colonisation and performance following an experimental challenge in 10 day old chicks. The experiment consisted of three diets: 1) basal diet, 2) basal diet + 500 ppm extract and 3) basal diet + 1000 ppm extract. Day old Ross chicks (n = 135) were housed in groups of three, with 15 replicates per treatment group. On day three, all chicks were orally gavaged with 0.1 ml 106 colony forming units of C. jejuni. Following humane sacrifice on day 10, caecal, ileal and faecal samples were collected for analysis. While supplementation with A. nodosum reduced C. jejuni counts in the caecum of the chicks at both concentrations (P < 0.05), decreases in growth parameters were also observed (P < 0.05). Supplementation with 500 ppm had no effect on the gut morphology in the ileum (P < 0.05), while potential disruptive effects were observed at 1000 ppm. However, there were significant increases in the expression of tight-junction genes OCLN and CLND-1 alongside increases in MUC2 and CCND1 expression (P < 0.05). In conclusion, an extract of A. nodosum is beneficial in reducing the caecal bacterial load in chickens colonised with C. jejuni. The negative impact on growth parameters at 10 days is a concern, however optimisation of both the timing of administration and dosage of this seaweed extract could circumvent the negative impact on growth, while capitalising on its antimicrobial effects. Industrial relevance The subject of this paper is of relevance to the Poultry Industry, as the described seaweed extracts decreased campylobacter levels in the caecum. As campylobacter is concentrated in the caecum it can pose a significant carcass contamination risk during processing. This paper is also relevant to the seaweed industry as it highlights more applications for natural seaweed products.