Positive impact of dietary marine sulfated polysaccharides derived from macroalgae during a necrotic enteritis challenge.

Caused by the Gram-positive bacteria Clostridium perfringens, necrotic enteritis (NE) is an enteric disease with significant economic implications in broiler production. This study employed an experimental NE model involving co-infection with Eimeria maxima and C. perfringens to assess whether sulfate polysaccharides extracted from marine macroalgae could mitigate the adverse effects of NE in broilers. A total of 600 day (d)-old Ross 708 male broilers were randomly assigned to one of four treatment groups: NC (negative control, fed a corn-soybean meal diet); PC (positive control, NC + 15 ppm Avilamycin and 125 ppm Amprolium); AGS (Algimun® Standard, NC + Algimun added at 0.1 % of the diet); and AGH (Algimun High, NC + Algimun added at 0.2 % of the diet). Average daily feed intake and weight gain were calculated and adjusted for daily mortality on d 14, 21, 28, and 42. On d 21, four birds/pen were examined for intestinal NE lesions. On d 14, 21, and 42, serum and jejunum samples from one bird/pen were collected to measure the concentration of the biomarker calprotectin and mRNA abundance of cytokines and tight junction proteins. Data were analyzed using JMP and significance between treatments identified by LSD (P ≤ 0.05). NE lesion scores on d 21, and mortality and FCR during d 0 to 42 were lower in PC, AGS, and AGH compared to NC birds. AGS birds had the lowest levels for serum calprotectin on d 21 while PC, AGS, and AGH had lower levels than the NC group on d 42. On d 14 and d 42, mRNA abundance of CLDN1, 3, ZO1, IL1β, IFNγ, IL10, and IL12B was greater in AGS and AGH birds compared to NC. Also, AGH had a greater abundance of TNFα on d 14 and d 42 compared to NC. Further, mRNA abundance of CLDN3, ZO1, 2, OCLDN, IL1β, IL10, IL12B, IFNγ, and ANXA1 was greater in PC on d 21 compared to NC and AGS. Based on these findings, dietary supplementation of this macroalgae-derived sulfated polysaccharides yielded a similar response to an antibiotic growth promoter presenting potential as an alternative additive.