Effects of Algae β-Glucan Supplementation on the Performance and Intestinal Immune System of Healthy Weaned Piglets

While β-glucans from plants and yeasts have been extensively studied in weaned piglets, studies examining algae β-glucans are scarce. Thus, the present study aimed to examine the effects of feeding algae β-glucan in weaned piglets. Male, 21-day-old, weaned crossbred piglets were allotted to three experimental groups, which were fed either an adequate basal diet (Control) or the basal diet supplemented with 100 (A100) or 200 g/t (A200) of algae β-glucan for 35 days. Performance parameters, apparent total tract digestibility of nutrients, gut morphology metrics, gut mucosa mRNA levels of most genes involved in gut function and integrity, and the number of different immune cells in the proximal jejunum did not differ across groups after 35 days. In the mid-jejunum, the number of lymphocytes in the lamina propria was higher in the A200 group than in the other two groups (p < 0.05) after 35 days. Mucosa score for mucosa fibrosis, villous stunting and villous epithelial injury in the duodenum and the proximal and mid-jejunum were not different across groups after 35 days. The proportion of acetate was higher, and that of valerate was lower in the colon digesta of the A200 group than in the other two groups (p < 0.05). While the abundance of Prevotella spp. was lower in the A200 group than in the other groups (p < 0.05), the abundance of Bifidobacterium spp., Clostridium-leptum-group, Faecalibacterium prausnitzii and Lactobacillus spp. in the colon digesta did not differ across groups after 35 days. In conclusion, feeding algae β-glucan to healthy weaned piglets marginally influences gut-associated parameters and the abundance of selected bacterial groups and the bacterial fermentation pattern in the colon digesta but has no effect on growth performance.