Dietary Alginate Oligosaccharides Supplementation Alleviates Intestinal Barrier Dysfunction in Piglets Induced by Soybean Meal

The objective of present study was to evaluate whether a diet supplemented with alginate oligosaccharides (AOS) could alleviate intestinal barrier dysfunction in piglets induced by soybean meal. Eighteen crossbred piglets were housed individually and randomly assigned to one of three groups: the negative control (NC) group (using casein, skimmed milk powder and fish meal as protein sources), the positive control (PC) group (using soybean meal as the main protein source) and AOS group (with 0.5% AOS substituted for 0.5% zeolite powder based on the PC group). Results showed that soybean meal impaired growth performance, intestinal morphology and barrier function, and increased the apoptosis of intestinal epithelial cells. Compared with PC group, the piglets in AOS group had higher average daily gain, lower feed/gain ratio (p < 0.05), higher levels of superoxide dismutase in the serum and total antioxidant capacity in the jejunum (p < 0.05), greater villus height and villus height to crypt depth ratio in the duodenum and ileum (p < 0.05), and higher mRNA expression of Occludin in jejunum (p < 0.05). Meanwhile, AOS supplementation decreased the diarrhea incidence (p < 0.05), the level of diamine oxidase in the serum (p < 0.05) and the mRNA expression of Bax and Caspase-3 (p < 0.05) in piglets. There was no difference in concentrations of short chain fatty acids among the three groups (p < 0.05). Moreover, the relative abundances of the phylum Spirochaetota and the genus Clostridium_sensu_stricto_1 was decreased in the AOS group (p < 0.05). In conclusion, dietary AOS supplementation efficiently alleviated soybean meal- induced intestinal barrier dysfunction by increasing the antioxidant capacity, improving intestinal morphology and microbiome and regulating cell apoptosis in piglets.