PSII-38 Tolerable upper intake levels of iron damage the intestine and alter the intestinal flora in weaned piglets

Abstract

Abstract Iron supplementation has been an intervention to improve iron storage and prevent iron deficiency anaemia in weaned piglets. NRC has set recommended nutrient intake (RNI) and tolerable upper intake levels (UL). The purpose of this study was to investigate the potential harm of UL iron to the gut and microbes of weaned piglets. Thirty 23-day old weaned piglets assigned to three dietary treatments: a basal diet supplemented with 100 (RNI), 300, or 3000 (UL) mg FeSO4/kg diet for 28 days. Piglets were then euthanized, and the gut and cecum microbes were collected. UL iron significantly reduced the height of the villi in the duodenum, ileum, and jejunum of weaned piglets, and showed duodenal mitochondrial swelling (P < 0.05). The addition of UL iron to the diet significantly reduced the expression of tight junction proteins Claudin-1, Occludin, and ZO-1 in weaned piglet duodenal mucosa (P < 0.05). The protein levels of DMT1 and Zip14 decreased (P < 0.05), and the protein levels of ferritin increased in the duodenal mucosa of UL iron fed weaned piglets (P < 0.05). Moreover, UL iron also increased the content of ROS and MDA and decreased the activity of SOD in the weaned piglet duodenal mucosa (P < 0.05). Additionally, UL iron significantly increased intestinal microbial diversity and species richness in weaned piglets. At the phylum level, UL iron supplementation was associated with a significant increase in Proteobacteria relative abundance, and significantly decreased the relative abundance of Firmicutes (P < 0.05). At the genus level, the relative abundance of Clostridiales, Faecalibacterium, and Prevotellaceae decreased significantly (P < 0.05), while the relative abundance of Desulfovibrio and Anaerovibrio increased significantly (P < 0.05). In conclusion, UL iron caused damage to the intestinal villi, damaged the intestinal barrier, reduced iron absorption, induced oxidative stress, led to histopathological changes, and modified the intestinal microbial structure in weaned piglets.