High Myoglobin Diet Induced Colon Dysbiosis and Inflammation by Regulating Heme or Iron Metabolism

Abstract

Abstract Objectives Changes in the gut microbiota caused by excessive meat consumption are often accompanied by various metabolic and inflammatory disorders, which are also largely related to the time and amount of dietary proteins. Myoglobin, a pigment in meat, which is difficult to digest. This study aimed to evaluate how the amount of myoglobin diets affected oxidative stress and colon homeostasis in mice. Methods C57BL/6J mice were fed casein, low-myoglobin (LMb), medium-myoglobin (MMb) or high-myoglobin (HMb) diets for 3 or 8 weeks (n = 10 each group). Proinflammatory factors and intestinal morphology in colon tissue, heme and iron metabolites in duodenum tissue were detected, fecal metabonomic was analyzed by LC-MS and gut microbiota was analyzed by 16S rRNA gene sequencing. Results Increased intake of a myoglobin diet decreased body weight, causing low-grade inflammation and colonic hyperplasia. The mice fed with HMb diets had the lowest feed intake and body weight, upregulated proinflammatory factors including IL-6, IL-12, IL-1β and TNF-α, and iron metabolites including SLC46A1, Ferridin-H, HO-2, TFR2, but downregulated ZO-1 and occuludin. As the myoglobin content increased, the relative abundance of Akkermansia and Bifidobacterium in colon increased at 3 or 8 weeks, especially in MMb and HMb diets. In addition, myoglobin diets at 3 and 8 weeks upregulated cellular processes and signaling, lipid metabolism and genetic information processing, and downregulated enzyme families compared to the casein diet. These changes were related to tryptophan metabolism and steroid biosynthesis pathway. Conclusions The negative impact of a high myoglobin diet may cause intestinal oxidative stress, inflammation and colonic hyperplasia, induce dysbiosis of gut microbiota and metabolism in mice through releasing heme and iron. Funding Sources This work was supported by the grants from NSFC (32072211).