Dietary ethylenediamine dihydroiodide improves intestinal health in Cherry Valley ducks

This study investigated the effect of ethylenediamine dihydroiodide (EDDI) on the growth performance, thyroid function, immune function, intestinal development, intestinal permeability, intestinal barrier functions and microbial characteristics of Cherry Valley ducks. The results showed that the addition of EDDI significantly increased body weight, average daily gain, serum level of lymphocytes, basophils, triiodothyronine, thyroxine and thyrotropin, villus height, and villus height-to-crypt depth ratio, and significantly decreased crypt depth, diamine oxidase, serum D-Lactic acid of ducks (P < 0.05). EDDI also significantly up-regulated the mRNA expression of zonula occludens-1, zonula occludens-2, zonula occludens-3, mucin 2, secretory immunoglobulin A, interleukin-10 and avian β-defensin 2 in the jejunum and ileum (P < 0.05), and down-regulated the mRNA expression of occludin and interleukin-6 in the jejunum and ileum. Additionally, the addition of EDDI significantly increased cecal level of acetic acid, propionic acid, butyric acid (P < 0.05). Cecal microbiome analysis indicated that the addition of EDDI significantly increased the relative abundance of these microorganisms that can produce short-chain fatty acids, mainly including Actinobacteria, Verrucomicrobia, Clostridiales and Lactobacillales, and decreased the relative abundance of pathogenic bacteria Deferribactere. Interestingly, triiodothyronine and thyroxine levels were highly positively correlated with the relative abundance of Actinobacteria. These results revealed that the addition of EDDI could promote the growth and development of meat ducks by improving their thyroid function, immune function, intestinal development and intestinal barrier functions of ducks.