Exposure to the environmental pollutant ammonia causes changes in gut microbiota and inflammatory markers in fattening pigs.

Ammonia (NH 3) is a major pollutant in livestock houses and atmospheric environment. It has been demonstrated that NH 3 can cause a series of damage to animals and human. However, toxicity evaluation of NH 3 on farm animals was rarely reported, especially in the intestinal microflora. Therefore, in this study, twenty-four 125-day-old fattening pigs were randomly divided into 4 groups: control group, NH 3 group (88.2 mg m⁻³ < NH 3 concentration < 90.4 mg m⁻³), Se group (Se content: 0.5 mg kg⁻¹), and NH 3 + Se group (88.2 mg m⁻³ < NH 3 concentration < 90.4 mg m⁻³, Se content: 0.5 mg kg⁻¹), and the effects of NH 3 and L -Selenomethionine on the microbiota composition in the jejunum and the levels of inflammatory markers in feces of fattening pigs were examined by 16S rDNA and ELISA, respectively. Our results showed that the content of Matrix metalloproteinase-9 (MMP-9), Myeloperoxidase (MPO), Lactoferrin (LTF) and Calprotectin in the ammonia group (A group) were significantly elevated compared to the control group, and the content of MMP-9, MPO, LTF and Calprotectin in the A + Se group were significantly reduced. A significant difference in microbiota composition in the phylum, class, family and genus levels was found in the A group and the NH 3 + Se group. There was a negative correlation between Streptococcus and Calprotectin. Our results indicated that excessive NH 3 inhalation could cause changes in inflammatory markers and beta diversity of intestinal microflora in fattening pigs. We found there was a positive correlation between MPO and Pseudomonas. In addition, we first proposed that L -Selenomethionine could improve the imbalance of microbial flora and the inflammatory injury caused by NH 3. Changes in intestinal microflora and inflammatory markers can be used as important indicators to evaluate NH 3 toxicity, and studying changes in intestinal microflora is also an important mechanism to reveal NH 3 toxicity. ga1 • Ammonia is a typical pollutant in atmospheric environment and livestock production. • Excessive ammonia exposure can cause the changes in inflammatory markers. • Excessive ammonia exposure can cause the imbalance of intestinal microflora. • L -selenomethionine can improve the imbalance of intestinal flora caused by ammonia. • Intestinal flora is involved in the toxic mechanism of ammonia. [ABSTRACT FROM AUTHOR]