Wang Tongxin, He Qiongyu, Yao Weilei, Shao Yafei, Li Ji, Huang Feiruo
Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China.
Front Microbiol. 2019 May 16;10:1083. doi: 10.3389/fmicb.2019.01083. eCollection 2019.
Exposure to gaseous ammonia, even at low levels, can be harmful to pigs and human health. However, less is known about the effects of sustained exposure to gaseous ammonia on nasal microbiota colonization in growing pigs. A total of 120 Duroc×Landrace×Yorkshire pigs were housed in 24 separate chambers and continuously exposed to gaseous ammonia at 0,5, 10, 15, 20, and 25 ppm (four groups per exposure level) for 4 weeks. Then, we used high-throughput sequencing to perform 16S rRNA gene analysis in nasal swabs samples from 72 pigs ( = 12). The results of the nasal microbiota analysis showed that an increase in ammonia concentration, especially at 20 and 25 ppm, decreased the alpha diversity and relative abundance of nasal microbiota. , and were the most abundant phyla. In addition, the relative abundances of 24 microbial genera significantly changed as the ammonia level increased. Four microbial genera (, and ) were significantly decreased at 25 ppm, while only two genera ( and ) were increased at 25 ppm. PICRUSt analyses showed that the relative abundances of the nasal microbiota involved in cell motility, signal transduction, the nervous system, environmental adaptation, and energy and carbohydrate metabolism were significantly decreased, while genes involved in the immune system, endocrine system, circulatory system, immune system diseases and metabolism of vitamins, lipid, and amino acids were increased with increased ammonia levels. The results of tests showed that an increase in ammonia levels, especially an ammonia level of 25 ppm, caused respiratory tract injury and increase the number of and species, while simultaneously decreasing respiratory immunity and growth performance, consistent with the increased presence of harmful bacteria identified by nasal microbiota analysis. Herein, this study also indicted that the threshold concentration of ammonia in pig farming is 20 ppm.
即使是低浓度的气态氨暴露也可能对猪和人类健康有害。然而，关于生长猪持续暴露于气态氨对鼻腔微生物群定植的影响，人们了解较少。总共120头杜洛克×长白×约克夏猪被安置在24个独立的饲养室中，并持续暴露于0、5、10、15、20和25 ppm的气态氨中（每个暴露水平四组），持续4周。然后，我们使用高通量测序对72头猪（每组12头）的鼻拭子样本进行16S rRNA基因分析。鼻腔微生物群分析结果表明，氨浓度的增加，尤其是在20和25 ppm时，会降低鼻腔微生物群的α多样性和相对丰度。厚壁菌门、拟杆菌门和放线菌门是最丰富的门类。此外，随着氨水平的增加，24个微生物属的相对丰度发生了显著变化。在25 ppm时，四个微生物属（罗氏菌属、短波单胞菌属、金黄杆菌属和不动杆菌属）显著减少，而在25 ppm时只有两个属（葡萄球菌属和芽孢杆菌属）增加。PICRUSt分析表明，参与细胞运动、信号转导、神经系统、环境适应以及能量和碳水化合物代谢的鼻腔微生物群的相对丰度显著降低，而参与免疫系统、内分泌系统、循环系统、免疫系统疾病以及维生素、脂质和氨基酸代谢的基因随着氨水平的增加而增加。检测结果表明，氨水平的增加，尤其是25 ppm的氨水平，会导致呼吸道损伤，增加葡萄球菌属和芽孢杆菌属物种的数量，同时降低呼吸道免疫力和生长性能，这与鼻腔微生物群分析确定的有害细菌数量增加一致。在此，本研究还指出养猪场中氨的阈值浓度为20 ppm。
