Date of Graduation


Document Type


Degree Name

Master of Science in Cell & Molecular Biology (MS)

Degree Level



Biological Sciences


Franck Carbonero

Committee Member

Ravi Barabote

Second Committee Member

Jiangchao Zhao


Early-life, Feeding Mode, Gut Microbiota, Soil Exposure


Several lines of evidence suggest that early-life gut microbiota composition is a crucial determinant of the susceptibility to diseases later in life. Understanding the evolution of early-life gut microbiota and critical factors that can modify this microbial community will espouse the prevention or reversion of health risk originating from dysbiosis of the gut microbiota in the early stage. In this research, we hypothesized that alterations in the environment (simulation of rural conditions by soil exposure) and feeding mode (breastmilk versus formula milk) will have significant impacts on the establishment of the gut microbiota in early life. At first, in literature review discipline, we present a holistic view on the current knowledge of gut microbiota and environmental modulations. Then, through empirical studies, we investigate the impacts of soil exposure and different feeding modes on gut microbiota composition. We applied 16s rRNA sequencing to examine the composition of gut microbiota based on fecal samples in two separate studies: 1) 4-day-postpartum piglets were exposed to agricultural soil until weaning day (day 21) and then grew under the same conventional condition with control treatments; 2) 4-day-old piglets were either mother reared and breastfed or artificial reared and formula fed, then grew in the same conditions at weaning. The results revealed that agricultural soil exposure and feeding mode could significantly modify the gut microbiota composition in early stages although this trend was not maintained until the later phases of life. The alterations in the early gut microbiota, albeit in a short period of time, caused by those extrinsic environmental modulators may still be sufficient to ameliorate or exacerbate health risk of the host.