Impact of oral compost-extract administration on gene expression in the rat gastrointestinal tract

Oral administration of an extract of compost fermented with thermophiles to pigs reduces the incidence of stillbirth and promotes piglet growth. However, the mechanism by which compost extract modulates the physiological conditions of the animals remains largely unknown. Here, we investigate the effects of compost extract on the gene expression in the intestine of the rat as a mammalian model. Gene expression analyses of the intestine indicated that several immune-related genes were upregulated following compost exposure. Thus, thermophile-fermented compost can contain microbes and/or substances that activate the gut mucosal immune response in the rat. In Male Wistar rats aged 3 weeks, tap water was supplemented with 1.0% (v/v) compost extract for the experimental rats, whereas water only was given to the control rats. The rats received water ad libitum for 12 weeks. Fresh gut samples were collected from individual rats at the end of the feeding test and stored at -80°C. The intestine were separated from the gut and used as samples for the isolation of total RNA. otal RNA was then subjected to microarray experiments using the Whole Rat Genome (4x44k) Oligo Microarray (Agilent Technologies, Inc.)