DNA isolation from equine faecal excrements

Abstract

Sampling and extraction procedures were elaborated for DNA isolation suitable for subsequent PCR amplification and other molecular manipulation experiments from horse excrements. Eleven Lipizzaner horses were split into two age groups and faecal excrements were collected as soon as possible after defecation and the DNA was isolated immediately after arrival to the laboratory. The excrements collected from the group of younger horses yielded on average 3-4 fold higher amounts of DNA than from the group of older horses. The variability of the DNA yield isolated on successive days from the same horse remained within 15% of the average yield. The DNA yield isolated on successive days from the same faecal excrement increased gradually from 4.61 to 7.96 μg g^-1 faeces until 48 hrs after defecation and dropped only slightly to 7.51 μg g^-1 after further four days. Our results indicate, that substantial microbial growth is taking place in the faecal excrements at least until two days after defecation. It is of utmost importance therefore, that the sampling is done as soon as possible after defecation if microbial community structure analysis of the equine colon and faeces is to be performed.