Terminal-restriction fragment length polymorphism
Terminal-restriction fragment length polymorphism (TRFLP)
fingerprinting is a reliable, sensitive and high
throughput method for monitoring the diversity, structure,
and dynamics of microbial populations (Nocker et
al. 2007; Schutte et al. 2008; Frey et al. 2009). It
involves PCR amplification of 16S rRNA gene and
digestion of PCR products with restriction enzymes.
The resulting fluorescently labeled terminal restriction fragments
(T-RFs) are visualized on an automated sequencer.
Based on the variation in size of T-RFs, a fingerprint is generated
in which the number of peaks indicates the number of different
T-RFs present, while the height and area of these peaks correspond
to their relative abundance. Each T-RF represents a
unique OTU. The peak patterns can be further analyzed using
online tools such as TAP-TRFLP, TRiFle, and TRF-CUT. Using
T-RFLP analysis, Fernando et al. (2010) determined the differences
in bacterial community between prairie hay-fed animals
and animals adapted to a high-concentrate diet. T-RFLP analyses
identified a total of 115 different bacterial genera. On the
basis of the phylogenetic assignment, it was observed that no
significant change occurs in the ratios of the phyla Firmicutes/
Bacteroidetes between hay-fed animals and high-concentratefed
animals. Khafipour et al. (2009) applied this technique
for the determination of subacute ruminal acidosis in
dairy cattle and revealed a decline in Gram-negative
Bacteroidetes organisms during subacute ruminal acidosis.
The establishment of bacteria (Yanez-Ruiz et al.
2010; Vasta et al. 2010) and methanogens (YanezRuiz
et al. 2010) in the rumen of lambs was also
evaluated by T-RFLP. In another study, the changes in
microbial diversity were studied as digesta passed from
rumen to duodenum (Frey et al. 2010). The main
drawback of this technique is that the incomplete or
nonspecific restrictions of amplicons can lead to the
ambiguous elucidation of microbial diversity.