Āsīb/shināsī-i Darmāngāhī-i Dāmpizishkī (May 2009)
Application of genomic densitometry for calculating the relative population of Escherichia Coli in the intestine of broiler chicks
Abstract
In this study, the densitometry technique for calculating of the relative population of Escherichia coli in various segments of the intestine of broiler chicks was evaluated. Following preparation of the intestinal contents, the process of extraction and purification of DNA from the contents of duodenum, jejunum, ileum and cecum was undertaken. A specific polymerase chain reaction (PCR) using two pairs of primers was employed to detect Escherichia coli and total bacteria present in the gastrointestinal tract of the chicks. Specific bands of E.coli were obtained using densitometry and Gel Proc Analyzer software based on linear regression with extrapolation. E.coli populations at different ages were also determined in various segments of the gastrointestinal tract of the chicks. The Results of this experiment indicated that 0.000004%, 0.07%, 0.64% and 2.51% of total bacteria present in the duodenum, jejunum, ileum and cecum respectively consisted of E.coli. Also, E.coli constitutes 1.76, 0.01 and 0.80% of the total intestinal bacteria of chicks at 4, 14 and 30 days of age respectively. Furthermore, it was shown that at 4 days of age, 0.30, 2.05 and 3.97% of the total bacteria present in the jejunum, ileum and cecum respectively were from E.coli species and this bacteria was absent in the duodenum. At 14 days of age these figures were 0.000009%, 0.00011% and 0.08% respectively while at 30 days of age 0.00011%, 0.009% and 2.40% of all bacteria in the duodenum, ileum and cecum were E.coli species and this bacteria was absent in the jejunum. In conclusion, the densitometry method based on PCR results can be regarded as a useful tool for densitometry the relative population E.coli in the gastrointestinal tract of poultry.
