The effect of addition of some commonly used antibiotics and acidifier
on the total bacterial count of defined intestinal microflora as Lactobacillus
sp., E. coli, and Clostridium sp. with special reference to Cl.
perfringens was studied.
Two antibiotic doses were used: from 14-16th day of age and again
from 29th -31st day of age. The second course was followed by an
acidifier for 3 days.
Results showed that doxycycline and amoxicillin had the most
inhibitory effects on Lactobacillus sp. This inhibitory effect was more
pronounced if an acidifier was used after these antibiotics than if they
were used alone.
Cephradin, spiramycin, doxycycline, tylosin, floramphenicol and enrofloxacin
showed good inhibitory effects on E. coli. This result
concerning E. coli can not be taken as a model of recommendation
because the continuous change in the drug resistance of this bacterium.
Spiramycin, cephradin, amoxicillin, doxycycline, tylosin, lincospectin
and enrofloxacin were effective against Cl. perfringens and other
Clostridium sp. The antibacterial action of these antibiotics was
increased if an acidifier was used afterwards.
One week after the end of the antibiotics and acidifier treatment, there
was a decrease in both Lactobacillus sp., E. coli and Clostridium sp.
counts in the intestine with one log lower (104) than that count in case
of antibiotics without acidifier (105). This finding encourages us to
recommend usage of acidifiers for chicken specially after antibiotic
courses to prolong their antibacterial activity.