THE EFFECT OF COMPLEMENT SYSTEM OF KHAZAK AND BROILER SERUM AGAINST AVIAN PATHOGENIC ESCHERICHIA COLI: AN INVITRO EXPERIMENTAL STUDY

Background and Aim:The pathogenesis of avian pathogenic Escherichia coli (APEC) is different from mammalian E. coli, since in mammals, intestinal form is more prevalent, while the extraintestinal form occurs more in avian. It is logical to consider that two distinct species of poultry, broiler and Khazak, may be act in different manner against APEC. To increase the knowledge about serum resistance mechanism against APEC, the present investigation is aimed to discriminate between the act of complement system of Khazak and broiler, as native-backyard chicken of Sistan and industrial poultry, respectively.Methods:Serum was collected, aseptically, from Khazak and broiler chicken. The active and inactive (56 ‘C-30 min) serum complement of birds was dispensed, individually, into flat-bottomed 96-well microtiter plate, triplicates, and then, 104 CFU of APEC was inoculated. The growth was screened every 30 min for 6 hr, at 37’C. The statistical differences of slope value of growth curve was considered at p<0.05.Results:Statistical significance difference was observed for inhibitory effect of chicken serum complement in comparison with khazak against APEC (p<0.05).Conclusion:Findings demonstrated that the serum complement of khazak are more inefficient than broiler to APEC and the bacterium may be affect internal organ more easier, and in total, the pathogenesis is different between these two distinct species. Therefore, strategies for treatment and control of colibacillosis in khazak may be differed from broiler, regarding serum complement.

کلیدواژه ها:

broiler ، khazak ، serum complement ، apec