Abstract
This study was conducted to determine hematological changes in two different age groups of pheasants (Phasianus colchicus) experimentally infected with 3 and 5 earthworms, 200 embryonated eggs of Syngamus trachea, and control groups. Comparing the hematological parameters, EPG values, and tracheoscopy findings revealed differences related to the age of the experimental birds. The most significant changes in RBC, Hb, and eosinophils (p <0,05) were found in a group of young pheasants fed with five earthworms, followed by three earthworms, and finally with 200 embryonated S. trachea eggs. In a group of adult pheasants, a decline in RBC and Hb was observed in groups fed 3 or 5 earthworms. The group fed with 200 embryonated eggs showed no significant difference. The hematological results revealed that the mean values of Hb and RBC were higher (P ≤ 0.05) in noninfected birds compared to infected ones. Comparison of the EPG values related to tracheoscopic findings confirmed a higher parasitic burden as well as a higher number of adults. The highest EPG value observed (1500) corresponded with the number of adults of S. trachea (4 pairs) recorded in a group of young pheasants fed five earthworms, with an average of 2.1 adult pairs in the trachea and an average EPG value of 750. Additionally, it was confirmed that young birds are more susceptible to S. trachea infection than adults. Based on the results, it was concluded that some hematological values were influenced by age. The differences between the pheasants and the data obtained in this study could help establish baseline values for hematological parameters in pheasants regarding the parasitic burden caused by S. trachea.