Haematological changes induced by experimental Escherichia coli infection in layer chicken

Abstract

This study examined the haematological alterations in layer hens infected with experimental Escherichia coli (E. coli). Twenty laying chickens (20 weeks old) were acquired and randomly divided into two groups of ten layers each (infected and control). After challenging the infected group with 0.5 milliliters of bacterial aliquot containing 109 colony forming units (CFU) of the bacteria intratracheally, 1 ml of blood was collected from each group on days 0, 2, 4, 6, 14, 21, 28, 35, and 42 post-infections (pi) for haematology. The mean PCV of the infected group dropped significantly (p<0.05) to its lowest value of 17.0 ± 0.71% on day 4, and then ascended to a peak level of 24.6 ± 1.03% on day 28. In the infected group, the mean Total White Blood Cell count grew considerably (p<0.05) from day 2 (14.81 ± 3.28 × 109/L) to day 14 pi, when it peaked at 29.16 ± 0.81 × 109/L. From day 2 pi to the lowest value (1.63 ± 0.07 × 1012L) on day 14 pi, the mean Red Blood Cell count fell; from day 21 to the maximum value (2.55 ± 0.08 × 1012L) on day 28 pi, it improved. The infected group's mean lymphocyte counts rose from day 4 to a peak level (21.59 ± 0.92 × 109/L) on day 14 pi. After that, it declined, but continued to be significantly (p<0.05) higher than the control group up to day 42. In conclusion, E. coli infection in layer chickens induced haematological changes.