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Date
2018-10-26
Journal Title
Journal ISSN
Volume Title
Publisher
Ahmadu Bello University Zaria
Abstract
This study determined the reproductive endocrine and clinico-pathological changes
associated with Escherchia coli (E. coli ) infection in layer chickens. A total of 20 laying
chickens (20 weeks old) were acquired and assigned, at random, into two groups (infected
and control) of 10 layers each. Each of the birds in the infected group was challenged with
0.5 ml of bacterial aliquot containing 109 colony forming units (CFU) of the bacteria,
administered intratracheally. Three (3) ml of blood were collected from each bird in both
groups and used for haematological and biochemical analyses. E. coli infection in the layers
caused reduction in feed and water consumption, watery yellowish faeces and weakness by
day 3 post infection (pi) and also decreased mean oestrogen profile from day 6 (347 ± 2.55
pg/ml) reached the lowest value (332.6 ± 5.41 pg/ml) on day 28 pi that differed significantly
(p < 0.05) from the corresponding value in the control group. The mean plasma progesterone
profile in the infected group started from day 4 pi and reached the lowest significant (p<0.05)
value (94.8 ± 1.98 pg/ml) on day 28 pi, against the control group. The mean plasma calcium
concentration decreased from day 6 to reach a lowest level (1.61 ± 0.11 mmol/L) on day 14
pi, which was significantly different (p < 0.05) from that in the control group. The mean
plasma phosphate concentration increased from day 6 to a significantly (p < 0.05) higher
level (1.64 ± 0.12 mmol/L) on day 14. The mean parathormone profile increased from day 6
(24.10 ± 0.56 pg/ml) to a significantly (p < 0.05) higher level on day 21 (31.04 ± 0.80 pg/ml).
The mean plasma aspartate aminotransferase (AST) activity in the infected group
progressively increased from day 6 pi to reach a significantly higher (p < 0.05) value (66.4 ±
0.93 IU/L) on day 28 pi while the mean plasma alanine aminotransferase (ALT) activity
progressively increased in the infected group beginning from day 6 pi to attain the highest
significant (p < 0.05) value (74.4 ± 2.11 IU/L) on day 21 pi compared to the control group.
The mean plasma total protein concentration in the infected group decreased from day 4 pi