Reproductive endocrine changes in relation to calcium metabolism in layers experimentally infected with Escherichia coli

Joshua Tersue Adeke; Hassan Abdulsalam; Halima Idrisa Gambo; Joseph John Gadzama; George Yilzem Gurumyen; Ladi Amos Chabiri; Talatu Patience Markus; Sani Adamu; King Akpofure Nelson Esievo

doi:10.5455/JRVS.20240715090307

Abstract
Aim: This study determined calcium metabolism-related reproductive endocrine changes associated with Escherichia coli (E. coli) infection in layer chickens.
Methods: A total of 20 laying chickens (20 weeks old) were acquired and assigned, into two groups (infected and controlled) of 10 layers each. Birds in the infected group were challenged with 0.5 ml of bacterial aliquot containing 109 colony forming units (CFU) of the bacteria, intratracheally. Two (2) ml of blood were collected from each bird in both groups and used for biochemical analyses.
Results: Escherichia coli infection in layers caused decrease in mean oestrogen profile from day 6 reaching the lowest value (332.6 ± 5.41 pg/ml) on day 28 post infection (pi) that differed significantly (p < 0.05) from the corresponding value in the control group. The mean plasma progesterone profile and mean plasma calcium concentration in the infected group decreased from day 4 and 6 pi, respectively, and reached the lowest significant (p<0.05) values (94.8 ± 1.98 pg/ml and 1.61 ± 0.11 mmol/L, respectively) on day 28 and 14 pi, respectively, which was significantly different (p < 0.05) from that in their corresponding control group. The mean plasma phosphate concentration and mean parathormone profile increased from day 6 to a significantly (p < 0.05) higher levels (1.64 ± 0.12 mmol/L and 31.04 ± 0.80 pg/ml, respectively) on day 14 and 21, pi respectively.
Conclusion: The E. coli-induced reproductive endocrine and clinicopathological changes recorded in present study may be responsible for the reported reproductive disorders in layers infected with E. coli.

Key words: Calcium, Colibacillosis, Layer-chicken, Oestrogen, Parathormone