Determination of Weight and Biochemical Changes in Layers Experimentally Infected with Escherichia coli

Abstract

This study determined the effect of experimental exposure of layer chickens to Escherichia coli (E. coli) on weight, egg production and some plasma biochemical parameters. A total of 20 laying chickens (20 weeks old) were acquired and assigned, at random, into infected and control groups, 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, administered intra tracheally. Five birds, from each group were selected at random and their live body weights were determined on days 0, 2, 4, 6, 14, 21, 28, 35 and 42. Also, egg production was monitored, and the weekly percentage egg production of birds was calculated. Two (2) ml of blood were collected from each bird in both groups and used for plasma biochemical analyses. Finding from the research showed that E. coli infection caused reduction in feed and water consumption by day 3 post infection (pi); with subsequent reduction in body weight and egg production. 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 from day 6 pi to attain the highest significant (p < 0.05) value (74.4 ± 2.11 IU/L) on day 21 pi. The mean plasma total protein concentration in the infected group decreased from day 4 pi and reached the lowest significant (p < 0.05) value (5.12 ± 0.28 mg/dl) on day 35 pi. In conclusion, the drop in egg production, loss of body weight, increase hepatic transaminases and decrease plasma protein may be attributed to anorexia or possible impairment of intestinal, renal reabsorption of nutrients from the infection.