Breeding for high specific immune reactivity affects sensitivity to the environment

Area of Science:

• Poultry Science
• Immunology
• Animal Genetics

Background:

• High levels of lipopolysaccharides (LPS) in chicken houses suggest potential immune-modulating effects.
• Divergent selection for humoral immune reactivity has created distinct chicken lines (H and L lines).

Purpose of the Study:

• To investigate the differential immune responses of high (H) and low (L) humoral immune reactivity chicken lines to lipopolysaccharides (LPS).
• To assess the impact of LPS exposure on growth and egg production in selected chicken lines.

Main Methods:

• Layers from the 30th generation of divergent selection for humoral immunity were intratracheally challenged with human serum albumin (HuSA) and LPS.
• A crossing-over design was used with challenges at 7 and 12 weeks of age.
• Humoral immune responses, antibody binding, body weight gain, and egg production were measured.

Main Results:

• Chickens selected for high immune reactivity (H line) exhibited stronger antibody responses to HuSA and higher natural antibody levels.
• The H line was more sensitive to LPS immune modulation at 7 weeks.
• LPS negatively affected body weight gain in the L line at 7 weeks and the H line at 12 weeks.
• Egg production was reduced and delayed in the H line.

Conclusions:

• Chicken lines selected for immune responsiveness differ in their environmental sensitivity, specifically to LPS.
• These differences influence reactions to infections, vaccinations, and other immune challenges.
• Selection for immune responsiveness impacts crucial production traits like growth and egg laying.