Impact on Egg Quality

A decrease in total production may reach 10–20% or more, depending on the severity and duration of the infection.

Weakened Shell Quality:

Thin and fragile shells leading to easy breakage.

Deformed or asymmetrical egg shapes.

Decreased Albumin Quality: The egg white becomes more watery, with a decline in “Haugh” units (yolk height).

Reduced Fertility and Hatchability: This occurs in the presence of males or in breeding flocks.

Increase in Unmarketable Eggs: Higher rates of dirty or cracked eggs that are unfit for marketing or incubation.

Impact on the Bird’s Immunity

Mycoplasma causes chronic inflammation of the respiratory tract, leading to a continuous depletion of the immune system.

Suppression of the Immune Response:

Weakened antibody formation following vaccination.

Reduction in Immunoglobulin Levels: Lower levels of IgA and IgG in both the mucous membranes and the blood.

General Immune Stress: Resulting from the secretion of inflammatory substances and cytokines that increase energy consumption.

The Result: The bird becomes weaker in resisting infections, and vaccinations become less efficient.

 Relationship with Viruses (A Catalyst for Viral Infection)

Mycoplasma paves the way for viruses for two main reasons:

It causes damage to respiratory tissues (cilia and mucous membranes), facilitating viral entry.

it weakens both local and general immunity, allowing the virus to replicate more aggressively.

Practical Examples:

With Newcastle Disease (NDV): Dual infection (ND + Mycoplasma) leads to more severe respiratory symptoms, higher mortality, and a greater drop in production.

With Infectious Bronchitis (IBV): It doubles the virus’s effect on the kidneys and reproductive system, reducing shell quality and increasing deformed eggs.

With Avian Influenza (AIV): It increases the severity of the infection and elevates mortality, especially in laying flocks.

Conclusion

Mycoplasma = A silent economic disease in laying hens:

It reduces productivity and quality.

It weakens immunity.

It makes the bird more susceptible to respiratory viruses (ND, IB, AI).

Control is the foundation of any successful layer program (Biosecurity + Mycoplasma treatment + strong vaccination program).