Researchers based at Wageningen University have studied the effects of a concurrent challenge on slow-growing broilers with 1) airborne particles of two sizes: fine dust (smaller than 2.5µm) and coarse dust (between 2.5 and 10µm) that were directly collected from a broiler house and 2) lipopolysaccharide on intratracheal immunizations with the specific antigen human serum albumin (HuSA).

In a paper published recently in Poultry Science, H.T.L. Lai (now at Hanoi University of Agriculture in Viet Nam) and co-authors explain that they measured primary and secondary systemic (total) antibody responses and (isotype-specific) IgM, IgG, and IgA responses in the birds at three and seven weeks of age.

All treatments affected immune responses at several ages, heart morphology and bodyweight gain, albeit the latter only temporarily. Dust particles significantly decreased primary antibody (IgT and IgG) responses to HuSA at three weeks of age but enhanced IgM responses to HuSA at seven weeks of age. Dust particles decreased secondary antibody responses to HuSA, albeit not significantly.

All of the birds that were challenged with dust particles showed decreased bodyweight gain after the primary but not after the secondary challenge.

Relative heart weight was significantly decreased in birds challenged with coarse dust, fine dust, lipopolysaccharide, and HuSA at three weeks of age, but not in birds challenged at seven weeks of age. Morphology (weight, width, and length) of hearts were also affected by the dust challenge at three weeks of age.

The present results indicate that airborne dust particles obtained from a broiler house when intratracheally administered at an early age affect specific humoral immune responsiveness and bodyweight gain of broilers to simultaneously administered antigens differently than when administered at a later age.

The hygienic status of broiler houses at a young age may be of importance for growth and immune responsiveness, and consequently, for vaccine efficacy and disease resistance in broilers. The authors discuss the consequences of their findings in the paper.

Reference

Lai H.T.L., M.G.B. Nieuwland, A.J.A. Aarnink, B. Kemp and H.K. Parmentier. 2012. Effects of 2 size classes of intratracheally administered airborne dust particles on primary and secondary specific antibody responses and body weight gain of broilers: a pilot study on the effects of naturally occurring dust. Poult. Sci. 91(3):604-615. doi: 10.3382/ps.2011-01829

Further Reading

-

You can view the full report (fee payable) by clicking here.