The humoral immune response and the productivity of laying hens kept on the ground or in cages

The effects of two different keeping systems on the humoral immune response and productivity were compared for 80 laying hens, divided into four group s. Two groups, each of 20 hens, were kept on the ground and two were kept i n cages. All the birds were immunised subcutaneously with human serum immun oglobulin G at a dose of 100 mug per injection. The immunisations were perf ormed twice at 4-week intervals. The lipopeptide Pam(3)Cys-Ser-(Lys)(4) was used as an adjuvant at a dose of 0.25mg per injection in one group from ea ch housing system. In the second group from each housing system, the hens w ere immunised without any adjuvant (antigen control groups). The mean egg y ield was significantly higher in both the antigen control group and the adj uvant group, when laying hens were kept in cages. Total egg weight remained constant in bath of the housing systems. Keeping hens in cages resulted in higher mean specific antibody titres and mean immunoglobulin Y concentrati ons in the egg yolk.