Comparison of the effects of infection with Salmonella enteritidis, in combination with an induced molt, on serum levels of the acute phase protein, alpha1 acid glycoprotein, in hens

Periods of inflammation due to infection, injury, or malignancy are marked by increases in serum constituents known as acute phase proteins (APP), and these proteins have been used as markers for early stages of disease. Four experiments were performed to examine whether levels in chickens of one such APP, alpha1 acid glycoprotein (AGP), would be affected by an infection with Salmonella enteritidis (SE) and if the added stress of induced molting via 14-d feed withdrawal would increase these effects. In all experiments but Experiment 1, hens were divided into four equal groups: molted infected, nonmolted infected, molted noninfected, nonmolted non-infected (Experiment 1 lacked this last group). Blood and intestinal samples were collected at various times from the hens and assayed for AGP and SE levels, respectively. Infection with SE significantly elevated serum AGP levels above those found in the noninfected groups of hens in two of four experiments, whereas in molted infected hens, serum AGP levels were significantly higher than those found in the noninfected counterparts in all four experiments. Comparison of AGP titer between the infected groups of hens revealed that significantly higher SE levels generally did not guarantee significantly higher AGP levels, although when individual values were plotted, a trend was observed toward increasing serum levels concomitant with increasing SE counts. Serum AGP levels show promise as a method to detect infection problems in hens, especially when the severity of the infection is exacerbated by stress situations. However, more work is needed to determine what other factors may elevate serum AGP levels and potentially confound the picture.