Molting in Salmonella enteritidis-challenged laying hens fed alfalfa crumbles.: IV.: immune and stress protein resnonse

Immunological responses of molting hens either infected or not infected with Salmonella enterica serovar Enteritidis were compared in 2 trials with Single Comb White Leghorn hens > 50 wk old. The hens were placed into 6 treatment groups with 12 hens per group: nonmolted Salmonella Enteritidis positive (FF+), nonmolted Salmonella Enteritidis negative (FF-), feed withdrawal Salmonella Enteritidis positive (FW+), FW Salmonella Enteritidis negative (FW-), alfalfa Salmonella Enteritidis positive (ALC+), and ALC Salmonella Enteritidis negative (ALC-). Each hen in the Salmonella Enteritidis-positive groups was challenged on d 4 of the study with 1 mL Of 10(6)-cfu Salmonella Enteritidis, and diets were administered for 12 d. Blood samples were collected on d 2, 5, 9, and 12, and blood smears were enumerated for heterophil to lymphocyte (H:L) ratios. Serum samples were also analyzed for alpha(1)-acid glycoprotein (AGP) levels and antibody level. On d 12, hens were euthanized and bile samples from the gall bladder and sections of the ileum and the ceca were collected, and an ELlSA was used to determine the intestinal, serum, and bile antibody responses. The FW+ hens produced more (P <= 0.05) cecal IgA than hens in all the other treatments except the FW-hens in trial 2. Bile IgA production in all Salmonella Enteritidis-positive groups was higher (P :5: 0.05) than in the Salmonella Enteritidis-negative groups, with the exception of the ALC- hens. In trial I on d 5, FW+ hens produced less (P <= 0.05) serum IgG than ALC-, FF-, and FW- hens but not FF+ and ALC+ hens, whereas in trial 2, only FW-hens had lower IgG levels than FW+ hens. On d 9, FW groups exhibited increases in the H:L ratios, but on d 12, these declined to levels more similar to the other treatments. The FW hen groups yielded generally higher AGP levels compared with the other treatments on d 9 and 12 in both trials. The ALC molt diets appeared to reduce stress and inflammation, based on the H:L ratios and AGP levels in the serum, when compared with FW-molted hens.