Reliable ELISAs showing differences between resistant and susceptible lines in hens orally inoculated with Salmonella Enteritidis

Abstract

-Reliable ELISAs were investigated with the aim to select hen lines resistant to Salmonella Enteritidis and producing high levels of antibodies. In the first experiment, the relation between the humoral response and the bacteriological results was assessed on hens from the Y11 resistant line and the L2 susceptible line, orally inoculated with 10 8 CFU S. Enteritidis per animal. Antilipopolysaccharide (LPS) IgG titres were higher but the liver and spleen were less contaminated in hens from the Y11 line than in hens from the L2 line (p = 0.013, 0.031 and 0.026 respectively). In the second experiment, the hens were inoculated orally with 1.7 × 10 8 CFU S. Enteritidis per animal in order to select the ELISA methods showing the more significant differences. ELISAs were based on LPS, flagella, LPS from rough (LPS-R) and smooth strains (LPS-S) and detected IgG and IgM antibodies from sera and yolks. No between-line host response variation was observed in the yolk, with LPS-S and R antigens nor with anti-LPS IgM in the sera. Otherwise, significant differences were encountered between hen lines with the ELISAs performed on the sera detecting anti-LPS IgG, anti-flagella IgG or IgM (p = 0.017, 0.017 and p < 0.001 respectively). When comparing the kinetics of the selected ELISAs, the IgG antibodies against LPS detected between-line variations as early as 1 to 4 weeks pi, whereas with IgG against flagella, the differences were only detected at 1 and 2 weeks pi and with IgM against flagella, the differences were significant at 1, 2, 4 and 8 weeks pi. In conclusion, resistant hen lines producing higher levels of antibodies than the susceptible hen lines may be selected with these ELISAs.

Use of Integrated Studies to Elucidate Potential Benefits from Genetic Resistance to Salmonella Carrier State in Fowl

“…Selection on higher resistance had mostly modified the hen's clearance ability while a higher rate of return to the susceptible state was responsible for the higher level of contamination of the other line, which had a shorter immune protection time. This is coherent with results on immune response of lines differing (among other resistance traits) in resistance to carrier state, whether inbred (Sadeyen et al, 2006), or outbred (Proux et al, 2002;Protais et al, 2003). Fig.…”

Strategies to control Salmonella in the broiler production chain

“…In a number of studies, S. enteritidis was shown to colonize internal organs of 4 different chicken lines (L2, B13, PA12 and Y11) at the same level, although caecal colonization was significantly higher in 2 of these chicken lines. (Duchet-Suchaux et al, 1997;Girard-Santosuosso et al, 1998;Berthelot et al, 1998;Proux et al, 2002;Berthelot-Hérault et al, 2003). Genetic tools have made it possible to identify genes associated with resistance to Salmonella.…”

Effect of genetic resistance of the hen toSalmonellacarrier-state on incidence of bacterial contamination: synergy with vaccination

“…Indeed, comparisons of lines differing in their ability to clear Salmonella show differences in both types of traits. Sadeyen et al [14] compared adult hens issued from poultry lines with different rates of Salmonella carrier-state; they observed differences in expression levels of several genes involved in primary immune responses while Proux et al [11] showed the existence of differences in immune humoral response (appreciated by antibody response) between two lines (among which the L2 line). Protais et al [10] obtained similar results on different inbred lines among which those studied by Sadeyen et al [14]; moreover these authors showed that these differences were associated with different vaccine efficiencies, which is in favor of a lower rate or return to the susceptible state in the lines showing higher antibody response.…”