Anti-IgY h+l Antibody polyclonal antibody [HRP]

Commercial poultry farms are increasingly threatened by bacterial infections from avian pathogenic Escherichia coli (APEC) and broad-host Salmonella serovars. Recombinant attenuated Salmonella vaccines (RASV) elicit cross-reactive immune responses against APEC in chickens; however, assessment of broad protection is lacking. Probiotics boost chicken immunity and improve vaccination responses. The objective of this study was to determine whether the RASV, the probiotics, or their combination had protection against APEC and Salmonella. White Leghorn chicks were randomly placed into 4 groups: no treatment (CON), probiotics (PRO), RASV (VAX), or both prophylactics (P + V). Chicks in the PRO and P + V groups were fed probiotics daily, beginning at the age of 1-day-old. Chicks in the P+V and VAX groups were orally inoculated with RASV at the age of 4D and boosted 2 wks later. Total and antigen-specific IgY responses to Salmonella (lipolysaccharide [LPS]) and E. coli (IroN and IutA) were measured in serum samples via ELISA. Bactericidal potential of both serum and blood against 42 APEC isolates comprising 25 serotypes was assessed in vitro. In vivo protection against APEC was evaluated by air sac challenge with APEC c7122 (O78:K80), gross pathological lesions were scored, and bacterial loads were enumerated. In a second similar study, birds were orally challenged with S. Kentucky (CVM29188), and feces were enumerated for Salmonella at multiple time points. Vaccination elicited significant LPS-specific antibodies regardless of probiotics (P<0.0001). Chicks in the P+V group demonstrated increased blood and serum bactericidal abilities against multiple APEC strains in vitro compared with the CON group. Following c7122 challenge, P+V birds had less APEC in their blood (P<0.001) and lower signs of airsacculitis (P<0.01) and pericarditis/perihepatitis (P<0.05) than CON birds. Finally, only P + V birds were negative for fecal Salmonella at all time points. This study shows this combination treatment may be a feasible method to reduce infection by APEC and Salmonella in chickens.

As a novel duck adenovirus 3 (DAdV-3) infection caused significant economic losses to the poultry industry in China, there is an urgent need to develop a safe and effective vaccine. In the research, fiber-1 and fiber-2 proteins were expressed and purified, respectively. To evaluate the immunogenicity of the two recombinant proteins, we investigated the IgY antibodies and virus-neutralizing antibodies in duck sera. The protective efficacy was evaluated by mortality, virus shedding and histopathological examinations after challenged with the DAdV-3. Results showed that the IgY antibody levels of the fiber-2 group was significantly higher than that of the fiber-1 group and inactivated vaccine group. Ducks vaccinated with fiber-2 group provided full protection with no mortality, no virus shedding and no histological lesions, superior to other groups. These results suggest that the fiber-2 protein can be an ideal candidate for subunit vaccine against the disease.