title: Performance of a commercial Chicken-Ovo-transferrin-ELISA on the serum of brown layer chickens infected with Gallibacterium anatis and Streptococcus zooepidemicus.
abstract: To evaluate Ovo-transferrin (OTF), a positive acute-phase protein in chickens, as a diagnostic biomarker of selected bacterial infections we checked the performance of a commercial Chicken-OTF-ELISA (ICL, Inc., Portland, OR, USA) by analytical and overlap performances using two groups of serum samples obtained from 26 Gallibacterium anatis-infected and 20 Streptococcus zooepidemicus-infected brown layer chickens. In addition, sera from 14 apparently healthy and 19 negative control chickens were analysed in the Gallibacterium group whereas sera from 20 healthy and 11 negative control chickens from the Streptococcus group were analysed. All calibration curves revealed high coefficients of determination (≥ 0.97) between optical density (OD 450nm) and concentrations of OTF (mg/ml). OTF concentrations in high, medium and low pools (made of sera from a combination of infected and/or non-infected birds) were >6.4, >3.8 to <4.5 and <1.6 mg/ml in the Gallibacterium group, and >6.7, >3.5 to <3.7 and <1.1 mg/ml in the Streptococcus group, respectively. For each pool, low coefficients of intra-assay (7.8, 5.7 and 5.3) and inter-assay (15.8, 18.0 and 18.0) variations were obtained in the Gallibacterium study. In the Streptococcus study only the intra-assay variation was low (3.7, 3.8 and 6.2, respectively). The linearity check was acceptable demonstrating a straight line with slope and intercept, not deviating from one and zero, respectively, using the Gallibacterium sera, whereas the Streptococcus sera deviated from the linear line. Detection limits were low (Gallibacterium, 0.01 mg/ml; Streptococcus, 0.32 mg/ml). OTF concentrations (mean ± standard error of the mean) in overlap performances were elevated in the sera of infected chickens (Gallibacterium, 4.4 ± 0.3 mg/ml; Streptococcus, 3.2 ± 0.4 mg/ml) compared with negative controls (1.7 ± 0.1 mg/ml) (P < 0.05). In conclusion, the Chicken-OTF-ELISA can be used to measure reproducible serum OTF concentrations in brown layer chickens as a response to G. anatis infections, whereas an adjustment of dilution process is proposed to optimize to use in S. zooepidemicus-infected chickens.
authors: a Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences , University of Copenhagen , Frederiksberg C , Copenhagen , Denmark.
authors: Krisna
authors: K
authors: Roy
authors: Mads
authors: M
authors: Kjelgaard-Hansen
authors: Susanne Elisabeth
authors: SE
authors: Pors
authors: Jens Peter
authors: JP
authors: Christensen
authors: Paritosh Kumar
authors: PK
authors: Biswas
authors: Anders Miki
authors: AM
authors: Bojesen
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000175:diagnosis / Q000662:veterinary*; D015415:Biomarkers / Q000097:blood; D002645:Chickens; D003207:Conalbumin / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D020563:Gammaproteobacteria; D011201:Poultry Diseases / Q000175:diagnosis* / Q000382:microbiology*; D018502:Streptococcus equi
chemical_list: D015415:Biomarkers; D003207:Conalbumin