Changes in Serum Ovotransferrin Levels in Chickens with Experimentally Induced Inflammation and Diseases

Abstract

A competitive enzyme immunoassay was developed to measure the changes in serum levels of ovotransferrin (OTF) during inflammation and infectious diseases in chickens. The assay is based on the competition of serum OTF with a fixed concentration of biotin-labeled OTF to bind to a rabbit anti-chicken transferrin antibody immobilized on microtiter wells. After several washing steps, the antibody-bound biotinylated OTF is probed with streptavidin-horseradish peroxidase conjugate (HRP) followed by a colorimetric detection of the HRP activity. The relative changes in the optical density of color are plotted against the competing concentrations of OTF with logarithmic regression to generate a standard curve that is used to determine the concentrations of OTF in unknown samples. Serum had no effect on the measurement of OTE By this method, the time course changes of serum OTF levels in 4-wk-old male broiler chickens that were subjected to inflammation by croton oil injection were measured. The results showed croton oil-induced inflammation elevated serum OTF levels at 16 hr postinjection. OTF levels reached a peak by 72 hr, remained high through 120 hr, and returned to a basal level of olive oil-injected controls by 240 hr. There were no changes in serum OTF levels at any of the above time points in olive oil-injected control chickens. For studies with poultry diseases, specific-pathogen-free (SPF) male chickens were challenged with known bacterial and viral pathogens, and serum was collected at the height of the infection, i.e., 7 days after the challenge. Compared with uninjected controls, the SPF chickens challenged with Escherichia coli, fowl poxvirus, respiratory enteric orphan virus, infectious bursal disease virus, infectious bronchitis virus, or infectious laryngotracheitis virus had higher levels of OTF in serum. Inflammation-induced changes in serum OTF levels were also evident in the changes in the density of a 65-kD band protein corresponding to OTF. These results demonstrate that serum OTF may be a nonspecific clinical marker of inflammation associated with traumatic or infectious avian diseases.

Gene expression responses toRiemerella anatipestiferinfection in the liver of ducks

“…We speculate that OTF peptides probably kill R. anatipestifer since R. anatipestifer is also a Gram-negative bacterium and thus shares a common outer membrane with other aforementioned Gram-negative bacteria. Recent work has also demonstrated that blood OTF concentration is modulated under inflammation and microbial stress and can therefore be used as a diagnostic marker of infection and inflammation in chickens (Xie et al, 2002;Rath et al, 2009). Ferritin is a major intracellular iron storage protein and functions as a cytoprotectant by sequestering iron to minimize the formation of reactive oxygen species.…”

Use of Organic Acids and A Competitive Exclusion Product as Growth Promoter and Salmonella Enteritidis Control in Commercial Turkeys

“…At the same time (d 5 post-challenge), SE CFU values of the cecal content were reduced relative to d 2 post-challenge, also in the Positive Control group. According to Xie et al (2002b), OVT is an antibacterial protein capable of sequestering and storing iron, which is essential for bacterial growth. Furthermore, it is believed that OVT exerts a specific action on Gram-negative bacteria due to its ability to permeate the external membrane of such bacteria, thus causing bacteriostasis (Aguilera et al, 2003).…”

Acute phase proteins: a review of their function, behaviour and measurement in chickens

“…Sequestering iron deprives bacteria of the iron essential for growth (Xie et al, 2002b). A direct action on the Gram negative bacteria E. coli has been identified as OVT is able to permeate the outer membrane causing bacteriostasis (Aguilera et al, 2003).…”

“…OVT has immunomodulatory effects inducing respiratory burst activity and degranulation in heterophils and macrophages, and facilitates tissue remodelling and angiogenesis, aiding post inflammatory repair of tissues (Xie et al, 2002c). Xie et al (2002b) investigated the serum OVT levels in response to a number of viruses and E. coli (Table 3). Rath et al (2009) compared changes in the serum OVT concentration due to infectious diseases, metabolic diseases and autoimmune disease.…”