Effects of florfenicol on the immune responses and the interferon-inducible genes in broiler chickens under the impact of E. coli infection

Abstract

Florfenicol (FFC) as a chloramphenicol's derivative is a special broad-spectrum antibiotic that was used in veterinary clinics. In the present study, we investigated the effect of different doses of FFC on the humoral immune response of broiler chickens to Newcastle disease virus (NDV) vaccine under the impact of E. coli infection. In addition, the expression of the interferon-inducible genes (IRF7, 2'-5'OAS and Mx1) were analyzed in the spleen tissue of these chickens using quantitative real-time PCR (qRT-PCR). The non-treated group with FFC and non-infected with E. coli had the highest immune responses against NDV compared with the FFC treated groups. In the case of E. coli infection, the group treated with FFC (30 mg/Kg BWt) showed lower NDV HI and IgG ELISA Ab levels compared to the group treated with FFC (60 mg/Kg BWt). A dose dependent up-regulation was observed in the level of the interferon-alpha pathway related genes (IRF7 and 2'-5'OAS) in the FFC treated groups compared to the non-treated group. At the slaughter time, the numbers of adipocyte in the bone marrow were significantly higher with moderate atrophy of the hematopoietic lineages in the FFC treated birds compared to the non-treated birds. These results indicated that this FFC dosage dependent increase in the humoral immune responses against NDV vaccine could be attributed to its efficient therapeutic effect on the E. coli infection. However, the increase in the FFC dosage can negatively but temporarily affect the chicken body weights. Additionally, it can exert up regulation effect on the chicken innate immune response with moderate hypoplasia of the bone marrow cells.

Impact of single and mixed infections with Escherichia coli and Mycoplasma gallisepticum on Newcastle disease virus vaccine performance in broiler chickens: an in vivo perspective

“…The mRNA levels of all studied cytokine's genes were remarkably lower in mixed infection group (up to 2Á30 AE 0Á79) in comparison with single infection ones (up to 4Á30 AE 0Á94), but the cytokine genes overproduction is still present in all vaccinated infected chicken groups. This can explained by infection with more virulent strains suggests an explanation for the higher induction of cytokine genes as has been previously reported (Bolha et al 2013;Hassanin et al 2014).…”

Prophylactic and immune modulatory influences of Nigella sativa Linn. in broilers exposed to biological challenge

“…Colibacillosis usually characterized by septicemia in acute stage resulting in death and pericarditis, airsacculitis, and perihepatitis in the subacute stage [ 43 ]. E. coli infection was clearly known to contribute marked gross and microscopic bursal lesions causing bursal atrophy that subsequently resulted in transient humeral immunosuppression [ 44 ].…”

Development and Validation of a Sensitive Indirect Competitive Enzyme-Linked Immunosorbent Assay for the Screening of Florfenicol and Thiamphenicol in Edible Animal Tissue and Feed

“…Therefore, FF and TAP had been widely used in veterinary clinical practice to control disease and improve the growth rate of animals (Cannon et al 1990;Fukui et al 1987;Ueda et al 1995;Varma et al 1986). However, several forms of TAP and FF-induced toxicity have been reported, especially damage to hematopoietic and immune function, such as inhibition of phagocytosis (Bretzlaff et al 1987), lymphocyte proliferation (Hu et al 2014), the immune response (Guan et al 2011), and hematopoiesis (Turton et al 2002;Hassanin et al 2014). Therefore, the maximum residue limits (MRLs) for TAP and FF have been set by many countries.…”