Antibody and Interleukin-6 Response in Local Chickens Infected with Salmonella gallinarum and Treated with Crude Extract of Aloe Secundiflora

Abstract

A study was conducted to establish the effect of crude extract of Aloe secundiflora on antibody and interleukin-6 response in local chickens experimentally infected with Salmonella gallinarum. At five months old, the chickens were screened for S. gallinarum antibodies and those found negative were randomized into five groups namely G1, G2, G3, G4 and GS. Birds of Gl (n=21), G2 (n=21) and G3 (n=21) were experimentally infected with 5.0xl 08 c.f.u/ml of Salmonella gallinarum (RD 8 strain). G1 birds were treated with 200 mg/kg Aloe extract two weeks prior to infection and were continued with 400 mg/kg up to day- 7 post infection (pi), G2 were untreated while G3 were treated with 400 mg/kg as from day-0 pi. G4 (n=10) were uninfected and untreated while GS (n=10) were uninfected but given treatment as in G1. Antibodies against Salmonella gallinarum were detected in all infected groups by day-6 pi. From day-9 pi, G2 (infected and untreated) showed significant increase in antibody titre (p<0.05). The treated groups G1 and G3 showed lower antibody levels with G1 (pre-treated) showing significantly lower level than G3 (p<0.05). All groups showed an increment in the levels of IL-6; however, levels in the uninfected groups remained below the cut-off point during the experimental trial. Between day-3 and day-6 pi, levels of IL-6 in the infected and treated groups (G1 and G3) were significantly high (p<0.05) as compared to 02. This experiment showed that administration of Aloe extract in chickens infected with fowl typhoid resulted into lowering of antibodies against Salmonella and an increase in IL-6 levels before the peak of the antibody production. It is concluded that the mechanism triggering antibody production was suppressed in Aloe-treated birds while the cellular response leading to IL-6 production was enhanced during the initial stage of infection. Therefore, Aloe extract could play a role in the immunoprotection to fowl typhoid. This phenomenon could be incorporated into the control strategy of fowl typhoid