Histo-immunological Response of Clarias lazera against Bacterial Vaccines

Abstract

One hundred and six tv catfish (C/arias lazera) were divided into 4 equal groups (gps. I - 4 ). Group (I) served as a control. The fish of group 2, 3 and 4 were vaccinated with Aeromonas hydrophila (A. hydrophila) bacter.ln •via .intra-peritoneaL oral and immersion routes, respectively.(2 mg I ml) using Aeromonas hvdrophila (A. hydrophila) bacterin. Sampling of blood (with and without anticoagulant) and tissue specimens were done from 5 fish, weekly, in each group for 4 weeks. The remaining 20 fish, in each group, were challenged with virulent strain of A. hydrophila (I gm bacterial cells I liter) one month post-vaccination (PV) for the determination of the relative level of protection (RLP) among the challenged fish. Some hematological parameters and antibody titers beside total protein, albumin, globulin and its fractions were determined. Tissue specunens were fixed in I 0 % formalin saline, 5 micron thick paraffin sections were prepared, stained with H & E and examined histopathologically.

Cattish ( Clarias lazera) . of the control group showed normal hematological parameters and' tissue throughout the period of the expenment. The catfish vaccinated via the intra-peritoneal injection showed a significant gradual mcrease of leukocytes especially lymphocytes from the I" to the 4'h week PV. Antibody titer, total protein and globulin, especially gamma globulin, was significantly increased from the l". to the 4'h week PV.