A study on the immunomodulating effect of gentamicin on broilers vaccinated with Newcastle disease virus

الملخص EN

The aim of the present work is to study immunomodulating effect of gentamicin on broiler chickens vaccinated against Newcastle virus at 18 days and challenged with a virulent strain of ND at the 30th day of age.

Three groups of one day old Hubbard chicks each of 30 birds were used in this study.

Chicks of the 1st group received 10 mg gentamicin /kg b.

wt and those of the 2nd group were given 20mg gentamicin /kg b.

wt .

All the birds of th two groups were injected S/C at 14th,15th and 16th days of age .Birds of the 3rd group were used as control non treated group.

Blood samples were collected from ten birds of each group at 25 and 35 days of the experiment.

Number of dead birds were recorded daily, body weight and feed conversion were estimated weekly till the end of the experiment (at 45 day).

Also, the lymphoid organs (thymus, bursa and spleen) were carefully separated & weighed and each organ relative weight was determined.

It was observed that administration of gentamicin (10mg/kg)did not induce any significant changes of blood cell count and relative weights of the lymphoid organs.

Additionally, it decreased the phagocytic activity, serum total protein and albumin upto 1 week post vaccination.

On the other hand, administration of gentamicin (20mg/kg) decrease the blood cell count, phagocytic activity and the relative weights of the bursa.

Both doses of gentamicin provoked a significant decrease in serum globulin, HI titer and protection %.