Abstract
Al-Bisher, A. A., Al-Mufarrej, S. I., Ali, A. K. A. and Hussein, M. F. 1998. Effect of short term heat stress on antibody production and blood constituents of Baladi and Leghorn chickens. J. Appl. Anim. Res., 13: 119-128.
Ninety chickens each of Baladi and Leghorn were divided into 3 groups (A, B and C) and each group was subdivided into 3 replicates (5 males and 5 females per replicate). Each replicate was reared separately in a randomly allotted pen at ≈ 18C, and 65% relative humidity. Immediately prior to immunization, group C birds were exposed to 40C for 48h. Each of groups B and C birds was immunized intramuscularly (im) with 1 ml of 7% sheep red blood cells (SRBC) suspension in phosphate buffered saline (PBS); group A served as controls, receiving 1 ml PBS per bird im. A second immunization dose was administered 4 weeks later to evaluate secondary antibody response. Serum samples were collected before and at weekly intervals after immunization and assayed for antibodies against SRBC, using a microtitre haemagglutination test. The sera were also analyzed for electrolytes, copper, zinc and cholesterol concentrations. The results indicated that heating stimulated antibody production during primary- and suppressed it during secondary-immunization. Leghorn chickens produced significantly higher antibody titres during primary-and significantly lower antibody titres during secondary-immunization, than Baladi chickens. In both breeds, the overall antibody production was significantly higher in female than male birds. On the other hand, with the exception of Zn, whose concentration decreased markedly in the immunized groups as compared to the controls, the treatments did not seem to induce significant changes in the studied serum chemical constituents.