In twenty broiler flocks the following antibodies against common viruses were evaluated: chicken anaemia (CAV), infection bursal disease (IBDV), infection bronchitis (IBV) and reoviruses. The antibodies against Marek’s disease virus (MDV) were additionally examined. The presence of antibodies against CAV, IBDV and IB was determined by comercial ELISA kits and against reoviruses by ELISA performed according to the modified method of Slaght. The antibodies against CAV occurred in 7 flocks, the percentage of positive sera was 5% to 22%. All the sera showed the presence of IBDV antibodies. The antibodies against IBV were found in 5 flocks. In 7 flocks 80% of sera were positive. The antibodies against reoviruses were found in 90% of the flocks examined. All sera were positive in 8 flocks and negative in 2 flocks. In 6 flocks antibodies against MDV were found in 5% to 40% of the chickens.
In the article the immunological status of piglets in the first weeks of life is presented. The neonatal period is a huge challenge for a piglet’s immunological system. In this time his virgin immunological system comes into contact with an extreme numbers of environmental antigens. It takes place when the efficiency of this system is relatively low. There is limited external stimulation during gestation resulting in the lack of or presence of a minimal numbers of effector T lymphocytes, as well as memory cells in a piglet’s body. The pool of B lymphocytes is also immature. On account of the epitheliochorial structure of the porcine placenta the piglets are agammaglobulinemic in the first day of life. Due to a lack of efficient adaptive mechanisms, after birth the piglets are only equipped with innate immunity mechanisms, but they are not fully developed in the neonatal period. The most dynamic changes of immunological parameters are observed in the preweaning period. Summarizing, the immunological system of neonatal pigs is different from that of adults, from both an anatomical and functional point of view. The attainment of its maturity takes place around weaning.