[Resistance of different breeds of laying poultry to Marek's disease virus].

Investigated were a total of 447 two-day-old chicks of lines 5-A, ia-73' ll and lS of the Leghorn breed divided into 2 groups: controls--99 males and females, and test ones--348 infected at the age of 2 days via intraabdominal injection with 0.4 cm3 heparinized blood each, containing 5000 PFU per dose of the Marek's disease virus (CT-1 isolate). Both linear and sexual variations were found in the resistance of the birds.

[Genetic polymorphism of alkaline phosphatase and the resistance to Marek's disease virus].

Experiments were carried out with a total of 222 birds of the 5-A, 6-E, Ya-73, LL, and LS lines of the White Leghorn breed to find whether or not there existed any correlation between the alkaline phosphatase allels and the resistance to Marek's disease. The polymorphism of alkaline phosphatase was evaluated in the blood plasma of birds through horizontal electrophoresis in starch gel after G a hn e [3]. The resistance of the five egg laying lines of birds was found to be associated with the Akps allel, and their susceptibility - with the AkpF allel.

[Changes in the polymorphism of the blood serum alkaline phosphatase in chickens undergoing subacute lindane treatment].

Investigated were a total of 123 birds of the White Leghorn breed and 50 birds of the White Plymouth Rock breed. Preliminary studies were carried out on the LD50 amount of lindane (151 mg/kg body mass) with 6 groups of chickens. The birds were divided into 4 subgroups for each breed.

[Serum protein spectrum in chickens with different degrees of resistance to Salm. gallinarum, and the relation between globulin levels and antibody formation].

An experiment was carried out with 231 chickens of the Leghorn breed, 177--of the Cornish breed, and 532--of the White Plymouth Rock breed. In order to check the resistance of the birds to typhoid all of them were infected orally at the age of 2.5 months with an 18-hour broth culture of Salmonella gallinarum.

[Phagocytic activity and antibody formation in relation to the resistance of poultry to fowl typhoid-pullorum disease].

Vulchanov's method (1954) was employed to study the phagocytic activity, and the classic method with the agglutination test served to follow up the production of antibodies. Some breed-associated differences were observed in the phagocytic activity and the normal serologic antibody titer prior to the infection with Salmonella pullorum and Salmonella gallinarum. Highest were the indices with the Leghorn breed, followed by the Cornish and Plymouth Rock breeds.