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The breeding history of the first inbred strain of Khaki Campbell ducks is presented. The genetic homogeneity of this strain was tested on the basis of serum amyloid A (SAA) polymorphism and it was established that it harbours only the SAA allele A, which is expressed in liver, lung and bursa of Fabricius tissues. Pathogenic changes in control and avian leukosis virus-C (ALV-C) persistently infected ducks were evaluated during the period spanning 1 to 10 months after hatching. In both groups, AA amyloidosis was revealed and characterized. In spite of the inbred nature of animals, the incidence of amyloid A deposition varied among experiments, suggesting that additional non-genetic factors are involved. Similar variation was found in ALV-C persistently infected ducks, where only in one out of three experiments was the incidence of AA amyloidosis significantly higher than in controls.

In a population of (CB X CC)F1 X WB hybrids, a chicken was found with a presumably recombinant haplotype, BR1, whose antigenic products detectable by hemagglutination contained determinants derived from both parental haplotypes, i.e. B1 (from CB) and B2 (from CC). This recombinant bird and its progeny from different crosses were tested by skin grafting, graft-vs.-host (GVH) and mixed lymphocyte reactions (MLR). The results define two regions of the B system, the B-F and the B-G. The B-F region determined serologically defined antigens, histocompatibility antigens, and controlled the GVH and MLR reactions, while the B-G region was responsible only for synthesis of serologically detectable antigens.