[The exogenous and genetic components of some vessel wall characteristics in the pig (author's transl)].

Insufficiencies of the circulatory system and increasing transport losses in pigs as well as analogies with respect to atherosclerosis of men and swine were the motives for a broad statistical investigation of important characteristics of the circulatory system in a big population of female German landrace pigs, fattened as progeny groups under identical conditions in a testing station and slaughtered at 100 kg weight. As the most essential results, highly significant seasonal and genetical influences on several traits are to be mentioned, and some meaningful correlations between them: Plasma cholesterol, ceruloplasmin and hematocrit showed markedly lower levels in the summer and increased values in the cold season; the thickness of the intima (aorta and arteria pulmonalis) was quite distinctly greatest in the spring, this phenomenon being almost exactly paralleled by augmented amounts of copper and iron in the aortic wall. Increased heart weights were again found in the cold, decreased ones in the warm seasons. On average, bigger hearts and vessels were accompanied by higher elastin contents of the aorta, but these contents stood in very significant negative correlation to the ash content and the amounts of certain mineral components (Ca, Mg and P) of the vessel wall, especially to the ash percentage of the elastic fibers. This indicates that calcifying and mineralizing processes in the wall obviously take place at the cost of the elastic components. The estimation of heritabilities in half and full sibs revealed with h2 = 60% high henetic influences on the elastin content of the aorta and equally so on the ash percentage of elastic fibers. Future investigations must correlate these findings with direct measurements of biomechanical and rheological properties of the vessels.