[The adaptation of the morphometric parameters of fat cell size for the purposes of animal science research. 2. Cellularity of subcutaneous adipose tissue of different swine breeds influenced by graduated feed levels and in relation to metabolic data and parameters of body fat degeneration].

Measurements of morphological and biochemical parameters in subcutaneous adipose tissue as well as investigations of energy metabolism and fat deposition of 89 male castrated pigs were performed. Breeding lines of swine (German Landrace) had been selected through 8 generations for high ("E(+)-Line") and low ("E(-)-Line") levels of NADPH-generating dehydrogenases. A control group ("K.") without selection was closely paralleled. For 21 days the animals were kept under feeding experiments within 2 sectors of growing period (67 kg, 85 kg body mass), and biopsies of backfat were examined subsequently. The inner layer of subcutaneous adipose tissue showed constantly bigger fat cells than the outer layer. The fat cell size increased generally with fattening and body mass respectively. The cellularity of adipose tissue was dependent significantly on the percentage of the very small fat cells measured up to 30 microns diameter (= "PKF30"). The breeding lines differed slightly with respect to their cellularity: The inner layer showed the gradation E+ greater than K. greater than E- concerning fat cell volumes and fat cell surfaces respectively. The PKF30 correlated significantly with food energy level as well as with the respirationally examined protein retention, particularly in inner layers of younger animals. Relations to the fat deposition (examined respirationally or with the D2O-Method and after slaughter respectively) were recognized, not showing validity for all cases. The parameters of lipogenic activity tested by tissue slice preparations and homogenates respectively correlated negatively with average fat cell size.(ABSTRACT TRUNCATED AT 250 WORDS)