Abstract
Studies were made on the occurrence rates and ultrastructures of intracyto-plasmic crystalline inclusion bodies in the parietal cells of fattened steers. The abomasum examined was collected from 90 Holstein-Friesian and 13 Japanese Black-hair steers approximately 20 months old. The occurrence rates were different between the two breeds. The inclusion body was detected in 100% of the Holstein-Friesian and in 53.8% of the Japanese Black-hair steers. Inclusion bodies appeared specifically in fattened steers. They might be induced by unphysiological conditions of the abomasum under fattening. Crystalline inclusion bodies were homogeneous, acidophilic, and rod-shaped in H-E stained sections. Electron microscopic studies were performed on 4 Holstein-Friesian steers. The inclusion bodies were rod-like, hexagonal or rhombic in shape, and electron dense, without outer membrane, and located in the cytoplasmic matrix. There was no relationship between inclusion bodies and cytoplasmic organelles. The inclusion bodies appeared to reveal rod shape in the longitudinal section, regular hexagonal shape in the cross section, and rhombic shape in the oblique section. The fundamental shape of the crystalline inclusion body was considered to be a regular hexagonal rod with hemispherical ends. One side of the hexagon was 1.1-2.0μ in length. The longitudinal length of the rod was about 13-23μ. The internal structure of the crystalline inclusion body consisted of regularly arranged micro-tubular structures, which were about 115-154 Å in diameter. The center-to-center distance between two adjacent tubuli was about 190-200Å. The cross sections of the tubuli were hexagonal. Three adjacent tubuli gathered to form a regular triangle.
