HACKING, M. A., J. BUDD, and K. HODSON. 1977. The ultrastructure of the liver of the rainbow !rout: normal structure and modifications after chronic administration of a polychlorinated biphenyl Aroclor 1254. Can. J. Zool. 56: 477-491.Rainbow trout (Salmo gairdneri) were fed dietary levels of 0-, 1-, lo-, and 100-ppm Aroclor 1254 for 229 to 330 days. The ultrastructural features of control livers were similar to those of other animals, but rainbow trout liver differed from mammalian liver in an apparent absence of Kupffer cells. Also small dense duct-type cells were present that formed a transition zone, combining with hepatocytes to form canaliculi; alone they formed preductules and in combination with cells of lower density they formed ductules. Microtubules were found in the vicinity of canaliculi and less frequently adjacent to the plasma membrane of other cell surfaces. They were not seen at the sinusoidal border as they are in mammalian liver. Peroxisomes lacked nucleoids. There were no ultrastructural liver changes in the 1-ppm group. The most frequently encountered alterations in both the 10-and 100-ppm groups were those involving the nucleus. These included irregular and bizarre nuclear outlines, separation of nucleolar components, and large nuclear pseudoinclusions. Other frequently encountered changes were slight increases in smooth endoplasmic reticulum, altered rough endoplasmic reticulum, increased lysosomes, reduced and altered glycogen, increased lipid, and hypoxic vacuoles. Seen also were concentric membrane arrays, myelin figures in intercellular spaces and Golgi cisternae, and bundles of fine tubules throughout the cytoplasm. HACKING, M. A., J. BUDD et K. HODSON. 1977. The ultrastructure of the liver of the rainbow trout: normal structure and modifications after chronic administration of a polychlorinated biphenyl Aroclor 1254. Can. J . Zool. 56: 477-491.Des truites arc-en-ciel (Salmo gairdneri) ont ete nourriesdedietescontenant 0, 1, lOet 100 ppm d'Aroclor 1254 durant 229-330 jours. L'ultrastructure des foies-temoins ressemble a celle d'autres animaux, mais le foie de la truite arc-en-ciel difFere du foie des mammiferes par I'absence apparente des cellules de Kupffer. On constate egalement la presence de petites cellules opaques semblables aux cellules des canaux, cellules qui forment une zone de transition en se combinant aux hepatocytes pour constituer des canalicules; seules, ces cellules forment des precanalicules, combineesad'autres, ellesformentdescanalicules. On trouve des microtubulesdans levoisinage des canalicules et, plus rarement, on les trouve adjacentes a la membrane plasmatique d'autres cellules. On ne les voit pas 2 la bordure des sinuso~des, comme chez les mammiferes. Les

Blood samples were taken from fingerling coho salmon (Oncorhynchus kisutch) that had been experimentally infected with either the bacterial pathogen causing vibriosis or that causing bacterial kidney disease. In the 2nd week after inoculation, smears from the Vibrio-infected fish contained enlarged thrombocytes, pinched erythrocytes, and neutrophils with vesicles. The total number of thrombocytes was reduced to 8000 per microlitre, though this returned to 20 000 per microlitre in the 3rd week in those fish that survived.Blood smears from fish given the kidney disease bacterium contained enlarged thrombocytes and what appeared to be collapsed reticulocytes, in the 2nd and 3rd weeks. The thrombocyte count averaged 6500 per microlitre, and there were reduced numbers of other cells. Bacteria were found in thrombocytes, neutrophils, and monocytes.Light micrographs of 26 normal or modified cells and electron micrographs of two granulocytes are included.

No abstract

A bstract:Vibrio anguilbarumn was identified as the causative agent of an epizootic in tropical freshwater fishes.It was pathogenic for selected species of other freshwater fishes, and was isolated from inoculated gravid guinea pigs, and their fetuses and dead young.Gross and microscopic lesions are described.