Buildings 33 Egg Incubation 39 Rearing Facilities 40 Circular Rearing Units 40 Swedish Pond 43 Rectangular Tanks and Raceways 43 Rectangular Circulation Rearing Pond 46 Earthen Ponds 47 Cage Culture 48 Pen Rearing 50 Selection of Rearing Facilities 50 Biological Design Criteria 51

Depth filtration has been widely used during process scale clarification of cell culture supernatants for the removal of cells and cell debris. However, in addition to their filtration capabilities, depth filters also possess the ability to adsorb soluble species. This aspect of depth filtration has largely not been exploited in process scale separations and is usually ignored during cell culture harvest development. Here, we report on the ability of depth filters to adsorptively remove host cell protein contaminants from a recombinant monoclonal antibody process stream and characterize some of the underlying interactions behind the binding phenomenon. Following centrifugation, filtration through a depth filter prior to Protein A chromatographic capture was shown to significantly reduce the level of turbidity observed in the Protein A column eluate of the monoclonal antibody. The Protein A eluate turbidity was shown to be linked to host cell protein contaminant levels in the Protein A column load and not to the DNA content. Analogous to flowthrough chromatography in which residence time/bed height and column loading are key parameters, both the number of passes through the depth filter and the amount of centrifuge centrate loaded on the filter were seen to be important operational parameters governing the adsorptive removal of host cell protein contaminants. Adsorption of proteins to the depth filter was shown to be due to a combination of electrostatic and hydrophobic adsorptive interactions. These results demonstrate the ability to employ depth filtration as an integrative unit operation combining filtration for particulate removal with adsorptive binding for contaminant removal.

When rainbow trout (Salmo gairdneri) were exposed to 167 and 250 ppm formalin for 1 hr, moribund fish showed severe histopathological changes in gill epithelium. Hematocrit values and numbers of immature red blood cells were increased, suggesting a physiological response to hypoxia. The results are discussed in relation to the probable cause of death.

No abstract

The performance of four strains of rainbow trout, (Salmo gairdneri) was evaluated under hatchery and field conditions. Growth, conversion, and survival were measured in the hatchery; catchability, growth and longevity data were collected in the field. Fish from each strain were stocked at equal densities into two ponds near Three Forks, Montana, for a replicated field evaluation. The domestic Winthrop and Spring Standard Growth strains grew faster, converted food more efficiently, and were harvested at a faster rate than the wild McConaughy and Fish Lake strains. However, the McConaughy and to some extent the Fish Lake strains remained in the fishery longer—up to 3 years, at which time the project was terminated.