Fatty-acid profiles of white muscle and liver in stream-maturing steelhead trout Oncorhynchus mykiss from early migration to kelt emigration.

The profiles of specific fatty acids (FA) in white muscle and liver of fasting steelhead trout Oncorhynchus mykiss were evaluated at three periods during their prespawning migration and at kelt emigration in the Snake-Columbia River of Washington, Oregon and Idaho, to improve the understanding of energy change. Twenty-seven FAs were identified; depletion of 10 of these was positively correlated in liver and white muscle of prespawning O. mykiss. To observe relative changes in FA content more accurately over sampling intervals, the lipid fraction of tissues was used to normalize the quantity of individual FA to an equivalent tissue wet mass. Saturated and monounsaturated FAs were depleted between upstream migration in September and kelt emigration in June, whereas polyunsaturated FAs were more conserved. Liver was depleted of FAs more rapidly than muscle. Three FAs were detected across all sampling intervals: 16:0, 18:1 and 22:6n3, which are probably structurally important to membranes. When structurally important FAs of O. mykiss are depleted to provide energy, physiological performance and survival may be affected.

Field trials of investigational new animal drugs.

Field trials provide an opportunity to determine the efficacy and safety of drug treatments in a variety of environments and fish stocks that would not be possible or practical in laboratory settings. The steps for executing good field trials are discussed. The University of Idaho coordinates numerous field trials at over 100 hatcheries throughout the Pacific northwest as part of an intensive and extensive program to register erythromycin injectable and feed additive to control bacterial kidney disease in salmonids. A standardized toxicity test conducted at 52 hatcheries following the completion of administration of erythromycin feed additive provided a way to compare responses by fish at different times of the year, locations, and among different sizes of fish. Some of these fish were used in an assay to quantify the content of erythromycin in kidney tissue post treatment.

Oral and injectable applications of erythromycin in salmonid fish culture.

Erythromycin is a macrolide antibiotic effective against Renibacterium salmoninarum, causative agent of bacterial kidney disease in salmonids. Although erythromycin is used on an experimental basis in private and conservation hatcheries, the drug is not registered with the US Food and Drug Administration for use in fish culture. Residues of erythromycin are retained in the tissues of juvenile and adult salmon for some time following administration of oral or injectable forms of the drug, a characteristic that may be important in the drug's efficacy against the slow growing R. salmoninarum pathogen. Before erythromycin can be registered, additional information must be collected about efficacy, toxicity, and environmental consequences of administration.

Gonococcal peritonitis in a patient treated with continuous ambulatory peritoneal dialysis (CAPD).

We report a case of gonococcal peritonitis in a sexually active female on continuous ambulatory peritoneal dialysis. The presumed route of entry into the peritoneal cavity was via the Fallopian tube. The episode responded rapidly to a standard antibiotic treatment protocol. Some episodes of culture-negative peritonitis may be caused by genital tract organisms which are not cultured by routine methods.