A purified diet for medaka (Oryzias latipes): refining a fish model for toxicological research.
The overall nutritional adequacy of a purified casein-based diet (PC-diet) for the medaka (Oryzias latipes) was evaluated and compared with three diets: commercially available flaked fish food (FL-diet), live newly hatched Artemia (A-diet), and a combination of FL-diet plus A-diet (F/A-diet). Survival, growth, reproductive success, general and liver histopathology, and selected hepatic enzyme activities were compared in medaka from first feeding through reproductive maturity. The PC-diet proved adequate in all of the above criteria. When compared with fish fed F/A-diet, an initial lag in early growth rates (i.e., 0 to 30 days) occurred with the fish fed PC-diet. The FL-diet alone was not nutritionally adequate for medaka, resulting in poor growth, reduced reproductive success, lower survival, and emaciation. A significant number of spinal deformities (5.4%) were noted in medaka fed the F/A diet. Ethoxycoumarin 0-deethylase and glutathione S-transferase activities were monitored and a trend toward increasing activity with age was noted. This suggests that PC- and F/A-diets provide adequate nutrition for development of the xenobiotic metabolizing enzymes necessary for detoxification and activation of endogenous and foreign compounds. The PC-diet supported good survival, growth, reproduction, and normal histology. This diet provides a standardized, nutritionally adequate, and consistent alternative to undefined conventional diets and is less likely to contain the range of xenobiotics possible in whole, live food.
DeKoven
D L
DL
Department of Animal Science, University of California, Davis 95616.
Núñez
J M
JM
Lester
S M
SM
Conklin
D E
DE
Marty
G D
GD
Parker
L M
LM
Hinton
D E
DE
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002273:Carcinogens / Q000633:toxicity; D002274:Carcinogens, Environmental / Q000633:toxicity; D004032:Diet; D008099:Liver / Q000502:physiology; D008954:Models, Biological; D009990:Oryzias / Q000254:growth & development / Q000502:physiology*; D012098:Reproduction / Q000502:physiology; D015996:Survival Rate
D002273:Carcinogens; D002274:Carcinogens, Environmental