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TESTS TO DETERMINE THE ADEQUACY OF NASA’S RODENT FOOD BARS FOR USE IN LONG-TERM SPACE FLIGHT EXPERIMENTS.   J.E. Barrett, D.S.Yu, B.P.Dalton. NASA Ames Research Center, Moffett Field CA.

Long-term space flight studies with rodents will require a diet that is nutritionally adequate, nutritionally stable during storage, and does not crumble. Rodent feeding studies and numerous other experiments are being conducted in order to determine the effectiveness of NASA’s current shuttle rodent food bar in preparation for use in long term (45-90 day tests) aboard the International Space Station. Beginning at about 7 weeks of age, male and female Sprague Dawley and Fischer 344 rats were housed in vivarium cages and fed either food bars or lab chow control diet for at least 100 days. Food bar acceptance by the animals was closely monitored, and no apparent decrease in food intake occurred as rats were switched from the weanling diet to food bar or chow. Growth, food and water intake, and necropsy values were obtained. Preliminary results indicate that there were physiological differences in some rat groups fed the food bar when compared to rats fed the control diet. Differences were noted in food and water intake in some groups, and in male Fischer body weights. Blood chemistry variables, some organ weights and organ to body weight ratios were significantly different for some groups. There were indications that lipid metabolism and storage were affected in rats fed the food bar diet. Cholesterol, abdominal and epididymal fat, blood urea nitrogen, and liver weights were significantly different for three of the four groups when compared with controls. However, the differences observed in the various parameters were inconsistent from group to group. Carcasses of the rats are being analyzed for moisture, fat and protein content. The food bars are tested periodically in order to monitor nutrient stability during storage. Additional rodent-feeding studies with mice are planned in order to obtain more information about food bar effectiveness as a diet for use in long-term studies. 

(Supported by NASA:  UPN393-25.)