Abstract
The Syrian hamster is becoming an increasingly important species in biomedical research, yet very little is known regarding its nutrient requirements. Most workers have assumed that its requirements are similar to those of the rat and have therefore fed them accordingly. However, accredited commercial hamster breeders have been unable to maintain maximum production solely on rat and mouse diets. This study was primarily concerned with determining the quantitative requirement of the fat-soluble vitamins A and E. However, breeding performance was unsatisfactory on control semi-purified diets and therefore the requirement for essential fatty acids was also investigated. Vitamin A deficiency under present conditions produced only degeneration of testicular germinal epithelium and none of the other overt symptoms expected. The absence of vitamin E from the diet stopped reproduction after conception, and resulted in resorption of embryos, confirming the observations of previous workers. Typical effects on skeletal muscle and testicular germinal epithelium with a concomitant decrease in testicular weight are described. No other effects on organ weights were observed. Factorial experiments investigating the quantitative requirement and interaction of vitamins A and E have shown several effects. Breeding performance was improved by increasing vitamin A from 500 to 50000 iu/kg diet, and feeding 100mg vitamin E per kg diet, no interactions were observed. Testicular degeneration was prevented by feeding at least 4000 iu but less than 40000 iu vitamin A per kg diet and greater than 40mg vitamin E per kg diet. Prevention of muscular dystrophy also required more than 40mg vitamin E per kg diet. The hamsters' requirement for essential fatty acids appears greater than that of the rat. Improvement in breeding performance was achieved by feeding sunflowerseed oil together with methyl linolenate. Supplementation of methionine improved litter size, viability of pups and milk production of dams.