Maintenance of a Standardised Breed of Young Rats for Work upon Fat-Soluble Vitamins, with Particular Reference to the Endowment of the Offspring

Abstract

This paper summarizes the experience gained during several years in the Lister Institute, London, of handling and breeding rats intended for nutritional researches connected with vitamins. The "breeding" diet, which remains unchanged throughout the year and consists of fresh milk, cereals, raw vegetables and marmite with an occasional ration of raw lean meat, is moderately rich in vitamin A but poor in vitamin D except in summer, when the "pasture fed" milk contains a fair amount of this vitamin. This seasonal variation in the nutritive value of cows'' milk proved to be the cause of a disturbing irregularity in the nutritive condition of the young. This was successfully lessened by the expedient of replacing fresh milk in the diet of pregnant and lactating mothers by dried milk prepared from winter milk.