SIMPLIFIED PREPARATION OF A REFINED MILK FORMULA COMPARABLE TO RATS MILK - INFLUENCE OF THE FORMULA ON DEVELOPMENT OF THE GUT AND BRAIN IN ARTIFICIALLY REARED RAT PUPS

Background: Milk formulas for artificially reared (AR) rat pups are mo stly based on complex cow's milk products, prepared by laborious and t ime-consuming processes. The aim of this study was to develop a simpli fied procedure for preparing a refined formula and to examine its infl uences on gut and brain development. Methods: The formula comprised a combination of purified cow's casein and whey proteins, five kinds of edible oil, minerals, and vitamins. Detailed analyses showed that the composition of macro- and micro-nutrients, osmolarity, and pH of the n ew formula closely resembled those of rat's milli. Rat pups, each with an intragastric cannula implanted at age 5 days, were artificially re ared for the following 10-15 days. Results: The body weight gain of AR pups matched that of mother-reared (MR) pups. Histoplanimetrical anal yses showed that the small intestine in AR pups was more developed In relation to area of a transverse section, number and length of villi, and thickness of tunica muscularis than that of MR pups. Fat component s in the formula influenced the fatty acid composition and the cholesl erol-to-phospholipid ratio in the sm all intestinal microvillus membra ne (MVM) of AR pups, but not the MVM fluidity. Brain weight was not si gnificantly different between the two groups at age 15-20 days. Conclu sion: This formula is useful for artificial rearing of rats and for id entifying dietary components contributing to metabolic adaptation duri ng the suckling period. (C) 1997 Lippincott-Raven Publishers.