Studies on the Comparative Nutritive Value of Fats XIII. Growth and Reproduction over 25 Generations on Sherman diet B Where Butterfat was Replaced by Margarine Fat, Including A Study of Calcium Metabolism ,

Abstract

The multigeneration experiment with a hydrogenated vegetable margarine fat replacing butterfat in Sherman diet B has now been successfully complete through the 25th generation. Such indices of nutritional value as rate of growth, fertility and lactation have continued at the same high level as was reported earlier for the first 10 generations. Somewhat better growth and lactation were obtained in a “second litter” series started with the 15th generation and continued through the 21st generation than with the main “first litter” series; however, the fertility index was some-what less satisfactory than with the “first litter” series. No significant differences in growth, reproduction and lactation were observed between rats maintained on the modified Sherman diet or regular Sherman diet, irrespective of whether the previous nutritional history of their mothers involved a stock diet or the modified Sherman diet over 20 previous generations. The calcium content of the whole carcasses of 21-day-old rats was higher in animals whose mothers had received a modified Sherman diet than in those where the previous maternal diet had been the usual Sherman regime. Calcium balances carried out at 90 days showed a somewhat more favorable positive balance for the rats on the Sherman diet modified by the introduction of a hydrogenated vegetable margarine than in those on the original Sherman diet containing butterfat. No similar differences in calcium content ascribable to the diets could be established in the adult rats. It is concluded that a hydrogenated vegetable margarine can supply the fat requirements of the rat over many generations. The employment of such hydrogenated fat results in equally effective calcification as that obtained when animal fat such as butter is present in the diet.