Abstract
The growth response and liver fat deposition of rats fed diets consisting of bread mixtures containing three levels of non-fat milk solids (3,6 and 12 parts per 100 parts flour) and these same levels of milk solids plus 0.25 parts of lysine have been reported. Twelve rats were placed on each of the diets numbering I to VI. Improved growth resulted with increasing milk levels. The addition of lysine stimulated growth at each milk level. The difference in mean growth rate was statistically significant for all diets except III (12 parts non-fat milk solids) and IV (3 parts non-fat milk solids + lysine). Food efficiency was increased with increased total lysine content of the diet. Nitrogen efficiency was likewise increased with the exception of diets III and IV which did not differ significantly with respect to their effect on nitrogen efficiency. A comparison of the mean liver fat content of the rats on the 6 experimental diets with that of rats on what was considered an optimal diet showed the latter to be significantly lower than the mean liver fat content of rats on all experimental diets except diet III. The elevation of liver fat levels was small and there was no statistically significant difference among the experimental diets. In this study 3 parts of non-fat milk solids per 100 parts flour plus 0.25 parts lysine gave results comparable in beneficial effects with 12 parts non-fat milk solids in bread mixtures. Since the latter is not likely to be used by commercial bakers because of cost and unacceptability of the resulting product, it would seem that the former might be given consideration for raising the lysine content of diets where this appears to be desirable. Further studies in this field are to be recommended, however.