The Nutritive Value of Several Foods Grown at Different Locations

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Abstract
A study of the relative nutritive value of several foods grown at widely differing locations demonstrated the superiority for the growing rat of turnip greens grown at Blairsville, Ga. in two different years. Turnip greens grown at two other locations—Experiment, Ga. and Raleigh, N. C.—were equivalent in nutritive value and definitely inferior to the Blairsville greens. No difference was observed in the nutritive value of corn and cowpeas which were tested similarly. Supplementation studies, using these all-plant diets, to determine the reasons for the superiority of the Blairsville (B) over the Experiment (E) turnip greens showed that diets containing either greens were improved by the following supplements: egg albumin, methionine, vitamin B12, and vitamin B12 + methionine. Vitamin B12 was twice as effective a supplement as egg albumin or methionine, and vitamin B12 + methionine was no better than vitamin B12 alone. A complete vitamin mix (without vitamin B12) significantly improved only diet E. The difference between the two greens was not in their mineral contents. Vitamin B12, or a substance with vitamin B12 activity for Ochromonas malhamensis and Lactobacillus leichmannii, was found in the B turnip greens; only negligible amounts were present in the E greens. Microbiological analyses showed the B greens to contain slightly more methionine and cystine than the E greens. This investigation showed that certain as-yet-undetermined factors associated with two different locations so influenced the composition of turnip greens grown there as to affect significantly their nutritive value for the animal. It also indicated that the principal difference between the two turnip greens was in that area of nutrition in which methionine, vitamin B12, and several other vitamins have been shown to be interrelated.