The nutritive value of potato protein for the pig

Abstract

The value of the N of the potato was compared with that of barley, for supporting growth of "fattening pigs." The observations were made upon 12 pairs of similar animals, one of each pair receiving a potato, and the other a barley diet. The rations compared contained equal amts. of N derived from potato or barley with and without supplementary N from casein. Half of the potato N was composed of fresh boiled (Majestic) potatoes and half of commercial dried potato flakes. The total N of the diets varied from 1.5% when no casein was given, to 2.4% when casein was included (dry matter basis). The food intake on a dry wt. basis, of each barley-fed pig was limited to the amt. consumed by its potato-fed partner. The kg. weight increase per kg. digestible N intake varied from 16.5 to 20.3 for barley rations and from 13.5 to 15.2 for corresponding potato rations. Conversion of food into live wt. was more economical in the case of barley. Addition of casein increased the conversion of food into live wt. in either case. The coeff. of (apparent) digestibility of a mixture in equal parts of potato flakes and fresh boiled potatoes was 93.7% for energy and 81.5% for total N. Corresponding figures for barley were 82.3 and 79.1%. Admixture of casein up to 6% of the diet or of 50% of barley did not influence the digestibility of the potato.