Measurement of Nutritional Value of Protein Source by Gross Protein Value Method

Gross protein value of 11 kinds of protein sources, i.e. fish meal, cotton seed meal, sesame meal, feather meal, meat born meal, fish soluble, soybeen meal, linseed meal, coconut meal, wool meal and hydrocarbon yeast, was determined by comparing the growth rate 2-week-old chicks on the sample with that on casein.The gross protein value estimated was as follows: fish meal, 110; cottonseed meal, 67; sesame meal, 13; feather meal A, 40; feather meal B, 4; fish soluble, 74; meat born meal, 92; soybean meal, 63; linseed meal, 54; coconut meal, 28; wool meal, -17; hydrocarbon yeast, 93.Among essential amino acids, content of methionine, isoleucine, leucine, phenylalanine, valine and histidine in hydrocarbon yeast was lower than that in casein. Supplementation of 0.1% of methionine to hydrocarbon yeast was effective to improve gross protein value.