Some Amino Acid Requirements of the Gravid Gilt Fed a Purified Diet

Abstract

A purified diet containing casein as the sole source of intact protein was used in several experiments to evaluate some amino acid requirements of the gravid gilt during late pregnancy. The daily consumptions of diet and metabolizable energy were 1.82 kg. and 6,100 kcal., respectively. Requirements not exceeding 0.17, 0.30 and 0.07% were determined for histidine, phenylalanine, and tryptophan, respectively, since the 6% protein of casein adequately met the needs for these amino acids. Satisfactory nitrogen retention resulted with 0.56% leucine and 0.38% arginine. but neither higher nor lower levels were fed. The gravid gilt requires 0.34% threonine and 0.46% valine to support maximum nitrogen retention. Glutamic acid was efficiently utilized as the sole source of supplementary amino nitrogen. Diammonium citrate could completely replace glutamic acid without influencing the efficiency of nitrogen utilization.