Estimation of protein reserves and the nitrogen content of organs in protein-depleted and repleted cocks

Effect of Non-Protein Nitrogen Supplementation of Low Protein Rations on Laying Hen Performance with a Note on Essential Amino Acid Requirements

“…The former results were not unexpected in view of the large proportion of the maintenance requirement (ca. 66%) which can be met by non-essential amino acids (Leveille and Fisher, 1958; and the ability of this same type of nitrogen to maintain (Shapiro and Fisher, 1962) and/or partially replete limited quantities of body protein reserves (Wessels and Fisher, 1965). Also understandable was the small production advantage (3.5%, Chavez et al, 1966) obtained with non-protein nitrogen supplementation of low protein diets, because maintenance N requirement relative to that necessary for egg formation is small (ca.…”

Effect of prior protein nutriture and nitrogen retention on the utilization of nonessential nitrogen in the young adult

“…could be replenished following depletion with a nonessential N source. Wessels and Fisher (1965) depleted adult cocks of body protein to varying degrees and then repleted them for a 16-day period by giving them the maintenance needs for essential amino acids plus additional N in the form of either fish protein, gelatin, or aspartic acid. As shown in Figure 2, cocks that were depleted beyond a body N loss of 2.6 g of N/kg of body weight (equivalent to 6.9% total body N) could no longer be repleted if aspartic acid supplied the extra N above the maintenance needs.…”