The effect of supplementing a poor wheat diet with L-lysine and DL-threonine on the digestibility coefficient, biological value and net utilization of proteins and nitrogen retention in children

Daniel, V.A.; Doraiswamy, T.R.; Rao, S.V.nkat; Swaminathan, M.; Parpia, H.A.B.

Indian Journal of Nutrition and Dietetics 5(2): 134-141


The effect of supplementing a poor wheat diet providing about 180g protein per kg body weight with L-lysine and a mixture of L-lysine and DL-threonine on the true digestibility coefficient (DC), biological value (BV) and net protein utilization (NPU) was studied in boys aged 10-12 years. Nitrogen retention on the wheat diet was low (10. 2 % of intake). The BV and NPU of the proteins of wheat diet were 41. 7 and 37.7 respectively. Supplementation of wheat diet with L-lysine brought about a significant (P<0. 05) improvement in N-retentlon (21. 5 % of intake), BV (53.4) and NPU (48.7). When the wheat diet was supplemented with a mixture of L-lysine and DL-threonine, highly significant (P < 0. 01) improvements in N-retention (30.4 % of intake), BV (60. 2) and NPU (57.3) were observed. The values observed containing milk proteins for a control diet were as follows: N-retention, 31. 3 % of intake, BV 61.4 and NPU, 59. 1. The net available protein (g/kg body weight) from the different diets were as follows: Poor wheat diet, 0. 67; poor wheat diet + L-lysine 0. 80; poor wheat diet + L-lysine + DL-threonine 0. 80; 1. 04 and skim milk powder, 1.11 as compared with FAO [ Food and Agriculture Organization] reference protein requirements of 0. 72gAg body weight.