Journal Paper Article Abstract

Dietary Lysine and Threonine Utilization by Young Pigs:
Efficiency for Carcass Growth

OLAYIWOLA ADEOLA
Department of Animal Sciences
Purdue University
West Lafayette, IN 47907
USA

ABSTRACT

Two experiments were conducted to determine the efficiency of dietary lysine and threonine retention for carcass protein accretion in pigs within a body weight range of 10 to 20 kg. At the beginning of the experiments, an initial representative group of 6 pigs were killed for carcass compositional analysis. In the first experiment conducted to determine the efficiency of dietary lysine retention, a basal diet was formulated to contain 6 g of lysine kg-1. Twelve pigs were fed the basal diet supplemented with L-lysine HCl to contain 6, 7, or 8 g of lysine kg-1. Daily weight gain and gain:feed ratio were higher (P<0.05) for pigs fed 8 g of lysine than for pigs fed 6 g of lysine kg-1 diet. The accretion rates of dry matter, protein, ash, and lysine in the carcass were higher for pigs fed 8 g of lysine than for pigs fed 6 g of lysine kg-1 diet. A linear regression of daily carcass lysine accretion on daily lysine intake resulted in a 72% efficiency of carcass lysine accretion above maintenance. In the second experiment, three diets including a basal diet formulated to contain 4 g of threonine kg-1 and supplemented with L-threonine to contain 4, 4.65, or 5.3 g of threonine kg-1 were fed to 12 pigs. Rate and efficiency of body weight gain exhibited a dose-response improvement (P<0.05) to an increase in dietary threonine. Carcass protein, ash, and threonine accretion rates were higher (P<0.05) for pigs fed 5.3 g of threonine than those fed 4 g of threonine kg-1 diet. Linear regression of daily carcass threonine accretion on daily threonine intake resulted in extra-maintenance efficiency of threonine retention of 60%. The efficiencies of dietary lysine and threonine utilization for carcass growth in pigs within the live weight range of 10 and 20 kg are 72% and 60%, respectively.

Key words: lysine, threonine, retention efficiency, amino acids, pigs


Prepared for the web 5-26-97