Amino acid requirements of pigs. 1. Requirements for methionine + cystine, threonine and tryptophan of fast-growing boars and gilts, fed ad libitum.

Abstract

In 3 experiments each of 4 treatments, crossbred pigs about 35 kg were given basal diets with a low concentration of 1 amino acid and DL methionine 0, 0.41 or 0.82 and 1.23, L-threonine 0, 0.5, 1.0 and 1.5 and DL-tryptophan 0, 0.31, 0.62 and 0.93 g/kg. Apparent faecal digestibility of organic matter, protein and amino acids of 1 or 2 diets from each feeding experiment was estimated with 4 pigs each. Average daily gain of the optimally supplemented groups was 875 g and feed conversion ratio 2.84. For maximum growth performance of pigs between 35 and 105 kg, the requirement for total methionine + cystine, threonine and tryptophan, relative to total lysine supply, was about 60, 66 and 19%, respectively. On a faecal digestible basis, requirements were about 58, 63 and 19%, relative to faecal digestible lysine, respectively. (Abstract retrieved from CAB Abstracts by CABI’s permission)