Amino acid requirements of South African Mutton Merino lambs 2. Essential aminoacid composition of the whole empty body

The essential amino acid (EAA) composition of the whole empty body of South African Mutton Merino ram lambs fed a standard diet was investigated. The standard diet consisted (%) of 30 lucerne, 8 wheat straw, 56.25 maize meal, 3.5 molasses meal, 1 urea, 0.5 salt and 0.75 ammonium chloride. Twenty lam bs were randomly allocated to four pre-assigned average target slaughter we ights (30, 35, 40 and 45 kg live weight): The EAA composition of the carcas s, blood, head and feet, skin 8 wool, liver, lungs, kidneys, heart, spleen, testis, digesta-free gastrointestinal tract (GIT) and whole empty body was determined. The composition of the whole empty body remained similar regar dless of slaughter weight. The concentration of the following EAAs increase d significantly (p < 0.05) with increasing live weight (30, 35, 40 and 45 k g): head & feet valine (3.87(a), 5.56(ab), 5.68(ab), 6.70(b)), spleen pheny lalanine (4.96(a), 5.00(a), 5.07(ab), 5.56(b)) and valine (5.31(a), 5.50(ab ), 5.69(ab), 6.03(b)) as well as GIT phenylalanine (5.00(a), 6.50(a), 11.10 (a), 18.78(b)). The amino acid composition of the carcass, skin and wool, a nd GIT plays a predominant role in regression equations used to predict the whole empty body EAA composition. The whole empty body EAA composition (g AA/100 g crude protein) was as follows: 7.72 arginine; 4.54 histidine; 3.06 isoleucine; 8.53 leucine; 6.46 lysine; 3.56 methionine; 5.22 phenylalanine ; 4.65 threonine and 5.18 valine. This composition can serve as an example of the ideal EAA requirements for whole empty body growth between 30 and 45 kg live weight of South African Mutton Merino ram lambs.