Amino acid requirements of growing pigs 8. The response of pigs from 50 to 90 kg live weight to dietary ideal protein

Abstract
The response to dietary lysine when provided as part of an ideal protein was examined in pigs over the range of live weight from 50 to 90 kg. Ninety-six pigs, 32 trios of littermate boars, castrated males and gilts were allocated to eight diets with lysine concentrations of 5·6, 6·2, 7·3, 8·3, 9·3, 10·3, 11·4 and 12·4 g/kg diet and corresponding concentrations of crude protein (CP) from 90 to 186 g/kg diet (all having a digestible energy of 13·38 MJ/kg). Pigs were given food on a restricted scale once daily. With increasing lysine concentration, there was a linear response (followed by a plateau) for growth and carcass characteristics up to dietary lysine concentrations of 91, 7·2 and 8·4 g/kg diet and CP concentrations of 142, 116 and 132 g/kg diet with daily lysine intakes of 22·9, 18·6 and 21·2 g and CP intakes of 357, 290 and 331 g for boars, castrated males and gilts respectively.