[The effect of the raw protein supply on the lysine requirements of young pigs of 12-40 kg. 1. Report. Feeding studies with wheat-peanut extraction residue rations].

10 feedings trials were carried out with a total of more than 500 pigs weighing 12 to 40 kgs. To investigate the lysine needs of growing pigs, the animals were fed rations of wheat + extracted ground nut meal. Different food mixtures were tested containing 5 levels of crude protein (19%, 17%, 15%, 13% and 11% of the dry feed. Within each crude protein level 6 graded lysine supplements were added to the ration. The trial showed that the lysine requirements of the weaned pigs were in a decisive measure determined by the percentage proportion of crude protein contained in the ration. The crude protein portion may be calculated (for the liveweight range tested) by using the following regression equation: y=0.28+0.075x (y=lysine requirements expressed as % of the air-dried ration; x=percentage proportion of crude protein in the ration). Rations containing only protein sources of vegetable origin, with a minimum protein content of 15%, produced the same daily weight gains (520 g) as a standard diet, if the lysine demands were met through the supplementation of synthetic lysine.