Protein and lysine levels in practical rations

Abstract

SUMMARYA co-ordinated trial has been carried out at twenty-one centres to obtain information on the following problems: does the addition of synthetic lysine to a ‘standard’ ration, widely recommended and used in this country, beneficially influence the performance of growing pigs, and is the effect influenced by whether the source of supplementary protein is white fish meal or soya bean meal ?In comparison with a ration providing levels of crude protein and lysine recommended in the A.R.C. ‘Nutrient Requirements of Pigs’, the ‘standard’ ration which contained less crude protein and total lysine, produced slightly lower performance, but about the same profit. The performance on the ‘standard’ ration could be improved by the addition of synthetic lysine, but such supplementation would not be profitable unless the cost of synthetic lysine was less than 21s./kg.The response to added synthetic lysine was similar on rations in which the source of supplementary protein was either white fish meal or soya bean meal.