Maize-meat meal and maize-meat and bone meal diets were supplemented with dl-tryptophan, l-lysine or a mineral-vitamin-antibiotic (MVA) premix and fed to pigs during the 1s to 45 kg growth phase. Diets were offered at an estimated 145 kcal of digestible energy and 7g crude protein per kg liveweight per day. The basal maize-meat meal diet produced poor growth and feed conversion and the combined addition of all three supplements increased growth by 46 per cent, feed conversion by 21 per cent, and lean in the ham by 4.7 per cent. This effect resulted from responses to dl-tryptophan, the MVA and an interaction between dl-tryptophan and l-lysine, with l-lysine depressing gain and feed conversion in the absence of dl- tryptophan and increasing gain, feed conversion, and lean in the ham in its presence. The basal maize-meat and bone meal diet also produced poor growth and feed conversion, and the combined addition of all three supplements resulted in an 82 per cent increase in growth, a 35 per cent increase in feed conversion, and a 3.3 per cent increase in lean in the ham. Both dl-tryptophan and MYA separately increased growth and feed conversion and combined they had an even greater effect. The l-lysine increased feed conversion and lean in the ham. The l-lysine also increased growth rates on the dl-tryptophan supplemented diets, but this effect was not significant (P>0.05).
Protein and amino acid quality of meat and bone meal