Nutritional evaluation of transgenic high-methionine lupins (Lupinus angustifolius L) with broiler chickens

The nutritive value of transgenic lupin seeds (Lupinus angustifolius L) with higher contents of methionine was evaluated with broiler chickens. The crude protein, methionine and cysteine contents in the conventional and transgenic lupins were 322 and 324, 2.0 and 4.5, and 3.6 and 3.7 g kg(-1) dry matter respectively. In the feeding trial, conventional and transgenic lupins with hulls were incorporated into a maize-soyabean meal diet at 250 g kg(-1) level and the diets were fed to female broiler chicks from 6 to 20 days of age. All diets were balanced to contain similar levels of apparent metabolisable energy (AME), lysine and sulphur-containing amino acids. The levels of free methionine added to the maize-soyabean meal control, conventional lupin and transgenic lupin diets were 2.2, 2.8 and 2.2 g kg(-1) respectively. Weight gain and feed intake were not influenced by dietary treatments, but feed/gain tended to be higher (P = 0.09) in birds fed lupin diets compared with those fed the control diet. Feed/gain of birds fed the conventional lupin diet was higher (1.82 vs 1.74) than for those fed the transgenic lupin diet. These results showed that the supplemental methionine required in poultry diets containing 250 g kg(-1) lupin can be lowered by 0.6 g kg(-1) diet by the use of high-methionine lupins. The AME values of conventional and transgenic lupins were determined to be 9.42 and 10.18MJ kg(-1) dry matter respectively. The higher AME value in transgenic lupins may be related to the lower content of soluble non-starch polysaccharides (45.6 vs 60.7 g kg(-1) air-dry basis). Data on ileal amino acid digestibility indicate that the amino acids in transgenic lupins are as digestible as those in conventional lupins. (C) 2002 Society of Chemical Industry.