Tryptophan and energetic availability of some feedstuffs determined with young and adult chicken

Abstract

Four biological experiments were carried out in order to determine de effect of the age of the birds on the metabolizable energy (ME), N - corrected metabolizable energy (MEn) and tryptophan aparent metabolizability (TAM) values of nine feedstuffs. A 10 x 4 factorial arrangement of treatments (9 feedstuffs, a reference diet and four types of birds) was used. The experiment was a complete randomized design, with ten birds/replicate and three replicates per treatment when 21 and 42 days old birds were used. Leghorn roosters were housed in individual wire cages with six replicates done bird in each experimental unit. Leghorn hens were housed in individual wire cages, with three replicates and two birds in each experimental unit. The feedstuffs MEe and TAM values for roosters, laying hen and 21 and 42 days old broiler, in Kcal/g, in percentage of dry matter, were, respectively: solvent extracted rice bran 2.26 and 61.45, 2.65 and 63.82, 2.20 and 57.47, and 2.43 and 61.13; incubatory waste meal 1.74 and 62.40, 1.63 and 70.28, 1.50 and 55.12 and 1.54 and 6284, gluten meal 4.10 and 75.62, 4.23 and 79.81, 4.16 and 78.83 and 4.24 and 80.95; fish meal 2.40 and 70.14, 2.20 and 65.62, 2.10 and 51.32 and 2.24 and 65.19 and soybean meal 2.59 and 91.14, 2.85 and 93.68, 2.74 and 90.94 and 2.80 and 94.89; and the feedstuffs MEc values were: algaroba meal, 2.04, 2.13, 2.20 and 2.07; cassava meal I, 2.34, 2.55, 2.56 and 2.36; cassava meal II, 2.34, 2.49, 2.43 and 2.42 and for ground com 3.63, 3.66, 3.69 and 3.72. The energetic values and the proximal composition analysis showed difference compared with those found in the foreign literature. However, similarity was observed (P>0.05) between feedstuffs ME and MEc values, among the several categories of birds.