Effect of threonine supplementation on Japanese quail fed various levels of protein and sulfur amino acids : 1. growing period

الملخص EN

This study was conducted using 420 unsexed day-old Japanese quail chicks which, equally divided into 7 groups of 3 replicates each, to explore the extent to which dietary crude protein (CP) level can be reduced in corn-soybean meal (C-SBM) starter-grower diets through sulfur amino acids (SAA) and Threonine (Thr) supplementation while maintaining adequate performance.

One positive control diet (A) was formulated to cover or exceed NRC (1994) recommendations of CP, SAA and Thr.

Two negative control diets (B and C) were formulated to contain lower CP (22 and 20% CP, respectively) than NRC (1994) recommended level but SAA and Thr were held at a constant ratio to CP for obtaining the same ratio in the two diets.

Two amino acid-supplemented diets (B1 and C1) were formulated to be similar in composition to diets B and C, respectively but still supplying the same SAA and Thr as in diet (A).

Two other amino acid-supplemented diets (B2 and C2) were formulated in a similar manner as in diets B1 and C1, respectively but supplemented with additional Thr at levels of 0.2 and 0.4%, respectively to ensure that it contained higher Thr levels than the NRC (1994) recommended level.

Live growth performance, carcass characteristics, some blood serum parameters and economical efficiency were determined.

From the nutritional and economical point of view, it could be concluded that the performance of Japanese quail fed low-protein diet (22% CP) supplemented with SAA as NRC (1994) recommendations plus additional Thr at 0.2 over NRC (1994) recommendations was similar to that achieved with the high-protein diet (24% CP) and gave economical efficiency value near to that achieved with the high-protein diet (24% CP).