An experiment was conducted to study the effects of three levels (5, 10 and 15%) of L-Glutamic Acid (L-Glu) and four levels (0, 5000, 10,000 and 15,000 IU/kg of diet) of vitamin D3 (VD) on bone parameters of 14 days male broilers, Hubbard. They were fed purified amino acid diets and reared in electrically heated batteries. The experimental design was a factorial 3 x 4 with four replicates with seven chicks each. The length of bones increased up to an estimated level of 9.51% of L-Glu and 15,000 IU of VD for femur bone (37.61 mm) and 9.99% of L-Glu and 15,000 IU of VD for tibiotarsus (50.36 mm). The femur (3.62 mm) and tibiotarsus (3.17 mm) diameters increased up, respectively, an estimated level of 10.49% of L-Glu and 15,000 IU of VD and 11.04% of L-Glu and 15,000 IU of VD. The maximum breaking strength for femur (52.47 kgf/mm) and tibiotarsus (43.35 kgf/mm) was obtained with 8,978 IU and 12,591 IU, respectively. No significant effects were observed on femur collagenous proteins contents (23.44 mg/100 g). On the other side, the smallest contents of non-collagenous proteins (NCP) were observed with 9.32% and 9.73% of L-Glu on femur (2.5 mg/100 g) and tibiotarsus (2.15 mg/100 g), respectively. The highest contents of total protein in femur and tibiotarsus were, respectively, 30.04 mg/100 g and 30.03 mg/100 g. Chicks fed 10% L-Glu and 15,000 IU VD had good development of bones, better performance, lower NCP contents and a lower incidence of leg problems.
L-Glutamic acid; vitamin D3; broiler chicks; bone development; bone proteins; leg problems
