Effects of L-threonine and L-tryptophan supplementation on the body weight and internal organs weight of native chickens aged 14 weeks

Abstract

The aim of this study was to determine the effect of L-threonine and L-tryptophan supplementation on the body weight and internal organs weight of native chickens aged 14 weeks. The experiment used 112 six-week old native chickens. They were allocated to four treatments and four replicates. The four dietary treatments were: (1) T0 (control); (2) T1 (supplementation of 0.25% L-threonine and 0.07% L-tryptophan); (3) T2 (supplementation of 0.58% L-threonine and 0.14% L-tryptophan); and (4) T3 (supplementation of 0.85% L-threonine and 0.20% L-tryptophan). The result showed that the body weight of T0, T1, T2 and T3 were 1044.28, 1081.91, 1115.95 and 1151.34 g/bird, respectively. The liver, pancreas, and gizzard weights and the intestinal length were 2.56, 2.66, 2.81 and 2.91 g/bird; 3.90, 4.17, 4.43 and 4.46 g/bird; 26.00, 28.63, 30.26 and 31.28 g/bird; 124.80, 131.90, 137.88 and 139.73 cm/bird, respectively. The result indicated that the body weight, liver, gizzard, and intestinal length affected by level of L-threonine and L-tryptophan (P<0.01). It was concluded that supplementation with 0.85% L-threonine and 0.20% L-tryptophan to the diet of native chickens resulted in optimal body weight and internal organs weight at 14 weeks.