Evaluating the impact of excess dietary tryptophan on laying performance and immune function of laying hens reared under hot and humid summer conditions

Abstract

1. Tryptophan (Trp), besides its role as an essential amino acid in protein synthesis, may also have other important effects on laying hens under summer conditions. 2. Babcock Brown layers (n = 768), 40 weeks of age, were allocated to 4 treatment groups, each of which included 6 replicates of 32 hens. Each group received the same basal diet, formulated with maize and soybean meal, for 8 weeks. Hens were fed on the basal diet with 0·0, 0·2, 0·4, and 0·8 g/kg L-Trp to achieve dietary concentrations of 1·7, 1·9 g/kg, 2·1 g/kg or 2·5 g/kg of Trp, respectively. 3. Supplementing L-Trp had no affect on laying performance. Adding 0·2 or 0·4 g/kg L-Trp improved egg shell strength compared with those fed on the control diet. Serum albumin concentration increased at 0·4 g/kg compared with those receiving 0·0 or 0·8 g/kg Trp. The addition of Trp at 0·4 g/kg increased serum IgM concentration quadratically. Serum superoxide dismutase (T-SOD) increased linearly and quadratically at 0·4 g/kg. 4. In conclusion, we suggest that 0·2 to 0·4 g/kg Trp may have beneficial effects on laying hens under conditions of high temperature and humidity.

Effect of dietary tryptophan supplementation on growth performance, immune response and anti‐oxidant status of broiler chickens from 7 to 21 days

“…The effect of Trp on immune function may be directed via melatonin receptors located on immune tissues. Similar results were illustrated by Dong et al () the immune response by Trp supplementation in Babcock Brown layers during summer climate. The study concluded that Trp supplementation was effective in the regulation of IgM, quadratically.…”

Effect of Dietary Tryptophan Supplementation on Blood Biochemical Parameters in Layer Chicken

“…During the later period (39 and 43 weeks), the plasma globulin level was lowest in T2 (low protein and 0.153 % tryptophan) than all other groups and it was similar in T1, T3, T4, T5, T6 and T7 groups (Table 6). Similar effects of increased plasma total protein and albumin by tryptophan supplementation were reported by Emadi et al, (2010) in broiler chicken at 0.07, 0.13, 0.20, g/kg, in 40 weeks old Babcock Brown layers at 0.4 g/kg of diet (Dong et al, 2012), at 0.22 and 0.30 % tryptophan in Goslings (Pan et al, 2013).…”

Proteome changes in the small intestinal mucosa of broilers (Gallus gallus) induced by high concentrations of atmospheric ammonia

“…T-SOD represents the oxidation resistance in the animal [33]. In TRET broilers, activity of serum CK was significantly elevated ( P  < 0.05) compared with the control group indicating extensive organ injury (Table 2).…”