Dietary supplementation with tryptophan improves the production and growth performance of breeding pigeons under 2 + 4 model

1. This study evaluated the effectiveness of different concentrations of tryptophan in the diet on reproductive performance, body weight loss and plasma biochemical indices of breeding pigeons. It included growth performance, carcass characteristics, meat quality and plasma biochemical indices of squabs.2. In this study, 360 pairs of Mimas breeding pigeons were randomly divided into six experimental groups based on the dietary tryptophan content. The pigeons with four squabs were fed diets containing 0.10%, 0.14%, 0.18%, 0.22%, 0.26% and 0.30% tryptophan (Trp) for 50 d.3. The results showed that dietary Trp supplementation increased egg-laying rate of breeding pigeons curvilinearly, with the highest rate occurring in the 0.18-0.30% group. The FCR of squabs showed a linear and quadratic trend and the 0.26% Trp group was the lowest. The increase in semi-eviscerated and eviscerated weight of squabs showed a curvilinear trend and the best slaughter performance of squabs was observed in the 0.26% Trp group.4. The 0.22-0.30% Trp supplementation resulted in an improvement in meat colour. Plasma biochemical index results showed that Trp supplementation significantly improved metabolic function in squabs and the best indices were observed in the 0.22-0.30% Trp group.5. A regression model was established using reproductive and growth performance indexes. Laying rate of breeding pigeons was highest during incubation and lactation periods at 0.210-0.272% Trp supplementation. At this rate, the level of oxidative stress in squabs was reduced, which improved growth.