Comparison of the effect of different levels of hot red pepper or synthetic pigment on performance, egg quality, immune response, and blood parameters in laying hens

This experiment compared the effect of different levels of hot red pepper (HRP) or synthetic pigment on performance, egg quality, immune response, and blood parameters in laying hens from 41 to 49 weeks of age. Two hundred laying hens of Nick-Chick strain were allocated to five treatments, five replicates, and eight hens for each replicate in a completely randomized design. The treatments were: 1. control (basal diet without any HRP or synthetic pigment), 2, 3 and 4. control + 1, 2 or 3% HRP, respectively, and 5. control + synthetic pigment. The results showed that treatments had no significant effect on performance and egg quality traits ( P  > 0.05), except for yolk colour and a* value (redness) that were significantly higher in the birds that were fed with HRP levels or synthetic pigment than control group ( P  < 0.001). The higher immunoglobulin T and G was observed by HRP levels in comparison to the control ( P  < 0.001). The inclusion of 3% HRP increased immunoglobulin M than other treatments ( P  < 0.05). Plasma glucose and cholesterol showed a reduction in birds fed with HRP levels ( P  < 0.001). However, plasma total protein and albumin were higher in the birds that were fed 2% and 3% HRP ( P  < 0.001). In conclusion, HRP could be recommended as a safe and efficient alternative pigment to diet of laying hens due to its favorable effects on yolk pigmentation, immunity, and blood parameters.