Turmeric bioactive compounds in poultry nutrition: current status and future prospects

Successful poultry producers aim to maximize their meat, egg, or offspring yields while also satisfying the quality expectations of consumers. Even when raised under controlled conditions, poultry are exposed to diverse stressors, such as the hatching process, transportation from hatcheries to farms, vaccination, presence of mycotoxins in feedstuffs, and transportation to slaughter houses, which can have unfavorable impacts on their immunity, productivity, reproductive performance, meat, egg yield, and quality. Curcumin (Cur) is a polyphenolic bioactive molecule found in turmeric, which is used as a natural feed additive in poultry production. The antioxidant characteristics of Cur are due to its chemical structure. Cur can improve the meat quality, such as the color and polyunsaturated fatty acid contents, as well as reducing the drip loss and malondialdehyde concentration in meat. Cur can enhance egg quality characteristics, such as the eggshell strength, yolk color, Haugh unit score, yolk contents of monounsaturated fatty acids and polyunsaturated fatty acids, and yolk Cur concentration. Serotonin secretion is stimulated by Cur, and it prevents heat shock protein 70 and corticosterone production in stressed poultry. Thus, Cur can boost immunity and the effectiveness of vaccinations, and decrease the likelihood of diseases. Therefore, Cur could be applied as an important feed additive and a suitable choice for poultry producers, but it is necessary to know how to select the most appropriate form and level of supplementation before adding Cur to the diets of poultry. The present review clearly describes the impacts of different Cur forms and concentrations of the active substance on poultry production, as well as considering its mode(s) of action. Clarifying the mode(s) of action for Cur could help to identify new uses for Cur that will require examination.