Abstract: Nutrition factors have an important role in immunity of domestic birds. The fat is one of necessary nutrition elements for them. The fat is indispensable component ingredients and nutriment of poultry, which not only keeps poultry’s growing, breeding, and producing normally, but also has a great effect on poultry’s immune organ, tissue and regulate its immune response. So, a survey was made on the effect of fat on poultry’s immune function such as immune organ growth, body’s immunity, cell-mediated immunity, non-special immunity, and production of Cytokines. This could provide the theory basis for preparing rational diets of poultry and improving their ability against diseases in poultry’s production practice.

Key words: fat; domestic birds; immunity