Compositions and methods for enhancing immune system of felines

A method to enhance the immune response of a feline to an antigen, the method comprising:

• administering to the feline in need thereof and to the mother of the feline while the feline is in utero, a pet food composition comprising:
• about 200 to about 1200 IU/kg vitamin E;
• about 50 to about 500 ppm vitamin C;
• about 0.1% to about 0.7% EPA;
• about 2400 ppm to about 7500 ppm choline;
• and
• about 0.1% to about 0.5% DHA,
• wherein the feline is a kitten born from a queen fed the composition prior to pregnancy and during the pregnancy;
• and
• wherein the kitten is also fed the composition prior to weaning and post weaning.