Animal nutrition mainly focuses on the dietary habits and needs of animals especially the domesticated animals raised for agriculture and food production. Improved animal nutrition helps in increasing the quality of livestock production leading to producing higher quality meat and eggs. An optimal nutritional program ensures adequate intake of amino acids, carbohydrates, fatty acids, minerals, and vitamins by animals through a planned program that corrects all the deficiencies in animals. Essential nutrient is a substance that is required to maintain health and prevent diseases in animals. For many nutrients there is range of acceptable intakes which is defined by the minimum amount required to prevent adverse effects resulting from too little intake (deficiency) or the maximum intake above which, also results in adverse effects (i.e. toxicity). Fundamental and applied research is carried out to meet the goals of optimized animal nutrition. Diet with certain important nutrients (e.g., arginine, glutamine, zinc, and conjugated linoleic acid) regulates gene expression and key metabolic pathways improving fertility, pregnancy outcome, immune function, neonatal survival and growth, feed efficiency, and meat quality. Proper balance of protein, energy, vitamins and all nutritionally important minerals in diets is required for improvised productivity and economical.