There are several enzymes that are associated with animal nutrition. They break down the complex form of food into simpler forms. The process of conversion of raw food materials into diffusible forms by hydrolytic enzymes is called digestion. In mammals digestion of food occurs at various sites such as digestion in the buccal cavity, and intestine. Substrate specific enzymes are secreted to break the complex forms into simpler ones. Some bacteria living in animal’s gut synthesise vitamin B12 and vitamin K. These vitamins are absorbed in the body and used in many functions.
One of the important nutrients required for body function is the vitamin. Vitamins are needed in small quantity. The animal body does not synthesize vitamins. Human depends on plants and other animals. The human body requires two types of vitamins for various functions such as water-soluble vitamins (vitamins B1, B2, B6, B12, C, folic acid, niacin, biotin, panthonic acid) and fat-soluble vitamins (example- vitamins A, D, E and K). Therefore, a balanced diet must be taken by humans for sufficient energy, proper growth, development and body function.