Introduction

Feed additive is an ingredient or combination of ingredients added to the basic feed mix or parts thereof incorporated in an animal feed for the purpose of improving rate of gain, feed efficiency, or for preventing and controlling disease. It is used in microquantities.

A variety of feed additives are used in animal feeding. Some are approved to be used as implants or in an injectable form. Feed additives are broadly classified into the following types.
1. Nutrient feed additives, e.g. amino acids, minerals and vitamins.
2. Non-nutrient feed additives, e.g. antibiotics, hormones, immunomodulators, enzymes, probiotics, antioxidants, surfactants, sweetening agents, etc.