Enhancing immunity level by using phytogenic feed additives in animal diets (review)

Abstract

It is established that antibiotics are one of the most important medical discoveries of 20th century and will remain an utmost way of treating disease of animals as well as of human beings. We, the human beings, get meat, milk, egg, etc. from animals being very important and inevitable part of our daily nutrition. The irrational, consecutive and extensive use of antibiotics in food producing animals particularly for growth promotion has lead to antibiotic resistance, microbial resistance and possible the drug residual threat for human beings due to consumption of milk, meat, egg, etc. It was found out that during the normal physiology the animals undergo various types of stresses mainly including environmental, pathogenic, etc which suppress the immune system as well as the GIT of animals and due to this the animals become vulnerable to different diseases which leads to immunosuppression, poor health status, increased mortality and decreased production. Due to this ban on using synthetic antibiotics in animals as antibiotic growth promoters (AGP), an alternative approach is to use phytochemicals in animals’ feed for growth promotion, optimum production and enhancing or modulating the immunity level of animal. These phytogenic feed additives are important and have many properties i.e. anti-fungal, antibiotic, anti-inflammatory, antioxidant, antiviral, etc which, when supplemented with diet and fed to animals, ensure the protection and improvement of health condition, integrity of GIT and enhance the immunity level of animal. This review illustrates the importance of plant-based feed additives supplemented with other feedstuff and fed to animals particularly their role in immunomodulation to boost the immunity level on animal under stress conditions. Key words: feed additives, phytobiotics, alternative to antibiotics, animal feeding, immunity.