Abstract

Probiotics have been recently defined by the Food and Agriculture Organization/ World Health Organization (FAO/WHO) as live microorganisms which when administered in adequate amounts confer a health benefit on the host. A good probiotic should be non-pathogenic, non-toxic and capable of exerting beneficial effect on the host animal. It should be present as viable cells and capable of surviving and metabolizing in the gut environment. It should also be stable and capable of remaining viable for periods under storage and field conditions. Probiotics have been shown to promote growth, improve efficiency of feed utilization, protect host from intestinal infection and stimulate immune responses in farm animals. In laying chicken, probiotics increased hen-gay egg production. Weight gain performance was significantly increased in broilers and turkeys. In ruminants, probiotics also improved growth rate. Increased weight gain and higher efficiency of feed utilization were the results of  the trials in pigs. Mortalities especially due to diarrhoea were reduced in pigs. The beneficial effects of probiotics in animal production have been related to different modes of action. The improvements in productive performance of all animal species fed with probiotics were mostly due to the fact that probiotics promoted the metabolic processes of digestion and nutrient utilization.

Key words:  Probiotics, nutrient utilization, immune, animal production.