Role of probiotics in nutrition and health of small ruminants.

Small ruminants represent an important economic source in small farm systems and agriculture. Feed is the main component of livestock farming, which has gained special attention to improve animal performance. Many studies have been done to improve feed utilisation through addition of feed additives. For a long period, antibiotics have been widely used as growth promoters in livestock diets. Due to their ban in many countries, search for alternative feed additives has been intensified. Probiotics are one of these alternatives recognised to be safe to the animals. Use of probiotics in small ruminant nutrition has been confirmed to improve animal health, productivity and immunity. Probiotics improved growth performance through enhancing of rumen microbial ecosystem, nutrient digestibility and feed conversion rate. Moreover, probiotics have been reported to stabilise rumen pH, increase volatile fatty acids production and to stimulate lactic acid utilising protozoa, resulting in a highly efficient rumen function. Furthermore, use of probiotics has been found to increase milk production and can reduce incidence of neonatal diarrhea and mortality. However, actual mechanisms through which probiotics exert these functions are not known. Since research on application of probiotics in small ruminants is scarce, the present review attempts to discuss the potential roles of this class of feed additives on productive performance and health status of these animals.