Influence of probiotic and yeast culture supplementation on selected biochemical and immunological parameters of growing lambs.

This study was carried out to evaluate the potential effects of 90 days-long dietary supple- mentation of probiotic and yeast culture on immunity condition of lambs. Fifteen Rahmani growing male lambs (about 5 months old and 23.21±2.75 kg body weight) were randomly allo- cated to three equal groups consisting of 5 animals each. The animals in the first group, served as a control (group C), were fed a basal diet without any supplementation. The lambs in the second and third group were fed the basal diet supplemented with probiotic (group Y) or yeast culture (group YC), respectively. The probiotic consisted of live yeast (Saccharomyces cerevisae) alone, while the yeast culture was composed of Saccharomyces cerevisiae and the media on which it was grown. In group Y and YC, each lamb was supplemented daily with 0.5 g and 7.0 g of live yeast and yeast culture, respectively. Blood samples were collected before feeding the supplements and then every 15 days until the day 90th. Total and differential leucocytic counts, total protein, albumin, IgA, IgG and IgM levels were measured in blood. There were insignificant (p>0.05) variations in the levels of total and differential leucocytic counts and total protein among the groups throughout the experiment. However, significant differences (p⟨0.05) were found in globulin, IgA, IgG and IgM in both (Y) and (YC) groups, but the effect of yeast culture seems to be better than that of the probiotic. In conclusions, the obtained results indicate that the tested probiotic and yeast culture improve the immunological status of lambs.

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.