Influence of dietary probiotic inclusion on growth performance, nutrient utilization, ruminal fermentation activities and methane production in growing lambs.

The use of two probiotic products as a means of improving in vitro and ruminal dry matter digestibility, fermentation characteristics and growth performance of Barki lambs were evaluated. The probiotic products in powder (PP) or liquid (PL) forms were produced from Ruminococcus flavefaciens, through an anaerobic fermentation process. Barki lambs (n = 30; 24.5 ± 0.5 kg body weight) were used in a completely randomized block design and randomly assigned among three experimental groups and fed for 75 days. Lambs were fed an equal amount of concentrate feed mixture with either no probiotic product (control), or with 20 g of PP, or 10 ml of PL per animal/d, with rice straw ad libitum. Both PP and PL treatments resulted in an increase (p < 0.05) in nearly all of the digestibility coefficients, nitrogen utilization, cell wall constituents, total volatile fatty acids, rumen volume, microbial nitrogen synthesis, gas production and average daily gain compared to the control group. Ruminal ammonia nitrogen, acetic acid and in vitro methane concentrations and protozoa count decreased (p < 0.03) in the treatment groups. Overall, the probiotic in a powder or liquid form increased in vitro dry matter digestibility, improved lambs daily gain and nutrient digestibility.