Growth performance, nutrients digestibility, and blood metabolites of lambs fed diets supplemented with probiotics during pre- and post-weaning period

Objective: Two experiments were conducted to evaluate the effects on growth performance, digestibility, and blood metabolites of lambs during pre- and post-weaning period of inclusion of a commercial probiotic (PRO) containing a mixture of two strains of Pediococcus, Pediococcus acidilactici ($1{\times}10^6$ colony-forming unit [cfu]/g) and Pediococcus pentosaceus ($1.3{\times}10^6cfu/g$), with dextrose as the carrier compound compared to a diet based on concentrate mixture and wheat straw. Methods: In exp. 1, 24 male lambs of about $15{\pm}2.6$ d age and initial body weight (BW) of $5.52{\pm}0.6kg$ were randomly allocated into three groups. One group received control diet without additives, and remainders received control diet supplemented with 0.5 or 1 g PRO/lamb/d. Daily feed intake and biweekly BW were recorded. In exp. 2, five lambs, (initial $BW=29.72{\pm}1.15kg$, $age=6.54{\pm}0.32mo$) were used as experimental animals in a digestion trial. They were fed the same diets as in Exp. 1. Results: The supplementation of PRO did not result in any significant differences in milk intake, average daily gain (ADG), or total gain between treatments during the pre-weaning period. Total dry matter intake tended to be greater (p = 0.07) with addition of PRO in the post-weaning diets. During post-weaning phase, the final BW, ADG, total gain, and feed conversion ratio of the lambs receiving PRO treatments tended to be greater ($p{\leq}0.10$) than the control group. Addition of PRO in post-weaning diet decreased ($p{\leq}0.01$) blood urea and cholesterol concentrations. With the exception of ether extract digestibility, all nutrients digestibility were improved with inclusion PRO in the post-weaning diets. Conclusion: Lambs that received PRO in post-weaning diet appeared to show a better performance than lambs in pre-weaning period. Addition of the probiotic in the post-weaning diet trended towards improved dry matter intake, growth performance, feed conversion ratio, and nutrients digestibility.