Effect of lactic acid bacteria and lactose on growth performance and intestinal microbial balance of artificially reared calves

The aim of the present study was to evaluate the effect of lactose and a microbial inoculum integrated by three lactic acid bacteria (LAB) strains of bovine origin to improve the growth performance and the intestinal microbial balance in young calves. The experimental group of calves was administered with an inoculum consisting of three microorganisms (Lactobacillus casei DSPV 318 T, Lactobacillus salivarius DSPV 315 T and Pediococcus acidilactici DSPV 006 T) suspended in a solution of NaCl 0.15 M, at a daily dose of 10(9) CFU/kg for 35 days, whereas the control group was administered only NaCl solution as placebo. A factorial design with repeated measures in complete blocks at random was used. Four blocks with six calves each were built and the six proposed treatments randomly distributed. The experiment was performed in 35 days. We found no differences in the growth performance parameters for the probiotic and lactose factors. The probiotic and lactose factors showed significant differences in the values of the Lactobacillus spp. counts in feces. The animals supplemented with the probiotic showed the highest LAB counts, which remained constant during the experiment. The animals which consumed the intermediate level of lactose showed the highest LAB counts. Although the probiotic treatment did not reduce the fecal count of coliforms, it generated differences (P < 0.05) in the Lactobacillus/coliforms ratio. The strategy achieved with lactose in this study allowed generating a controlled imbalance in the gastrointestinal tract of calves. This model may be useful to evaluate the beneficial effect of the microbial inoculum with a probiotic potential, especially when adequate sanitary and environmental conditions hinder viewing. (C) 2011 Elsevier B.V. All rights reserved.