121 Inclusion of probiotics in the maternal diet modulates reproductive microbial composition

Prenatal microbial colonization is thought to play a key role in the development of the immune system. The present study was a proof of concept to determine whether nutritional supplementation with probiotics from Bacillus spp (Bovacillus TM, Chr. Hansen A/S) in ruminants modulate pH and microbial composition in the vagina. Seventeen prepubertal (determined by absence of corpus luteum (CL) on every sampling by ultrasonography) Aberdeen Angus females of 10 ± 1 months old at the beginning of the experiment with 316 ± 39 kg average body weight were used. Females were randomly assigned to one of two treatment groups: control (N = 8) and probiotic (N = 9). Each group was supplemented 200 g of ground corn with or without probiotic (2 g/animal per day) fed as top dressing daily on the morning feeding. Vaginal swabs and collection of vaginal mucus were done at Day 0, 30, and 60 from beginning of probiotic supplementation. Vaginal mucus samples were used to evaluate pH while swabs were placed in Stuart transport medium and seeded in McConkey and de Man, Rogosa, and Sharpe agars, then incubated at 37°C for 24 to 48 h. Data were analysed with Infostat^® software using a generalized linear model. Count of colony-forming units (CFU) for both Enterobacteriaceae family, Lactobacillus spp gender, as well as pH were analysed including fixed effects of treatment, time, and their interaction, and a random effect of heifer. The pH response was adjusted for normality, whereas CFU models were adjusted to a Poisson distribution. pH was affected (P < 0.05) by time but not by treatment or treatment by time interaction (P > 0.05). Both groups of microorganisms were significantly affected (P < 0.05) by the interaction of treatment and time. The CFU increased overall in both treatment groups over time, with the main difference between treatment groups laying on the dynamic of the increase. Control group had more CFU for both microorganisms at Days 30 and 60 than the supplemented group of heifers. The control group had a parabolic curve peaking on Day 30 (110 and 196 for Enterobacteria and Lactobacillus spp, respectively); while probiotic group had a constant increase for Enterobacteria whose maximum number was 37.7 on Day 60, and a parabolic curve for Lactobacillus spp with the maximum number of CFU on Day 30 (130.8). Results suggest that oral probiotic supplementation may affect dynamics of microbial composition in the vagina, increasing beneficial bacteria like Lactobacillus spp. and a minor reduction in Enterobacteria. However, further research is warranted to test the hypothesis that those microorganisms are colonizing the reproductive tract.