The development of a healthy microbiota in the young pig is determinant to avoid post-weaning disease and to reach an optimal growth performance. The weaning is a stressful period that may disturb the normal microbiota stabilization.

The objective of this experiment was to monitorise the microbial changes of caecal population that are associated to early-weaning using molecular methods.

 

Twelve pigs (20±2d), from six different littermates were selected from a commercial source. One animal from each litter was weaned onto a post-weaning diet (W) and the other one remained with the sow (S). After one week, the pigs were euthanized and caecal digesta samples were taken and preserved in ethanol until analysis. Microbial counts for total bacteria, enterobacteria and lactobacilli populations were determined by quantitative-PCR using 16s rRNA gene specific primers and SYBR Green(r) dye. Microbial profiles were assessed by terminal restriction fragment length polymorphism (t-RFLP) using fluorescently labeled 16S rRNA gene forward primer (FAM 0008) and restriction enzyme Hha. Dendograms of similarity were constructed using UPGMA method and Fingerprinting II software.

Weaning promoted a decrease in  lactobacilli population that resulted in a significant increase in enterobacteria: lactobacilli population that resulted in a significant increase in enterobacteria: lactobacilli ratio (0.27 vs. 1.67 log/log 16S rRNA gene copy number, P=0.005) (Figure 1).

 

Total bacteria and richness of microbial ecosystem (number of fragments obtained) were similar between both experimental groups (49.3 and 53.4 for S and W groups, P > 0.05) although the band patterns were clearly grouped in two different clusters by dendogram analysis (Figure 2). Some particular bands were present or absent in each of the groups. In silico restriction using Ribosomal Database Project II was used to infer potential ecological changes in the samples. Even though only assumptions can be made about, the suckling pigs showed a higher diversity in lactic acid bacteria species than the weaned group and showed peaks that were absent in weaned pigs compatible with C. coccoides and C. butyricum species (Figure 3).