Evaluation of probiotic bacteria for their effects on the growth performance and intestinal microbiota of newly-weaned pigs fed fermented high-moisture maize

The effects of feeding high-moisture maize fermented with Lactobacillus acidophilus or Pediococcus acidilactici on the growth performance and intestinal microflora of newly weaned pigs were investigated. A total of 270 newly weaned pigs (equal numbers of castrated males and females) were allocated to 3 dietary treatments (5 pens per treatment and 18 pigs per pen) in a randomized complete block design on the basis of body weight (BW) and litter. The dietary treatments included a basal diet supplemented with: 1) naturally fermented high-moisture maize without any microbial inoculants (Control); 2) high-moisture maize fermented with L. acidophilus (LA); and 3) high-moisture maize fermented with P. acidilactici (PA). Pigs were fed diets in liquid form for a 5-wk period. Quantitative polymerase chain reaction (QPCR) analysis with PCR primers specific to L. acidophilus or P. acidilactici indicated a well-developed bacterial population of each inoculated bacterium in the fermented high-moisture maize. Lactic acid was the major short-chain fatty acid (SCFA) produced from the fermentation. Among the 3 treatments and on most sampling days, LA-fermented maize had the numerically highest concentration of lactic acid. Dietary treatments over the 5-wk period did not impact pig growth performance. However, during last 3 wks of the trial, pigs on the LA treatment had higher BW gains than pigs on PA. Pigs fed LA-fermented high-moisture maize showed fewer coliform bacteria in fecal samples when compared to pigs fed PA-fermented high-moisture maize (P < 0.05). The PCR and denaturing gradient gel electrophoresis (DGGE) analysis on the relatedness of bacterial profiles of colonic microbiota revealed 3 bacterial clusters and the microbiota from PA-treated pigs formed 1 cluster. In addition, feeding LA- or PA-fermented maize reduced the diversity and richness of bacterial microbiota in the colon (P < 0.05). Both L. acidophilus and P. acidilactici colonized poorly in the intestine of pigs regardless of the dietary treatments. These results indicate that feeding the probiotic-fermented, high-moisture maize can modulate the intestinal microbiota, and LA has the potential to impact pig growth performance.