Quantification of the absolute abundance of the jejunal mucosa-associated microbiota of pigs using spike-in control

The objective was to quantify the absolute abundance of the jejunal mucosa-associated microbiota in pigs and develop a standardized spike-in control protocol. The spike-in control, containing bacteria that are Gram-negative (Imtechella halotolerans) and Gram-positive (Allobacillus halotolerans), was diluted 100 times and 10 μL (100,000 bacterial cells of each species) was added to 100 mg of porcine jejunal mucosa samples. The relative abundance of the jejunal mucosa-associated microbiota differed between the diet groups, whereas no difference was observed in their absolute abundance. In conclusion, the spike-in control containing 100,000 cells of Imtechella halotolerans and Allobacillus halotolerans can be used to quantify the absolute abundance of microbiota in 100 mg of pig jejunal mucosa.