When chicory extract is added to a culture of Lactobacillus acidophilus, bacterial growth and metabolic activity are enhanced

Chicory root extract is rich in inulin. Inulin is a dietary fiber that naturally exists in many plants, has a high content of fructo-oligosaccharides (FOS) and acts as a natural prebiotic.

Many studies show that prebiotics can significantly modulate the digestive microbiota by increasing the number of beneficial species such as Lactobacillus sp. and Bifidobacteria. Prebiotics can also reduce undesired intestinal colonization by pathogenic bacteria acting as “decoy receptors”: prebiotics mimic the attachment sites used by pathogenic microorganisms to adhere on the intestinal mucosa, preventing the pathogens from colonizing the intestinal walls.

Complex dietary prebiotics, such as the fructo-oligosaccharides (FOS) contained in chicory root extract, can reduce accessibility of Salmonella sp. to digestive colonization in poultry as well as are able to increase the concentration of Bifidobacterium sp. in chicken cecum.

Additional beneficial effects of prebiotics include enhancement of mineral absorption, reduction of lipid levels in serum and reduction of the production of putrefactive substances.

Recently, we made an experimental test in our lab to prove the beneficial impact of chicory extract on the growth of Lactobacillus acidophilus.

Experimental place and time

Made in PlusVet Animal Health  laboratory, July 2017.

Target 

Verify the effect of chicory extract on the growth of Lactobacillus acidophilus.

Hypothesis to prove

Lactobacillus acidophilus uses carbohydrates as “building blocks”to grow, multiply and produce acid. When we incubate a selected Lactobacillus acidophilus strain in broth and anaerobic conditions, as a result of the acid production, the pH of the broth will decline. Therefore, a low pH is linked to enhanced growth and metabolic activity.

In this test, we assess the growth of Lactobacillus acidophilus using the final pH in the culture broth as evidence of growth and acid production. Also, we added bromocresol green dye to the medium in order to visualize the change of pH, as its color changes from green to yellow when the medium is acidified.

Materials

Strains: Lactobacillus acidophilus strains isolated from swine intestine, purchased from China Center of Industrial Culture Collection (CICC). A solution is preparated containing 1*10⁴cfu /mL.

Material: Chicory extract, provided by PlusVet Animal Health.

Reagent: 3 g/L Bromocresol green indicator.

Groups – Microbiological media

1. Blank Control group —MRS broth-Basic (10 ml/tube)

Components（L^-1): Peptone, 10.0g; Beef extract powder, 10.0g; Yeast extract,5 .0g; K₂HPO₄, 2.0g; Sodium acetate, 5.0g; M(NH₄)₃C₆H₅O₇·2H₂O, 2.0g，MgSO₄·7H2O, 0.1g，MnSO₄·H₂O, 0.05g and Tween 80, 1.0g，pH6.5±0.2（25℃）.

2.  Positive control group —MRS broth with glucose (10 ml/tube)

8% glucose+MRS broth-Basic.

Lactobacillus acidophilus can also use glucose as substrate for growth and acid production, and content of glucose in commercial MRS broth is 8%, so we choose this composition as positive control.

3. Test groups —MRS broth with chicory extract (10 ml/tube)

1% chicory +MRS broth-Basic

2% chicory +MRS broth-Basic.

In all media. for every of 100ml broth, we added 0.2ml bromocresol green indicator.

All media were sterilized at 121℃ for 15 min.

Methods

In aseptic conditions, in each tube of all the groups, we added 1ml of the Lactobacillus acidophilus suspension.

The tubes were anaerobically incubated for 48 h at 37ºC.

Results