Modes of Action of Saccharomyces cerevisiae as a Probiotic in Glucose or Omega-3 Diet Supplements in Monogastric Species in vitro against Escherichia coli k-12
Introduction
I. Purpose:
The purpose of this experiment is to determine the modes of action of the probiotic S. cerevisiae in monogastric species in vitro as those modes are compared to differing dietary practices (high in glucose or high in fats). It has been proposed that S. cerevisiae is an antagonist against pathogenic micro-organisms, represented in this research by E. coli k-12, in monogastric species.
II. Significance:
Probiotics, as defined by the World Health Organization, are "live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host." The improvement of health and productivity from energy consumption in ruminant species (cattle or other animals with a four chambered stomach) and monogastric species (humans or simple stomached animals) is of peak interest and probiotic supplements are frequently turned to in medicine and agriculture. Diet supplementation by S. cerevisiae (more commonly known as baker’s yeast) in monogastrics has shown to have anti-adhesive effects against pathogenic micro-organisms; the pathogens, like E. coli, more readily adhere to the cell walls of the yeasts rather than the lining of the stomach or intestine. Thus, understanding this probiotic mechanism is vital to understanding ways in which we may protect against bacterial infections, to a certain extent, through consumption of a yeast supplement. Yeast supplementation has shown to be more effective in certain diets such as those high in high sugars and starch content. Knowledge of how these diet choices affect a probiotic organism may better improve the health of many monogastric species.
III. Hypotheses:
H1 – E. coli k-12 colonies cultured with S. cerevisiae will decrease in growth as indicated by a lower E. coli colony count for higher levels of S. cerevisiae.
H10 - E. coli k-12 colonies cultured with S. cerevisiae will show no difference in growth for higher levels of S. cerevisiae.
H2 – E. coli k-12 cultured with S. cerevisiae will have a higher rate of agglutination (adhesion) to yeast as indicated by a higher count of E. coli colonies within 1 mm of S. cerevisiae.
H20 – E. coli k-12 cultured with S. cerevisiae will have no difference in rate of agglutination (adhesion) to yeast.
H3 –S. cerevisiae cultured on glucose enriched media will have higher colony counts of S. cerevisiae.
H30 –S. cerevisiae cultured on glucose enriched media will have no difference in colony counts of S. cerevisiae.
H4 - S. cerevisiae cultured on glucose enriched media will have more probiotic effect against E. coli k-12 indicated by a higher Agglutination Ratio of agglutinated E. coli colonies to yeast colonies.
H40 - S. cerevisiae cultured on glucose enriched media will have no difference in probiotic effect against E. coli k-12.
IV. Variables:
IV: Concentrations of Glucose and Omega-3 additives in agar (4% Glucose/4% Omega-3, 4%Glucose/0%Omega-3, 0%Glucose/4%Omega-3, 0%Glucose/0%Omega-3).
IV: Concentrations of S. cerevisiae plated with E. coli k-12 as determined by serial dilution to produce a high and low (and no yeast plated as a control and another control with yeast but no bacteria) spectrum of treatment.
DV: Colony counts of E. coli k-12 and S. cerevisiae at all stages of experimentation.
DV: Colony counts of S. cerevisiae at all stages of experimentation, to establish a normal bell curve of growth.
DV: Size of S. cerevisiae colonies in all stages of experimentation in mm2.
DV: Colony counts of E. coli k-12 adhered (within 1 mm of) and not adhered to S. cerevisiae colonies.
