Question

4a. You want to test the hypothesis that the microbiome of a milk-fed infant is different from that of a formula-fed infant. Describe how you would test this hypothesis.

4b. Assuming that you do see a difference in your experiment, how would you then test whether these distinct microbiomes have the same health benefit for developing an immune response using germ-free mice?

Answer 1

Ans 4a) In this hypothesis is that microbiome of a milk fed infant is different from formula fed infant and this will be tested by analyzing the microbiome present in the infant after feeding is done. In formula feeding the infant gets the alternative of the breast feeding and formula feeding is feeding commercially prepared formula which is alternative to breast milk, contains vitamins and nutrients. The hypothesis can be tested after the feeding is done by testing the microbiome of both the type of milk – breast milk and the formula fed milk. The breast milk often has more number of immune cells and helps to provide high level of immunity from the mother. There is high concentration of IgA in the breast milk. The microbiome is micro-organisms that form a part of healthy biota and help in protecting our body.

Ans 4b) On noticing the difference between the microbiomes, these microbiomes can be tested to see if the same health benefit can be imparted to the immune response with help of germ free mice. The germ free mice allows one to study something in complete absence of the microbes and hence when the milk is injected or the mice is fed with that milk, the microbiome will enter the mice body. Once inside the mice body, a test can be done by exposing the mice to certain antigen and check if it is able to resist that exposure or not. If it is able to resist that exposure, it means the microbiome is able to help with imparting immunity to the mice.